Systematic revision of the Hydrobiidae
(Gastropoda: Rissoacea) the the Cuatro
Cienegas Basin, Coahuila, Mexico
Robert Hershler
Malacologia 26(1-2):31-123 (1985) http://biostor.org/reference/100960
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MALACOLOGIA. 1985. 26(1-2)' 31-123 
SYSTEMATIC REVISION OF THE HYDROBIIDAE (GASTROPODA RISSOACEA) 
OF THE CUATRO CIENEGAS BASIN. COAHUILA. MEXICO 
Robert Hershler' 
Edwards AqUifer Research and Data Cenler. 
Southwest Texas State UnNerSity. San Marcos. TX 78666. USA 
ABSTRACT 
thIS study gIves detal~ morphological desenpbons. Includlllg aspecIs of Shell and soft-pan 
analomy. lor 12 spe<:ICS of nne genet'a 01 hydrobnd snaIls (Gastropoda Alssoa<;eallrom the 
ISOlated desef1 SIlf1ng sySlem 01 CoallO Ctenegas. Coatlulla. Mexw;o Snatls were collected Irom 
103 Ioeabtl(!S If'I the baSIn and sunvTla/les of the dtStJ1b\Jtlon and eooIogy lor NI;h specoes ale 
gwen One new genus and ttlree new spe<:IeS ale descnbed 
The $IX r1CII'IW\IIl specl(!S of McnpytgcJS are reduced to one ~allable specoes. McNlfJyrgus 
chunnceiJfllJS. as tflefe are no SUItes of morphologICal teatures that can constStently dellne 
separate taICa when a large nUfT"ber of populahons IS sludted A mu/!tvanale morphological 
analysis 01 l'If(mpyrgus chulrncean(SS Iwolvlng 2{1 morphologocal characters Irom 33 pOp?
u\abOnS Ifl the baSH'l. shows that the trends 01 ~anatlon only par1ly IoIow the dlstnbutl()fl 01 
poptAittlOOS among the draInage systems 01 !he baSin 
ContJary 10 prevlOllS thought !tIere are no sublamlhes 01 hydrobMds endetr\I(; to the Cuatro 
CII!negas bason. all ta~a studIed belong to eother the NymphOphd'nae or lIItorl(!rrunae. widely 
dlstrtbuled subtamohcs FIve genera and alleaSl none 5pe(:1e5 are endemoc 10 the baSltl PhenellC 
and phyletIC analyseS Show that of the Itve endemIC genera, t!Vee are more dOSeIy relatC<l to 
nonenoernoc genera lound .... the basin 1h3n to eacn othel. suggestrng a potyphylebC orogln lor 
lhe endemoc sna~s The endemic snails may also be 01 a more recent an::IlOcal or'9'n than once 
thought SnaIl taxa Irom the PIoocene Peoos Formation of Peru, the shells of whoch are 
superlooaty SIIT1I\ar to those 01 the Cuatro Cl8fV!9as endemIC taxa, are not Hydrobotdae and thus 
!tie oondloIogocal sHTulantv os due 10 conve<genre 
Four of the Cu.atro C,enegas hydrobood genera are OVOVIVIparous Analomlcal Slud18S show 
that the evolullOfl ol ttllS reprodudrve mode If\ the Hydroblldae has IflVOIved modtIicahons 01 the 
lemale reproductive system to separate rncomong sperm Irom OUtgoong emboyos. IflCrease the 
amount of space avaIlable for hOldIng embryos, and allow lor tonIrot of the release 01 young 
Key WOlds Hydfobrldae. Cuatro Coenegas, systematICS. morphology. endemosm. 8II01utlOO, 
"''''''P'''' 
INTRODUCTION 
The small (30 by 40 km) desert valley of 
Cuatro C.enegas, CoahUila, MexICO (FIQ. I ) 
harbors a remar1table endemIC bIOla (Con?
treras, 1978: Minckley, 1969) Masl of the 
endemIC laxa are aSSOCiated wIth the exten?
sIve spring fed aquatIC enWOI1menls of this 
closed-drarnage basIn and Include one genus 
and lour specIes of cruslaceans (Cole & 
MII'!Ckley, 1966. 1970, t 972, HolsInger & 
Mlrrekley, 1971). e.ghHen species 01 lishes 
(Mlnckley. 1977), and two specl8S 01 turtles 
(Schmtdt & Owens, 1944: Webb & Legler, 
1960) In addltron, three subfamilies, live 
genera, and 12 species 01 hydrobtold snarls 
(those nssoace3n snails thai resemble Hy?
drobIa In sheW. operculum. penIs_ Of radula) 
have been conSIdered endemIc to the valley 
(Taylor, I 966) 
Apart Irom therr h"9h endemISm, the hydro?
btold snaIls 01 Cuatro C.enegas are 01 Interest 
for the follOWIng reasons. I) a number of taxa 
have large, sculplured or color-banded shells 
whereas most hydroblOlds have small. 
smooth shells WIthout color bands: 2) several 
taxa may have been Involved In coevolulton 
with snall-ealtng ClChIld fishes In the valley 
(VermeIl & CoVlCh. 1978): 3) the snails ale 
deployed wllhm a nearly unique vallely ot 
spllng led aquatIC enwonments within the 
desert. 4) differentIated populatIons 01 snaIls 
are lound among the v8nous sprIngs 01 the 
valley and oller the opportUnity to study 
evolution In a nalural laboratory (Taylor, 
1966: Taylor & Mlnckley. 1966). 
The Original deSCription of the Cuatro 
Clenegas hydroblOlds (Taylor. 1966) stImu?
la ted thIS study and slands as an exemplary 
contnbutlOl1 lOf thatltme penlJ(j Credit should 
laIesI __ -. Dr F...-d G TtIomp!oon FloIIOe Slate Mu5eun1. Ga.-.es..-e Fl 32'61' USA 
(31 ) 
32 
Rio Guncle 
~ 
COAHUILA, MEXICO 
HERSHLER 
J?io W-
I '"", 
TE XAS, U.S. A. 
Del Rio 
Acui'la 
Eagle Pan 
Piedras Neijras 
MuzQu;ze 
Sabina~ 
27?- -
_____ _ ___ __ __ L __ ___ _ ______ _ 
Cualro C.enegas? I 
. San Pedro 
TOfreOn 
I Monclova?
I 
I 
I 
I 
I 
I 
I 
I 
I 
I 
I 
I 
Pan e! I 
I 
I 
N j 
FIG I Map 0 ' Coahuila Me~oco. showmg!he IocaIIOrl Cline Cuat.o Coenegas ~sm The arrows IndlCat. 
!he d .. ecbon 01 !low o. the RIO Grande 
CUATAO CIENEGAS HYDAOBIIDS 33 
be given 10 tha i author for recognIZing !he 
umqueness of both the hydrobtoid launa and 
the enVlfonmenlal setting 
The classl ficallon scheme Within whICh lhe 
Cuatro C~as hydroolOld snails were de?
SCribed was based on a characler set re?
stncted 10 shell. operculum. pems. and a few 
olhef aspects of el<:lernal morphoklQy (Taylor. 
1966). IllS now known. on the baSIS 01 overall 
soft pari anatomy. that such characters have 
frequently converged In hydroblOO taKa that 
are noI closely reta ted (DaVIS. 1979) In a 
senes 01 papers (DaVIS. 1968. 1979. 1980: 
DaVIS el aI" 1976. 1982: DaVIS & Pons <Sa 
Silva. 1984) It was shown thaI the Hydro?
blldae (pre- I 980) are poIyphylelic and that 
sludy of all aspects 01 soft pari morphology. 
parllcularly the enllre female reprodUCbve 
system. IS necessary to recognize con?
vergences and d anfy the systematIC rela?
tionships of hydrobioid snails. As lhe onglnat 
descnphoos of the Cuatro Clenegas hydro?
bIoIds did not Include aspects of Intemal an?
atomy. these laxa s claSSIfication IS suspect 
The specieS descnpllons were usually based 
on coIIecllOI'IS from Single localities. and only 
12 locali tieS were sampled (Taylor. 1966) 
This paper. I) presents detailed morpho?
logical descnptlOflS 01 the Cuatro Ctenegas 
hydroblold taKa and assesses their systema?
lie affmltle'S. the resuhs of whICh are Irequent?
Iy at odds With prevIOUs classlflcatlOO (Taylor. 
1966) One new genus and three new specieS 
are descnbed Morphological data Irom pop?
ulations are analyzed to reSOlve specIeS prob?
lems: 2) summaflzes the dlstnbuhon and 
ecology of each species (103 localities sam ?
pled In the valley): 3) diSCUSses the results of 
!he above as they relate to the ongln, evolu?
tion. and endemism 01 the hydrobtotd snails 01 
Cuatro Ci&legas: 4) discusses the evoIutlOl'l 
of OVOVIVlpantyl In hydroblOld snails. 
EnVifonmental Seiling 
Cuatro Ctenegas lies In the mldeaslern 
section of the Chlhuahuan Deserl (Miller, 
1977: FIQ 1). The valley receives less than 
200 mm 01 preclpltallon annually (Mlnckley. 
1969), The mean annual temperature IS 2J C 
(Mofalka . 19n), With midday summer tem?
peratures eKceeding 40 C. The valley lloor IS 
140 m atxwe sea level. bounded on all sides 
by tall (10 3000 m) peaks 01 the SIerra Madre 
Orientale The valley floor IS relatrvely flat 
The baSin COOSIstS 01 two lobes. separated 
by the norlhern end of the Sleffa de San 
MarCOS (FIQ 2). There are far more SPflngS In 
the eastern than In the western looe Spnngs 
are particularly coocentrated around the Sier ?
ra de San Marcos The sprlllQs vary there are 
small seeps. small SPf!'l9s With spnng pool 
areas of less than 10 m2 that run for only tens 
of meters: and much larger spnngs With 
spring pool areas In eKcess 01 SIX) m2 and 
depths to 7 m. whose outflows are large 
streams. While mosl of Ihe springs are IIm?
nocrenes. With spring pools at the headS. 
there are also rheocrenes. where water 
rushes out of the grOUnd as flOWing streams 
Other aquatic environments Include playa 
lakes, receiving flow Irom large streams. 
spring led pools that have no oulllows; and 
eKlenSlVe $prIng led marshes. ThiS great di?
versity of desert spnng led aquatiC enViron?
ments can only be matched in North Amenca 
by thaI seen In Ihe Death Valley- Ash 
Meadows area (Deacon & Mlnckley. t974 : 
Soltz & Nalman_ 1978) 
Spnng levels vary seasonally. as the water 
table rises In the Winter and drOps In the 
summer The spnng water IS generally qUite 
hard and high In sulphales (Mlnckley & Cole, 
1968). Mosl of the SpringS are thermal (to 
34 C), but cooler ( 14-25 C) spnngs are also 
lound. The larger spnngs have fairly constant 
water temperatures throughout the year 
(Mlnckley. 1969). while spnng runs and shal?
low pools can be sub,eclto considerable var' 
latlon In water temperature. For example. 
North Spring has a spnng pool area 01 about 
230 m2 and a maKlffiI)m depth of 1.5 m. Its 
waters flow Into a second pool and then run 
as a Wide shallow stream lor 77 m belore 
dlsappeanng Into a hole. The spring IS ther?
mal: 10 separate headspnng temperature 
readings dunng 1981 gave a mean 0132.9 C 
(29 5---34.5 C). MaKI-mlfll thermometer read?
Ings lor lour days (beglnfllng &1881) had a 
vanatlon 013 1-34 5 C lor the head ancl20 6-
378 C at the hole where the water goes 
underground Thus. dunng thiS lime penod, 
the headspnng water temperature vaned only 
3 5 C while downstream It vaned t72 C 
The larger spnngs and thetr out!lows have 
considerable mICrohabitat diverSity, usually 
Including several types 01 aquatIC vegetallon 
(sedges. Nymphaea, Chara, Utnculana): a 
soil sediment conSlsllng of snail copropel 
and or an algal-detn!US mlJ(Ture: a sand con-
HERSHl ER 
, SI(RR. D( L . .. ( Nett.e. 
SltAA. OC L .... DCA. BOO m 7 
? \ CU.I~O Clt .. ?G.S 
, , S I?R~. s. " 
, , VIC? N IE 
, , 
{ , , 
, 4 
{ , , , , 
, , , 
" 
" , 
, , / 
, , S IERR. D[ .-
, , puRISI .. . 
SI[RR. D? 
s ... ""RCOS 
6 
FIG 2 Map 01 the Cuatlo C.eoegas Bason showmg the porhon 01 the bason that was II1tcnsively sampled 
(area enclosed by dashed hnes) The numbefs Ii'ldtCate the ortgtnsol the seven mapr dlalllagesoC the basin 
(I.om Mtnd<Jey. 1969) 1. the Chunnce system. 2. the Becerra sySlCm J. the Roo Mesquites system 4. Roo 
~tB ChlqUito. 5. TIO Cancltdo. 6 Santa Tecla Laguna. 7. RIO Salado de Nadadores 
SlSttng 01 travertine pieces and shelt debrIS; 
large travertine blocks; and the banks. whICh 
can be gently sloptng or greatly undefcut The 
smaller spnngs and their outflows have fewer 
mlCroI"latJ.tats. typically Includul9 a dar1o:: Of?
ganlC mud, fIne travertIne sand. and occa?
SIOflal Chara mats. 
Five 10 seven major drainage systems 
occur tn the valley (Ftg 2). wtth posSible 
nalurat connections eXlsltng between them 
Via underground nvers. Of surlloal walers dur?
Ing raIny penocis (LaBounly. 1974. Mlnckley. 
1969) A number of Imgahon canals draIn 
waler hom the large spnngs, Ioweong therr 
levels and destraymg penpheral aquatIC hatJ.?
lats (Mlnckley. 1969) Ifflgalton canals Irom 
d,llerent draInage systems are often con?
nected. allerlng oppol1unltle5 lor gene llow 
between prevlOUsty Isolated IXlI)Ulalions. The 
baSin currenlly has no sut1IC,al conneclj()('l to 
outside drainage, but waler has probably 
drarr"lCd Irom the baSin to Ihe nearby RIO 
Satado de Nadadores (FIQ 2. locality 7) ,n 
the past (MIller & Mlnckley, 1963; MrnckJev, 
1969). More mformatron on the aquatIc en?
vironments of lhe baSin can be lound In 
Arnold (1972). erown (1974), Oeacon & 
Mlnckley (1974). and Mlnckley (1969) 
MATERtAlS AND METHODS 
Localrlles 
The waters of only a portion 01 the valley 
drainage (dashed line In Ftg 2). encompass?
Ing parts 01 lour 01 the basin drainages. were 
IntenSIvely sampled One hundred collectIon 
localities 'rom thiS area are shown If\ FIg 3 
and dcscnbe<l In AppendiX 1 Three OIher 
tocalrbes (101-103 In AppendiX 1) trom olher 
areas were also sampled The vanous Iocall-
CUAlRQ CIENEGAS HVDROBIIOS 35 
" , 00 
? 
.. 
.. 
SERRA DE SAN MASlCOS 
> " 
\ " 
? , ... 
fIG 3 Map 01 the portlOfl oI!he basin df81011ge!ha1 was ,nlensl\lely sampled The n..mbers 11- 1(0) refer 10 
c:oIIecIlOfllocallbeS The dashed Itnes rete< 10 omgiIboI'I canals The.-rows ondocale walers!hal conIWlue 10 
IIo?tI IOwafd !he eaSi 
ties (and ANSP catalog numbers lor the lotS) 
lor each speoes are given Ifl Appendix 2 
Snails were co/Iec1ed and Sludled If'! the valley 
dunng September. 1978; APfI)- Augusl 1979 
Apflf , 198O-June, 198 1: and December, 
1981 
Collecl00n Methods 
Fine hand SIeV(IS were used to coIfecl 
snails from sedlmenls ranging Irom Hocculenl 
copfopel to coarse havertme sand. In some 
cases, the sediment llsell was cottecled and 
HEASHlER 
examined under a dlssectn'lQ mICroscope to 
determine whether very small snalts. whICh 
would pass through the Sieves. wC'e present 
Snal ts were picked all targe pieces o f 
travertine l,JSll1g tweezers Samptes 01 aQl.JatlC 
vegeta tion were collected and carefully 
washed In a bucket to remove clinging snaltS. 
The materral was then sorted lJf'der a dissect?
Ing microscope. A number 01 snait taxa are 
suspected 01 hVlng In groundwater outlets or 
SlJblerrarrean waters of the valley (Taylor, 
1966). To co llect such snai ls. ordinary 
domeshc mops were placed Into small sprlng ?
heads, removed a!(er a 24 hour perIOd. and 
tlleo washed In a bucket The snails that 
coIonrzed the mops were collected and sorted 
under a dlsseclrng microscope (method sug ?
gested orally by Dr. W. l. MlI1dtley: Similar 
method described in HolSinger & MII"lCkley. 
197t). For each small sprrngtreoo, one to ten 
mop samples, spread out over a perIOd of 
monthS. were taken. ThiS method IS crude as 
It carYlOl dlstrngulsh between smuls liVing at 
the groundwater outlet and those being 
washed out from underground A supetror 
method. sampling only snails from sub?
terranean waters. would be to place a fme 
mesh net over the groundwater outlet. es? 
senllally littering snalts from the water stream; 
such a method has been successfully used to 
sample the fauna 0 1 artesian wells (HolSinger 
& Longtey. t 960) 
Anatomy 
[)Issecll()tI techniques are those of DaVIS 
(1979) and DaVIS & Carney (1973) Several 
other techniques were also employed 
The peniS was cut from the mate. examined 
on both SlGeS at SO x magnlflCallon, and thCfl 
wel'fTlOUnled on a shde With COlIer sliP for 
study uSing a compound mICroscope fitted 
With an ocular mICrometer The length 01 the 
pallral oVIduct IS the length hom the anterror 
end to the posteno rmost pornt, excluding any 
length ber'ot back upon llset! at the posterlOf' 
end. The length of the duct from the seminal 
receptacle IS the length trom the seminal 
receptacle body to the JUnction With the OVI ' 
duct or sperm duct The nervous system was 
Studied 10f' species of all genera except Mex?
rstma n, gen, and Coahur/rx and showed no 
varrance exce~ I In size and coocentratlOfl of 
ganglia Therefore, the measurements 01 the 
nervous structures are not presented For 
OVOViViparous species, shelled embryos were 
gathered by cracking the shell of an adult 
lemale. remoVing the brood pouch, and plac? 
mg It In a drop 01 ClOROX for several mlll?
utes (DaVIS. 1969b) The embryonIC shells 
were then counted and , In some cases. 
measured. In additIOn, the brood pouches 01 
several snails were teased apan so the small , 
nonshel!ed embryos could be counted. Shell 
measurements 'or the varIOus taxa are Irom 
mature adults (those haYIng a complete aper? 
ture) The aPIcal whorls 0 1 shells were meas?
ured USIng the method 01 DaVIS (1967, pl. 3, 
fig . 6) . Radulae and shells were stuOred and 
photographed USIng lhe SEM lacility at the 
Academy of Naturat Scrences of Phlladelptlla. 
Stalrshcal technrques, for the most part. are 
restrICted to H ests and correla t'l)fl roelli' 
clents. 
The generIC descrlphons are necessanly 
brlel. as anatomical data IS generally avaIl?
able tor only one species per genus {due 10 
monotypy or lad<. of Studies 01 congeners) 
The deScnptlOOS Will have 10 be altered as 
more data become available. Only character 
states unrque to the varIOUS taMa, or 01 use In 
assesSing therr syslematic stal us. are 
stressed. Olher characlers and Iherr char ?
acter states that are standard for the Als?
soacea: Hydroblldae (DaVIS, t966, t 979 ; 
Hershlel & DaVIS, 1980) are nol menllOned 
and Include. lor example. the charactCflstlC 
loop 01 lhe Intestine above the style sac. the 
POSItIOn 01 the sal ivary glands on top 0 1 the 
nerve nng. and the OVOid shape of the fecal 
pellet s Filly-one characte rs and their 
character sta tes that were used 10 distingUish 
genera and genenc groups In the Hydroblldae 
are listed In AppendiX 3 With notatrons as to 
where they are hgured. Common radular for? 
mulas for species Studied are given In Table 
1. Several characters may be unfamlhar to the 
reader and require explanation. The bolster 
and ventral channel 01 the pallial oviduct are 
dehned and dlSCtJssed In DaVIS el al. (1982). 
and Davls & Poos da Silva (1984) The caecal 
chamber (dehned In DaVIS eta/ , 1982). while 
apparently present In all Hydrobrrdae, IS re ?
duced In some laMa so as not to prOject 
posterIOr to the stomach. Tentacle cdlatron IS 
diSCUSsed In DaVIS et al. (t982) The digestive 
gland 01 hydroblotd snai ls usually has linger? 
like tuberctes prOjeCting from Ihe main Ixrdy, 
but In sma" SIZed snarls the tubercles may be 
mere swel~ngs. In resolVing SpecteS prQl). 
lems, emphaSis was placed on whether pur?
por1ed specres were sympalnc or not. and 
whether consrstent mOf'phofoglcal differences 
between purported specres could be found 
CUATAO CIENEGAS HYOAOBIIOS 37 
TABLE 1 Generakle<l cusp lormulas lor !he lour tooth types altha radula 01 all speaes studoed 
Spooeo "'"' .? 
NyrnpIIoptWu5 nvnckJey' 4(5t:H-4(5) 
Me,wI$I,oobta mananflah 4!5lJl -4!5! 
? 
""'--
;!I4lJ I ;!I4! 
-. 
PaJudfscala catamba 4j5lJl-4 j5! 
-. 
CccMcpno..- 4j5~~"j5! 
Me,w,1hauma quadnpaludrum '~Ii'4jS' H( ) 
Ourangonella coahuriae 4j5~~"(5! 
Me,wlpyrfJUS chunnceanus 
.\SIi'4jS, ( F2( ) 
...men numerous populallons were stOOled. 
The descftptlOOs Of taxa not named In ,his 
paper are modIfied from Ihose 01 Taylor 
(1966) and Thompson (1979). 
For a mulllvanate analySIS 01 Me,w1pyrgus 
chunnceanus populallOf\S the computer pro?
gram used was 'he June. 1974 versron of the 
SUNY at Stony Brook numencal taxonomy 
program . NT-SYS (Rohlf et a/ .. t972) 
Charaders were s'andardlzed In the usual 
manner (Sneath & Sokal. 1973) In'he 0-
mode analy51s. a taxonomIC distance malnx 
was generated. usmg the unwelQhled patr?
group me'hO<l wl.h arr,hmetlc averaging 
(UPGMA) The minimum spanning 'ree 
(MSn and ?subse's" components 01 NT-SYS 
were used . F o r the R-mode analYSIS, 
character correla'ions were subjected '0 Pnn?
opal Componen,s AnalySIS (PCA) . WIth Ihe 
frrSllhree components used 10 Yield a matnx 
01 OTU proJechons In pnnc'pal componerrl 
space. These OTU 1oca'lons In the ,rwee-<ll?
mertSlOflaJ PCA space were used as 'he Inlltal 
conllgura'ion fo r a nonme'flc mullldlmen?
Slona' scahng (MOS) placemenl of Ihe 0-
mode taxonorlllC dlslances between OTUs 
The Pnm Networ1t was used. As ,he dus'er 
analySts and phenograms genera'ed are sub?
jectto distCM1lO11. only the ordinatlOl1 and MOS 
are presen'ed here. Componerrts were ex?
Iraded unt.1 eigenvalues were less lhan 1 O. 
Subsel SOIulIOflS and 'he minimum spanning 
tree are supenmposed on the ordmatlOO dl-
'9""" 
"'- (",,~ Lateral ~ .... , ma'lI'nal 
2(3)- ' -2(3) '2-'7 , '-20 
4(5)-1-3 '9-24 22-26 
5-1- 3<4) 1&-2' 16-19 
4(5)-1-3 18-24 ' 6-25 
3(4)- '-3 ' &-2S '9-28 
3(4)- 1-3(4) 10-14 ' 2-16 
4(5H --4(5) 19-27 20-" 
4(5)-1-4(5) 21-36 2<-38 
SYSTEMATIC FRAMEWORK 
The basic teatlXes 01 nssoacean snails are 
reVIewed In Freller & Graham (1962). DaVIS 
( 1979) has IIs' ed the tea'ures that dlsllngulsh 
hydroblOid walls Irom othel" nssoaceallS. The 
definitions below are modified trom those 01 
DaVIS (1979. 1980) and Davis et al. (1982). 
Family Hydrobttdae 
These ,ndude hydroblOlds In which sperm 
enter the anteno .. end of the palhal oviduct 
and pass alorlg an Inlernal. CIliated ven' rat 
channel to lhe bursa copulatnx; or, In which 
sperm enter a separate spermathecal duct. 
presumably tarmed by separahon 01 the ven?
tral channellrom the pallial oviduct (not 10 be 
confused Wi th 'he oonvergent s'ruclure of the 
PomaltQpSldae), and pass Ihrough It '0 the 
btJrsa copulatnM. The spermathecal duct IS 
never assocl8ted WIth elher lhe kIdney or lhe 
pencardlum (oontrast the TrlCulinae). The 
mode of reproduc'lOfl IS ovlpanty or OVQVIVl' 
panty. The peniS may (Thompson, 1968. IIg 
39) or may nol (T~son. 1968. Itg. 371) 
have lobes. The pervs may also be 'Mthou' 
specialized glands (Hershler & Davis. 1980. 
fig. 40), or may have glandular ridges conslsl?
Ing at an elevated area In wtllcn rows of sma" 
gtands d ischarge through a central sil l 
(Thompson, 1968, ftg 42): apocnne glands 
(Andrews, 1977, p 82. Irg A); glandular papIl?
lae (HubendlCk. 1955. Irg 88). or mammiform 
HERSHLER 
glands (Fig 44) The latter two gland .ypes 
ale OfIly bofne on pemal lobes, whereas 
glandular ndges and apocl'lne glands can be 
loun:! on the pefliS as we ?? (Thompson, 1968, 
IIgs. 44 , 38, respec" vely) Thefe IS !leI.her a 
pedal crease roof a suprapedallold (contraSI 
the PomatlopSII'\ile); lhe snails move by ciliary 
gilding. The mantle collar may Of may not 
have a paliiallubercle, fitamen' , Of numerous 
paPlllatlOflS. The tenlacles may Of may not 
have hyper1roptued ciliary tutts. The eyes are 
located In shght swel lings at the base 01 Ihe 
tentacles. The central tooth 01 'he radula 
usuaNy has pronounced laleral angles. giving 
the loolh a trapezoidal shape. and one Of 
more pailS of basal cusps Ihal usually Oftgl?
nate Irom the lateral angles (contras' lhe 
PomallopSldae). The stomadl has a caecal 
dlamber that usually protrudes poslerJOr to 
the Stomach Chambers. An anteoor digesllve 
lobe may be present. The sheW may or may 
not have wnnkled. pilled apICal mlCfosculp?
ture 
Sublamlly Nymphophllinae 
These Include Hydroblldae In wtlldl the 
palhal oviduct has an Internal CIliated ventral 
channel. and the peniS IS btlobed and bears 
one Of more elevated glandular ndges The 
tentacles do not have hypertrophied CIliary 
tufts The apICal whorl has wrl~led . pitied 
fllICrosculpiure The only mode of reproduc, 
tlOl1 thus far reported for thiS sublat11lly is 
OVlP<In'Y (Thompson. 1968, 1977. 1979), 
Sublamlly LlitOfonlllae 
These Include Hy<lrOOildae In whICh there is 
a spermathecal duel separale (at leasl poste?
!lorly) Irom lhe palhal oviduct. The spermalhe?
cal duct may be short or lon9? The pallial 
OViduct otten has three or four tiSSue types 
The pel'llS may be Without specialized glands, 
or With large apocnne glands, glandular papil?
lae, or mammdOfm glands. The tentacles 
often have hypertroptlled CIliary tufts The api?
cal whorl may or may nOl have wnnkled, 
pined mlCfOsculplure, The mode of reproduc?
tion may be OYIpanly or ovovlvlpaflty, 
The sublaffiliial placement 01 the Cuatro 
Clcnegas hydroblOlds, based o n analolTlical 
study, IS contrasted With Ihal of Taylor (1966) 
In Table 2. 
DESCRIPTION OF TAXA 
Nymphophlhnae 
Nymphophllus Taylor, 1966 
Type-species: Nymphophr/us mlnckley, 
TaylOf, 1966 
D,stnbutlOn eoc!effiIC to lhe Cuatro elene?
gas BaSIn. 
SpecieS Included: N. mlflckleyl. N. acanna? 
tus n. sp. 
Descnp!1Of\ 
DiagnostIC leatures of Nymphophllus In, 
clude lhe large (length. 3.!'r8 3 mm) trochoid 
TABLE 2 Subfam,~aI placement 01 the Cuat.o Coenegas nydrobood genera 
(based on the lesutls 01 Itos study) contrasted With that at Taylor (1966) 
T aylo.- (1966) 
Family Hydrobudae 
Sublamlty Cochhopmae 
Coahu.I,N' 
CodlllOP'na 
SOOIam,ty LIUordtntnae 
M eN1fJ)'f!}IJs' 
Durangooella 
Sublamoty NymphopbIInae" 
NymphophIlus' 
Subfam!y Mex,lhaumat>nae" 
Me~llt1auma? 
Subfamlt~ PaludlS(:.alloae" 
Pa/udfsc.ala' 
'Genus ef"democ 10 tne c...-o Cencg.as nas,n 
"'" ,"'" 
F amdy Hydrot;Jodae 
SlbIarnty L'UOl'ldllWlOO 
CoahlMr~' 
Pa/udOSC.ala' 
"fe ?? /hauma' C_ 
""?MexWgtlS' SlbIamoIy Nymphopt"hnae _. 
MexlSllOboa ' 
$ulj'amly l.Inl\I1own 
~'" 
"$ut)l3""~ _I!d erdI!moc: 10 !tie CU81<O c:.ooega.. s...1I'\' T~ (1966) 
'--'systemS!'" Slalul unte<tan ? ? ~ II f"(lI yet ilo,.w;Ioed 
CUAlRO CIENEGAS HYDRQBI1DS 39 
FIG 4 Shells 01 Nymphopht/us I1IInck/eyl1rom Localoly 76 The shell 0f1 the left IS 8 0 rrm long. the OIhers are 
print@(! at the same enlargement 
snell (FIgS 4. 9). multlsplral operculum (Fig 
58). elongate osphradlum (30% of the elent? 
dlum length). and bush-like mate gonad (not 
shown) 
The bUrsa (Bu) IS POSitiOned posteoor to 
the pallial OVIduct (FtgS. 7A. B) . the duct 01 the 
bursa 10 the comlTlOf1 openmg of the albumen 
gland and ventral chanrlel IS elongate: the 
semmal receptacle (Sr) and oviduct COIls 
(Col) are located antenor to the bursa (Fig 
78); the bolster 01 the ventral channel IS well-
" \ A 
10 mm 
deyeloped (Bvc. Ftg 70); the palhat oylduct 
opens laterally as a oomrTl()(\ genttal aperture 
(Cga. FIQ lEI; the per1IS (Ftg SA) With mas? 
Slve. folded pell4allobe (PIo) bears one to four 
glandular ridges (Glr) on ItS yentral surface 
Amortg nymphophdlnes. Nymphophrlus IS 
most Similar 10 MarslOfNa. as both la)(a have a 
pefilS With lew glandular ndges (for Mars/c? 
-, 
, ~ 
\ , (I' 
'\ ell 
I 
- B 
10 mm 
FIG 5 Head and opetculum 01 N ~ A Head soon dOI"sally 8 ()pefculum. WlIto dashed hne 
l!"'(Iocating atlachmenlarea 10 opercutogerous lobe e~. Sn-snout Tn-tentacle 
40 HERSHlER 
1118. see Thompson. 1977. "gs 5. 7 . 1 I) and a 
large bursa po5Il lOI'Ied posten(lI' to the palll.a l 
0IIIdud (101' Mars/oma. see Thompson, 1977, 
IIg 10) 
B 
c 
I 
? 
FIG 6 SEM photos 01 shell ..-.d r~ 01 N 
~ A PorIoon 01 body whorl itowIng !he 
poriphofal keel ;n:I wavy ooIabrllll ~o 
B Porbon 01 .aduIar robbof> C Se\l!:!fllll cenlral 
-
Nymphop/ll/llS m'nclde)'I Taylol' , 1966 
HoIoIype" UMMZ (l/oIversily 01 Mdll93" 
Museum of Zoology) 220188. 
Type?locallty. locality 53 
Habitat. NympIJopflllus mmckle)'l IS found In 
large springs and their ouUlows. Nymp/IopIll. 
Ius rrnncI</eyI was rarely taken from the small?
er Spfll'lQS: mops )'IeIded specImens from the 
heads 01 only three 01 38 such springs In the 
large spnngs. N. r'rWIC/(JeyI was collected Irom 
aquatIC vegetallOl1 (Nymphaea. Chara. Ume?
ulana). Ir8vl!f1lf1e. and, to a lesser extent, 
Irom gentle, sloping baiV(S. On a mICrohabitat 
scale, this specieS IS occasionally sympalnc 
With Mexllhi!uma quadopaluc1rum and Ccch?
/IOpIM millen 1\ has been suggested (Arnold, 
1972) that N. ttIInCkJeyi. as well as Mel(?
i,hauma and Me)(rpyrgus. IS nocturnal, mov?
ing about at mght when the predaceous ach?
liel fish ale If\aCIlYe 
The egg capsules of thiS speoes were 
found on waler ~Iy (Nymphaea) leaves Irom 
many Iocab\leS lhI'oughout the year. It was not 
IJIlCCmmon to lind over tOO capsules on a 
smgle 15cm lear The capsules were rat'et)' 
found on the shels of liVing Sf'IaIls. The egg 
capsule IS heIl1Isphencal and IS coated WIIh 
detrllal material along the SIdes. butlhe top of 
the capsule IS clear 01 detritus andlhe yellow?
colored embryo is ViSible inSIde. Usually. fly ?
droblold egg capsules are completely coated 
With either sand Of detfituS. For t 3 egg cap?
sules from Locality 76. the egg capsule d,a? 
meler IS 0.52 .. 0.40 mm. The helQht 01 the 
capsule IS aboot 0.25 mm The efl'lbryOnlC 
shells IflSlde have 1 00-1 25 whor1s 
Descflpllon 
~11us rmncldeJII IS disllncbve Ifl 
hailing a large shell (FIQ. 4), wllh 5.5-60 
Ilattened to slightly rounded whorls. There IS a 
strong spllar keel . at or lust above the su1ure, 
that fades on the body whorl and IS barely 
nobCeable at the aperture. 
Shell 
The splle IS moderately high, the base 
rounded, and the umbilICUS narrow. The su?
lures ale ShaIOw The aperture IS longer !han 
It IS Wide, somewhal angled adaptCally, 
founded abapcally, and With a complete 
thlckened peflstome Ifl adults In adult sheIs, 
the aperture IS adnate 10 or s1.g11tly separated 
from the peruillmate whorl The plane of the 
CUATAO CIENEGAS HYDAOBIIDS 
" 
'., 
'"" '" ~ '~Ga , ~ 0 0$ ,"m 
? 
'" 
.. 
.. 
. , 
? C , 
? 0 '"., 
?? 
FIG 7, Female reproductive analomy 04 !oJ rJWIddtoyt A Snail (jrlCOj!ed , eXposIfI9the Yenlral aspect Wl1I"oCIIJ1 
head and kidnt'y tissue Nole'he POSltoon 04 the bursa (Su) posle"or 10 lhe palloa1 OVIduct (Apel , PpO) B 
OIienled as on A. but Wl1h a porjlOll 04 the pallial OVIduct cut awa~ 10 'eveallhe bursa CoplJlatnx complex. 
boistef (BYe), and veotral channellVc) The lett'hand dashed tone ondocates the posterOOf exteot of the pallial 
ovoduct C. Onenled as on B. bul woth the bursa. lis duct lObo) and the antenor portM;on 01 lhe duC! 01 the 
5emIna1 receptacle ren1OV(!d 10 reveal1he OVIduct cools (COl) 0 Cross?sectOOfl 01 the palkal OViduct (loolong 
anlenorty). CUI whe<e lhe right-hand dashed lone ondicales In B Nole lhe lhId<.ened bolS1ef (Bve) and 
weII-deveIoped ventral channel (Vc) E Dorsal aspecl of the capSUle gland (Apo) showing the lalefal 
openong 01 !he common genital apemJle (Cga) Apo-capsule gtand AsI-anIerOOf SlOmach chamber 
Bu-bixsa, Bvc-bOIster 01 ventral channel. Cae---caecum ot stomach, Cga COO'.11On genlat aperture, 
Cl--<:okJmellar muscle. Cot--cotl 01 OVIduct Clbu-duc:t 01 the bursa, Dsr--<lucl 01 semmal receplacle 
Emc-posle<OOf end of manne caVity Go-gonaod. Il'1--<nteShne. Lpo-Iumen of palkal ovoduct. Ma-man!le 
edge, 0v--0vIducI. Ppo-albumet1 gland, P51-poste<1OI" stomach chambef , Sf---$6flll(\8I recep1acle. SIS?
slyle sac, VC--Yenlral channel 
aperture IS only shghlly tilled away Irom the 
COIhng axIS The Shell IS colOfless and translu' 
cent. The pI tied apical microsculpture IS 
shown In Thompson ( 1979. Ilgs . 4-7) 
Poslembryonlc whorls have coarse, wavy 
growth "nes (Fig 6A), giving lhe sheU a sahny 
sheen SheM measurements for three pop-
u latlOns, all 'rom large spnngs or streams. are 
given In Table 3 Shell lengths of males are 
slgnlhcantly larger (p <- .0 1) than those 01 
lemales lor all three populations. Shells were 
removed 'rom egg capsules Irom Locality 76 
and thelf aptCal whorls measured For 16 
shells, the WIdth of the lip 01 the apiCal whorl 
42 HERSHlER 
TABlE J She_ measuremenlS (mrn) of males and females f.om Itvee pOpUlatIOnS 01 Nyrnphophllus 
1TWICt./eyI Snails Wllh the dominant ma~mum ....nor l number were used N 9. Mean ' standard deviation 
' J) retefS 10 the Slgrul,cance level 100 file (j,tfe<cnce belwecn sheW lengltrs or males and femaleS U-I651) lor 
tl\al IJOI)I.MIIOfl 
-'" 
Length W,," 
Locahty 76 
, 60 786 ? OSO 590~O42 
, 55 689 ' 028 5.51 ' 022 
Loc.1IIty 97 
, 60 790 ' 030 568 ' 0.27 
, 60 749 - 032 5.58 ? 020 
''''''''' 53 , 55 630 - 036 652 ? 037 , 55 779 ' 0.18 633 ' 027 
a .... eraged 0 135 .!. 0017 mm. the WIdth 01 the 
IirSI whorl was 0.339 :!; 0.040 mm. The width 
of the lirs t whorl for shells from the type?
locality was 0 30 mm (T~. 1979) 
NomeprOOuclive Fealures 
Details of the anatomy are from the popIJla-
1100 from Locality 76 unless otherwise In?
dICated Measurements 01 organs and struc?
lures are gIven In Table 4 The snout (Ftg SA) 
IS I 77 mm long and relallvely squat while the 
tentacles are thick and elongate (relabve 10 
the snout) . The snout and teo'acles have 
B 
? 
c 
'" 
length 01 length of W,(ilhof 
body whorl -~. ape<1 .... e p 
599+049 438 ' 042 3 53 ~ 0.24 ' 005 
537 ' 031 392 ' 011 3.21 -+ 020 
586 "' 027 405 - 058 356 "" 015 ' DO 
552 ' 026 2 77 ' 024 322 ' 018 
657 ' 039 481 ' 0 27 393 ? 0.19 , 005 
608 - 01'" 445 - 023 371 ? O20 
embedded In ' hem yellow granules The eyes 
are parbally surrounded by clear. closely 
packed granules lhat e)(tend back aioog the 
neck A hgh' dustn""iQ ot melanm on the ros?
trum and tentacles was occa sionally seen. 
The foot IS targe (relallve to that or other 
specieS). thICkened and dusted With melamn 
on ItS dorsal sur/ace a nd sides. Body 
pigmentatIOn conSiStS 01 a dusllng ot reddISh 
melamn on bolh dorsal and ve ntral surfaces. 
The male gooacI occasionally has very dark 
pigmentatIOn on Its ventral surface. The oper? 
culum (Fig 58) has 5.5-6.0 whorls. and the 
nucleus IS p05Il lOned at 39% of the long a)(IS 
, 
, 
A 
FIG 8 The pens 01 N rrlI(Ido.leyr A Dorsal aspect 01 the peniS NoIe the talge peooa' lobe (PIa) w"h 
r"lUmelOUS IoIds 10 ,I B. C Ventlal aspect 01 the penial lobe showoog the glanclutal ndgels) IGII) Vd-Vas 
dele<ens 
CUAl AO CIENEGAS HYDROBUDS 43 
TABLE 4 DImensIons (nvnl or OOU'1ts 04 non? 
neu,at organs and st'l.J(;tu,es 01 Nymp/loplll /vs 
mmd.1eyI N 5 UflIess stated otl\efWtSe Mean 
siandard <IevIalO(lfl L lenglh. W Mdth 
Females "' .. 
"'" 
L 930 + 033 1240 - 031 
Gill Mallle"l f>tJITlbef 
'" 
~ 2 11 
O'P'''''~ L 089~013 
"""'" 
L 249"'018 476-059 
W 109"009 119 -001 
P'OSlale L 133 ~ 012 
W 065+008 
p~, L 410-046 
W 
'" 
,<5 
PaHoa! OVIduct L 296"035 
W 116"013 
80fsa c:opuLat,,~ L 101'" OOS 
W 044 , O.OS 
5emona1 receptacle l 051 ~006 
(body) IN - 6) W 0.21 .. 0.03 
Sem",,,1 rereplacle l O14~O10 
(duct) W 012"002 
01 the operculum The ope,culrgerous lobe 
has a dustrng 01 melanm along ItS penmeter 
The caecal chamber (Cae) extends posterIOr 
to the stomach chambers (Fig. 7A) 
Radula 
The raclula IS shown In Figs 6B 8. C. There 
are three pairs 01 basal cusps on the central 
tooth. arising Irom the lateral angles (Fig 6C). 
The central cusp 01 the central tooth IS broad 
and large relative to the cusps 0f1 either SIde 
The lateral looth also has a maSSive central 
cusp (FIQ 69) The margmals have relatively 
few cusps. Radular statIStiCS and the vaflCUS 
cusp arrangements 101" the lour tooth types 
are given In Tables 5 and 6, respecllvely. 
Female ReproductIVe Anatomy 
The ventral view 01 the uncoiled lemale IS 
shown In Fig 7A The tobe--lIke gonad (Go) IS 
short (27%) relallve 10 body length. There are 
three to five gonad branches. each conSISilng 
01 small lobes 
The OViduct (Ov) passes beneath the pallial 
oVIdUCl lust at the end 01 the style sac. A shOl1 
gonopericardlal duci IS present (Thompson, 
1979, fig . 15). The pallial OViduct IS 32% 01 the 
oody length The two sechons 01 thiS organ. 
!he anterior capsule gland (Ape) and the pes. 
tenor albUmen gland (Ppo). are eaSily dlshn? 
gUlshabie even In unstained specm"lens The 
postenormost 20% ollhe pallial OVldUCI over? 
lies the style sac (SIS, Fig 7A) The antenor 
paUlal ovl(\uct ends 1.14 mm Irom the manlle 
edge The relatlOllShlps between the bursa 
copulatnx complex and palhal OViduct are 
shown In FigS. 7B, C. The bursa (Bu) IS 
sac?llke and large; 34"", the length of the 
pallial OViduct. The duel 01 the bursa (Obo) IS 
FIG 9 Shells 01 Nymphopillius aca,ona,us Irom Loeahty 113 The shell on the left IS !he hoIotype (ANSP 
355255) and IS 4 25 mm I(IIlg On the light pooled 10 1fle ~rne enlarg&ment IS a palatype (ANSP 3552561 
HERSHlER 
11 0"4 01 the bursa length (FIQ 76). The duct 
01 the bursa. seminal receptacle (Sr) . and 
OIIldud COlts (COl) lie appressed to the dorsal 
surface oj the albumen gland The scmll"lal 
receplacle and OViduct COils are largely anteri?
or to the bursa and dorsal to the duct 01 the 
TABlE 5 Radulal statistICS Irom 12 lOdMduals 01 
~rrHrlC~teY'. X mean. S Slandard 
devrabon. MeastJIements are in mm 
Aadular lealure X 5 
length 
'" '" w""" 0274 0019 Numbef 01 rows &<7 ,., 
Numbef 01 rows In 
IoffTl<ltove Slage ' .58 
' " Wi(!!h 01 cenlral 
_,N ,,, 0.081 0"'" 
bursa. The pear-shaped seminal receplacle IS 
relatively large: 50% 01 the tength ot the bur ?
sa. The OVIduct cor ls twICe. wi th lhe Irrst 00II 
dorsal 10 the second one. belore rccelVing the 
short duct of the seminal receptacle (Dsr. FIQ 
7C) and JOliling the duct of the bursa al the 
Opelling to the palltal OVIduct (Ftg. 76). 
The bursa coputatflx comple~ has a c0m?
mon opening With the albumen gland and 
ventral channel (Vc) at the posterior end 01 
the mantle caVi ty (Fig 76). The ventral chan?
nel IS considerably fokle<l toward the venlral 
Side of the pallial oviduct (Fig. 70). The bol ?
ster 01 the ventral ctrannel (6vc) IS rounded 
and thlCk?fled (Figs 7B. D) Sperm masses 
were lound rn the ventral channel below the 
bolster. The walls of the ventral charrnet do 
not fuse anierlOfly to form a tube separate 
from the capsule gland (compare Fig. 7C With 
Davis & Pons da Silva. 1984: fig . 6). The 
TABlE 6 The varIOUs cusp arrangemetlts IOf the /our too1h types on 12 faduJae 01 Nymphopll!ltJS m.ncIr/e)'l. 
WlItlItle percentage of ,adolae showing thai al'fangemenl at least once 
'"~ Outer Central l ateral marg.naf marginal 
% 
" " " W , 2-1- 2 " 9 " " 50 
W " 3-1- 2 " " ,. " 50 
W " 3-1- 3 75 " 
., 
" 
50 
W , 3-<-4 , " 
., 
" 
58 
W , 4-1- 1 , .. 58 " " 
W " 4-1-2 
, 
" 
58 
'" " 
W 50 4-1- 3 58 " 58 " " 
W , . ,~ " " " " 
, 
W 67 " 
, 
W , 
W- , 
W- , 
W , 
W , 
CUATRO CIENEGAS HYDROBIIDS 
capsule gland does not open at Its ante"Of lip, 
but opens as a common genital aperture 
(Cga), lateral 10 and 03 mm poslenor to Ihe 
tiP (Fig. 7E). 
Male Reproductive Anatomy 
The male gonad IS relahvely long. 36% 01 
the body length. and extends 10 the posteoor 
end of the stomach. The gonad has seven 
branches, each with many small lobes. giVing 
the Ofgan a bush?like appearance The pros? 
tate IS QUite small. 11 % of the body length, 
and largely poslenor to the end of the mantle 
cavity. The anten()r vas delerens exllS from 
the posterl()f por1lOfl of the prostate. 
The peniS (FIQ 8) is relahvely large and 
thICkened, With an elongate pelllalfilament. It 
IS rleIther cihated nor does It have an evers? 
Ible terminal papilla. The single pernal lobe 
(PIo) IS posdlOned Or'! the IMer Curvature 
sllQhtly more toward the base of the verge 
than toward the lip Thompson (1979. figs 
11 - 14) Illustrates a mUCh stouter penial 111a?
menl lhan that shown here. posSibly because 
he was StUdying preserved matenal. The 
penis has no p.gment The vas deferens (Vd) 
travels near the outer curvature 01 the peniS 
and cods only dunng a portion of ItS length. 
The peniS has numerous GI2 glands (see 
DaVIS. 1969a. for a diSCUSSion of gland 
types). partICularly In the penial filament The 
pems has no folds on ItS outer curvature. 
whi le the Inf"lef curvature has folds 'rom the 
base to Just beyond the penial lobe 
The penal lobe IS qUite stout and does not 
taper appreciably towards ItS distal end 
Numerous 'olds extend inwards from ItS 
Sides. The lobe curves both ventrally and 
towardS lhe lip of the penis. VIeWed from the 
ventra! aspect (Figs 8B. C), lhe distal edge of 
the lobe appears as a narrow prOjection 
lalded above the proximal portion of the lobe. 
The surtace 01 thIS distal edge. whICh cannot 
TABt..E 7 Percent ollfld.viduats (N 251 With 1.2. 
Of 3 glandular rldge(s) 1)11 the distal edge at the 
penial lobe 1ft three populatlOllS 01 ~
"""''''' 
LOCi/ltty 76 
LOCi//rIy 97 
Locahly 53 
" 52 
" 
Numbel or ndges 
2 3 
" 28 
" 
o 
,. 
" 
be seen In FIQ. 8A. has one 10 three (see 
Table 7) glandular ndges (Glr) along lIS length 
(FlQs. 8B. C). The Ihnd ndge (not shown) IS 
otten lateral 10 the other two Taylor (1966. IIg 
21) Illustrates a fourth ndge near the base 01 
the pelllal lobe (ventral surlace); !hls was 
seen In only one 01 the 75 specimens Studied 
Irom three pouiallons 
Nymphophllus acannalus HersNer, n. sp 
Synonymy. NymphopIlIIus Hershler. n. gp. 
Hershler In press. 
Etymology the speclE!S name comes from 
the acaflnale shell 
Holotype. ANSP 355255, FIQ. 9A. para?
types (11); ANSP 355256. Fig. 98 
Type-locality: Localrty 98. 
Habttat: NymphoptII/us acarina/us IS known 
only Irom empty shells from the type?locality 
and severat specImens collected live lrom 
Santa Tecla Laguna (Locality 101). Nym?
phophl/us acaflna/us IS allopalnc to N mlnck?
leyl. 
Description 
While there are InsuHlClE!nt anatomical data 
lor a detailed account comparable !o that of 
N mlnckleyr, thiS speoes IS ptaced In Nym? 
phoptulus because the organlzallon of !he 
bursa copulatfiM complex and 10rm 01 the 
peniS are like those 01 N. mlnckleyl. 
The shell (Ftg 9) dllfers from that 01 N. 
mlnc/deYI In thai II IS somewhal smalier 
(lenglh, 4 .20 mm), has lewer whorls (10 4.8) 
that are qUite rounded. and lacks a peripheral 
keel. even on early whorts The growth IU"les 
are less pronounced Ihan those 01 N. mlnck?
leyl Measurements of the type and paratypes 
are given In Table 8 
DISCUSSion 
While Ihe dlHerences between N. SCSflns?
Ius and N mlnck/eyl are lew and reslncted to 
shell features. there IS no blumng of these 
differences In any of the populations Studied. 
SpeCimens of N mlflCkJeyJ from small SpringS 
can be as small as N acanna/us. but !he 
whorls remam "anened and the penpheral 
keel IS always present The consistency 01 
these dll!erences suggests !hat the taxa are 
dlslincl specIes and not mere allopa!lIc var?
Iants. 
46 HERSHLEA 
TABlE e Measurements (mm) oIllle shells oIlhe hoIotype (ANSP 3552'55) and palalypes (ANSP 355256) 
01 Ntmpllophdus acaflnalUs All Shells life hom ildul1s Wllh 4 S-4 e whofIs 
...,,, 
""" length 
-
"""""" 
"5 '33 
p&-
'" 
289 
P(lfa\ype ", '26 Pa.atype 
'" 
,,, 
MexIsl,0018 Hershler. n. gen 
EtymolOgy: the name was formed by add?
Ing Ihe prellx Mexl-. relcrrlng to dlstnbutlon 
wlthm MeXICO, to 51,ob/a Thompson & 
McCaleb, 1978, a very SimIlar nymphophlhne 
from the southeastern U S.A. 
Type-species. Mexlsllobia mananl lall n sp. 
OlslnbutlOll. thus far known only from the 
Guatro Clenegas BaSin and Durango. MexICO 
(U S NatIOnal Museum 01 Natural History 
351617. labeled " Valva/a") 
SpeCIes Included . mOllOlyptc. The speclhc 
status 01 the Durango population IS not 
know". 
Description 
Among nympnophlhnes. lhe unIqUe lea?
lures of Mex,sllObla Incll.lde lhe pOSilIOfl 01 the 
small bursa (60) anterior 10 Ihe sermnal 
leng1h 01 length 01 Width 01 
--
apef1ule 
.... "'. 
3.37 230 
'" 298 222 
'" '30 23' 
'" 3.45 250 
'" 
receptacle (Sr. Fig 146),lhe very short ducl 
of the bursa (Obo). and 1he position of the 
male gonad ovel1Y1ng the posterior stomach 
chamber (not shOwn) 
The shell (Fig 10) is minute (Ienglh, 
t 20 mm) and broadly conical: the bolster of 
the ventral ChamellS weakly developed (Fig. 
14C); the capsule gland opens at lis anlenor 
lip as a common genital aperture (ega. Fig 
140): the peniS has an elongate pelllallobe 
(With one fok:lln .1) bearing a single glanclular 
ndge along .IS venlralleoglh (Glr. FIg 130). 
OlSCUSSIOfl 
Mex/slma mananlUlIi bears a remarkable 
conchoioglcal resemblance to SIIObIa Thomp?
son 8. McCaleb. 1976. a monotyPlc genus 
endemIC to a spnng In Alabama. yel It diners 
In 1 t mOrphologtcalleatures (Table 9). Twoof 
Ihese features (4. 6) may have been In. 
correclly mterpreted by Th ompson & 
FIG 10 SEM phoIosol paralype shells (ANSP A9887d) 01 MexlStOOa mananlla~ hom Loca illy 51 The shell 
on lhe lell.s I 15 mm long. H'I31 on lhe /IgN IS p', nled allhe same enlalgen'lCl1l 
CUATRQ CIENEGAS HYDRQBIIDS 47 
FIG " SEM phoIo$ 04 the apot8I 'egoon 01 !he 
shell 04 .uex.s/JOOla manan/.ah. showlng the wrll'l?
kNld. pl1,ed mlCl'O$Culpiure al 5evefal magnota?
,~, 
McCaleb as these would be htghly Uf'l.lsual 
traits lor hydrobtold snails. Separate genenc 
status IS SI.J!1tIested lor these two taxa be?
cause of the maJOr differences In the positIOn 
and orgarazatlOn 01 the bursa copuLatnx com? 
plex. and In the form 01 the perIlS and rumber 
of glandular ndges. 
While the stunted appearance 01 the lemale 
reproduclNe anatomy 01 MexlslJObla IS ul"IIQUe 
among nymphoptlltlne5. a peniS With lew 
glandular ridges IS atso seen In NymplJophl/us 
and Mars/oma (see above) 
MexlstOOta mansntlal, Hershler. n. sp 
Synonymy: -StIObfa- Hershler. n. sp. Hersh? 
Ier In press. 
Etymology. the speaes name IS formed 
Irom the Spamsh word mansn/lm. meal'1ln9 
spring. and relers to the spnng?led habitats of 
thts snail 
Types: hoIolype. ANSP 355205: paralypes. 
A9887d. A9888I. 355204 Ftg. 10. Because 01 
then small Size, the shchs had '0 be photo?
graphed USing the SEM. which leaves gold 
coating on the speamens. so the holotype 
was not used. The paratypes look tike the 
holotype. 
Type?locallty. locality 51, a small spong 
This speoes was shown. but Undescribed, by 
Taylor (1966. IIg 4) 
Habitat: Mex/ShOl)fa mananll8111S restncted 
10 the smaller spnngs 01 the valley It IS lound 
11'1 aSSOCIatIOn wrth Durangonel/8 coahu,lae. 
Pa/udlscma caramba. and Coa/JuIhx sPP Ifl 
the headspnngs, and IS sympatnc WIth D. 
coahudae In the spong f\HlS. In terms of mIC?
rohabttat, Me1l1strobta manso/Ia/' IS common 
In hne orgaOIC sediments and Char8 mats. 
and prefers a hner sedllTl(lnl than does 0 
coahwlae. While found In mop samples Irom 
20 01 38 small sprlngheads, MexlSflOb,a 
man8n/lah probably does not live In subterra?
nean waters as a. specmens roIlected have 
e-yespolS and because the spectes IS most 
adapted lor ~Ie In open. downstream habttats 
(see below) 
She' 
The coIor1ess shell has rounded whorls and 
an open umbilICUS Adults have 3_00-3.3 
whorls. The whoI'ls somehmes have a very 
sltght angula1JOn at the shoulder. The latter 
por1lon 01 the body whorl Irequenlly pulls 
away from the precediflQ whorl In adults 
PostembryoOlC sculpture IS restricted to 
stronggrowth~nes(Ftgs.10. lIA) . The plane 
of the aperture IS blted about 10 toward the 
COIIIOQ axiS. The apcaI whorl mlCfosculpture 
IS shown at several magfllhcahons In FtgS 
12A-C SheI measuremen1S Irom Ihree p0p?
ulations are gIVen III Table 10 The shell 
length for females IS Slgfllflcantly larger than 
46 HEASHLER 
FIG 12 SEM photos at the r!lO..lla 01 Me ... ~mananlla. A Pan 0I'!he rlIOM nbbon e, C Centr,)lleefl 
o Ou4e1' rnargor.al leell> 
thai lor males 11'1 two of the three popula\lOns 
(Table 10. 
NocYeproducbve Features 
ObsefvallOl1s and data on e~ternallea lures 
and anatomy are Irom the type populallOl1 
Measurements 01 organs and StructUI8S arB 
grven In Table 11 The snout IS ek:lngale. 
while the tentacles are relahvely shof1 and 
thICkened t FIQ 13A) A small concernrabon 01 
granules partlaly surl'Ol.Wlds the eyes The 
snout and tentacles usually have a dark ~?
nm dusleog Body p.grnentall()r'\ OOIlSISts 01 a 
dark rnelarun dus\Jng on [he dorsal and ven? 
Ira! sur1aces Adults have only 10-13 gill hla?
ments (Table t 1) A p!"ormnent caecal cham? 
bel' (Cae) eJdends posl6110r 10 the stomach 
CUATRO CIENEGAS HYDROBIIOS 49 
TA8lE 9 lJ$I 01' 11 mDlphoiogocal (Iof!i:!fet'lCe$ between SlKlbIa ~ IWld McIfl5klbr8 man_mall' The 
rncwp/loIogIcaIlIllormaloon on ~ nana IS '.om Thompson & McCaleb 11918, 
S<.-MM 
I She' Wllh IwO sporal keels 
:1 W'lIlkled. pitted mlC.osculphJf8 on aU shell 
--3 OperaAum WIIh :1 5 whorls 4 HypobranchIal gland Pfes.enl 
5 lalera! looth 01 radula WI'" massow!. hoe-W<.e 
cenlral cusp 
6 Bursa IWld duct 01 burSa .rrCedded nlhe pallial 
......, 
7 0u::1 at burSa elongate 
8 SemInal receptaCle anlefl()' 10 burN 
9 PenoIII IoIIw'nenI 35' 01 pe<VS ~ 
10 Penoailobe lTIiISSIVe and slout 
I I Numerous gia'ldular ndges over ant". sulface 
~ ""'" 
Operculum Wlih 3 5 whorls 
HypObranchial gland abSent 
Cent,aI cusp small and dagger-llke 
Bursa and (U;1 dor'5IrI 10 PIAIII OVIduct 
Duct IS Short 
SemonaI rocepcacte posIPrIO' 10 buM 
Pe..aJ Irlament 045' 01 pens IengItr 
lobe IS smaA and sIenOer 
Songle gLandula, rrdge on "entia! SUI1ace 01 penoal 
"'" 
TABLE 10 Shell measu.emeols (mmj ot males and temales trom three populahons 01 MCI(ISIIOCoa 
""......,.,,,. SnaIls: Wlih !he dorl'llnanl mll).lI'n.Im whorl numbef we,e used N 
.-
Slanr;lard devlabOfl 
11- retefs 10 the sognrlrcance 1eYel1or!he (Iol/eleilce belween shelllenglhs 01 main andlcrnales (t-!esl) lor 
'''''-
'"""'" 
L .... ~ W""" 
Loa/Ity 5' 
, 30 ". 008 099 ~ 004 , 325 121~004 104"007 
LocaWy 65 
30 098 - 004 095" 004 
325 1 10' 005 103 ?005 
LOCII~ry 68 
30 llO'OOS 107 " 004 
325 "5 OOS 1111002 
(Fig 14AJ The operculum (Fig (38) has 3_5 
whorls. and !he nucleus IS positIOned al 39'\. 
01 !he long aKIS 01 the ope,rulum. 
IndIViduals wIth reduced body pigment 
were sometlllleS taken from the mops, whllo 
snaIls from downstream always have dark 
body p.gment The upstream P'9f116nl loss 
may be because the SPflnghead IS usually 
coverNl by nparran vegetatJon. and mlllllCS a 
subleffanean enVironment A simIlar up?
strean,-downsi'eam pM]ment change IS ro+ 
ported lot the amphlpod HyaleHa In Cualfo 
Clenegas (HolSinger & Mlnckley. 1971 ) The 
usual dar1l pgmenlabon ollhe Sllalls IS prob?
abty an adaptatlOfl to lIfo In the open sl,eam 
waters thai are subjeclto g,eal Insotahon 
length 01 
"""" ~ Wldlhot 
--
"""' . ...... " P 
I 08:!: 006 0 .. 00< 053?004 
" II:1~OO5 063 - 003 062 ! 003 
084'002 OS, 0" 0<, 002 005 
093-004 056 003 047'002 
094"'004 059-003 OS" 002 025 
095 OC" 060 000 052 003 
Radula 
The radula IS snown In Frg 12 Tho cenlral 
cusps of lhe cenlral and laleral toolh are 
blade?1rke The marglnals have nume,ous 
cusps. The cenlral tooth has a single parr of 
basal cusps Oflglnatlng I,om lhe lateral angles 
(Frgs 128, CI Raclular SlatlS11CS and the var?
IOUS cusp arrangemenls 01 .he lou, looth 
types are gIVen In Tall'es t2 and 13. respec?
lively 
Female Reproducllve Analomy 
The Ofgal'llZatJOn 01 the lemale reproducllVe 
system IS shown In Fig 14 The female gonad 
50 HERSHl ER 
"-I-.._..-T ' 
, 
, 
, 
0.5 mm 
v, 
~. ' , , , ill. ... _-
I----E, 
B 
A 
.' .r. 
-----
c 0.5 mm 
FIG 13 Head. operculum and penos 01 Me)(lSfJOboa mananl!8l. A Dorsal aspect 01 the head e Opefcuh,Jm 
C Do<saI aspect or lhe porus Nola the small slendet peOial1obe (PIo) The dashed lone mdlCiHes the regan 
WIth melanon 0 Ven1f a! aspect at 1he penial lobe showIng the glandular rodge (GI.). WIth a close-up oIlhe 
smaN glands Ey-tlve. Gif-giandular ridge. P\o-pen.allobe. Sn-sooul To-tentacle. Vii-vas deleleos 
(Go), a single lobed mass. occuptes only 17% 
01 the bOOy Iefl91h. The OVI(IuCl IOv) diS?
appears beneath Ihe pallial OViduct (Apo + 
Ppo) at the end 01 the style sac (SIS. Fig 
14A) The palhal oViduct IS diVIded ,nto two 
equal sectIOns the albumen gland (Ppo) and 
the capsule gland IApo) The pallial oviduct 
conS\ltutes 2~ althe body length. The pelS' 
tellormost 30% 01 the pelihOlI OVl(luCl overlte$ 
the style sac The antenOr end 01 the pal~al 
oviduct IS 03 mm Irom Ihe manlle edge. 
The relahoflShlp between the bursa copu?
laln)( complex and the pallial OViduct IS shown 
In Fig 14B. The bursa copulalux complex IS 
CUATAQ CII: NEGAS HYDAOBIIDS 
" 
TABLE II DImensIons (mm) 01 counts 01 non? 
nawal organs and SI.llC!\lres of Me"lSlrQbla man-
iIIl/liJ/I N 5 u~s Staled otherWIse Mean 
standald devlallon L kmglh W WIdIh 
Females M"'" 
"'" 
, 257 ' 018 240 - 020 
G~I "'ament nunbef 
'N 
" '" 
? 095 
Gonad (N 
" 
, 045 -,, 006 094 -0 11 
W 030 ? 002 029-003 
Prostate (N - 8) , 039;004 
W 021 ? 003 
'",,''' 
, 150 ? 017 
W 034' 004 
PaUla! 0\I0dud , 073 + 009 
'N 
" 
W 031 ~ 003 
6u'sa copulat"" , 015?002 
,N 
" 
W 007 - 002 
Senwlal receptade L 010 -;: 002 
(bodyl {N 
" 
W 006 ? 001 
Semio1a! roceplade l 0 .09 + 001 
(duct) (N - 7) W 004 -;: 001 
TABlE 12 Radulal stallsbcs!rom 12 ondrvoduals 01 
MexlS/!obfa mananllah X s mean. 5 standard 
OOvI8!>on Measurements In mrn 
Raa.rla. teatUfe X S 
,,,,,-
" .. 000:1 W""' 000' 0005 Numbe< 01 rows 565 
" Numbel' 01 rows on 
Iormatrve stage 
'" '" Width 01 central 
_,N 
" 
o Ot3 0""'" 
dorsa) to the pallial OVIduct The bursa (6u) IS 
21% of the pallral OViduct length, and lies 
about 0.27 mm antenor to the end ot the 
pallial oviduct The seminal receptacle (Sr) 
and SIngle oviduct cod are largely posterIOr to 
tt1e bursa In four Of nine females dIssected. 
the lip of the seminal receptacle protruded 
slightly posteoor 10 the end 01 the pallral ovr?
duct The pouch-lIl(e seminal receptacle IS 
SimIlar In shape to and only sloghtly smaller 
than the bursa. bot was eaSily distingUIshed 
by Its pink sheen. The duct 01 the semmal 
receplacle (Osr) IS shor1 No gonopenC8rdral 
duct was seen. 
The bursa copula ln" lOinS the common 
opcntng of the ventral channel and albumen 
gland Just posterIOr to the end 01 the mantle 
cavity (fog 146) The ventral channel IS only 
slightly Iolded toward the ventral Side 01 the 
pallial OViduct and the bolster IS small (Ftgs 
146. C) The waNs of the ventral channel do 
not luse anteriorly (Fig 140). 
Male Aeprooucltve Anatomy 
The male gonad IS lobe<! and IS 38% 01 the 
body length. The semmal veSICle cods on the 
poslenor stomach chamber The prostate 
overlies the mantle C8vrty. The antenor vas 
deJerens eXits Irom the posteoor portlOO of 
the prostate 
The pentS (Fog 13C) has a slender. taper?
Ing penial Illament. and the slender pefHal 
tobe IS POSItiOned on the Inner curvature 
slightly closer to the lip lhan to the base of the 
peniS. The peniS has neither clIJa. nor a ter-
TABlE 13 The vanous rusp arrangements 01 the lout tooth types 01 Me"rshotJoiJ tnaIIW1hah. counled ,.om 5 
.adulae U5IrlQ SEM. WI,h Ihe percentage 01 radulae shoWIng thai arrangement atleaSl once 
'M~ ""~ Cenlral Laleral marQlnai marginal 
" 
cusps 
" 22 
" 
W 60 5-1-3 60 ,. " 23 '" 
W 20 5-, .... 20 " 60 " 60 
W 20 22 60 25 60 
W 60 23 " 26 60 
" 
20 
52 HERSHlER 
0.5 mm 
PO' 
coi Bu 
~ Obu 
S, _ ~A'O I , 
0" , ( APO-----/ 
/l D o. ? Em, B lie Bve 
ego 
FIG 14 Female reproductive aoatomy 01 Me.,51lOOla mananllilh A SnaoI uncooled exposong the venlral 
aspect ... 1houI head and kidney tISSUe 8 Qllented as In A. 001 Wlln il po<1>On 01 the pallial o~lduc:1 removed 10 
reveallhe bursa eopulalnx COfT'4lIex, boiste< (Bvel and venlral charnel ,Ve) C CIOSS?secl,on 01 the palla! 
0Y1duct (Iook..-.g anteno,ly). cut Just al !he oomrnon opentng 01 the bursa copuIal" x comple x and albumen 
gland Noll! the small Size 01 the boIsler (Bvc) and .educed ventral dlannel (Ve) 0 Dotsal \flew 01 the 
~ gland lApel). showlJlg the opernng oIlhe oommon genital ape<1 ..... e (Cga) al the anterIOr end of the 
palloat 0VKIucI APO---Capsule gland. AsI----anIerOOf stomach charrber. Bo---bufsa. Bve-bolster of ventral 
channel C<MI-<'ilOCum 01 stomach. CgB common genital apen .. e Cl---a:lIumetar muscle, Coo-<ool 01 
(JVO(Iuct Dbu---dud 01 the wsa Ost-<luct 01 the semonal receptacle Emc-poslellof end 01 the mantle 
caVIty Es--esophagus. Go--gonad, io-tn1eSline. Lpo-Iumen 01 palbal ovodud. Ma--manlle edge. Ov?
oYIducI, Ppo-aibumen gland Psl-poslentlf stomach chambel. Sr-sernonal receptacle: Sls--style sac 
Ve- ventral dlannel 
CUATRO CIENEGAS HYOROBIIOS 53 
mmal evt!fSlbIe papilla The penial hlament IS 
da",-Iy p.gmeoled (Plgmenled area IndlCaled 
by dashed lines m Fig. 13C) and occaSIOnally 
Ifle perllal lobe IS also pigmented The vas 
deferens does not COil In the peniS. The peniS 
has GI, and Gi2 glands. While the ouler CUf?
valure has no folds. the mner curvature has 
folds from the base to the pental lobe. 
The penial lobe IS slender and lapers 
toward lis distal end Viewed from Itle ventral 
aspecl (Fig. 130), lhe single curved glandular 
ndge IS seen. The ndge IS elevaled above lhe 
ventral surface of lhe penial lobe and COflSlSts 
of two rows 0 1 small glands Ihal discharge 
through a central sill (see Close-up. Fig 130) 
CoahUlll1I Taylor. 1966 
Type-species: Coatlwllx tlubbsl Taylor , 
1966 
DlstnbuttCm: endemiC 10 the Cuatro Clene?
gas BaSin 
Species Included. C08tlullix hubbsi. 
CoafJulhx /andye n sp 
Descnplloo 
DIagnostic 'ealures (ur"'dque among hllondl?
nines) Include a minute (width, 085-
1 40 mm) plaOlsptral sheM (FigS 15A-G, I- K) ; 
intestine with a COIl near ,ts anterIOr end (Inc. 
Fig 17C): basal cusps on the cenlraltoolfl 01 
the radula anSIflg 'rom the toolh l ace (Fig 
16C): COIling of the semmal veslcte on the 
posleflQf stomach chamber (Sv. Fig 17C); 
and POSlliOO 01 the proslate postenor 10 the 
mantle cavity (Fig. 17A) 
The apical whorl has PItied mICrosculpture 
(Fig. 16A); the animal IS b1,nd (Without eyes) 
and unpigmented; the digestive gland tuber?
des are reduced to low swellings; the caecal 
chamber does not protrude postefior to the 
stomach; gooads 01 00th selles are a Single 
non-lobed mass (Figs. 17B, C), With Ihal 01 
the female overlylllg the posteflor stomach 
chamber: the pallial oVIduct IS d, .... lded IOtO 
three lIssue types (Fig. 178): the oviduct 
COi ls, gonopencardlal duct . and sem,nal 
receptacle are absent (Fig 178). Ihe 
spermattlecal dud IS elongale and opens 
separately from lhe pallial oVIduct (Sd. Fig. 
FIG 15 SEM phol05 01 Coahui/'" /luDOSI Cooht.lth.r landyel and ()-ygoceras (1) sp Shells A-E afo Coohu.1I/l 
/IWbsI lrom l ocal,Iy 64. shellS F. G L J. K are paralyC)CS 01 Coalwfhlllandyef IANSP 355211) I.om l ocal'ty 
64 . and shell H IS Orygoce.as (1) sp Irom LocaIoIy 67 Shell A '5 0 871 mm woo. and a_ olhcfs aro pJlntOCI to 
the same enlargement c~(:cpl H. the tube ot whoch IS 2 26 mm long 
54 HEASHlEA 
A 
FIG '6 SEM photos o' shel' and radula 01 
CoahotIut tIubbsI A. Apocal sI1el1 ..mons, showing 
WrInkled. potted m+c'OSClllplure B Pari oIlhe radu? 
lar nbbon C Cenlralleelh showIng the oogon of the 
basal cusps lrom the fate 01 the Iooth 
178 ): the females are oViparous: the pems 
has a bull).l lke lObe bearing a large apocnne 
gland (AgI. Fig. 170) 
DIscusSIOn 
W,thm the L,ttondm.nae. CoahU/II;,r and 
Paludlscala form a subgroop as they share 
numerous lealures. many relaled to the small 
size of.he snruls and their unique habitat (see 
Tables 53-55. FIgS 49, SO) The female re?
productive sySlem of lhese snails is Charac?
'cnzed by loss 01 the oviduct COIls, gonopcn?
cardlal duel . and semmal receptacle. 
Coahuill)( IS dlSllnguIshed from Paludrsca/a by 
the unique lealures listed above and by dif?
ferences In the secondary sperm slorlJge 
sacs (Coahu;/ix, absent: Paludiscala. present) 
and the Con(lltlOfl 01 the opemngs of the 
spermathecal duel and palhal OVlducl 
(CoahullllI. separale; PaltJdlscala. pned). 
Coahwlix hubbsl T aylDr . 1966 
Holotype: UMMZ 2220180 
Type-locality: pozo de la Becerra (locality 
10): only emply shells of thiS Species have 
been found tn this large spnng. 
Habltat? UVtOg Coahu;hx tUJbbsi has been 
oblained only from mops placed into or just 
below small spnngheads. Downstream col?
lecting ellor/s. with line hand sieves. never 
yielded live speomens. Nor wele they loone! 
when bonom material Irom the spmlQ IUns 
was collected and examined under the micro?
scope. However. at locahty 64. mops Wefe 
aCCidentally placed three meters down trom 
the spring head. where the stream was still 
completely covered by npanan vegetatIOn. 
and numerous liVing specimens were ob?
tamed. 
Coahw/lx hubbsl was only moderately c0m?
mon In the mop samples: while the specieS 
was found on mops from I S of 38 small 
spnngheads. " never comprised more than 
t5% 01 the snails Irom the mops Irom any 
spnnghead. Only a lew spnngs Yielded more 
than 10 Coahul/ix hubbsl per mop. 
The fact that Coahui/lx hubbSl is blind and 
unpigmented . together with Its apparent 
restnchon to groundwater outlets. suggests 
Ihalthe speoes may also live In subterranean 
walers In lhe basin O1her snail taxa In Cuairo 
Clenegas with a SImilar hab,tal are Coahu./Ix 
landyei, Paludlscala caramba, and Ory?
goceras (?) $p_ 
Oescflption 
The shelf (FigS. 1SA- Ells less than ' .0 rrrn 
Wide and has 2 3--2.5 whorls when adult The 
lasl tenth of a whorl is sllQhtly ,nllated (FIQ. 
15A) The aperture IS Inc~ned about 30 to the 
C(lIhng axiS A small segment of the !nnel hI' 01 
the aper1ule IS notICeably Ita/ed (F'9s. 15B. 
C) Post?embryonlC sculpture conslsl s of 
CUATAO CIENEGAS HYDAOBlIDS 55 
.. 
., 
C 
... 
o .... 
A 
, . 
? 
o 
FIG 17 Aspects 01 the anatomy 01 CoahuIIut Ilubbs< A Operculvm B Ventral aspect 01 uncotled female 
WIthout head and lIodney tissue Nole the swnp.boo gonad (Go). lack o' seminal rec;eplacle. and differentia? 
bon of the capsule gland Into two tiSSue types (Ape, and Apo,) C Ventral aspect of urnllied male Without 
heoo and kldney bssue Note the sunpllfie(j gonad (Go) . COIlmg of the semmaI vesode (Sv) on lhe stomach 
small prostate IPr, and Mlenor Intestine COlI lint) 0 OotsaJ aspect 01 the pet\lS stowong the large bulb-Ioke 
penial klbe (PIc) WIth a songle apocnne glilJld (AgI) Agf-apocnne gland. Ape,-postenor cap!)Ule gland. 
Apo,.-antenor capsule gland; Ast-antellOf SIomach chamber Bu--bu'sa Emc-posteflor end ot mantle 
cavity. Es-esophagus. GCI--i/Ofloo. Io-alllenor Intestinal COIl Ma-nantIe edge. DY---<IYtduct. PIo-pet\IaI 
klbe. Ppo--aIbumen gla .... ;!. F'r- prQSlale. Pst- posleroor stomach chamber. Sd--spe<mathecal duct. Selv?
sperm duel. SIs-style sac. SV- semlnal YeSICle V~vas deferens Vd,-vas deferllflS from semonal 
veSICle to prostate. Vd..--vas deferens from prOSlale 10 pems 
weak growth lines. The anlmallacl<s gills. but 
has an osphradlum. 
Shell 
SheH measurements for specrmens from 
one populatIOn (Locality 64) are gIVen In 
Table 14 The shell wldlhs lor females are 
greater than those for males (p < 0 05, Table 
14) For each of three other POPUlatrons 
(Localities 58. 38 and 67), shell Widths 'Of 20 
adult specrmens (se~es ml~ed) were meas? 
ured With the following means and standard 
deViations: a 822 ~ 0.055 mm, 0.829 + 
0.056 mm. and 0 799 :!: 0075 mm. respec? 
lively 
The shell occaSlOflalty has a small spne 
(Fig 15E). The tast quar1er whorl dips abap!' 
cally away from the preceding whorts. The 
penstome IS oompIele and sllQhlly IhlCkened 
56 HERSHLEA 
TABLE 14 Shell measurements ((TIm) 01 males and lemales of Cca/lvfh" hubbsI (Irom LocalIty 64) N 9 
Mean ? Slandard OOVloltl()n .p' ,efers to the iS09O,l ocarlCe level lot the dllterence between shell WIdthS 01 
maleS al'l(llernales (I lest) 
, 
, 
_. 
2l-25 
25 
036'" 002 
0.37 ' 003 
085 ~ 0.04 
089 ? 0.05 
TABlE IS Omensoons (mm) 01 llOn-ne\lfal OI'gans 
and SlllJClures 01 CoohWl'J< hu/Jbsl N 5 Mean ~ 
Slat'ldard devlabon l length , W _ wodlh 
F~" ...... 
-
, 1 25 ' 008 124 ! O08 
"""'" 
, 036 ~ O04 029! 003 
W 016 :!: OOl 0 16 - 0004 
....... , 019 ' 001 
W 010+001 
..... , 035 - 001 
W 010 ' 001 
Pall3l 0VIduc1 , 033 ---0 02 
W 013' 002 
6utsa copula'''. lO l l ' OOI 
W 007 '002 
TABlE 16. Radular statlstocs 110m 510dMduals 01 
CoaIut/Ix htJbbst X ~ mean, S standard devIa? 
bOn Measurements on mm 
Radular leah .? C , 5 
Lenglh 0214 0011 
""'. 003< 0002 Number 01 rows 68. 
'" Number of rows In 
lom'l(ltlve stage ". 055 
No speCImens were found WIth the extreme 
llanng 01 the aperture shown by Taylor (1966, 
"gs. 9, 12). For nine spectmens from ooe 
jXlpUlallOl'l (Locality 64). the width 01 the tiP 01 
the aPICal whorl a .... eragedO 081 ... 0006 mm: 
the width of the 11151 whorl was 0 136 ... 
0.0 15 rrwTl . No specimen seen had the strong 
growlh ~nes shown by Taylor (1966. hg. 13) 
Nonreproouctlve Features 
Observations and data on externalleatures 
and anatomy are from the population at 
Local.ty 64 Measuremoots 01 organs and 
structures are gIVen In Table 15 The snout IS 
squat and the tentacles are short and thick. 
The buccat mass. plnk?red In color. IS vlSlbte 
Lenglh 01 
"""''' 036 +002 
036 ' 002 
Width 01 
aperture 
0.32 - 002 
0_33+002 
, 
through the snout. There IS a concentrallOl1 of 
white granutes and a stlght pinkish color 
where the eyespot normally would be. The 
tentacles are Without hYPeftrophled CIliary 
tufts The operculum (Fig. 17A) has 3.3 
whorlS and the nucleus IS POSitioned at 42% 
of the long axIS of the operculum. A hght pink 
color and scallered white granules are seen 
on the operculigerous lobe 
Radula 
The radula IS shown In Figs. 168. C The 
central tooth has well develOped latefal an? 
gles. a small basal process. and a dagger? ~ke 
central cusp The basal cusp s upporls clearty 
anse from the face 01 the central tooth (Fig 
16C) Radular StallStlCS and the varIOUS cusp 
arrangements lor the lour tooth types are 
given In Tables 16 and 17. 
Female Reproductive Anatomy 
The organlzatlOfl 01 the lemale reproductive 
system IS shown .n Fog 178 The gonad '5 
28% of the body length. The pallial oVIduct 
(lxtends to the anterior edge o f the stomach 
and IS relallvely small. comprising 26% 01 the 
body length. The oviduct enters the posterIOr 
portion 01 the albumen gland (Flg_ 178)_ The 
capsule gland IS comJXlSfld 01 a large poste? 
nor whlte-colored sectlOfl (ADO,. Fig 178) 
and a smaller anterIOr grey?colored sectlOO 
(Ap021? The sac? lI!<e bursa IS posiliooed 
dorso? laterally to the pallial OViduct and has 
ItS postenor end evoo With that o j the albumen 
gland. The bursa IS 38"'0 01 the length of the 
pallial oviduct A thin sperm duct (Sdul ISsues 
Irom the anlOOor end 01 the bursa and JOIns 
the OViduct at the opening 01 the albumen 
gland (Fig. 178). The postenOf portlOll of the 
albumen gland. where the OViduct (Ov) and 
sperm duct (Sdul JOlfitly enter. has a pink 
sheen. Indicating thaI sperm IS Inside thiS 
regIOn diNers trom the rema.nlng albumeo 
gland In tha t II IS thln?walled and non? 
glandular. It may be a secondary sperm slor? 
CUATRO CIENEGAS HYDROBrtOS 57 
TABLE 17 The vanous cusp affang(!fl1(!r1ts oIlhe foul tooth typeS 01 CcahcJ,Ivt r."bbsI. oountoo from five 
radulac usong SEM with tho pe'CC!1tago 01 .adutae showing that arrangl'<l'Cflt at k:!ast OOCQ 
Lateral 
% .. 
"Xl 5-1-3 '00 
., 'H~ 20 
&-,~ 20 
age area (as there IS no seminal receptacle). 
The spermathecal duct (Sd) IS usually tlQhtly 
appressed 10 the palliat OViduct 
Male Reptooucttve Anatomy 
The male gonad IS 23% of the bcxly length. 
The vas deferens branches off the anterlOf 
erx! 01 the gonad and the seminal vestde 
consiStS of only a few COils (Sv, FIQ 17C) The 
antenor vas deferens e~lts Irom the antenor 
\lp of the ptostate 
The pems has a short pemal hlament The 
peflIat lobe (P\o, Ftg. 170) IS located at 46c .. 
01 the length of the peniS Irom the base (on 
the outer curvature). and IS slightly taller than 
It IS Wide, measullng 0.098 by 0.060 mm. 
Fokls are seen on the outer curvature of the 
peniS from the base to the pemal lobe; the 
InflCf curvature has folds lor 75% 01 the penis 
length from the base. The vas deterens does 
not COil In the pents. Infrequent COil?
centratoos of GL2 glands are seen In the 
peniS The penIS IS neIther Ciliated. nor does It 
have a terl1'tlnal paPIlla. 
The SIngle massIVe apocllne gland In the 
penial lobe ()(Xuptes shghtly more than one?
hall 01 the hClght of the lobe. The gland open? 
II"Ig IS clearly vIsible and almost Circular 10 
cross-section Its detailed structure IS the 
same as that of He/eobops (Thompson. 1968_ 
figs 380. E) 
Coahud,x /andye, Hershler. n sp 
Synonymy Ccahwllx. n sp Hershler. In 
"n,,, 
'"~ Oute. 
ma.gonaI marginal 
... ,~'" % 
" '" " 
20 
" 
OJ 
" 
OJ 
" 
!Xl 
" 
!Xl 
" 
20 
" 
20 
20 20 
" 
20 
Etymology named after Mr. J . Jerry Land?
yeo a student 01 the freshwater molluscs of the 
southwestern U.S A .. and Me~lCO . 
Types hoIOtype. ANSP A9894n: paralypes 
(7). 355211. Figs. lSF. G. I. J. t< Again. 
because 01 thell' small size the shells were 
photographed USIng SEM. and there lore the 
holotype was not used The paralypes used 
look like the hoIotype. 
Type-locality? Locality 64. 
Habitat: Coahwbx landyet has been w?
leeted. With one e~cephon. only from mops 
placed In small spnngheads In one spnng 
(locality 63) several specllnens were taken 
live Irom Chara mats hve meters downstream 
lrom the groundwater outlet. CoahUlllx land?
ye, was collected from mops from t 3 of 38 
small spllngheads. The species always com?
prised less than 13""0 01 the collection from 
any spnnghead. and never totalled more than 
four specimens per mop. 
Descnptlon 
While only a few 5pCClrTICf1S 01 Coahu,l,x 
landyOl were dissected. all aspects of anat?
omy seen were baSlC3l1y the same as those 01 
Coahwllx hubbsl 
The shell (FlQs 15F. G. I. J-L) d!lIers Irom 
that 01 Coahvll,x hubbSl III the follOWing re?
spects 1) adults have one more whorf and 
are larger (wtdth. 10 1 31 mm) than Coahu,lIx 
hubbs,; 2) the lasl tenth of a whorl IS much 
more inflated than that 01 Coahwl,x flubbSl; 3) 
the growth lines of the body whorl are much 
more pronot.MlCed than those of Coahwl,x 
hubbss: 4) lhe last thIrd of the bOdy whorl 
58 HERSHLER 
TABlE 18 Shell meas.;.emenls (mm) 01 adu/1 Coohulb;r: landyel ( 325lNhor1s. se~es ,rued) trom two 
populall(ll'lS Mean ? standard deIMtKlfl The shellS measured 110m LocaIoty 64 are paratypes (ANSP 
355211 ) 
length 01 Width 01 
Shell IengIIl Shell wld'h ,,, ... ,,. -~. 
LocaMy " 
N 9 050 ",0 04 128 " 002 052 ~ OO3 039 ? 0.04 
Locahty 67 
N , 049 ~ OO3 1 31 ? 006 049~O03 041 ' 000 
30-
" 
~ 10 
? ,
c 
> 
c 
z 
A 
"'- 0663 0832 101 o 
L e. hubbSl 
. c_ '8nd~e, 
[ ' .0 196 I11I'I'I 
1 19 1.21 
'" 
ffi I B 
! 'l rr'L ?? I. 
0 .6"53 0 .8'32 ,'.01 Lie 1.i1 1.54 
SHEll WIQTH 
FIG. 18 She" w.cIth t.eq..eocy dlslnbubons hom 
Coatu/Ix IlubbsI and Cooho,/JX /andyeI ooIIecle<l 
from mop$ hom two IOcahhes A LOc;alt1y 67 B 
Loeahly 64 Almas! all specImens taken we,e 
aduhs Note Itle otwooos SIze d'lle<ence between 
the two 5)'1T11)at.1C specoes (analyred 11'1 Table 12) 
ovef1aps the precechng whon (FIQS 1SF. J , 
KJ, whIle that of CoahwllJC hubbs, merely 
touches the preceding whorl : 5) the aperture 
IS mudl more Inclined to the COIling axIS than 
Ihat 01 CoahUlI'J( hubbss: and 6) the Inner hp 01 
!he aper1ure IS much less flared than thai 01 
Coahwhx hubbsl. The animal has 10-12 gill 
filaments (Coaflulllx flubbSi lacks gill hla-
ments) Shell measurements lor two pop?
ulahons 01 Coaflul/Ix landyel are grven In 
Table 18. 
o.SCUSSIOll 
The dilfereoces between these two specieS 
are all assoCIated With CoaflUlllx landye1 hav?
Ing one more shell whorl than Coaflull,x f1ubb. 
51. Separate specdlC slatus is suggested by 
the two taxa be" lQ fcund together 011 mops at 
SIX Iocahhes (suggeshng sympatry); In these 
cases lhe whorl count ollference remained 
pror.ounced The shell width frequency dIStri?
butIOnS (Vlrlually all adult shells) lor mop c0l?
lections ot the two speCIes trom two of these 
localities are shown In Fig. 18 and analyzed In 
Table 19 . NOIe that the oilferences between 
the shell Width means are highly Significant lor 
both localities Immature CoaflUl/IJ( landyel. 
With the same size and whorl number as aclun 
Coafluilix flubbsl. are olstu-.guishable Irom the 
latter as their apertures are neither ttllckeoed 
nor tlared (Fig. 150). Very small Immature 
specimens (< 2 whorls), were not lcund and 
probably could no! be specilically ldentlhed 
Other WOA<ers have noted two small, plalll ?
spiral hydroblold specieS 10 Cuatro C,enega.s. 
and It IS likely thai the snail referred to but not 
descflbed Of figured as Hauffema sp. (HolSin?
ger & Mlnckley. 1971, p 444 ) IS Coaflvlilx 
landyel 
Pa/udlscala Taylor. 1966 
Type-specieS: PaludlScala caramba Taylor, 
1966 
DistnbutlOfl endemIC 10 the Cuatro C.ene?
gas BaSin. 
Species Ineluded monotypic. 
DeSCriptIOn 
UnIQUe tealures Include lhe two 10 three 
promu)8nt swellings on the cQiliess oviduct 
(Fig 22A) and Ihe disc-like ?pouch" that 
CUATAC CIENEGAS HVOA08110S 59 
T A8lE 19 ~ 01 shell WKllh I!equency (II5Inbunons shown ,n FIQ 18 -P- .elEn to It1e liOQnO!ocance level 
lor It1e (IotIetence befweefl $hell WICIIh5 0I1t1e two lympatnc SpeCIeS (I \esI) 
Shell wodIh (mean ? 
N stilOCSa!d de\oldtlonJ p 
--- -~ 
LOCIIhry 67 e """'"' 20 0799'0075 005 e,.-
" '" 
. 0 134 
LOCIIIrty 66 e """'. 
'"' 
0818:!0024 005 
e_ 8
'" 
- 0290 
fIG 19 SElIA pt'dOSoI shelsol Pa ..... S!"3\acarwnba SI1eIsA and 6 arefrom lr;Uollly63. CandO arel.om 
locaIfty 38 Shell A IS 2 42 mm long (6 IS pnnted to liIffiI! enargement). shell C 05 1 58 nwn long (0 IS pnnled 
to same eQargetnenl) 
buJges Irom ,he venlral surlace 01 the albu?
men gland (FI!)S 22A C. OJ. 
The shell (Fl!). 19) IS small (length, 1 40-
260 IT'ITI) and turnform, Wllh or wI,houllamel?
liform costae: the apiCal whorl has PItted IT'II ?
aosculplure (Fig lOA): lhe anlfMl IS blind 
and unpigmen ted, the ten tac'es have 
HydrobIa-Wte hypertrophied clhary tuhs, ,he 
dIgesl/\/e gland tuberdes are recluced '0 low 
SweMlngS (FIQ. 228); ,he caecal chamber 
does noI protrude pas'eoor 10 'he slOrTlaCh 
(Fig 228). the pallial oviduct contams four 
dlstmc' tissue ~lIonS (FIQ 22Aj: 'he Selmnal 
receplac' e and gonopencardlal duct a.e 
absent: ,he sperma'hecal duct (Sel) IS elon?
gale and has a COI'TWT'IOn operIIng with tha' o. 
the pallial OVIdUCI (F.g. 22F), females are 
OViparous; ,he pens has a bulb-hke lobe be?
anng a large apocooe gland (AgI, FI!) 21C) 
Among IlttondllltneS. Pa/udIsca/a IS most 
Slmtla. 10 Coahuthlt (see above; Tables 53-
55. FIQS 49, SO) 
60 HERSHlER 
20 u 
FIG 20 SEM ptlo1os ot tllC aptCIIII whoJls and radula 01 Pal(J(1tscata caramtJa A. Apl(;alsh{:11 whollS, showing 
potted lTIICloscutpture B, D Ceotralleeth C Part of the radula nbbon 
Paludlscala caramba Taylor. 1966 
Holotype UMMZ 220164 
Type-locality Locality 74 llYlng Paludtsca ?
la carambiJ have not been Ioond at thiS Ioca!?
"y 
Habitat Paludlscala caramb<> was by far 
the most common species found In the small 
sptlngheads; 32 of 38 of these spnngs yielded 
this speoes from mops. Of the 23 springS that 
YJeIded more than tOO snails from mop col?
lections. Paludlsca/a caramba compnsed 
greater than 10"!" of the collection lor spnng 
18, and greater than 50"/.:. of the coIlectlOll for 
15 Perhaps more so than Coatw,hx. Pa/udls?
cala caramba can extend downstream when 
there IS npanan vegetatIOn covenng the 
stream, At lIxality 63. a small thermal (33-
35 C) spnng ISSUes IIlto a pool (see Brown. 
1974. IIg 5). and then runs 170 m before 
termmaltng In a marsh Pa/udrsca/a caramba 
was very abundant on plant and rock surfaces 
for the upper 83 m. whICh had w1ually com?
plete vegetallve cover Befow 83 m the 
vegetative cover ended and no Pa/ud,scala 
caramba were found. despite IntenSIve col?
lecting whICh yielded Quant,lIes 01 Duran?
gonel/a coahUl/ae and MexlsllDbra manantlah 
Paludl5Ca/a caramba appears to have a Slm?
!Iar pattorn of dlStnbutlon III Olher springs 
Shell 
The shell of Paludlscala caramba has up to 
7,5 rourded whorls Shelf measurements tor 
two popuiahons are given In Table 20 For 
CUATRQ CIENEGAS HYDROBIIDS 
" 
?? 
, 
." 
c 
.-
.. -
, 
FIG 21 Head penos. and opercull.m 04 Pit/udlscaJa cariJrnba A Dorsal _ 01 !he head NoIe Itle 
1"/ydtOb ?? H.ka hyptinrophl\ld Ciliary tufts on the lett tentacle and the lack 01 eyes B Opercutum C Dofsat 
lisped 01 !he pent!; showmg the bull"hke penoat lobe (PIa) with II Single IIPocnne gland IAgt) The lIt1actment 
area (An) of the pernal lobe to Itle pens IS hodden by the lobe s cuvature Agl-apocrme gland 
An-a1ta(:hmem 04 pemal lobe 10 peNS. PIo-pemaJ lobe Sn-snovt T n--tenlade Vo-vas delefens 
bolh populallons" there was no SlQmhcant 
seJ:ual dnnorptusm In shal! length Ip 0 I). 
For mosl populahons sampled. lhe shells 
have fairly tall. thin costae that are curved In 
profile (Ftgs_ 19A B) The costae begin atter 
08 whorls and COI'1tlllue to the aperture Cos" 
tae spacong IS Irregular for t6 shells (seJ:e5 
mixed) With 7 5 whorls from locality 63. the 
penulhmate whorl had 9.5 1.7 costae 
(range 01 6-12). and the body wtlofl had 
10.5'" 1.4 costae (range 01 9-13). A lew 
populahons (localilies 38. 67) had smaller 
Individuals (6.5 whorls. 1,4 mm shell length) 
With costae reduced Or abseot (FlQs 19C. 0) 
The aperture.s Inclined only 10 10 the COIling 
aJ:ls The peustome IS complete. SllQhtly thICk" 
ened. and adnate to or lust Iree from !he 
preceding whorl. The Inner lip IS sllQhUy 
flared 
Nonreprodudlve Features 
The anatomICal descl'lptlOn and data (Table 
21) are from the populahon from Locailly 63 
The snout (FIQ 21A) IS elongale. as are the 
tentacles There are four or hve Clilaty luftS on 
the tentacles and the tufts ale restllcted to the 
outer edge of the left lentacle, There IS a 
small conceotratlOn 01 white granules and a 
pmk color In Ihe <!feas where Ihe eyes pots 
normally would be Cryslailine glanules ale 
seen on the venlral body surface The 9111S 
are reduced 10 number (Table 21). The oper" 
culum (Ftg 21B) has Ihree whorlS and the 
nucleus IS poSitIOned at 38"0 of the long aXIs 
of the operculum The opercullgerous lobe 
has a narrow band 01 crystalline granules and 
a small area of red-pmk color 
Aaelula 
The raclula IS shown III FlQs. 208-0. The 
central tooth has a Single pall' of basal cusps 
that Oftglnate from the lateral angles (FIQS 
2OB, 0) Aadular statIStICS and the vanous 
cusp arrangements fOf lhe four tooth types 
are given In Tables 22 and 23 
Female Reproducllve Anatomy 
The organlzahon of the female reproductive 
syslem IS shown If! FIQS 22A. C. 0, E. F The 
62 HERSHlER 
... 
o. 
~$-
???Sh 
A 
0.5_ ... 
.~-  o ??? 
0 ?? 
FIG 22 Aspects 01 the anatomy or Pa/r.JdIsc8Ia cafamba A Ventral aspect al the uncOIled fema~ WlIhouI 
the head and kidney tISSue A sectIOn 01 the oviduct ~Ov) has been removed. Note the swellings of the 
OYIdud, !he albumen gland pouch (Agp). and capsule gland dlfferenllated IIlkl three d,srlllCl .egoons (Apa,. 
"""". and Apo,,) 6 Venhal aspect 01 the dlgeStlVtl gland 109). showlng the lubel!;ies reduced \0 mel'e 
swellings C PoI;tenOf palhal o'ollducl onented as In A. bu1 w,lh the atbumen gland pouch (Agp) IoIded 
venlralty to expose ,ts basal connectIOn 10 the mall'1 pOOtOIl at the albumen gland 0 C'OSS?sedlOOal VIeW of 
the posIenor end 01 the pallial oVlducl snowong how the albunlel1 gland pouch (Agp) and ovoducl (Ow) pOa"IlIy 
open IrlIO the albumen gland Pfopef E Base ot !he albumen gland pouch (AgrJ) Nele that the oviduct (Ovl 
and spem! ducllSdu) JOOn together at the openong to the albumen gland. whod> IS d,l1e.enhaIOO from the 
&sial porUon o/tha albumen gland pouch F Onenled as In A. but Wlih MosIoIlhe paliitil oVIduct rul away 10 
reveallhe busa (Su) Note thai much 01 the bursa IS anlenor 10 the end 01 the mantle cavIty (Emc) and lhal 
the spermalhe<:al duel (Sd) JOIns the pallIal oviduct a t ,Is anteflor end Agp-albumen gland pOUCh: 
Apo,----p;)Sletoor capsule gland Apo,.--inIddJe capsule gland. ~nlenor capsule gland, AsI- an\e11Of 
stomach chill1'lbel . Bu-OOISa. CI-ixlIume!IaI muscle. Dg---<:Jogesbve gland. Emc-posterlOf end of the 
manlle .:;av~y; Es---esophagus. Go--gonad. tn- mtestlne. Ma-mantle edge. Oo---<xocyte; Q:)v- opefllog of 
the CMduct. ()po--<openong ol lhe pallial 0VIdud. OY-ovtduct. Ppo-posIenor palkal oviduct Pst-...-posle<1Of 
sIoII\adI ch-ambel . Sd-spermathecal duel . Sdu-spem1 duct . SIS-SI)1e sac 
gonad (Go) IS a Single non-lobed mass lhal 
compnses 15% of the body length. The pallial 
oviduct IS 17'% of Ihe body lenglh and extends 
slightly over lhe style sac The albumen gland 
(Ppo) IS 01 nonnal size The capsule gland 
has thlee dlSllnct tissue sec1100s: a large pas?
teOOf one (Apel. Fig. 22A). a smaller grey?
colored one (AP02'. and a somewhat larger 
whlte-colored ooe (Apol )? The sac?hke bursa 
lies dorsolateral to the pallial ovidUCt. and 
does not extend postefiOf to It. The bursa IS 
58% 01 the pallial oviduct length. and ItS an-
tellor thlld l.es antell()l" to Ihe end 01 the 
mantle cavity (FlQs 22A. Fl. A thin sperm 
duct (Sdu) ISSueS Irom the antc rlor end 01 the 
bursa and COIls slightly on its ventral surface 
(Ftg _ 22F) The atbumen gtand "pouch" (Agp) 
appears as a disc appressed to the ventral 
surface of the albumen gland (Fig 22A)_ 
When the pouch tS pulled away Irern the 
pallial OViduct. liS basal connection 10 the 
latter IS readity seen (Ftg 22C). This IS also 
seen In cross?secllOl"l (Fig 220) The oviduct 
(Ov) and spelm doc! (Sdu) jOintly enter the 
CUATAQ CIENEGAS HYDAOBIIDS 63 
TABlE 20 Shell meaSUfCments (mm) o. males and .emales hom two poptAabons 01 Paludlscala caramba 
Snails WIth the domInant m3~lIllum whort number(s) were used N 9 unless stated otherwIse 
Mean ~ standard devoahon ' p' refers 10 Ihe Sog ... bcance level IOf the drHerence belween shell lenglhs 
(1-,est) lor ,ha, popuIallOfl 
"""", Length -. 
Locality 63 
" (rt ~ 10) 10 226~00El 109~00El 
" 
244 --- 009 "3 ~ 0'0 , 
" '" 
- 0 '3 111~009 
Locality 27 , 
" 
2.50 ~ 010 118-0.07 , 
" 
254-006 1 18- 006 
TABlE 21 DImensIons (mm) or countS 01 non?
ne ... at organs and SlIUClures 01 Pa/udlscalacatam?
ba_ N - 5 ooless Stated o'herwlSe Mean!: Sian. 
dard dev1iIlron l length, W WIdth 
Females "'., 
Body , 3 't t- 021301 
'" G,N 1IIamen1 nt.W'fII)ef 
'" 
? 0 89 
Osphrado,Jl'Tl (N 
'" 
O t 5~ 002 
"""'" 
, 048 ~ 007 047 ~ 006 
W 029 .1 004 027 - 003 
Prostate , 044---004 
W 019~003 
p~, , 066-004 
W 019 - 002 
Pallral ovrcbcI , 055~006 
(N 
" 
W 015?0.02 
Borsa copulal"" , 032?003 
(N 8( W 014 : 0.02 
Length 0' Length 01 Width 01 
body whorl apert ... e aperture p 
'04+005 07' !: 004 053 ~ 004 
t09~007 07' ~ 003 0.53 " 003 
107 "' 005 07' ~ 004 053~002 
108-007 074 - 006 057 - 003 
109'006 074 - 004 054 !: 004 
TABLE 22 Radulao- Slahsta from 5 Indl\llduals 01 
Paludlscala car-amba X mean. S - slandard 
OOvlalN)n. Measurements 11"1 mm 
Radular leatures X S 
Lenglh 
"'3 0016 Width '050 ,00< 
Number 01 .ows n, 
" Number 01 rows 11"1 
.ormatrve stage 
" 
, , 
TABlE 23 Theva.IOIJS cusp arrangements 0I1he tour tooth types 01 pafudtscaJa caramba. counted hom lrve 
.adlAae USIflQ SEM. WIth the percentage 01 .adulae showIng thai arrangement at least once 
'"-
(M" 
"""''' 
Lateral ~."" margrnal 
.. .. .. .. 
W 80 ~'-<I 80 " 
W " ,>-1-<1 20 " 20 " 20 
W 80 4- 1-4 20 20 20 " 20 
W 20 " 
., 
" " 
W 20 " 
,. 23 eo 
23 
" " 
... 
" 
20 25 20 
64 HERSHLER 
FIG 23 SEM pho4os 01 CocIIiIopIna IIWlen and CochIICJPlfl8 nogranden:srs. Shells A- H B.e CocMopna 
m.IIen Irom locality 38. snetlll$ Cct;:hI.cpna flO9randenS/s 'rom Locakfy 101 Shell A IS 3 26 mm WIde. the 
oIt1ers are ponted 10 the same enlargernetlt 
albumen gland al the base of lhe pouch, this 
area IS somewhat differentiated and appears 
to be a sphincter (Fig 22E). There IS no 
semmal receptacle of normal shape Of pos. ?
tlon . The pouch, while non-glandular, IS 
obvIouSly of pallial OVIduct origin. yel was 
seen 10 hold sperm and probably serves as a 
secondary seminal receptacle, as may the 
OViduct swellings. The spermalhecal duct 
(Sd) may be lightly appressed 10 lhe col? 
umellar slOe of the pallIal oviduct (Ftg. 22A) Of 
may be sI.ghlly separated from It (Fig. 22F). 
The male gonad IS a single non-lobed 
mass The proslate IS relatively large and 
elltends cooSlderably anlenOf to the end of 
the manl le cavity. The anterIOr vas deferens 
ellists 'rom the anlenor lip 01 the prostate 
The perilS IS bluntly shaped and has fletlhe! 
Cilia nor a lerm.nal papilla. The pel1lal lobe 
(Pia) IS Iocaled al 67% of the peniS leng1h (on 
the outer curvature) lrom the base. and has a 
spherICal shape with a diameter 01 0 15 mm 
(FIQ. 21e) The lobe overlies Its atlactvnenl 
area to the peniS, which IS short and located 
on the outer clJVature (AIt , Ftg. 21 C). The 
apocnne gland (Ag') ellteods lor sltghlly more 
than one-half of ' he diameter 01 the peflIill 
lobe. The SfruClure 01 the gland IS precisely 
that o f Coahuthl( FokIs are seen on the CIUle!" 
curvature of the peniS trom the base to the 
penial lobe The II""IIlef curvature has folds lor 
Vlr1ually liS enllre length The vas deferens 
(Vd) does no. COl' In the peniS. Infrequent GI2 
glands are seen 11"1 the peniS 
CUATRQ CIENEGAS HVDROBIIOS 65 
FIG 24 SEM pt1oIo6 01 shell and rildullo 01 Cochk:IpwlB ",,/let, A Shell ..,e~. 5howw'Ig wmklcd. pItI(!d 
fI1ICfOK\.llpCure B POf1ICI'l 0I1he body >Mol ~ &pfal lines and ooIabf .. \IfO'!dl1oncl C Close-up 01 B 
o Cenlfal tooth ollhe raduIa E 0uICl" margwlll ted1 f Part 01 raQ.olar rUIon 
Cochhopma Momson. 1946 
Type-species CochIK)()Ins 'lOfJ,sndensis 
(Pllsbry & ferrlss. 19(6) 
DIStfibullon: RIO Grande drainage. Irom 
Tekas south to Panama. 
Species Included ' 20 speclElS listed by 
Taylor (1966) 
Cocho\Jopna has no dlShnclNe ul"IIqUe fea?
tures. bullS real9fl1zable by a combinatIOn oC 
character states (see below) 
The shell (Ftg 23: Mornson. 1946. pi 2. 
"gs 7-9. II- t3) IS small (wldlh. 5 mm) and 
plamspirallo low-trochoid In lorm, the sculp?
lure conSlsls 01 spiral lines or cords. Irequenl' 
Iy beaflr19 per lOslraca l bnstles: the apICal 
whorl has pilled mICrosculpture (FIQ 24A). 
the tentacles have Spurw'nkls-Ilke hyper?
trophied akafy tulls (FlQs. 25A. 8). lemales 
are OVOVIVIparous. the palhal OVIduct has a 
slight postCflOf bend. the albumen gland IS 
reOJced If'! SIZe (Ppo. FIQ 26A); lhe semnal 
receptacle opens Into the oviduct tF'9S 268. 
C). the OVIduct and anleflOf end 01 the bursa 
are COfY'Iec!ed by a shor1 sperm duct (Sdu. 
F'9S. 268. C): the non-muscular spermalhe-?
cal duel opens JUsl beyond the posterIOr end 
0 1 the mantle caVIty (F'9S 26A. C); !he anten ?
or end 01 Ihe blood pouch IS musculaflzed 
and COiled toward the columellar Side (FIQ 
2tiE) ; lhe peniS IS non-Iobed. With an elongate 
penial filament , and lacks specialized glands 
(fIQ 250: Morrison, t946 . pi 3. hgs. 9--t5) 
CochllOpffls and Me~Jlhauma share numer ?
ous features (see Tables 53-55. FlQs 49.50) 
retallng to shen shape. sculpture. tentacle 
Cillahon, reproducbve mode. COl~ng 01 the pal?
lial OViduct red\Jct1Ofl 01 the albumen gland 
size. connection between the semmal 
receptacle and oviduct musculanzal lOn and 
COiling 01 the end 01 the brood pooCh, and the 
form of the pel'llS (and lack of spetl8hzed 
glands). DIstinctIVE! features of the female re?
productive system shared by these ta~a tn?
clude the sllQht postenor bend 01 the palkal 
oviduct. the openrng oIlhe seminal receptacle 
1010 the OVlduel. and the weU?developed 
muSQ.llanzatlOfl and COII.ng 01 Ihe anl6f1Ol" 
end of the brood pouc:tl 
The two taxa dtllCt" If'! the Iotlowlng leatures 
66 
, 
. ' 
.. 
. ;; . 
... 
. '. ~.: . 
". , 
0.5 mm 
0.25 mm I 
HERSHlER 
B 
c; 
0.1 mm 
vo 
o 
FIG 25 Head. operculum and penos 0/ Cochhopna rrnllen A Dorsal aspect of 1he head Note the 
~hke hypertroptued c,lIary lutts IC.~ on the lenlacles B Close~p at c,hatlOl1 pattern on lett 
tentacle C ClpeR;ulum 0 Pens Wllh penoallolds {PI) . but no lobes Ct--<:.ary IIJlts on lenlacle. Ey-eye. 
Sn---snovt. Tn-Ienlacle; Vd-vas delerens 
, .. 
.. 
on_ 
CUATRO CIENEGAS HYDRQBIIDS 
'" 
"----Dl 
D ?? ,\\ 
o 
B 
'" ? 
-
67 
'\--. 
FIG 26 Female reproduct,ve anatomy 01 ~ III mt/Ier, A Venlral lisped 01 unoooIed snelt w,lhQut 
head and kodney bssue Note,he posIenor bend 01 the patllat ovoduc! B PosIenOr .egoon ot !he pellat 
OVIduct Ofrented 8S 111 A, but WIth 8 ponoon at !he albumen gtand (Ppo) and the bufsa cutaway'O reveelthD 
OVIduct cools (Coo). semona' receptacle ISr), &peI'm duct ISdu). and openong 01 the OVtdUCIlllto the a'bumen 
gland (00Y) C Onented as In B. but wdh the bursa ISu) In place 0 The semonal receplacte IS<) WIth 
pgment patches E Portoon ot the erllerlOl' end at !he mantle C3V~y ~ the muscvla. cool (Mus) of the 
anlenor end 01 the brOOd poudllBp) AsI-anlenor slomach chamber. 8p---Orood poudl. Bu-------Oursa. 
Cee CleOWll 01 stomach. Cot---<:ot 01 CMlIuCI. ~rdlat duCf Dsr--<lucl 01 the serTWIiII 
.ecept.ade Errb--eoUyonoc sheIj Emc ... -vm' 101 end (II the mantle ca.-.y Es-esopI\agus, ~
~eshne Ma--rnantle edge M~ secloon 01 !he brood pouch.~' opel. '9 01 the CMlIuCI 
Ppo-aIburnengtand,Pst--p:>lleoOfslOmadocharrtler ScI tpetr, ... lhecIIduct Sdu-sperm 
duct . Sr WI."" .eceptacle. SIs--styIe NIt 
68 HERSHLEA 
oond.\101'1 0 1 the manlle edge (Cochhoptna, 
smoolh: MeJClfhauma. paPIllate!. apc;al mICro?
sculplure (Cochl/Opma. Pitted: Mexlthauma. 
absent); relative size of the female gonad 
(each/lopma. large: MeJClrhauma. small), 
length or the spefmalhecal duel (CocIl//Opma. 
shaft , Mexi/hauma. long); insertIOn of the 
sperm duct from the OViduct (CochI,opma. to 
bursa. Mex/Illaurna, to duct 01 bu"sa): and 
male gonad morphology (Cochhopma, slITlple 
lobes. Mexlthauma, bush-like) 
CochllOpma nullen Taylor. 1966 
HoIolype: UMMZ 220 182 
Type-locality: Locality 53. 
Distribution ' endemIC to the Coalre Clene?
gas Basin. In the eastern lobe of the baSin, II 
has not been found south 01 Locality 97 (Fig. 
3) 
Habitat: CochilOpln8 m/llen IS most com?
mon In the oul!lows 01 cool ( , 28 C) spnngs, 
and IS usually sympatnc WIth NymphopIlIlus 
mmac/ey, on aQualiC vege1311Or1. partICUlarly 
Chara and U'"cu/aria. CocMopma millen was 
rarely found In the large SPring pools, and was 
never found In mop or sieve collections Irom 
the small springs. 
Descriphon 
The geneflC placement of Cochhoplna m/?
len IS tentative as the detailed anatomy of !he 
type-speoes. Cochlloplna nograndensJs. IS 
not known. CochitOpma millen does resemble 
the type-species In shell form and edernal 
anatomy 
The shell (Ftgs 23A- H) IS Ih,n, relatIVely 
small !length, t 16- 1 48 mm). and broadly 
oonical to ~1"IISp!ral. wllh IItlie whof1 overlap. 
the narrow spiral cords are numerous, prOmt?
nent. and fringed WIth IlQht-colOfed penoslra?
cum; the aperture IS nearly circular and 
adnate to or Iree from the penultnTlate whorl 
Shell 
The shell has rounded whor ls and deepty 
Impressed sutures. The aperture IS slightly 
angled adap!C8l1y and Inclmed 30-45 to the 
COIling axiS. For the population Irom Locality 
38, COIling abnormalities were Irequent and 
remarl<a.ble; val)1ng from a sllght1oosenlfl9 01 
the whorls (Fig. 23E). to a change In COI~ng 
direction near the end 01 the body whof1 (Ftg. 
23H), to near-open COIling (Fig. 23C). Other 
poputallOl"lS Show less coiling varia lion than 
lhat Irom Locality 38. There are generally 
10-20 sp"al cords, and numerous spiral lines 
on the last two whorls. Occasional specimens 
are almost smooth? shelled (Fig. 23F). The 
apical whorl microsculpture IS somewhat 
coarser than that sem In other hydroblld 
snails (Fig. 24A) Splfal sculplure begins after 
the first whorl. Close-ups of the spiral sculp?
ture are shown In Figs. 24B. C. There are 
strong axial growth hnes that become es?
peCIally prominent near the aperlure (Ftg. 
24C) 
Shell measurements from the poputahOl1 
Irom Locality 38 (exckJdlng aboofmally COIled 
specimens) are gIVen in Table 24. Females 
have a greater 5hell wtdlh (p < .005) and are 
also relallvety taller (H ast lor difference be-
TABlE 24 Shell measurements (mm) 01 males and lemales Irom one popuIallOrl 01 CochllOplna TfIIIIen and 
two popuIalJOllS 01 C. (fograndcns4s. Snails Wllh lhe d(101l1li1nl max,rrum whorl number we.e used N 9 
unless othe<wIse ondicated Mean :<- standard dev'illlOrl -p- relers 10 the s.gnohcance level for the difference 
betweeII shell WIdths 01 males and females (Hestlloi lnat poputahon 
Length 01 Length 01 Wldfh 01 Shell length 
...... , Length w'"' body w\)Orl -~ aperture ....... " C mtI/er! (Locahly 38) 
.' 30 116 - 006 229 - 0 15 111 - 010 096 - 006 089 ' 007 050 -0 03 , JS 1 78 - 010 308 !: 018 1 57 ~ 0 1 1 119 :!. 010 11 0 ~ 006 058 ~O OS 
P < 005 
C novandensls (Localdy 101) 
d 4.' 2.23 -- 0.10 <!.74 .::: 0 18 1.64 !" 009 148 .::: 009 1.Z2 ;t- 007 062 :<- 006 
9 45 278 " 015 3 12 - 028 2 18' 0.15 159 " 014 136' 010 089'" 006 
C nogran:k.'flSlS ( Loca~1y 102) 
, JS 1.54 - 004 2 14 ~0 11 134 1 011 1 09 " 009 093 ~ 008 072 " OOS , 
" 
221 - 017 279 -0 15 186 - 012 143 - 008 1 .24 ~ 008 079 - OOS 
4 O. " 4 5 2 5<\ '0 15 306~0 1 2 203' 006 15<\ -0 06 1 33 ' 007 083 -003 
CUATRO CtENEGAS HYORQBIIOS 69 
TABLE 25 Dornensoor'$ Imm) Of oounts ~ r()n. 
neural organs and structures 01 CcchIoopna mtIIefr 
N 5 unleSS staled Qlt\e(WrS(! Mean ? S\anr:lard 
devtatoon L length. W wodth 
Females 
""" 
_,N 6) ( 6,47 + 039 515 ' 031 
Grll hlameot number 2" ? 228 
Osphradrum (N 8)( 035+005 
Gonad (N-61 ( I 69 ~ 0.09 328~015 
w 055?005 057 ~ 003 
PrOSlate ( 056 + 006 
W 028 + 003 
p~, ( 124'005 
W 036 ' 004 
Pallial 0YKIuc1 ( 265 ," 028 
W 072+006 
Bursa IXlplIialfl)[ ( 027 ~ 004 
W 0 10 "001 
Semonal receptaCle L 010 + 001 
(body) (N 6) W 006~001 
Sertwlal receptacle L 0.04 .~ 0 Ot 
(duel) (N 9( W 004+001 
TABLE 26 RaOuLar stalIS,"CS Irom 12 rndMduals 01 
Coch/ft:Jpna mtIIen X or mean. S standard devt,a. 
tron Measurements In rrrn 
Radular leature X S 
Length 0563 0028 
WK:t1h 0"" 0006 
Numbe< 01 rows 
'" 
", 
Numbe< 01 rows on 
Iormalrve Slagel 236 
'" Wrdth 01 central 
IOOIh (N . 21) 00" 00014 
tween means of shell length width, p < 0.005) 
than males. This seKual dimorphism is seen 
by canpan ng Figs. 23A and B (adun female 
and male, respecbvely) . 
Nclf1reprocluctlve Features 
Detads and data concerning anatomy are 
from the populallon from l ocality 38 Mea?
surements 01 Ofgans and structures are given 
In Table 25. The snout IS squat and the tenta ?
cles are elongate In comparison (Fig. 25A) 
The left tentacle has 10-12 hypertrophied 
allary tufts protrUCIing from the outer edge 
and numerous CIliary Ifacts (0. Figs. 25A. BJ 
CUrving Inward loward the center of the lenla? 
cle from both SideS. These tracts are present 
tor 67% of the tentacle length from the base. 
The tentacle also has a central oll3ry tract 
along liS length. The light tentacle alone has 
the central CIliary tract The snout and tenta?
cles are dusted WIth melanin to varying de?
grees. A dark melaflln patch CIt the bclse 01 
each lenlacle. across from the eyespot. IS 
seen In most IndiVIduals OccaSIOnal speo?
mens had a dark melamn palch at the tenta?
cle tiPS. There IS a cluster 01 dull white gran?
ules around the eyes and smaller granules 
are found In the neck. snout. and tentacles. 
The SideS of Ihe head-loot are Sometimes 
darkly ptgmenled. and In those specimens a 
non-pigmented stnp was seerr e)('endlng from 
the neck to lhe foot Body ptgmentatlQrt lor the 
lemale ConSiStS 01 small melanin patches on 
the dorsal and venlral body surlaces that 
Interdigitate WIth dusters of white granules, 
proclUClng a mottled appearance. The male IS 
similarty PlQmented. bu1 has solid dark mela? 
nln on the ventral sur1ace 01 the gonad, The 
caecal chamber IS prominent 
The operculum (Fig. 25C) has 5.5 whorls 
and the nucleus IS poslhoned at 42% of the 
long a)(IS of the operculum. PIgmenlatlOrt on 
the opercuhgerous lobe consiStS 01 two 10 
three large melanIn patches. 
Radula 
The radula IS soown In Figs. 24D-F. The 
central tooth has ooe 10 three pails of basal 
cusps Ihal OIlQlnale Irom Ihe lateral angles 
The central cusp of the central tooth IS 
dagger-like. The marginal Teeth have many 
cusps. Radular StatiStICS and The various cusp 
a rrangements lor tne Jour toolh types are 
given In Tables 26 and 27. 
Female ReproductIVe Anatomy 
The olgantzahon 01 the female reproductrve 
system IS shown In FIQ 26 The gonad (Go) 
has Ihree lobate brandles, and occupies 26% 
o f the body length The pallial oVIduct occu' 
pies 44% of the body tength and overlies most 
01 the style sac. The anterIOr portion of the 
pallial OViduct IS modified Into a thln?walled. 
non-glandular brood pouch (Bpi fOf the stor?
age of embryos. The palhal oviduct oolls pos?
tenorty. the distance from the postenormosl 
pomt of the pallial OVIducl and the end of lhe 
COIl being 0 67 mm. The small albumen gland 
(Ppo, Fig 26A) constitutes Ihls coiled porlron. 
The oviduct (0...) disappears beneath lhe 
anteflor pot1lOrt ot the albumen gland (Fig 
26A). There is a short gonopencardlal duct 
70 HERSHLER 
TABLE 27 The ~anous cusp aIfangemoofS tor me lour tooth types., 12 radulae 01 CochIIDP'fl8InllIen. with 
the percenlage of fadulae showmg thaI arrangemool 31 leaSI once 
COl1ll31 l alGl'al 
" 
= .. 
W 8 ~.-3 
W 8 ~.-< 
W 8 ... ,-< 
W " 5-1- 5 
W " .... -3 
W " :>-. -3 
W " 
W 8 
W " 
W 67 
W 25 
(Ope). The bursa (Bu) IS small. dofsallo . and 
almost enl.rely hKlden by the albumen gland 
(FIQ 26A). The elongate seminal receptacle 
(Sr) IS dorsal to and moslly hidden by the 
bursa. There IS usually a light melamn dusting 
on the seminal receptacle (Fig. 260 ). 
The oviduct loops several limes dorso?
laterally to the bursa before receIVing the 
short duct 01 the seminal receptacle (DsI, 
FlQs. 268 . C). The mmUSaJle sperm duel 
(Sdu) enters the OViduct Just where the laner 
turns 10 open Into the end of !he albumen 
gland (FIQ 268). The spermalhecal Duct (Sd) 
e)(leocIs 0 14 mm beyond the pas.enor end 01 
the mantle cavity. 
The well developed muscular loop (Mus) of 
the anlenor- brood pouch IS shown In Fig. 26E. 
For 15 adult females, there was an average of 
I I 6 :!: 2 97 shelled embryos In the brood 
pouch. as well as another etght to ten very 
sma" I'1CIfl-shelied embryos. For 108 shelled 
embryos. the range ol shell wldltl was QUite 
narrow. 0317-0.475 mm. and the mean was 
0.400 ? 0.178 mm Embryoruc shells have 
~ to 1 3 whorts. 
" 83 
83 
8 
8 
8 
" 
'"- ""'" "",- ~."" 
=<" 
" 
00'", .. 
" 
8 
" 
.. 
" " 
2Q .. 
" 
5<J 
" " 
2Q 58 22 .. 
" " 
23 80 
22 J3 
" 
.. 
23 58 
" 
.. 
" 
8 26 
'" 
2S 2S 
" '" 
26 8 28 
'" 
" 
8 
" 
8 
Male Reproductive Anatomy 
The male gonad ConSIsts of 10-12 lobed 
branches and fills lhe entire length 01 Ihe 
diges\lve gland. covering Ihe posterIOr stom?
ach chamber The gcJf1ad IS 64% 01 Ihe body 
length. The prostate 15 relatively small , 11 % of 
the body length. but does overlap Ihe mantle 
cavity. The antef1O( vas deferens e~lts from 
the antenor tiP 01 the prostate. 
The pentS (Fig 250) has numerous lolds 
(PI) on the Inner curvature for one hall ol the 
peOis length. While one of the talds was 
sometimes nohceably Wider than the others 
(as In Fig 260). It did not prOlect outwarel as a 
penial lobe In any specimen The outer curva?
ture IS Without folds. Scattered throughoul the 
penis are GIl and Gl2 gland types_ The lias 
deferens (Vel) COIls and thICkens Irom the 
base ollhe pems until It IS ellen With the end 
of the penl3l folds . atter whICh II narrows and 
slops COIling The peniS. e~clu sl\le of the long 
penial !llamen!. has a dark brown color that IS 
not an e~ternal melanin coaling. but colored 
!Issue 
CUATRO CIENEGAS HYQROBIIDS 71 
Cochllopma rlO(}rancJensss 
(Pllsbry & Fernss, 1906) 
HoIotype: ANSP 91324 
Type-locality' debriS 01 the RIO San Felipe 
neal 'he RIO Grande, Val Verde County, 
Texas 
Olstnbul!on: RIO Grande drainage of Texas 
and IlOf1heastern MexICO. While thIS specieS 
had been previously known from the RIO 
Salado de Nadadores, and an adjacent 
spnng, both JUSt eas, 01 the Cuatro Clenegas 
BaSIn (Taylor, 1966), the author also col?
lected It at locality 101 in lhe southeastern 
lobe 01 the baSin. 
Habitat: ThiS species has beeI1 Iound In 
spIlngs and SPring outlets of varIOus SIZes 
(Fulhngton, 1976: Taylor, 1966). Locailly 101 
IS a large spnng pool (the Santa Tecla la?
guna) and Cochllopma flO(}randenSlS was 
abundant on unidentified vegetation along its 
shallow edges. 
Descnptlon 
ThiS specieS has been amply descnbed by 
Fulhngton (19TS) and Taylor (1966). Its shell 
IS distinguished Irom that of Cocfliloptna mil?
len by Its thlCller , larger, and relatively laller 
appearance (see Table 24 note the ratios 01 
shell length width) Its whorls overlap greatly 
and It has a more conICal shape than does the 
Shell 01 Cochhopma fTllllen The aperture IS 
an91ed adap!C8Uy and the Inner hp IS partty 
fused to the peouitllnate whorl. The spiral 
cords are tew In nurrtJer and lack promi?
nence, but the perlostracal bands are darker 
and wider (espeoafty In the umbilical area) 
than those 01 CccI1l1optna mtller'. 
OISCUSSlOll 
The soulheastern lobe 01 the basin has 
several nonendemc taxa 01 unchsputed RIO 
Grande (= RIO Bravo) onglO, Including the 
clChhd IIsh, CICh/asoma cyanogul/atum (see 
Mlnckley, 1977). The distinctive RIO Grande 
aspect of the fauna lrom thiS portion of the 
baSin contrasts WIlh the more endemic aspect 
of the fauna from the remainder of the baSin 
Hubbs & Miller (1965) suggested that !he 
southeastern lobe had a recent sultlClal con?
nection to the RIO Salado de Nadadores (FIQ 
2, Number 7, a RIO Grande tnbutary), thus 
explalOlng thiS pattern. The discovery 01 
Cochllopma "ograndensls 10 the southeast?
ern lobe of the baSin supports thiS hypotheSIS. 
The rela\looship between endemiC Coch? 
JlOpma miller; and non-endemlC Cochllopma 
flograndenSIS IS unknown as the Internal 
FtG 27 Shells of MolflthBuma quadnpaIutJIum from locality 1 The shell on the leh IS 7 38 mm long, lhe 
0Iher IS pnnt~ 81 lhe same entargemen1 
72 HEASHLER 
FIG 28 SE t.A phoIosolsheilandraduiaolMe.outhatnl.l~ A ApcaIwtorlsolshetl NoIelackol 
rJIICIOSCUptufe B PorbonolpenulltmalewhotlshowlngstrongsporalCOfdsandcolatlraimocrosculplu.e C Pat1 
01 ram..la. nObon 0 isolated cenllal \Ixlth e Outer marQlnal teeth 
anatomy 01 the lalter IS not known The dis?
!JI)Cllvely fragile and loosely-COI led shell 01 
Cochllopna ITlII/efl may be aSSOCIated with liS 
rcSlncl100 to falfly clChhd-free waters II e., low 
predatIOn prcSSlIl'e) 
Mexlfhauma Taylor. 1966 
Type-speoes: MeXltIlaurna quadnpaluchum 
Taylor, 1966. 
o.SlrIbutlOfl endemtc to the Cualro C~? 
gas BaSlfl. 
Speoes Included" monoIYPIC 
Descnpll()fl 
o.Shncllvc features 01 MeXlttla...na Include 
the paPIllate mantle edge of both $eKes (Pma. 
FIgS. 3M. 3 1A) and the open channel IOc) 
comectmg the qJenlngs of !he spermathecal 
ruct am pal~al OVIduct (F.gs 3OC. EI. 
The sheI (f ig 27) IS large (length. 70 fOOl) . 
globose. Without urrobcus, and w,lh pl'0fTlI?
neol splfaJ cords Il1ngcd WIth pefloSlracvm. 
!he tnnef lip ol the she. IS thickened. the 
tentacles shOw Spurwmlua-like Cillation (flQS. 
29A, BI: females are OVOVIIJ lpalOus: the 
female gonad IS very reduced in sIze (Go. Fig 
3OA), a large pallial oviduct overlies the stom?
ach and has a slight posterlOt' ben:! (Fig. 
3OA); the sefl"ll"lal receptacle (Sr) IS posI?
honed latera! to the butsa and opens 11'110 the 
oviduct: (F.g 3(0). the ovtduct connects With 
the dUCI 01 the bursa Via a short spel'm duct 
(Sdu. F.g 3(8); the anterlOf end of the brood 
pouch IS musculaflZed and COiled (Figs. JOe. 
E); the male gonad is bush-like (Go. f.g 
31A); the perMS IS non-lobed and lacks spe?
cialized glands (f.g 3 tB). 
MeJII/hauma IS most Similar to CochllOpma 
(see above. Tables 53-55. FigS. 49. SO). 
Mexlrhauma quadrJpiJludlum Taylor. 1966 
HoIotype: UMMl 220214 
Type-Iocaltty l ocality 97 
Habitat MeJCJIhauma quadnpaludium has 
been Iound orYy 10 the larger sprmgs and !heir 
outllows. h has been collected from all typeS 
01 aquatIC vegetatIOn. sand (composed 01 
CUATRO CIENEGAS HYORQBIIOS 73 
. . 1.0 mm 
I I 
0.2 mm 
I 1.0 mm I c 
FIG 29 Head;;lOd operclJlum 01 MeXllhauma quadnpa/udlum A. DofsaI asped 01 Ilead. Note the 
~hI<.e hypenropt1,ed c,hary lulls (CI) ard lhe cent.al pogmenl 51.eak (PIg) on lhe lentacles 6 
Close-up 01 CIIoaIIOfl p;lllern on lell tentacle C Operculum The pogmool paUem on the opercWgeroos lobe 
IS also shoYin C.-ohary tufts OflIen1acles. Ey-eye i".g---pgment. Sn-snout Tn-tentacle 
74 HERSHLER 
-
"" 
? 00 .... 
? 
" 
.~ 
/ ? 
-0 
~ . .... ~ 
?? 
----.-h1 
'//" -0 0 ? - , ." - B 
FIG JO Female repwducl,ve analOmy 01' Mexlrt!avma quadnpaludn.Jm A. Venlfal aspect oIvncooled snail 
WllhouIlhe head and kidney tissue NoIe the VflfY small gonad (Go) and large palkaloVlduc! CBp ~ Ppo) Wllh 
a poslenor bend 6 Onented as In A. but WIIh most oIlhe a lbumen gland (Ppo) Wi away to e xpose the bufsa 
copulalllK complex C Arnenor porllOfl oI lhe marule caVI'Y showIng the musculat bend (MuS ) o f the anlenof 
end oIlhe brood pouch. 0 Onenled (and scale) as ,n C . but Wllh a pof'IlOfl ot the epithelIum of the iIIllenor 
end oIlhe brood pouch cui away to eqJOSe the If1Il6f muswla. layer (ImI) E ()oenled as ,n A. shoWII'91he 
ope<WlgS or the spe<malllOCal duel (Osd) and paH/at oVlduc1 (Cpo) connected by an open channel (Ocl 
AsI- arltenor stomach chambe<. 6p---brood pouch. &.-bursa. Cl-<oIurneIIar muscle. Obo-<luct 01 !he 
busa. Ope--gonopencardoal duel. Dsf-dua Dlthe 5emlflalreceplade. E'_lIerenl vessel: Emc-----1J05Ieno< 
end 01 the mantle caVIty , Es------e;ophagu, GI~1I1 hlamen!. Go---<}:load. Iml- mnef muscular iayeo-. 
In--onieslll"e. Mus-muscular secloon oIlhe brood pouch. ()c......()perl channel. O;lY-()perung of the OYIducI , 
Opo-openmg 01 the palhal OVIduct Osd--openmg 01 the speo-malnocal duct, OII-ovoduct, Pe?
pencardo\.nl , Pma- papllale mantle ed!)e. Ppo--albumen gland PsI-poslenor slom.ach chamber , Sd?
spermatheCal duct . Sdu-sperm duel . 5f- semll1al receptacle 
traverllne pieces and shell fragments), 
travertine blocks. and the gently stoplng 
banks 01 spring pools While M. quad? 
rlpaWum and Nymphophllus mrnck/e)'l over? 
lap broadly In then microhabitat usage. WIthin 
any gIVen spring they are largely allopatnc on 
a mICrohabitat scale. tn springs With mlCroha? 
bltat diverSity. N mmckleyr IS most common 
on Nymphaea and Chara. while M quad. 
rrpaludrum IS most common In sand or on 
travertine t>tocks_ However. when one of the 
Species IS of reduced abundance or absent, 
usually In a spnng With low microhabitat d" 
verslty. the other species may "switch" to 
other mlCrohabrtats. including that usually 
occupred by !he specieS that IS rare or absent 
CUATRO CIENEGAS HYOROBIIOS 75 
o mm 
vo 
I I 
B 
FIG 31 Male reproductIve anatomy 01 Mex,fhatJma quadnpalud4Jm A Ventral aspect 01 an Unc<JjJe(j snail 
w~hout head and kidney tissue Note the bust>-lIke gonad (Go). B Dorsal aspecI 01 the 11()(1-1obed peniS 
AsI-antllOOf stomach chamber, CI-<:okJmeII3f muscle: Emc---iXlS1eoot end !lithe mantle caVity. Es?
esophagus. Go--glnad. Irl--Intesllfle Pt-penoal lold. Pma- paplilate manlle edge. Pr-prostate. PsI?
IlOSteoor slomach chamber: Sts-styte sac. Sv---semlnal vesocle , Vd-Yas deferens Vd,-vas deferens 
/rom semnat vesode to proslale, Vd,.-vas deferens from proslate 10 peo1's. V&-vas elferens 
76 HERSHlER 
TABlE 28 Shell measurements !mml 01 males and temales 01 Mex"i'lauma quadtlpa/ud,(,m trom locality 1 
The shells me3S0red are lrom the largest 10"10 o/lt1e popuIahOfl ( 48 wnons) N 9 Mean ~ standard 
c\e'voallOfl .p. relers 10 the Slgr'llhcance level lor the d,!1e<eoce between shelllenglhS 01 males andlemales 
(HesI ) 
! 128 ~ 016 
'i 734"041 
Width 
606 -0 19 
630 "027 
Length 01 
body whorl 
646 ' 050 
678+031 
Length 01 
.-." 
489 ' 018 
494 '018 
Width 01 
aperture 
3_66 ~ 0 .31 
384 ~ 0 .29 
p 
> 10 
TABLE 29 Frequency d.Slnbutoon tor numbef 01 spral cords al lhe apef1ufe 01 Mex,lhauma quadnpaWum 
shells F,l1een shells (sexes rTued) per .....noo1 Stage were used The mean and standard deWil10fl for the 
shell IeogIh of the shells used tor each .....newt 5lage are given 
--
Sheilleogih 7 , 9 
" 
" 
3_30 .. 0.32 3 , ? 
<5 511 "0 54 
SO , 7 44 +034 
Shell 
Shell measurements for the populahoo 
from locality 1 are given In Table 26 The 
ellilC! number of whorls In large adults cannot 
be determmed as the apex IS usually some?
what eroded In such specimens. There IS no 
s'!;Intlican! sellual dmlOrphlsm In Size of shell 
(Table 28). The spl.al cords begin al 2_3 
whorts and Increase In number With shell size 
(Table 29) Adults have t5-22 COfds on the 
body whorl that vary In hel9ht (Ftg 288) 
Strong axial microsculpture. also Ilinged With 
penoslracum. IS present (Fig 28B). The aper?
ture IS large. occupying more than one-halt of 
the height of the body whorl . and IS iflCtifled 
only 10-20 to the cOIIII"lg axiS. The aperture IS 
elliptical In shape, and IS somewhat more 
angled above than below wtllie the Inner lip 
IS greaHy thlckef1ed. the outer lip IS thin The 
apical whorl does not have mICrosculpture 
(Ftg. 28A). 
Nonreproducllve Features 
AnalOrTllcal descnpllons and data (Table 
30) are from the poputatlOn from LocaJlty t 
The snout (Ftg. 29A) IS relatively squat. while 
the tentacles are thickened and elongate 
Each tentacle has a Cef1tral dar1<. pigment 
stnp. e_tendlng from lUSt beyond the eye to 
the tentacle lip (Pig. Ftg 29A) 00 The left 
tentacle. there are numerous hypertrophied 
CIliary tufts P"ctechng from the outer edge. as 
Numbef 01 sporal cords 
" " " " " " " " '" 
? 
,
? ? 
, , , 
3 7 , , 
TABLE 30 OimenSlOflS (mml or counTS 01 non?
neu,aI organs and Slrucll;res 01 MeIl,Ih;tiJma quad?
flp81ud1um N 5 LnIes.s stated otherwise Mean :!; 
slandard devoatron L _ length. W ~ WIdth 
Females MoO. 
Sod, L 
'" 
+ 0 48 8 9ru: 032 
Gin lrtameot rrurnber 51' . "" 
Osptuadll)lll eN ~ L 076 ' Ooa 
""""" 
L 088 :!: 007 354 ' 0_26 
W 065 ' 006 I 29!"O.12 
Prostate L 197 :!; 024 
W 0.95 '" 0.07 
"""" 
L 412 ~0_22 
W 15<i :!:O l3 
Pallial OVIducl L 672 :!: 035 
W 191 ~ 0 .34 
Bufsa copulatn. L 026 ->- 0_03 
W 019'001 
Seminal leceptacle L 016 :!: 001 ,_, W 013 ~ 002 
Semrnal receptacle L 012 ;!: 001 
(dvet) W 005 ~ 001 
well as Ciliary " acts CUrving inwards from both 
srcles. The nghl lenlacle tacks the CIliary TUfts 
projecting from the outer side. and the Clhary 
tracts rlXl along the length 01 the tentacle. 
rather than curvrng Inward The under-surface 
01 each tentacle also has Ciliary tracts runmng 
along Its length (not "gured) Small wtIIte 
granules are scaTlered In the neck. snout. and 
tentacles The snout and neck have a light 
CUATAO CIENEGAS HYDROBIIDS n 
dusting 01 melanm. The loot IS large and 
thickened There are distinctive PIgment 
streaks IlIst below the eyes and along the 
sides 01 the 1001 The dorsal body sur1ace has 
yellow and white Pigment granules as well as 
melanm The digestive gland IS dark brown 
and has white granules scattered on Its ven? 
tr aI S041ace A prormnent caecal chamber pro?
tnJdes posterIOr to the stomach. The oper? 
culum (Fig 29C) has 3.5 whorls and the 
nodeos IS POSitioned at <II'\. of !he long aXIS 
oIlhe operculum. The characteristIC pgmcot 
streaks on the opercullgerous lobe are shown 
III Fig 29C. 
""'" .. 
The ladola IS shown In FigS 28C-E The 
central tooth usually has three pallS 01 basal 
cusps arlSlOg from pron-.nent latefai angles. 
The margillal teeth (FIQS 28C. E) have re1a? 
lively lew cusps Aadular stallsllcs and the 
various cusp arrangements lor the 'our IOOIh 
types are given 11'1 Tables 3t and 32 
TABLE 31 RaduIao- SlaI,SIoCS trom none ,nckvIdua/s 
of Me"'lhauma ~t.m X mean. S 
standard devlabOn Measuremef11S are on mm 
Length 
w""" NLmbe< of rews 
Numbef 01 rows In 
IOfJTlstlYil stage 
Wodttl of central 
tOOlh IN 23) 
, 
'" 
" .. .. , 
... 
"" 
5 
'058 
, 006 
'98 
'" 
'0002 
TABLE 32 The vanous cusp arrangemetlls lor the lour tooth types 11'1 \I ,adlJae 01 Me.,lhauma 
QUIJCk~. woth the percentage of rac:l\llae showing Ihal arrangemenl III leas! once 
w 
w 
w 
w 
W 
',!;' 
W 
W 
W 
W 
W 
W 
W 
W 
W 
" 9 
9 
9 
" 
9 
36 
" 
27 
9 
" 
" 
27 
" 
9 
" 
Lat9fal 
""'" " 2-1-3 9 
""-3 55 
4-t -3 
" 
'-'-3 9 
4? 1-4 
" 
..... 
-' 
""'" 
... 
' ..... 
.. 
" 
27 
" 
9 
" " " 
.. 
" " " 
92 
" " " 
92 
" 
, 
" 
., 
" 
9 
" " 
" 
9 
78 HEASHl ER 
Female Reproducti ve Anatomy 
The temale gonad (Go) occop.es only 6% 
of the bocty length and IS a mere terminal 
th lCkefllng 01 the OViduct with a few small 
lobes. The palhal oViduct IS 58% 01 the body 
length. The posterIOr bend of the pallial 0111-
duct extends lor 2.5 mm. of whICh 1.2 mm is 
albumen g land (Ppo. Fig. JOA). The remain?
der 01 the pallial oviduct IS a thill-waIled brood 
pouch (Bp) A gOl1Operlcar(1Ia1 duct (Ope, 
FIQS. JOA, B) IS present The sac?like bursa 
(BtJ) IS only 4% Of the length of the pallml 
oviduct and IS enllrely dorsal \0 the albumen 
gland (FIQ 3OB). The oviduct (Ov) COIls once 
Of twice before receiving the shofl duct from 
the semmal receptacle (Dsr, Fig. JOB; and 
Ihen COIls to enter the ventral surface of the 
end 01 the albumen glarl(t The spermalhecal 
duct (Sd) IS lightly appressed to the col?
umellar side 01 the pallial OVIduct (FIQ. JOA). 
In Fig 300. the musculanzed pot1lOfl ollhe 
antenor brood pouch (Mus) IS slit open and 
the epithelium has been cut away to reveal 
the Inner muscular layer (ImI) For 15 adult 
females, the number 01 shelled embryos In 
the brood sac averaged 19.4 !: 4.5 (range of 
14-26), and there were an additIOnal 22--35 
small. non?shelled embryos packed In the 
poslenor bend of Ihe brood pouch. For 111 
shelled embryos. Ihe mean shell length was 
048 '" 0 .37 mm. The range 01 shell lengths 
was lour-fold, Irom 020 to 0.87 mm The 
embfyonlc shells have up 10 2.5 whorls The 
embryos have red?brown p.gmenl splotches 
and yellow-white granules ()I1 lhe dorsal IXldy 
surface. 
Mate Reproducllve Analomy 
The male gonad (Go. Fig. 31A) has l ive 
branches and occupies 29% of the body 
lenglh. ahnost IIlhng the d.geSllve gland The 
proslate overlaps the mantle cavity and the 
antenOI vas deferens e.,ts Irom the anlenor 
lip 01 the proslate The semmat veSICle COIlS 
(Sv) overlap slightly onto Ihe stomach. The 
peNS (Ftg. 3 t B) has an elongate penial Ilia ?
ment. There are numerous folds on liS Inner 
curvature for slightly more Ihan one hall of 115 
length. Where lhe lolds end. Ihe peIlIS sud?
OenIy 08rrQWS on Ihe outer curvature, giVing 
the peniS a peculiar bulging appearance at 
IhtS POlIll The pentS has numerous GI, and 
GI2 glands . The vas deferens (Vd) only COils 
SI.gh.1y In the penis. The peniS has nei ther 
Cilia nor a terminal eversible papilla 
Durangonella MOrtlson. 1945 
Type-species: Durangonella 5eema", 
(Frauenfeld. 1863). 
Olstllbullon. known Irom Isolated dra inage 
systems In and north-central MeXICO. 
Species Included: live SpeCICS listed by 
Taylor (1966). 
Descnption 
Ourangone/la IS distinguished 1rom other 
Ituondmlne genera by a combmatlon 0 1 
Character states (see below). 
The shell (Figs 32. 33: Morllson. 1945, 
Ilgs. 1-4) IS smooth. slender. tumform, With 
live to eight stowly Increasing. rounded 
whorls: the tefllacles have Hydrob,a-Itke cllta?
tion (Fig. 35A); temales ale ovoviVIparous; 
the female gonad IS a very small. non-lobed 
swelhng at the end 0 1 the OViduct (Go, Frg. 
36A); the palliat OViduct IS large and bends 
posteriorly With several loops In one plane 
(Fig. 36A) ; the albumen gland IS reduced 10 a 
mere glandolar smear on one 0 1 the loops 
(Ppo. Frg. 36A); Ihe seminal receptacle (Sr) 
connects With the oviduct via a shot1 sperm 
duct (Sdu. Ftg 360): the spermalhecal duct IS 
elongate With an opening separate from that 
FIG 32 SEM photos 01 shejls 0 1 Durangonel/d 
coahullac lrom Locahly 6 The shell on the IeI1 IS 
360 mm lOng . the Olller one IS pflnled atlhe same 
enlalgernenl 
CUATRO CIENEGAS HYDROBIIDS 79 
or the pallial oviduct (Figs 36A. F. G). the 
anterior end 0 1 the brood pouch IS weakly 
COIled and musculanzed (Figs 36F. G); lhe 
peniS has a blunt. ciliated liP, a terminal 
evel"Slble paPilla. and one IF'fI 350) or two 
(Morrison. 1945. rig 5) simple lobes that lad<. 
speoallzed glands 
, 
f~ 1 "-I 
J /\ '-l 
A B C 
A ) () .A 
G H J 
~ -< 
r ~ /" "--' ~ 
0 p 0 
DISCuSSion 
Ourangonel/a IS most SImilar to MC1tJPyrgus 
(see Tables 53--55. Figs. 49, SO), and these 
taxa share the Iallowing dlSllncllVe features 
pallial OVIduct WIth pes'enOl" coil In several 
loops; albumen gland reduced to a mere 
I~ fl 
:) f' r ) r ) t {) 
0 E F 
j 
--< 
I 
I 
, /\ 
'\ I 
'---
K L M 
n ) \ 
~ 
Y 
-(I C ,A /' I ',,---
R S T U 
FIG 33 C3mefa lucca draWings 01 sIleils " om SIX populations 01 Dtuangonella coahuII8e The shells are 
'rom the loIIowIng Iocahl>es A-C. locality 6. D-F. Locahty t4 G-J. loca.ty 9 K-M. locah'V 38, N-O, 
locality 13. R- U locality 65 Shell A IS 2 42 mm long, a,.,d the o1her$ ale at the same scate 
80 HERSHlER 
FIG :M SEM phoIos 01 shell and ra(Ua of DutangoneUa ooa~ II ~.....toorts of.he shell NoIe the 
laO; 01 n-.:rosculpl ... e e Part 01 lhe raclljar "boon C. 0 Isolated central IIIeIh 
glandular smear: seminal receptacle coo?
neded to the oviduct vIa a short sperm duct, 
aotenot' end of the brood pouch weakly mus?
culallzoo and COIled: penIS WIth a blunt, CI~? 
aled bp and a terminal eYersibie papilla 
lJtJrangoneld dlllers 'rom Me.WfJUS In 
!he IoIIawIng features: peniS glands ll:li.H"an?
gonefa, absent; MelfqJyTgUS. mammlOfm), 
CIliary lulls on tentacles (Durangonella, 
Hydrobta-hke. Mex'Pyrgus, absent), female 
gonad (Durangonel/a. small and non-lobed . 
MeJCIPyrguS. large and lobed): posterIOr COIls 
of pathal 0VIduc1 (Durangonella. In one plane: 
Mexlf)yrgv5. In several planes): duct 01 sem?
nal receptacle (DurangoneNa, nol COIled, 
Mexlpyr9US. COiled) : sperma lhecal duel 
(DurangonelJa. short, Mex'P)'f9Us. long) 
CUATRO CIENEGAS HYDRQBIIDS 
" 
A 
0.5 mm 
c 
0.25 mm 
P'o 
, , 
, 
, 
~----- , 
0.5 mm 
, 
, 
, , 
, 
, 
, 
, 
, 
, 
, 
, 
B 
~ IG 3S Head. operculum and pems 01 DurangoneHa coohullae A DofsaI aspect 01 head showIng the 
HycrobIa?like COllatIOn 01 the leh tentacle and central CIlIary b3nds (Ct) on boIh tentacles B Opercu,,", C 
TIp at the penrs snowIng Ihe col,ated ooIumna, epothellum 0 Dorsal aspecl at the penrs showing the blunt 1'P 
and smah penat lobe (PIO) Note the reduced C:~IatoOn (compared to C) of thos specImen Ey-eye 
s.-snout Tn-tentacle: Vd-llas delerens 
DurangonelJa coahw lae Taylor, 1966 
HoIotype' UMMZ 220159 
Type-locality Locality 9 
Oistnbubon endemIC to the Cuatro C,ene? 
gas BaSin. 
Habitat Durangonel/a coahwlae IS found In 
the baSin In a wide vaflety of aquatIC enwon? 
ments that Include a playa lake, pcxllS formed 
where lhe water lable IS at ground level, small 
sprlng? fed pitS Without outflows, marshes, and 
spnngs and sl reams of all sizes. Duran?
gonelJa coahwlae was loune! on ITIOpS from 23 
01 38 smalt spnngheads. but. as With MeXIS?
tlObta manantlil/I. It probably does not Inhabit 
subterranean waters as It has eyespots and 
body PIgment, and IS very common d0wn?
stream Durangcnella coahUilae IS most com-
mon In soft orgamc sediments. but was also 
found 10 Ctlara mats and on marl PieceS. 
More SO than the other hydrot lllds of lhe 
baSin, D. coahwlae IS lound In waters whose 
temperatures l1ucluale greatly on a diurnal 
and seasonal baSIS For e~ample. D. C'Oa?
hwlae was collected Irom pools With sea? 
sonally flucluahng IfNels (Localilles 7,8) thai 
had water temperature ranges of 9.5-35 6 C 
dUfing 1980 Sn3J1s disappeared Irom the 
pools only w11en they went temporarily dry 
dUfing an arid perIOd 
DescnptlOl1 
The shell (FIQ 33) IS not readily distinguish?
able Irom those 01 the othel' Duranganalla 
spp. (Momson. 1945. Itgs 1--4) It valles In 
82 HEASHLER 
/ 
" Eme B 
", /' 
, 
, 
C 
025 ...... 
0, 
o. 
" / 
F 
\. 
G 
. ~ 
" 0 .. 
. ___ Sd~ 
} . D 
,,~ 
O.d .. 
.0' 
FIG 36 Female reprOduchve anatomy 01 CNrangonelia (X)<lhullao A Ventral 8SpeCI 01 uncoiled temale 
wlihoul head and kidney [Issue Note the smaM gonad (Go). po5lCfOCif 000I0ng 01 the palhal OV>duct (Bp ? 
Ppol. and very small albumen gland (Ppo) e Ollcnlcd as ,n A. but wllh The pallIal OViduct cui away 10 
eXpOSe the bursa (Bu) The spermalhecal dud (&I) . whICh ,s elongate. hasbeen cut C Onenledas In B. but 
WIth the bursa removed 10 expose the semonaI receplacle (Sr) , .ts duct (Dsr) and 0Ii0duc1 (Ovl 0 Onenled as 
In C. buI WIth the seminal receptale (Sr) .00ated SI"1htly 10 expose !he short sperm duct (Sdu) E 
Frequently-seen kl#1k In the duct ClIChe semonal receptacle F. G VanabOn ... 1he POSItIOn ollila end 01 the 
spemI<Ilt!ecal duct relat've 10 the openng 01 the palhal oviduct (Opo) AsI- anteOOf stomach chamber; 
Bp--brood pOUCh, 8u--bursa, ~um 01 stomach. Cl----<;oIumeIar muscle. Cot-cool 01 !Mdud 
Obti---iiuct oIlhe bursa , Ope go<opeuca.d.al duel. Dst---duc1 01 the semonal receptacle, Erm;--postenoo 
end (lithe mantle cavIty. Es-esophagus Go-gonad, In-onteslone. Ma-mantle edge. Mus-muscular 
secIIOn althe brood pouch. ()oo.o opel"' og 01 the ovoduct. Opo--openong althe palltal OYoduc1, Osd--<lpenong 
01 the spermalhecal duct. Osdu-opening 01 the sperm (lu.ct . Ov---<Mducl. Ppo-albumen gland, PSl?
poslenQl' slomac:h chamber Sd-speJmalheeal duct. SdU-speflll duct. St--semonal receptacle. SIs-style 
~ 
CUATRO CIENEGAS HYDROBIIDS 83 
size. number and roundness 01 whorls. and 
depth 01 sutures 10 such an e~leot thai In?
diVIduals can be found that correspond to the 
types of all of the nominal specieS 
frequenlly pulls away from the penultimate 
whorl The umbilICuS valles from a slight chmk 
to an open slit Growth hnes are prorTllnent 
(Fig 34A) PopulatIOnS vary not only In size of 
shell and number Of whorlS. but also m rela? 
tlve shell width. relatll/e size of the body 
whorl. whorl roundness. sulure depth and an? 
gie. and degree 01 se~ual dimorphism (FIQ 
33) The shell has a smooth aPIcal whorl (FIQ 
34A). Shell measuremer1ls Irom mne pop. 
ulatlons are given III Table 33 For all POP' 
ulallons, females are clearly larger than 
males and have more whorls 
aurangonella coahwlae does diller from D 
seemanr (the type 0' the genus) In lerms of 
nurrtlef 01 pemal lobes (D coahwlae. 1. D. 
seemaro. 2). and number of basal cusps on 
the centrattooth of the radula (D coahtJIlae. 
t . D. seemafll. 2) 
Shell 
Nonreproducwe Features The shell varies In length Irom 23D-5 10 mm and has 5 ~ 5 whorls The aper? 
ture IS crescent?shaped The penstome IS eo? 
'lie III adults and the end 01 the body whorl 
The measurements 01 organs and Struc?
lures lor snails from lour populaflons are 
TA6LE 33 $hell meaSUlements (111m) 01 males and lemares from fine popuIatlOllS 01 Ot!mngone1la 
coahodae Snails Wl1h lhe donllnafll maximum whorl numbe' isl we.e usod Mean' standa.d dell,atlOl1 The 
IOCaIlloe!; are the toIIowlng IypeS 01 aquatIC enwonments 6. IltJctua11fl9 pool semt-eonnected 10 Slream, 9 
playa lake. 13. 38, 8, large streams. 14. 51_ 74. 65. 43. small streams 
Length 01 l_d Wodlhol 
"""'" 
N l""" 
-" 
bOOy_ ~" aperture 
Localdy 6 , 55 7 258:!:017 116~007 143 -!- 0 10 0"' 006 056"" 003 
, 65 9 354?017 145:!:004 177-<-007 099'005 0,66 ? 0,04 
locaMy 9 
60 9 275:!.017 121'007 15Q !008 0,85"!" 004 061 +0OS 
65 7 311?013 131 ~OOS 162 '009 091 ' 006 063~006 
65 9 340:!:028 144'011 178 ' 014 101 ~009 071+007 
Locahty 13 
, 55 oo 235'014 099~006 126-006 074'OOS 049'003 
70 ' 0 375' 016 138 '007 165 '006 097+0OS 066'005 
75 9 415 '020 143'010 172 '010 100-006 069'003 
Locality 14 
, 55 9 251 :!: 0 11 107---008 1 37'006 080?004 058 +0 04 
60 7 273-<-011 109:!:OOS 142+006 084-006 0.56 ? 0.04 
70 9 385 ?017 151+006 185""006 108 ? 0OS 074 ' 003 
locaMy 38 
, 60 oo 285<0.11 I 18---0OS 1 52' 008 091'004 061 '002 
, 80 8 4 83~0 1 8 161'009 200 ' 0 10 114?007 079'004 
85 oo 508 '030 158?007 1 99-010 111+007 079'004 
L0C8UIy 43 
, 55 oo 275~ 0 18 120'008 1 52' 009 090+005 061 '004 
65 9 4 07' 0 19 164 ,007 2OS' 010 119 ' 007 083+004 
L oaillty S 1 
, 70 9 355 '0 11 126'006 158 '0ee 089 + 004 063'002 
, 75 8 436 + 0.t6 153?OOS 1.89 < 009 1 08+004 074 "" 004 
Locality 74 , 65 7 306+018 114 -007 148 ""007 082 + OOS 058 -0 04 
? 70 9 396 ? 027 147 - 009 166 ' 008 104 ?006 072 ~0 04 
LOC8hty 65 
, 65 
" 
328 '0 19 125' 007 156 '010 092' 007 083'004 
? 70 oo 390 ' 025 144 +0 09 179'011 106 !007 
'" 
' 005 
HEASHLEA 
TABlE 34 Dmeosooos (mm) or counts 04 nco? 
neUlal o<gans and slr\JCIures o. DuTangone/la 
coaIuIae trom locahty 6 N 5 ut*!ss stated 
OIhefw1se Me!ll1 ' stondald deVlatoon l length. 
W ... 
F~" ..... 
-
l 5.04' 039 335 ' 012 
Gilt filament number 267 ~2 00 
Osphladlum l 021 '003 
"""" 
l 033 :!"006 113 ?009 
W 0()6 ~ 002038?0004 
PlOSlale (N 
" 
l 068?009 
W 034 '004 
p~, l 055'005 
W 021 ? 003 
Palbal 0VIduCI l 220"023 
W 051 " 006 
Bursa copuIatnx l 0.33 " 004 
(N K 7) W 0.22 ' 001 
SemInal receptacle l 011 " 001 
(body) (N a 6) W 009 + 001 
SemIna. reoep\acle l 004 ' 001 
(r:tuct) (N - 8) W 004 ' 001 
TABlE 35 OomenSlOllS (mm) 0< COJIlIS ot non? 
neural organs and slructures 01 Dvrangonella 
coohurtae lrom l ocall ly 9 N - 5 ...-.less stated 
otherw1se Mean ~ standald OOWltoon l length. W _ 
Females .... ~ 
-
l 509"043 446 +030 
G~11lIamenI numbef 26.4 ? , 82 
"""'-
l 020'003 
"""" 
l 026 ' 004 13(} ?0 11 
W 009 ' 001 043 '003 
Prostale (N 61 l 072 .:; 006 
W 034 + 004 
Penes (N 6, l 056+004 
W 021 :!:00l 
Pallial OIIrduct l 2 10 ' 021 
W 053 ?005 
Bursa copuIatrlx l 029 - 002 
W 018 '002 
SemInal 'l!C8placle l 013-002 
(body) (N 81 W 010 "002 
SemonaI receplac!e l OOS-OOI 
(dr.oct) (N 81 W 004 '001 
gIVen In Tables 34-37 The analorl1lcal draw? 
IngS and ra(lula pholographs are Irom specl? 
mens from locality 6. The srout (Frg 35A) IS 
elongate and the tentacles are relatIvely 
short In addition to the seven 10 nIne hyper? 
trophled CilIary tufts on the outer edge 01 the 
leU tentacle. each tentacle has a central Cill ? 
ary tlact (CI, FIg. 35A) Small granules are 
TABLE J6 Oomensoons (mm) or counlS of non? 
neu.a. organs and st.vehJles 01 Durangonella 
coahudae Irom localIty 13 N 5 un.ess stated 
othelWlSfl Me!ll1 ? standard deviatIon l lenglh, 
W _h 
Fema'es ...... , 
BOO, l 5.50 ? 0.27 40E1 ~0 26 
Gil' fI'ament number 3" ~ 1 76 
Osphfadoum l 021 :t 0.04 
"""" 
l o J6 1. 0.05 174 ~0 18 
W 010+002 044'003 
Prostale l 074"010 
W 032+003 
Penis l 042'004 
W 016 ~ 002 
Pa'"a' OVIduct l 239?021 
W 0 47 " 005 
Bursa copula-tnx l 030:.003 
,N 9i W 017:t 003 
SemIna' receptacle l 013 "0.01 
(body) (N 
'" 
W 010 .:; 002 
Semona' receptacle: l 003 + 001 
(ducI) (N 61 W 004" 001 
TABLE 37 Oornensoons (mm) or counts 04 non? 
neural organs and structures 01 Ourangonel/a 
cuahVllae Irom locality 14 N 5 unless stated 
olherw1se Mean ' standard devoallon l lenglh. 
W ~ WIdth 
Females M"" 
BOO, l 6 44?063 476 ' 034 
Gillhlament nurnbet 3" !" 1 75 
Osphradlum l 021 '004 
GooOO l 041 ?0 02 170:.023 
W 009 + 002 047 '0 04 
P,ostate (N 11 l 100?009 
W 040:!:004 
PenIs l 046"004 
W 0.21 ? 004 
Pa'"aI oVIduct l 219+0.25 
W 059.:; 006 
eu.sa copula''''' l 034 + 004 
(N ~ 6) W 019' 002 
Sommal receptaCle l 012 .1 002 
(body) (N 
" 
W 011'002 
Semmal 'ec:E'PlacIe l 004 + 0002 
(ducI) W 003' 0004 
seen around the eyespots and In the neck 
The snoul mayor may nol be dusled wllh 
melanIn. The sides of the head?loot usually 
have a light melanin dusting. and an un? 
pIgmented striP, eKteocilng Itom the eye to the 
base at the loot. can be seen Body PIgment 
can be red or black The male gonad always 
has dark melanIn on Its ventral surface Pop? 
CUATRO CIENEGAS HYOR08110S 85 
UlatlonS may have snails deVOId 01 other body 
pigment (locality 6), or with a dark melarnn 
coaling (LocalitIeS 9. t 4), or a spotted pallern 
(Localities t 3, 39) on the ventral body sur?
face The caecal chamber protrudes po5lerl()( 
to the stomach (Cae. FIQ 36A) The paUCI?
spiral operculum (FIQ. 358) has 3.3 whorls 
and the nudeus IS poSItioned at 26% of the 
operrulum length. The opercultgefOUS lobe 
has several melanm streaks. 
RadUla 
Radular StatiStICS lor specm'lens trom the 
type-Iocahty (LocalIty 9) and a second Iocatlty 
(Locality 6) are given In Table 3S The cusp 
arrangements lor the four tooth types (lor 
specimens Irom Loca~ty 6) are given In Table 
39 The central tooth of the raduta has one 
(and ocC<lsI()(1al1y a se<:ond) pair of basal 
cusps that anse Irom prominent lateral angles 
(Figs. 34C. 0) 
Female Reproduchve Anatomy 
The female gonad (Go. FIQ. 36A) OCCupieS 
only 6% 01 the body length. Oocytes were 
frequently seen In lhe gonad IhrOlighout the 
year The pallial ovlducl OCOJpies 34-44% of 
the body length. depending on Ihe populatIOn. 
The length of the postenor bend 01 the pallial 
oviduct IS 06 mm, and the bend extends 10 
TABLE 38 Radular statistICS "om mdtYlduals 01 Durangonella coahul/ae lrom two populatIOnS. X ~ mean. S 
~ standafd devJalion Measurements If1 mm 
locahty giN ", locahty 6 {N 5) 
Radular teattJl"e X 5 X 5 L_ 0444 0035 0'"" 0023 W"'" 0087 01"" 0074 0008 Numbef 01 rows 
'" 
325 
'" 
207 
NI.IITtJe< 01 .ows III 
lormabve stagE! 30 
" " " Width 01 central 
looIh {N ", 0020 01"" 
TABLE 39 The VaIOOI.lS cusp a"angemenlS for the 'OU' l004h Iypes or /JunJngoneIIa ooahUtlae. counted hom 
5 radu'.ae !,ISIng SEM. Wllh the percentage at rClOJl&e Showing that anangemet'll a l leaS! once 
.... cru,~ 
Centrat Laleral margonal ma.gmal 
anlenor cusps 
basal cusps % 
""" " """ '" "". " W 20 :>- ' -3 20 " '" 20 20 
W 20 4 - 1-3 " 20 '" " " 
W 60 4- 1-4 " 22 " 22 60 
W 60 5-1-5 " 23 '" 23 " 
W '00 " " " " 
W 20 25 40 25 " 
W 20 26 20 26 20 
W 20 " 20 " 20 
86 HERSHlER 
WIthin 0 13 mm 01 the end 01 the mantle cav?
Ity The albumen gland (Ppolls no more than 
a glandular smear on the poslCilor-mosl 
o 28 mm 0 1 the pallial oviduct The remainder 
of the pallial oviduct serves as a brood pouch 
,B<>' 
A gonopencardlal duel (Opel IS present 
(F.gs 36B-D) The sac-like bursa (So) IS ooly 
12- 16% 01 the length 01 the palbal oVIduct. 
The seminal receptacle (Sr) , dorsal to the 
bursa. IS CIrcular In outline and 44% the length 
of lhe bursa. The OVIduct lOY) has a Single 
cod dofso-Ialeral 10 the selnlnal receplacle 
(FIQS 366, C) and then receIVes the short 
sperm duci (5<lu) from the duct 01 the seminal 
receptacle (oSI). The length 01 the ducl of the 
seminal receptacle to the openlog 01 the 
seminal receptacle IS shof1, 003-005 mm. 
and !hen the duct travels (dorsal 10 and hid?
den by the bursa) for 0 .41 mm until II JOIns the 
ducl 01 lhe bursa (Obu. ~ig . 36C). ThiS JUnco 
ture occurs 0.20 mm anterIOr to the end 01 the 
manlle cavity The duel of the semmal 
receplacle ol len nas a kink III It Just after tne 
opening o j Ille sperm ducl (Fig. 36EJ. The 
opening 01 tile spermathecal duel IS 0.0&-
020 mm poslerlor to tnat 01 tile patllat oVIduct 
(Frgs 36F . G ). 
Dala lor number of snelled embryos 
br()()(le(l for females from Sl~ poputatlOns are 
gIVen In Table 40. To these numbers can be 
added one to two non-shelled embryos tnat 
were dissolved In tne Cloro~ For 39 
embryQf1lC shelts (l ocality 61. shell lengtn 
averaged 0364 .? 0.158 mm. Wltn an elgnt? 
loIe! range In lengths Irom 0079-0693 mm. 
The largest embryoniC shells have 2 5-2 8 
'Nhorls. 
Male Reproductive Anatomy 
The lobed male gonad has lour to live 
branches and conStitutes 29-43% ollhe body 
leoglh. The proslale IS 0 16--{l.2 1% lhe body 
langlh. and overlaps the mantle cavlly The 
anterrOf vas delerens e~ lts Irom the anterIOr 
tiP 01 lhe prostate. 
The SIngle pemal lObe (PIC>. Fig 350) IS 
located at 61 % lhe peniS lenglh from the 
base. Folds are present on Ihe Inner curva? 
ture from the base to Just beyond the penIal 
Iobe_ The blunt tip 01 lhe pems has tall col? 
umnar cells e~tendtng back 0 .10 mm 10 
where the penial Iolds end Ciliahon ot these 
cells IS vanable: for the populahon lrom l ocat?
Ity 6. one 01 lhe itve penes studied had no 
Cilia. and the other lour had a small CIliated 
patch (Frg 350). OIher populatIOnS. partICU?
larly lhose WIth large-sized males. usually had 
the enhre coIumnar-celted area Clhated (FIQ 
35C)_ The vas (lelerens (Vd) COIls onty sllQhtly 
In lhe penls_ The peniS has bOlh GI, and GI2 
gland types common Some populahons have 
males WIth a small PlQmenled patch near the 
penis tiP 
DISCUSSIOn 
Among the Durangonella species. only 0 
coahUllae has receIVed complete anatomrcal 
study_ The peniS and (aoula of D. seem3rn 
have been flgured (see above). while the 
other four species are known only from the 
shell Anatomrcal study 01 these allopatnc 
species IS necessary to resolve thatr syste?
matic status 
Durangone//a coahullae h ad been pre?
VIOusly known (Taylor. 1966) only hom la?
guna Grande (l ocality 9). the playa lake that 
is the termInus 01 the S1feam from Laguna 
ChuflllOO. a Large Spring (l ocaitly 1). It has 
been suggested that other populations In the 
basin may represent new Ourangonella spe?
Cies (HolSInger & Mlnckley. 1971 . Taylor. 
1966) 
The author collected undoubte(\ D. c;oa-
TABlE 4() Dala tor numbel- 01 shelled embryos brooded by females .rem so- pcip\llahons 01 Ourangoneila 
cca/IuIIae The mean Shell !engln (lor shels ""til max,mum domonanl whorl numbe<) tor adu~ lemaleS 01 
each popuLatoon ' 5 also goVer1 
N~ ot VOOll9lemales 
"-"ean shell 
lengll1 tmm) N X SD 
.. "" 
lOC.1lil)l 9 3<0 
" 
187 D64 1-3 
''''''''Y 6 3" 
" "" 
"0 ,~' 
locaM)' 14 385 
" 
377 169 1-< 
' '''''''Y ., ? 07 
" ." ' " 
&-10 
l oc.awy .3 
'" " 
56' 167 H 
' '''''''Y 38 ' (J6 
" 
'50 
'" 
~ 
CUATRO CIENEGAS HYDROBIIDS 67 
htJ,Iae no, Oriy lrom Laguna Grande. bul also 
,n pool areas along the stream IcedIng It 
(Localilles 7. 8). groundwater-loo pools near 
the stream (Locahtles 4. 5. 6) and Irom a mop 
placed In a small seep near Laguna Churlnce 
(Locahty 2) 
The shells 01 D. ooahUlIae from populatlOOS 
Irom the above localities of the Chunnee sys?
tem (Ftgs. 33A-C. G-J). wlllch IS currently 
ISOlated 'rom other waters 01 the baSin. do 
diller trom sheIs from other popuIatlOflS (FIQS 
33O--F, K- U) IfI lhal the lemales have fewer 
whorls arcl smaller shells. and the shells are 
relaltVety wider With a relallvely Larger body 
whorl (FIQ 33; Table 33) The shell dlller?
ences may be partly allomelrlc, as the Chur ?
lnee shells are sma". but In some cases Chur?
lnee shelts that are smaller (In length) than 
Ihose 'rom oltler populahons are also abso?
lutely wider 
Despite these differences. the Cualro 
C.enegas aurangonella IS nOl being spilt InIO 
several speoes because. II there are no 
QUa~ta"ve anatomcal dllferences among lhe 
popuLa11Of"lS studied. 2) the Chunnce aqua\1C 
envwonmools diller Irom those 'rom wtllch 
other popu!ahons were sampled, and 3) the 
above shell differences are nol always pro?
nounced and the author can not confidellily 
separate oul ~speoes. whoo lots are lTIi)(ed 
MelllP)'rgus Taylor. 1966 
Type-species ' Mexlpyrgus carrsnzse 
Taylor. 1966 
o.stnbullon: endemIC to the CualrO C.ene?
gas BaSlfl. 
Speaes Included: reduced 10 monotypy 
(see below) 
DescnptlOll 
o.S11f'lCtIve 'eatures of MexJ(1yrgus are as 
fotlows I ) the masSIVe pallial oviduct lhal 
eKlends 01"110 lhe stomach and then bends 
Into a senes 0' loops that COIl progreSSIvely 
dorsal 10 one anolher (Figs 42. 43). part.ally 
enveloping the bursa and restflchng the 
space for the kidney (KI ) and pellcardlum (Pe. 
Ftg 42A). and 2) the greally COIled duct ot lhe 
serrunal receptacle (Dsr, FIQS. 426, D. E), 
The shell (F ig 37) IS large (number of 
wIlorIs. 55--7.5. lenglh. 3 03--8 45mn) usu?
atly ttrlened. and eIongale-conlC III shape. 
low spiral welts and nc:xted nbs may or may 
not be prOffllnenl 01"1 the last lwo wtIorIs (FIQS 
37. 38), peooSlracal cotor bands may or may 
not be preSCflt and (when present) vary from 
one 10 thlr1y dislloct bands. 10 a SIngle w1de 
solid band. the margmat tooth 01 the radula 
has numcrous cusps (FtgS 398. C): lamales 
are OVOVIVIparous. the albumoo gland (Ppo) IS 
reduced 10 a glandular smear 0f1 Ihe dorsal?
rnosl loop of the palbat OIIlduct (FlQs_ 42. 43): 
the bursa .s enlarged and elongate (Bu. FigS 
42A. 43); the sclfllnaJ receptacle IS dorsat 10 
the bursa and comecls WIth the oviduct VI<! a 
short sperm ducl (Sdu. F.g. 42C); Ihe 
spermalhecal di.Jd (Sd) IS shor1, musrular?
l2ed, and separated trom the bursa by a sttght 
constnClIOll (mdicale<l by arrow 10 Fig 428). 
lhe antener end 01 brood pouch IS weakly 
musculanzoo and COIled (Mus. Fig 4t8) lhe 
penIS (FIQ_ 44A) has a blunt, Cilia te<! hp, ter?
minal papilla. and lobes (ouler curvalure. one; 
Inner curvalure. one or IWO) beamlg mamml?
lorm glands (Mg, Ftg. 44A). 
Mex!pyrgus IS most Similar 10 Durangonella 
(see above; Tables 53-55, FigS. 49. SO)_ 
Mexl(Jyrgus d1unnceanus Taylof". t966 
HoIoIype' UMMl 2201SO, 
Type-Iocakly- Loca~'Y 1 
Synonymy M chunnceanus Taylor, 1966 
M escobedae Taylof, 1966 
M IUf}OI Taylof". t966 
M Cilffanzae Taylor, 1966 
M ~rrah$ Taylor. t966 
M mull,lInealus Taylor. 1966 
The name Mexlpyrgus churmceanus, 
ralher lhan M carranzao (type 01 tho genus IfI 
T aylor, 1966). IS appbed to thiS speoes be?
cause the type populatlOl"l lor the tormer has 
recetved the most morpt-ootoglCal study, 
Habi lat MexlPYf!1US chmnceanus IS Iound 
almost excluSIvely 10 lhe larger 5pf11lgS and 
streams of the baSll1 The specieS was rever 
found In sieve collections Irom smaller 
streams, and only a Single spec.moo was 
taken (Local.,y 65) trom mops Irom 38 small 
spflngheads Mex'pyrgus churmceanU$ IS 
restrlCled 10 soli sec:hments whICh appear (at 
SOl') to be composed 01 snail copropel or 
decayn-.g plant maner To a lesser eKtent, 
specimens wcre taken Irom a ffiI~ture of soli 
sediment and coarse traver1lne sand. DensI?
t ies of snails were determined USIng a boK 
core sampler (225 em square bottom) and 
ranged up 10 49 000 m~ (Localily 30). The 
only speaes found sympatrl(; wllh M chuI~ 
ceanus III ItS ffilCfohabltat was Durangone/la 
coahUllae 
.. 
" t:" ~= 
.. -
~\ 
HERSHLER 
? 
I 
, >0-
.. 
.. 
,:~ VJ ;I .. 
.~ 
.,? w 
." 
.. 
FIG 37 LocahlleS from whlCt1 ~01 MeJCIp)"9CJS ctruflnceanus were taken for the mul\IVaflale analysos. 
WIth JhlIOS of shells from selected popuIa100ns The phoIos of shells Irom l ocahllf!'S 1. 5. 37. 50, 99, 76. 78. 
79. 80, and 97 are p!'loled al the same enlagemet11 The shell on the IeI1101 locahly 1 IS 5 36 rnm long The 
phOIOS 01 shells lrom Locahhes 10. 20 30. 48 73, 88, and 95 are pnnted at the same (!f11i'lrgernen1 The 
phoIo on lhe !ell for Locality , 0 IS 4 29 mm long 
CUATRO CIENEGAS HYDROBIIDS 89 
FIG 36 Photos 01 shells 01 Mfwpyrgus chvurcearus The lop row has shells {penoslracum removed)lrom 
Loca~ry I . showing sculplural vallatlOO The shell logured on the lett IS 7 20 IT?llIong The otnels In Ihls row 
are ponIed allhe same enlargement. Tne botIom row has shells hom LocahI~ 90 (easlem lobe of lhe baSlfl. 
Fig 3) showrng the ttllckened sutural pEl.1OSI1 acaI band The shell on the lett IS 3 76 mrn long and the othe<s 
111 this .ow are prlf'ted to the same enlargement 
She. 
Shell measuremen,s and other data lOt 
adulls Irom 33 populatIons are gIven., Table 
49. The shells are usually whtte-colored and 
opaQue. but In a lew populatIOns lhey are 
colorless and Iransparef1t. The whorls are 
flattened and the su'ures are not very Im?
pressed The apICal whorl IS smooth (Fig 
39A). Sculpture begrns at or IUS' before the 
beglnnrng 01 the thIrd whorl (Fig. 39A) Spiral 
cords domInale the thtrd whorl whtle 3.)(lal nbs 
predomrnale on the tourth whorl. Sculpture on 
the lasltwo whorls IS variable both wIthin (Fig 
38. top row) and among (F'9. 37) populatIOns 
Aher the 'ourth whorl , noded fibs may be 
prOtmnent. reduced. or absent. and the sprral 
sculpture usualiV conSists o' 'WO low wel,s 
Cancellate sculpture was rarely seen In pop?
ulatIOns wIth adult shells haVIng prominent 
a~lal sculpture. 12-20 fibs were seen on the 
penultImate whorl In some cases. a small 
number 01 narrow sprral cords IS seen below 
the suture on the body whort. Sculpture IS 
generally reduced on the body whorl relatIve 
to that of the penult,mate whorl. A~lal growth 
90 HEASHlER 
FIG 39 SEM phoI05 olshel! aocI radula of Mex'PY" 
gus chunnceanus A Apocal voew oi embr,'ornc 
shell Note smooth ape~ 8 Pari of rac:kJlar flbbon 
C COSe-up shI:lwIng cenlralleelh 
lines are usually prominent. Adult females 
generally have larger and relallYeIy WIder 
shells than males, as well as more prominent 
sculpture. The aperture IS elOO9ate and 
somewhat pyriform above The outer lip 
usually has a pronounced SlnuatlOfl The 
umbilicus IS a naHOW sill 
-
.. 
? ? 
, 
? 
, 
r \ 
, 
FIG 40 Head and opefCUlum of MexWgus chur? 
,oceanus A- Dofsal aspect 01 the head Nole the 
concenltallon 01 glandular umts (G) and dar1<e< 
color streaks 6 Clpercull,.Ol1 WIth the dashed hoes 
ShoWIng the attactmenl area to ,he operrul.gerous 
lobe E~ye; G--gial'1OJlar uM. Sn-snout Tn?
tentacle 
TABLE 41 Omensoons invn) 01 rlOI1.neorai organs 
and struclures of MeMf?glJS chc.",nc;earw; from 
Locality 1 N 5 Mean ... standard dev>allOl1 l 
length. W = WI(IIh 
Females Mo., 
-
l 633'" 036 6.82 ~ 034 
Osph,ac\oum l 030~OO2 
"""'" 
l 166 ? 0.23 268+011 
W 059 '" 0.03 075-008 
PfO$lale l 1 50 .. 0 12 
W 090 " 008 
PenIs l 261 ' 017 
W 115 " 005 
Pallial 0V>duct l 435 ? 0.34 
W 108 ~ OI0 
Bursa copula,,,,, l 125 ~ O16 
W036 ' 005 
Semonal receplade l 030 ' 0.04 
(body) W 009 ' 001 
Semmal reoeplade l 013 ' 0 01 
,-, W 006 ' 0002 
CUATRO CIENEGAS HYDROBIIDS 91 
'" 
~o "'''' 
A 
" B 
MOO 
, 0 "'''' 
FIG 41 General o<gam:zatlOl1 oIlhe lemale .eproduclMI anatomy 01 Mexwgus c:hUflnceanus A Vent.al 
aspect 04 UflCOIIed snaol WIthout the head and Iudney IIssue Nole the paste-nor bend 04 the brood pood1 (Bpi 
B PCW1lOn 04 the antefOor end or the mantleC<Mty showing lt1e shght muswlar twost (Mus) or the ante.oor end 
01 the brood pouclI. Ast~antooo< stomach chambe ?. Bp-b.ood pouch. Bu-bursa. Cae--<:aecum 01 
stomach. CI-oJIumeilar muscle. Emc:-posterlOf efl:! 01 the mafltie cavny. Es--e!iq)hagus C30--9<Jr!ad 
Ifl-tfltest,ne Ma-mantie edge, Mus-muscuIa. sectlOf1 01 brood pouch. ~uct. PsI-poste.1Of 
stomach chamber. Sd-spetmathecal duct Sts-style sac 
92 HERSHl ER 
/ 
... 
/ 
.. 
?? 
Eo 1ft 
o ? .... A 
, 
." B 
___ 0 " .~. ~ 
?? '2:?J d'>' o. ~ C ? Op. , .. 0 ... , 
FIG 42 Female reproduchve anatomy 01 Mel<lPyrgus Chunnceanus A One.l ted as ,n FIQ 4tA, but Wl1h 
much 01 the brood pouch (BpI co. away to exlXlSe Itle bursa (Su) and oonhnuanon ot the pall ia l OVIduct COIls 
dorsal 10 the part thai has been cut away NoIe the .eductlOn 01 the Slzeo! the albumen gland (Ppo) and the 
infringement 01 the bursa (Bu) and palla! oYKIud onto the space occupoed by the pericard,um (Pe) and 
kidney (K.) B Onented as In A. but .... lIh portoon of the brood pouch (Bp) and bursa (Su) cut away to elq)O:Se 
the CMdud (0,,). seminal rec::eplacie (SrI. lIS 00ct (OM). and the openongollhedud 01 rhesem,nal receptacle 
",to the dofsaJ SIde 01 the bursa (If"dIcated by small arfOW) The large allow ondlC<ltes the conSlnctlOll 
between the bursa (Su) and spermalhecal dud (ScI) POint C IS ,nduded tor oomparlSOl1 WIth f ig 43 C 
Onenled as In B. but WIth part of theOYlducl cui 10 expose the sI!!ndef spe<m dud (SdIJ) D. E Onenled as 1'1 
C 10 show vanatl()rl In the codIng pattern of the dud 01 the sem,nal'ecep!ilCle 6p---bfood pouch. Bu---bulsa. 
Dpe-gcnopeucilldlal duct, DSf-ducl 01 the semInal receptacle Ef-eHerent branchIal vessel , Emc?
posIenor end 01 the manlle CaY1ty E~s. Ir.-mleshnll . K>-Iodoey. OIo--open'ng ot the kodne)l . 
Qsd.-()penong 01 the spermathecat dUC1. Os<kl--openong 01 the sperm dUC1 OII--ow:IUCI. Pe--perl(;;lf(loum. 
Ppo-aI:lumen gtand , Sd-spermathecal dl.ICI soo-sperm dUCI Sr- semonal recep1ac1e 
Nonreproduchve Features 
Measurements of organs and structures 
from three populations are given 10 Tables 
4t-43 The descflphon 01 e~ternal leatures 
and anatomy IS largely based 00 study of the 
type popu!ahoo (IrOm l ocality 1). The snout 
(Fig. 40A) IS elongate and the tentacles are 
thin and Short by compansoo. The tentacles 
ale WIthout hypertrophied CIliary tufts l arge, 
mllk?whlle granutes (G. F'9 4OA) are con?
centrated .n the rostrum and reck A light 
dUSling or melanin may Of may not be seen 00 
the rostn,Jm and neck The pauclsp,ral oper-
CUATRO CIENEGAS HYDROBIIOS 93 
... 
A 
B , 
.~ ? , 
? 
. ) , , 
\ . 
? ) ? 1 
-' 
,. 
.. 
E'"' 0.0 
, c ,. D , 
, , ? 
FIG 43 The nature oIlhe cools 01 the posleoor palhal O'olducl as revealed by prog.esswe removal 01 portIOnS 
oIlhe COols Or~aloOl'1 as In Fog 42A A Palll3lO\lOducI cut at potnl A B Parlo! the bursa (Bul IS cut away 10 
e~pose lheoools on 'IS dorsal SIde C Sedoon A-8 ' 01 the pall,al oviduct has been.ernovoo 0 Section C-C 
has been removed The MTlall arrows nchcate!he dwectlOr1 01 rrovemef1! 01 eggs aI"d emb<yos Ihrougtllhe 
pan.al 0\I0dud cools 8j>-b<ood pouch. Bu--bu'5a. Emc-p051enor end oIlhe mantle ca",ty. Ov-ovldud 
Ppo-albumen gland. Sd-spem\3thecal duct. Osd-openong 01 the speflnalhecal I1.oct 
TABLE 42 OIr'nensIoos \1TJTl) 01 nO'Nleurai OI'gar'lS 
and sl.uct\l.es 01 Me""Py'gus chlElflCe8flUS I,om 
loca~IY 30 N 5 Mean .!: standard devlal00n l _ 
length. W ~ WIdth 
Females 
-
L 5,46 + 0 14 
""" .. = 
L 0.22+003 
"""'" 
L 0.80 " 006 
w 0 46+005 
Prostate L 
W 
",," L w 
Pal~al OVIduct l 2 38 ? 0 14 
W 070+013 
Borsa copuIalroc l 0.80 '" 0 06 
W 0.21 :! 003 
Semonal .e<:epIade L 0 15 ? 0 02 
(body) W 007 " 002 
Semnal receplade L 0 10' 001 
(duct) W 006 - 001 
501" 0.21 
166 ' 0 10 
054 '0 07 
1 00"013 
053-006 
186-011 
079 .:. 007 
TABLE 43 [)uneoslOflS (mmj 01 non?neural orgaos 
and structures 01 MeI(Ipyrgu5 Chu,IfICe,IlntlS Irom 
locahW 50 N ? 5 Mean ? Slandard <lIMa"on L 
lenglh. W WIdth 
F~" M"" 
-
1958~033 910 ? 028 
OspOradlum lO38 ' 013 
Goo" L 142 .. 017 3.26 '" 0 76 
WOn"008 076 -009 
PrOSlale L 171-011 
W 098*006 
Perus L 3 24 :*: 023 
W 152 " 023 
Pallial ovl(!l)Cl l543 ?023 
WIIO .!: 008 
Bursa coputa.I". L 141.!:010 
W038 ! OOS 
$cmlnal receptacle l 0 36 ~ 0 07 
(OOdy) WOI6 *002 
SemInal receptacle l 0 .21 ? 005 
(duel) W 006 . 0004 
HERSHLER 
M 
PI Vd 
A J 
0.5 mm 
0 .25 mm 
FIG 44 The peniS or Mcxopyrgus chunnceanus Irom Locahty 1 A Oorsal aspecI or the pen'S NoIe the Iok:Is 
on the penIS. the blunl lop w,th coIoated columnar epothellUm. and slender penaliobes (PIO I w'th mammoform 
glands (MgI B The lop 01 the penIS showong the coloated cells and pogment patch Mg-mamm,'onn gland. 
PIo--penoaIIobe. Vd-~as deferens 
TABLE 44 Radular statlsllCs lor lemaies Irom 6 populationS or Mex'PY'fIUS clltmnccanus Measurements 
are III mm Mean <- Slandard ooWlbon ",. and 11? re.e.' to the IXlfrelahon coelllClefl1 (and sognlbcance levell 
between !hal partlCula, ,adular lealu.e and mean adult female shell Ieog1h (Irom Table 33). lor the 6 
popuIal00ns 
Raduiar 51allSllcs 
'""" 
Width o. central 
,,",," N 
""'. 
Wldlh No_ tOOlh (N) 
L-" 73 
'" " 
057?002 009 ? 0001 494<-149 0030 ? 0 0012 (32) 
L-" " 
'" 
, 065' 003 01 1 ' 0006 533' 296 o 033 ' 0 00 II (33) 
LocaMy 76 
'" 
, 078~003 0 1 3~0005 541 '276 0038 ' 00017 (27) 
Locatry I 
'" 
, 070,003 012'0007 532- 1 92 0034 ' 00013 (46) 
Loc.Vty 97 
'" 
, 07 1 ?002 0 12 - 000s 547 '180 0034 ' 00015(29) 
Locality 5fJ .25 , 077'002 0 14 '0005 54 1 - 196 0039 ? 00018 (22) 
,0.860 0833 0'5' 
p ' 025 . 025 05 
CUATAO CIENEGAS HYDAOBIIOS 95 
TABLE 4S The varIOUS cusp arrangemenls lor the 100' toolh lypes on 18 ,adulae 01 MIWPyrgUS chunn-
ceanus. Wllh !he pel"ceolage 01 rOOv1ae showing lhal arrangement at least once 
, ..... "",~ 
""""~ Lateral rTl3Jgonat marg,nal 
anlenor cusps 
DIISal cusp5 % 
"""'" " ""'" 
... cusps ... 
W 6 , .-4 " " " " " 
W " ,;->-4 " 22 6 " " 
W 28 "-'-5 " 23 33 26 22 
W 33 'H-4 " " " " " 
W " 0-.-4 , 25 33 " 33 
W 22 6?H " 26 56 29 33 
W " 1-1-4 
, 
" " 
30 
" 
W 6 &-Hi , " 56 " 56 
W 28 29 39 32 33 
W 33 JO 39 33 39 
W " " " " 28 
W 6 32 28 35 " 
W " 33 28 36 " 
W " " " " " 
W 6 35 " " " 
W 6 J6 " 
W " 
W 28 
W 6 
W " 
W 6 
W " 
~ 6 
W 6 
W 6 
W 6 
96 HERSHlER 
TA6LE 46 Comn-on ( 40"'0 01 radulae sludoedl 
0l!0I,0l! 100Ih cusp formulae lor 6 pop .(Ih()n$ 01 
MeK.JItfgtI$ chuntlceanus 
localrty 7J 
'''''''''' 95 '''''''''' ,. 
'oc#r , 
LCICiIlJIy 97 
'''''''' 50 
4---1-42- 2. 5-1-42-2 
5-1-42-2 
5-1-52- 2. 6-1-5<2-2 
5-1-43-3. 5-1-5.3-3 
5-1-53-2 
5-1-43-3. 5-1-5.3-3 
OJlum (Fig 408) has 2 0-2.5 whof1s and the 
nucIevs IS positioned al 23% 01 the long aXIs 
01 the operCl.Jlum. The body p.gmenlabon 
COI"ISISIS 01 Itlln bands 01 dark melanm on the 
c\ofsal surface. and yellow and while gt'anules 
on the venlral body surface The opereul.ger?
ous lobe has several .h,n ,ed-purple melanm 
streaks as well as a large central duster of 
white granules The caecal chamber extends 
posIeflOf to the stomach (Cae, FIQ 41 AI 
The radula IS shown In FigS 39B. C The 
central tooth has one 10 three pail'S of basal 
Cusps lhal arise from 'he la'eral angles 
Radular SlabstlCS lOf the Iype populations 01 
lhe 51)[ .,cffimal Species ale gIVen In Table 44 
Radulae were removed from large females of 
each populallOl"l. As seen Irl Table 44, ,he 
Iong,h 01 lhe radula ribbon, number 0 1 lOWS 0 1 
Icclh, and WIdth 01 the oon',al tooth ate all 
h.ghly cOlfelated wllh the average shell 
lengths of the females lor lhe populaTIOtIS 
(p <: 0 OS) The cusp arrangcmenl lor the lour 
toolh typeS lor the populaIJOfI Irom LocaIrly T 
are gwen In Tabie 45 Common formulae f0r?
me C\J5p arrangements lor The central toolh 
lor the same Silt populatlOf'ls as above are 
gl\leo In Table 46 Note that orvy !he three 
popuiabOflS WIth large'Slzed I(lmales com? 
monIy have three pailS 01 basal cusps. 
Female Reproducllve Anatomy 
The female gonad (Go) conSlSls 0 1 tour to 
Silt lobed branches (Fig 4t AI and IS only 
15-20% 01 the body length The pallial OVI? 
duct IS 44- 57% 0 1 the body length, and the 
posleoor COIls exlendlo Wllhlf1 0 38 rrm of the 
end 01 the mantle cavlly When part 01 the 
l1Otl-reflected por1lOf'1 01 the palll31 OVIduct IS 
dISsected away II IS seen thai the postenor 
bend oontll'lue5 to loop dorsally (Fig 42A) 
Seclrons of these loops are PfogesSlVety cut 
away In FIQs 43A- 0 10 reveal Illetf COfTIPIeIt 
nature anclthe way thatlhoy parllally eovetop 
the bursa (Bu) 
The bursa IS elongate, wllh a narrowed 
posterIOr secllOtl. and IS 26-34% 01 the pallIal 
oviduct length The semInal receptacle (Sr) IS 
appressed to the dorsal side 01 the bursa near 
ItS af1\enor end (FIQ 428) The oviduct, alter 
gl\llng 011 a short gonopencardl al duct (Ope). 
drsappears beneath the bursa and 00IIs once 
before re<:eMf1Q the narrow sperm duct (Sdu) 
Irom lhe duct 01 the semrnal receptacle (Ost, 
Frgs. 428, C). The OVIduct lhen loops back 10 
the IIet1tral SIde of the bursa 10 eoter the 
posterlOf end 01 the palhal OVIducl The sperm 
duct IS trghtly appressed to lhe ducl 01 the 
semInal receptacle. Alter the juncture With the 
sperm ducl , the duct 01 the semInal recepta ?
cle COIls variably several limes before enter?
Ing the dorsal side of the anterior end 01 the 
bursa (FIQS 42S-E) 
The large bursa and maSSIve tnls 01 the 
pallIal OVIduct cover the kidney (KI) and a 
small porbon of the pericardIum (Pe. Frg, 
42A). The kidney and pellcard lum are rela?
tively sma. and nanened compared to those 
of other hydrob!cl snarls. 
Oata for number 01 embr yonIC sheilS 
oolalned from adult females f rom 10 p0p?
ulatIOns are glllet1 If1 Table 47. Non-shelled 
embryos were ralely seen in dIssected spec?
mens. The conelatlOl'l between shell length 
and r.umber 0 1 blooded young (data Irom 
Table 47) IS 0862 all(! highly srgnlhcant 
(p < 0 0(5) FOf 100 emoryomc $heMs from 
females 110m localIty 1, shell length averaged 
0.386'" 0.190 rrm, WIth a flve-iold range 
from 0 .119--0634 rrm The embryos have 
led pigment on the doI'sal body surface. 
Male ReproductIVe Analomy 
The male gooad has frve to s.1t lobed 
branches, 1IIIIng most of lhe dlgesllve gland 
and comPfISlIlQ 33--39% 01 Ihe body length. 
The Pfostale IS 26-34% 01 the body length, 
overlaps the mantle cavIty, and has the all ?
leflOr vas defereflS eltli lng 110m Its anteflOr tip. 
The pefliS IS shown III Frs 44A. II has deep 
folds over most ollis length The s.ngte pelllal 
lobe 0fI the ouler cvrvalure IS located at 67'lf. 
the penIS length 110m the base One Of (more 
corm1OIiy) two lobes ale on the Inner CUtVa?
tUfe, agatn begII1nrng at 61% 01 the pens 
length "om the base (Frg 45) In one popuIa. 
tlon (110m l ocahty 76) a lew specmens had a 
CUATAQ CIENEGAS HYOAOBIIOS 97 
B 
c 
\ 
( 
A 1 0 mm 
FIG 45 Vallabon III the penlalioballon 01 MeJflPY'gus c/ltJnnceanus A The most conwnon peniS type with 
two lobes on the IIlfleI' curvall.11e and one lobe on 1t>e outer OJrvature B Pfesenoe 01 a second, "bud,loke 
pen<allobe (wllh mammltorm glandf on theoutef WfVature, seen only lr'lspecIm(!n$irom Localily 76 C Rare 
pents type With one lobe on both lhe Inner and OlItef curvatures, seen only III specwnens !rom Localities 73, 
76, and 99 
TABlE 47 Data tor nurrber ot shelled embryos brooded by temales trom 10 1XlPIb!1OOS ot lvieltrpyrgus 
chunnceanus. The mean sheli leng!h (tor shells wlth!he maximum domrnanl....nor! rumbefflor aduM !emales 
lor each 1XlPIb1r01l IS alSO given 
Shell length 
Imm) 
Locahry 6 '93 
Locahry 16 
'" Locahly 10 
'" Locahry 18 
'" Locallry 21 
'" Locahly I I 590 
Locahry 5 599 
Locahly 22 
'" 
''''''. 
, 
'" 
''''''" 50 
6.25 
second small bud-Irke lobe wllh marro-nl lorm 
gland Ofl the outer curvatu,e (FIQ 4 58 ). 
The mammlorm gland occupies about one? 
hall the length 01 the penial lobe (Mg, Fig 
44A). While an apocrine gland IS Cllcular In 
shape and has both a very large central lu?
men and large te rmrnal opening (see Thomp?
son. 19GB. 119 ME), the mammllOfTTl gland '5 
more corucal In shape and has a very narrow 
NI.fi'Iber ot young female 
N , SO ,~,. 
" 
'56 
'" 
.. , 
" 
'60 '00 .. " 
" '" 
'07 6-" 
" 
8" '" 4- t7 
" 
667 
'" 
6-" 
" '" 
, 3-" 
" '" '" 
0-" 
" '" 
". J-B 
" 
,. ,
'OB 14_24 
" '" 
5~ 14-35 
central lumen (surroun<led by a muscular 
layer) and a small. pore-like terminal opening 
The peniS 01 Pyrgophorus c(Xonaru5 also has 
glands lhat would be COI'lsKlered mammiform 
(see Fullington, 1978.1'9 16). 
The vas delerens (Vd) corls lor mosl 01 fhe 
length 01 the perllS The tiP 01 Ihe peniS has 
cltla ted columnar epithelia extendlflQ back to 
the end 01 the folds on the Inner curvafure, 
98 HERSHl ER 
~.~ , .. 
, - ~- " '" '" , -~- " .. .., 
-.... 
, ~ on .~ 
? ........ 
' " 
,w , .. 
, -_. ,u ,~ 
'" f, l ""'}t> 01 ~ _ . ~ 
'" '" l l ""'flll'lol_ ,. 
'" '" ~ -",--.. .. 
'" '" '" 
? "'''' 11''' - .0 . , ., 
.. 
IIocIy _ .... _ .. 000<l 0 ? ? 
" 
_ .... _a:.I_ , 
? ? 
" ------.. -
, , ,
" -,-"" ....... """' ..... 0 ? ? 
" 
__ 2_ " ... .. . <1'>' , . .. , , ,
" 
_""", ?? d 0 0 ? 
" 
No 01 Pt< ___ , , 
" 
FMII '" .....,.,.. ........ , 
" 
0 
" 
fOOqol_~ 
" 
0 
" 
f'"" (II _ $COre-3 
" 
00 
~ fteq ol ~ ? 00 
and 0 3 mm back on lhe outer cuNatuf6 (FI9. 
44). A P'9mef1ted patch IS somehmes seen 
near lhe lip of the peniS (Fig 448) The pems 
has GI, and GI2 glands. 
DlscusslOfl 
While complete anatomical data are p.-o?
vlCled for only three populall{)f's, Specimens 
from numerous other populallOflS (includIng 
those of the types for all nominal species) 
were dissected as well (see Table 48), yet no 
QUalltalive difterences in sofl-par1 anatomy 
were seen The main di!ference between pop?
ulatlOl"ls IS In shell features, especially Size, 
and anatomICal fealures correlated WIth SIze. 
such as number of young bfOOOed by Ie?
males. radular slallslies. and number 01 gill 
filaments. The purported differences (shell 
and analomy) belween nominal specieS are 
blurred when numerOUS populabons are stud? 
led For example. one 01 lhe diagnostic lea? 
lures of Mex/pyrgus mo/arralls (sensu Taylor. 
1966). which IS considered endemIC to Local?
Ily 73). IS a penis wllh a single lobe on lhe 
Inner curvature (the usual number IS two) Vel 
In Ihe Mo)8rral East Laguna (Localtly 76), 
wtlldl has a s i ream connecllon WIth locality 
73. Individuals aSSlQnable 10 M. munibnealus 
(sensu Taylor, 1966) may also have this pelllS 
type (see Table 49). 
As there are no morphologICal Cfltefla by 
whICh separate species can be recogl'llzed. 
lhe SIll normnal species are reduced to one. 
MeXlfJyrgus churmeeanus A detailed analySIS 
" 
" ..
~ 
TASlE 48 Data malrox for lhe muIIl 
" 
.. ~ 
" 
u 
" 
~ 
" * 
" '" '" '" 
.. 
" '" " '" 
" 
..
" 
..
" " " '" 
..
W ". . ~ ." ,. w 5'" . ~ . .,
' 00 , .. 
'" 
", . ~ ." ,~ 
'" '" ,~ 
'" ' " 
.. , ,, 
' " 
,,0 
' * 
,w
'" '" 
,. ,,, 
'" 
'00 '00 '00 ,w 
' D 
' " 
," 'a ,~ 
'" 
, ,, 
'" '" '00 ' .. ' " '" , " 
,. 
'" 
,., 
'" w ? ... ... " . ?? 00. ". ". 00. 
0 ? ? 0 ? 0 0 ? ? 0 , ? 0 ? 
, , , 
? , , , , , , , , 
? 
0 ? ? 0 ? ? 0 ? ? , , , , , , , 
? 
0 , ? ? ? 
, 0 ? 
, 
, 
? ? 0 
, , , 
? 00 00 ? 00 ? 0 ? 0 0 
" " " " 
00 .. ? ~ ~ 
" " " " 
00 00 
" " " 
" " 
0 0 ~ 00 
" 
0 
" 
01 morphologICal vanallOl1 01 M. chunnce? 
anus. and liS relallOl1 lo lhe species problem. 
IS presenled below. 
Subfamity Unknown 
Orygoceras Brusina, 1882 
Type-species . Orygoceras comucopiae 
Bruslna, 1882 
OISlnOOlion lhe Single hVlng species IS ra?
slrieled 10 two localitieS In the southwestern 
deserl s 01 North and Cenlral Amenca (see 
below). Late CenoZOIC losSils are known Irom 
eastern Europe (BruSlna. 1882) and the 
northweslem United Slates (Dall. 1925: and 
others). 
Species Included: the hvmg specieS re?
mains undescnbed Numerous lossll SpecieS 
have been descnbed 
OescnpllOn 
The shell IS vanable In size (lNidlh. 2.0-
120 mm), bul always uncoils after a whorl or 
so, prOOUClng a tube-like shape (Fig 13H) 
Axial sculpture may (BruSlna, t882. pi II) or 
may not (Fig. 13H) be present. 
Otygoceras (?) sp. 
Dlslnbullon restrlCled to Roaring Spnngs, 
Real County. Texas (Taylor. 1974) . and a 
Single SPring In the Cualro Cillflegas Basin 
(see below). 
" 
" 
" 
." ,~ 
'" 00
'" '00 
'" ? , 
, 
0 
, 
0 
00 
? n 
~ 
CUATRO CIENEGAS HYDROBIIOS 99 
vallaTe analysis (measuremenlS on mm) 
I , '.,:---=.,:---'~:::---'~::-c',:---'":::---":::--"'O;:-c"c:---'~:::---'.::--"c,::--,,~c:---,a:::---,A::--=" w.l r.. ~1 \!IIi 
O ~ O~ 6~ 7G es es 8S 6G 6~ 6~ 10 6~ 8S e~ 6G ~; 6~ 6~ 10 eo 
H 10 6S 1~ 10 10 10 6~ 6S 10 1~ 65 6~ 10 e~ ~S 70 65 10 60 
I~ . ~ . ,7 7ID 6 ~ S~ 6ro 3~ S ~ ti2' 131 5R S~ 5" ,~ 310 S~ o~ e~ .~ 
. ~ ~~ o~ 12'> 130< 653 61'2 010 SIlO 616 '05 6113 62ti tillti 63<1 3ro 653 5~ 7~1 ' )1 
211 213 203 o:re 391 3.2$ 3.311 2~ 33< 331 ' 36 3&01 326 318 311 111 3'9 27f> o ro 257 
3 02 3 S1 299 ~ ,~ ' S!> 0 :13 0" 21'S .,0 '" 531 ' 70 ,2, '''' 'lI> zoe 032 3~ 481 J" 
"S 2 18 I. 3~ 2W 2 ~ 2~ ,~ 2~ 2~ 3" 300 261 213 21' lD 213 2" 300 1113 
I~ 1~ 132 2~ 210 1~ 1 ~ . 2. 1~ 1~ 231 2~ 17f> 1~ 190 O~ ,~ 15' 20e Ill> 
*11 ~16 " 6 61>8 532 ~ o 530 "8 532 538 646 ~16 S26 1i26 636 3012 <62 '111 606 18' 
0 0000001000000000000 
222222022G110020022' 
2 220000 "000'2012 ' 2 
00000 ' 100000000000 
? 
? 
, , , 
? ,
1 0 0 1 " " 1 1 1 
? ? 
? ? ~ ~. 
2000101220000022 
222022222120'211 
? 
'. w 
21 96 56 06:' 30< 21 02" ~ m" 02 0200 
~ ". V ~ 311 :' D,. 311 02'" 311 21 5011 06 OI!O 0 
" 
16 0 06.6 2\1 32 Xl 12 ,2 12 62 Xl 60 " 13 
" n u ? (13 00 0200 OI! 51 00 "0 32 \6 tiT 
Habitat reSTricted to small spnngheads 
Taylor (1974) lound one liVing specImen 
close 10 the source 01 lhe spong aher heavy 
ralOS I collected three live specimens and two 
empty shells Irom mops placed al the small 
spnnghead at Locailly 67. The rarity of live 
speamens al These Iocalilles and the lact that 
lhe sna~ .s blind and unP'9mented. suggest 
that Its malO habitat IS swterranean 
The shell (FIQ. 13H) uncoils after t 3 whorls 
and produces a tube shape that.s very Similar 
10 all specimens seen. For two spec1tTlef1S 
'rom Cuatro Clenegas. the shell lengths (par?
allello the COIling alliS) are 1_70 and 1.58 mm. 
and the Wldlhs are 2.26 and 2 06 mm. respec?
lively Adult RoamlQ Spnngs speamens are 
about 2.0 mm Wide (Taylor. 1974) The apiCa' 
....nor! nas pitted microsculpture. while lhe la?
ter whorls have strong growth ~I16S The oper? 
culum IS pauclsplfal . 
The ammal IS blind and unptgmented The 
buccal mass and Gperculigerous lobe have a 
red-pink color Similar to that 01 CoahUIIIX and 
Pa/udtscala. The Inles11116 has a loop near ItS 
antenor end (Taylor. 1974 . 119. 1). While not 
dissected. the animal IS hydroblOld In Its el(?
lema! appearance. 
There are three dlSllnct groups 01 Qy. 
goceras species. 1) large (WIdth. to 8 mm). 
sculptured specIeS from Lale CenozOIC: Bal?
kan lake beds: 2) large (to 12 mm). smooth?
shelled speCIes 'rom MIOCene? Ptlocene Idaho 
lake beds: and 3) the very small (to 2 mm). 
smooth-shelled lIVIng species found In small 
spnngheads_ The relalJonshlp$ among these 
three groups remain obscure: the liVing spe?
Cies IS probably nol closely related to the 
fOSSil lalla as It d.tiers greatly In shell SIZe and 
habitat 
MORPHOLOGtCAL OIFFEFIENTIATION 
AMONG POPULATIONS OF 
MEXIPYRGUS CHURINCEANUS 
Populations of Mexlpyrgus churmceanvs 
show conSiderable vanattOn ot shell features 
(FIQ 37). The Sill nominal species 0' Mextp)ff?
gus were descflbed by Taylor (1966). all but 
one Irom Single localities. based on Charac?
ters InvolVing shell size. shape. SCi.llpture. 
number and lh1ckness of penostracal bands. 
and the number 01 penial lobes I collected 
Mexlpyrgus hom over 40 localll1es In the 
baSin. and noled pal1erns 0' vanatlOn In?
conSISleot WIth the speCIes concepts of Taylor 
(1966). To analyZe these patterns of vanat101'l 
and to assess the Slffillani1es and differences 
among populatIOns . a dala base 01 20 
Characters ( 16 from shell. one from body ptg?
menl . Ulfe6 110m soli parts). Including mosl of 
lhOse employed In the diagnoses 01 the 
nominal SpeCIes. flom 33 populatIOnS lOTUs) 
was subfeCted to mullivanate analySiS. These 
100 HEASHLEA 
TABlE 49 Ch.alactcrs used ,n assessong SInlolanbes and d,Ue.onres between popuIahons of Mexrpyrgw> 
chunnceanc.rs CharOClcrs 3-9 represen. means (of whICh 4-9 are lot lema1es only) In (0. 1) pal,S, 0 
fepfesents I:Ibsef"ce of a characICf ?stale. I represet1ts ,IS presence Charoclers 17- 20woro also SCOI'ed only 
trom !ihells 04 l emales as those characters elthlbl se~ual dmlOfptusm 
1 Ma~ornum Ill.IfI'Oe< 01 whor1s. males. 2 Mal<Jmum number of wt-cos, lemaIEt$. 3 5helllenglh, males 4 
5heMlenglh. females , 5 Shell w>dIh , 6 Length 01 body whorL 7 Length 01 aperture, B Wid,h 01 aperture. 9 
Numbe< 019'15; 10 Pfommem spiral COld on body whorl (Fog 37. shells 01 Local~y 73) (0 . 1). 11 Shell WIth 
peflOSlracai bards (0. 0-33% 01 shells banded: I . 34-67%: 2. 68-10Cl'0/01. 12 Banded shells wrth Ihtdo; 
sutoxal band !Fig 36. bottom fOW) (0. 0-33% 01 banded shells WIth !hid< sutural band , 1. 34-67%: 2. 
66-100"1.) . 13 PeoIS Wllh one lobe on the onner curvature (Fog 4x) (0. 11. 14 Pems WIth lwo lobes on lhe 
!me' ~all.lre (Fog 45<1) (0 . I). 15 Roslrum pogmenled (0, G-33% of popuIatlOfl. 1. 34-67%; 3, 68-100"1.1. 
16 Number 01 pefloslracal bands al the shell aperture (0. < 8, 1, 8-14,2. '4). 17- 20 Frequency 01 sheIs 
WI,h the loIIowIng a ~oal sculph."e development at the et1d o' the penuH,mate whofI. 17 Absent (see Fog 37 
Locahhes 76. 88). 18 Low nbl; 0' low nodes w'thout nbs (Fog 37. Locat' tv 48) . '9 Mode<a1e1V high . rooded 
,itl$ (Fog 37. Local,ty H . 2Q Hogh, noded nbs (Fog 37. Locahtoes 30 94) 
lABlE 50 ust 01 Mf!"'P'trgvs chuooceartl.lS pop?
uiallOnS (used on the multlVanale analysIS) acco?I?
tng to drUlil!)e systems. 
",,"'.,. 
110 
'b 
III 
Locaht'f!S (see Fog 37) 
' . 5 
10. II 
18, 2Q. 2 1. 22, 37. 38, 30, 43, 46. 
47, 48. 49 
99 
IVa 50, 78.71.73. 76. 79. 80. 81 . 82. 
83, B6 
'Vb 88, 93, 95 
V 96. 97 
characters are listed and el(ptamed In Table 
49. The el'llire data set is g,\Oen ,n Table 48. 
The locatIOns 0' the 33 poputahons, toge ther 
With pholographs ot shells trom many ot 
them. are shown in Fig. 37. 
The vanous populatoons are listed (by local?
Ity nunt>er). dramage by dramage. In Table 
50 Dramage I , terminating In a shallow playa 
lake (Locality 9). IS currently Isolated Irom 
other waters 01 the basin Drainage 2a COfl?
SlStS of the large thermal Ilrnnocrene, the 
Pozo de ta Becerra (Locality 10). and lIS 
outflow. the RIO Garabatal Dralr"\age 2b con?
SIsts of the large number 01 springs on the 
area known as EI Garabatal. to the north 0' 
the Pozo de la Becerra. and to the east 01 the 
R,o Garabatal These sprongs all flow to the 
nof1h or west and may have pned the RIO 
Garabatal In the recent past Wtule some 01 
these spnngs How Into the waters 01 Draonage 
4a (see below). the downstream portion 01 
these spnng outflows are last Ilowlng over a 
hard bottom and no Mexlpyrgus was found 10 
them dunng an Inten5lve survey dunng t sat . 
Drainage 3 conststs 01 the Isolated AnteotO 
spring CornpleK (Locality 99) which. poor to 
alterations. may have 'lowed south to JOin 
Drainage 4a. Draonage 4 COnsists of the large 
rheocrene. the RIO MesqUItes (originating at 
LocahtV SO), and nearby springs that tlow Into 
It (together conslll\Jllng Drainage 4a). and the 
large thermal Ilmnocrene. Laguna Escobedae 
(Locality 95). and nearby spnngs that lOIn the 
RIO MesqUites well downstream (together 
constituting Drainage 4b). DraInage 5 con?
SIsts at the large thefmallimnocrene. Laguna 
Tlo Candido (Locahty 97). and a nearby 
spnng. that l low to the south 01 Oralnage 4 
Five pronClpal compooents account tor 
7993% 01 the vanatloo The forst component 
accounts lo r 40 41 %: the second 17,89% 
(accumula ted 58.30%) . the third g 69% 
(accumulated 68 00%). the lourth 666% 
(accumulated 74 66% ), the folth 5.27% 
Character loadIng lor each component IS 
given In Table 5 1. Characters are conSIdered 
highly corretated II the" load IS greater than 
0.60. Characters With values of greater than 
0.50. but less than 0 60 were aSSigned to the 
pr,nclpal ~t tor wnlch the characters 
had the hlghest vatue 
Characters hoghty correlated wlth,n the first 
component are number of whorls lor males 
(Character I , Tabte 51). measurements trom 
sheilS 01 'emales (Characters 3-6). gill num?
ber (9), and nurrtler 01 peroos\tacal bands on 
the shell (16). ThIS component IS one 01 SIze: 
the number of penostracal bands on the shell 
logically correla tes With adult shell length. The 
second component has highly correlated 
characters of shell sculpture (10. 17. 19. 20). 
InCidence ot a thICkened peroostracal band 
( t 2). and number at penoal lobes p3, 14) 
CUATRO CtENEGAS HYDROBIIDS '01 
TABlE 51 FaclOf loadIng 01 characters lor the lIve prlnClpat OClf1'lIOI"ICnls lhat ootlectlvoly iICCOUf1t lor 
79 93'lI. 01 the vanatlOn 1f11he multlv8nato analysis 
ella.actCO' 2 
? 0653 0"" 2 0<06 0180 , 09" "m 
? 096' 0110 5 09" 0173 , 0911 0 124 
, 0958 0151 , 0'<5 0181 , 00;5 0058 
" 
0277 05<' 
" 
01 47 006' 
12 om 0597 
" 
0006 076< 
" 
0121 0591 
15 0.234 0248 
" 
0.765 0137 
" 
0388 0"'" 
" 
015, 0571 
" "'" 
0690 
20 0016 0520 
These characters do not Involve SIze The 
\turd component Includes highly correlated 
characters of Incidence of penostracal band?
Ing (11 ). number of penial lobes (1 4) and shell 
sculpture ( 18). The sole characters htghly 
COITelaied wlthm the lourth and ftfth com? 
ponents are ptgmentahon 01 the rostrum (15) 
and number 01 whorls for females (2), respec' 
Itvely 
OrClmatlOn diagrams following non?metnc 
three-dimenSIOnal scaling are given In Fig. 46 
(1st vs_ 2nd component), Ftg_ 47 (1st vs_ 3rd 
~t). and Fig . 48 (2nd vs 3fd com? 
ponent). The varIOUS poputaltons ale referred 
10 by locality numbers m the orotnahon di?
agrams. The stress was low (0 (010). The 
matm( correlation between ta l<.onomlC diS?
tance and distances In the three dllnenSlOl1al 
scalll"l9 was 0988 
In Fig 46. lhe ordlnalton of component 2 
versus component I , the smaller -shelled pop?
utabons are In Quadrants I and IV. and the 
larger-shelled populatiOns are tn Quadrants II 
and III. PopulatlQns In Quadrants III and IV 
are sculptured, have th ICkened sutural bands 
and are from four of the drainages. especially 
Dramages t and 2 Populaltons In Quadrant " 
are wllh large, smooth shells. Without a thICk?
ened sutural band. and somel lmes With males 
PJlf1Clpal c:;()ff(lOnents 
, 
? 5 
006' 000< 0<0 ? 
025. -0011 052' 
".2 0058 0." 
003< 
-0 "" 0106 
0076 00"' 0132 
00" oon 0158 
0"" 0085 015' 
0060 ooa, 0"0 
0006 0143 0124 
0<58 0152 0006 
05<' "95 0.512 0095 0<" 0114 
0421 012' "2' 
0593 0011 0238 
om 0.646 0022 
0071 000< 00", 
0060 0075 0099 
,,6< 00 18 0000 
0032 0<58 - 0261 
05<' 0511 015' 
haVing a SIngle lobe on the lOner curvature of 
the peniS (Irom localities 76. 99): and are 
e~cluslvely from Dramages " I and IVa. In 
Quadrant I are poptJlatlons With small'SlZed 
stlells from Oramages II and tV. Of the f"I()fTl?
nal species. the IXlPUlatlCms in Quadrant " 
would be considered by Taylor as Mexrpyrgus 
/1J9OI Of M. mvlt,hnealus (type populahons 
from Iocallhes 50 and 76, respectively) . Quad?
rants I" and IV have the type populallon of M. 
churmceanus ( I ), M escobedae (95) and M. 
carranzae (97). that differ largely In shell SIze 
and SC1.Jlptural development. The type popula?
tion of M rTIOIarraJrs (73) appears as an outlier 
In Quadrant I as ItS members have very small 
shells, With a prominent spiral cord on the 
body whorl. and males wllh a Single lobe on 
the Inner cUfValure 01 the penis. 
In Fig. 47, the ordmallon of component 3 
versus compooenll . the smaller?shelled pop-?
ulahans are again In Quad(ants I and IV. and 
the larger-shelled populations are In Quad?
rants II and III. Populations With sculplured 
shells and a hlQh IllCIdence of peflOstracal 
banding are In Quadrants 111 and IV. while 
smoother-shelled populations Wllh a lower In?
cidence 01 penoslracaJ banding are In Ouad? 
ran ts I and II Quadrant II has only pop?
utahons from Oramage 4 wnlle the other three 
102 HERSHLER 
o 1ii168 
" II I I 
" 
0 . 100 
" 
0 . -4 32 \ 
" rf'\ ~, e .. Im_ " I ---- 88 0 . 164 " 2 , 
-0 1 03 
8~ III 3 
? A..: ~ IV 2 t' ~ -4 
97 / 1 ' ,- ~ too 95 {g6 '" / ~7 1 ~ 
38 31 
" -0 31 1 
- 1.1.3 -0 886-0629 -0.372- 0 . 11 50 . 14 20 . 3980.6550. 912 
1 
FIG <116 OrdIflilllC1r1 diagram 011 " 2 pnropal COi"pOlients, drawn according to nOfHTletnc; mullO(1I1T1Or1S1OOaI 
scalong The num/Jefs .ele< to the 33 populiIhons 01 Me~,pyrgus cIIunnceaIIus (Fog 37) The m, ... rnt.m 
spilnnooQ tree anod subset solutIOnS have been superimposed 
quadranls have populations from several 
drainages each. The population Irom LocalIty 
88 appears as an oulher In Ouadrant I be?
cause ,ts members have a very small , 
smooth, non-banded shell 
In FI(I 48, the ordination of component 3 
versus component 2. the tnlluence 01 Size IS 
removed. In this case, the populallOOS group 
to an even lesser degree by dramage In 
Ouardanl I, smooth-shelled populalJoos from 
Oramage 2 (10 , 20. 21) group WIth those of 
Drainage 4. In quadrants II and III. pop?
ulabons with sculplured shells With Ihtckened 
sutUfal bands are round: note that \t1eSe 11'1-
elude populahons trom Drainages n. IV and V. 
The populahons trom localities 99 and 73 are 
outliers In Quadrant tV as their shells are 
usually banded and the males have a Single 
lobe on the Inner curvature of the peniS 
The muilivanate analysos Indicates that. of 
the characters used. there IS no conSistent 
pattern of geographIC vanall()l'\ among the 
various populatIOns In relallOO 10 drainage 01 
the eight subsets Iorrned. three are formed 
among pofXJlatlOfls of Drainage 2 (10-21. 
48-49. 18-47). three are tormed among pop?
ulations of Drainage 4 (50-79. 80-83, 78-
61). but two are formed among populatlOllS 
Irom Widely separated drainages' 22- 93 
(Drainages 2t and 4b) and 30-96 (Drainages 
2b and 5): and these two subsets Illustrate the 
p roblem of recogrltz.ng dlflerent "speoos" of 
CUATRO CIENEGAS HYDROOUOS "XI 
o ? 1 1 
02'" 
" / 
, 
0 .0 77 
II 
" 76?62 
? 
" 
.. 
/ 
/ 
" 
" I 
" 
3 r---------1;'?r-~~~~~~+_----~----
-0 . 089 
III IV 
" 
" 
- 0 . 256 
.. 
" / 
.. 
1 
FIG .7 0?II0a1lQn diagram 04 1 ) 3 pnnc!plll (X)InpOlle1lt5 
MeXfPYrgtJS. The two populations at OraJOage 
5 are highly sculptured and are relerab4e to M. 
carranzae (sensu Taylor. 1966) Yet one sees 
a reman<ab/y Slmllar?shelled popuiallon (30) 
Irom OramagEl 2b, on the other SIde at the tall 
SleHa de San Marcos. Wl th a low probabili ty 
of prevIOUs connechon between the two 
dramages (Fig_ 37). In the other case. while 
populahons Irom Drainages I and II. In gener? 
al . are moderately sculptured. Wlth thK;i(ened 
sutural bands. and are re 'erable 10 M chunn? 
ceanus (sensu Taylor. 19661. populatlOfls 
WIth SIm1Iar features are seen II"! Oralflage 4 
(71 . 78.81.86,93, and loca~1y 90. Fig 38 
bottom row). ~sedly the dr8lnage harbor? 
IIlQ M tIgoI (sensu Taylor, 1966. smooth?
shelled. Wllhout a thICkened SUlural band) 
WhIle some 01 these Oratnage 4 popuiahons 
(partICUlarly 71) are located dose enough to 
the low. northern tip of the SlCfra de San 
Marcos (Fig 37) that they COIJId have been 
founded by snruls 'rom western lobe waters 
(and hence their M cIlunncesntJs?llke lea? 
lures) given a prevIOUSly dllferenl topography 
the other popuIatlOllS (86. 93) are conSIder? 
ably 10 the SOlJItl and east 01 the mountwn hp 
and probably could not have been louroded II"! 
such a fashlOfl 
One musl conclude. therelore. thai despite 
some geographIC ddlerenhallon 01 M. chtmn? 
ceanus popUallons, separate speoes cannot 
be distingUIshed. as SImilar ~
feallJres mvolvlng shell SIze. SOJtpture and 
banding pallern have apparently been 10? 
dependently aCQuired In separated pop?
oIalions The panem seen In the ordMlatlOIl 
.o' HERSHlER 
o .. I I .. 
II \ 
0.2 44 
" " ,. 
" 0 . 011 
3 
-0.0 69 \ 
" 
" " 
\ 
-0 . 256 3. 
/ 
" 
97 .. 6 
- 0 .. 2 2 ."": _ _ :"-,--,--:"-,.'-,---=-'...,-,--,-'.,..,.,......,-'.,..,.,....-:"':-:-,-...,..'=-_...,-'-:-_ 
-0 . 31 1 -0 2 1 2-0,052 0 . 1 0 1 0 . 2 66 0 . 4 2 6 0 . 585 0 . 145 0 .90 4 
2 
diagrams. with many populations clustered 
together and a few outliers WI.h unusual fea?
tures. IS one 01 a single variable speclE'S_ 
While 'he S, I( nominal species must be re?
duced 10 one, there may be three races Of 
subspecies, corresponding to M chunn?
ceanus. M /ugOl and M carranzae (sensu 
Tay'OI, 1966), as populahons 3SS1Qnabie to 
each are concentrated In dll/erenl portions of 
the baSIn dr3lnage, Oralnages I and 11. III and 
IV, and V, respectively. 
The she" features 01 Me'(Jpyr9US chunn?
ceanus may be somewhat plashc phenotYPI?
cally and dependent on enVlf()"1rnental lac?
lOIS. While populations located close to one 
another may be QUite SImilar (sum as subset 
48-49), In other cases populations Irom 
close-by spnngs (even those With an aquatIC 
connection) are QUlle diSSimilar on shell 
characlers, espeCIally when lhe spnngs diller 
In Size, tempefature, or substrate type For 
example, the populahons from l ocalities 80 
and 79 are Irom spnngs (one smail-Sized and 
cofd , the olher large and warm) separated by 
only 100 m 01 sileam, 001 diller grealfy In shen 
size and Irequency 01 a Ihlckened SUlural 
band (Table 49, FIQ 37) Populatlons from 
l ocalitieS 76 and 73 are also from close-by 
spnngs (one farge and warm. the other small 
and very warm) wllh a shor1 stream connec?
tion, but diller enough 10 have been placed N"I 
different SpecIeS (Fig, 37: Taylor, 1966). How?
ever, when I collected and studied snails from 
a transael along the slream connection be?
tween the springS. InlergradatlOn of the two 
forms was appareol (Hersl1ler, 1ft prepara?
lion) In several cases I VISIted spnngs thai 
had been altered by dredging In these cases 
CUATRO CIENEGAS HYDRQBIIDS ,os 
the lIVing specimens dlUered greatly III Size 
and sculpture Irom sub-fossil specwnens 
found In the dredged sediment alongside the 
spong, suggesting Ihat (as the drec:lgtng was 
recent) the habitat change qUICkly resulted In 
a shell change, 
Shelileatures may also depend on whether 
the populatlOfl lives to a lentlC ($pf1ng) versus 
IotlC (stream) habitat. note that the spnng?
head and downstream populallons In two tn?
stances (from locallhes 1 and 5, 10 and t t) 
differ greatly In size. sculpture. and baoong 
fequeocy Banding frequency comelates With 
subslfate color: populatIOns from Spl'lngs With 
light-colored sediments are generally un? 
banded while those from Spl'lngs With darker 
sedlmenls are usually banded A banded 
shell may appear CryptIC In dark sedmenl. 
making It more difficult to be seen by pre? 
daceous clchlld fish as they disturb and 
search the sediment when feeding 
RELATIONSHIPS AMONG THE 
CUATRO CIENEGAS HYDROBIIDS 
The results 04 anatomICal sludy of !he Cua? 
Iro Clenegas hydrobuds show that all of the 
taMa belong to the Nymphoptlltll'lae or Uttor? 
tOmnae (see Table 2) are widely distributed 
subfarmltes. Thus while there are endemIC 
genera. there are no subfamlhes 01 hydroonds 
endemIC to the Cualro C.enegas BaSin WMe 
the relatlOflshlDS among the vanous hydrOOlid 
ta)(a 01 Cuatro C!l~negas are diSCUssed be?
low. and shed some light 0010 the 0"9,n 01 the 
endemIC taxa. the diSCUSSIOn IS necessanly 
limited as the hydrobuds of the southwestern 
Untted States. MeXICO. and Central Amenca 
are almost entirely unknown In terms of soh 
part anatomy. wllh many taxa shit unde?
SCribed 
The two nymphophiline genera 01 the 
basin. Mex/sflObfa and endemic Nymphophr?
Ius, differ In at least 10 morphological features 
(Table 52) However, many 01 these dif? 
ferences may be Slmpfe correlates of the 
great sl1:e dIfference between snails 01 these 
ta)(a. and the two genera may. tn facl, be 
closely relaled 
A comparison 01 the SIX 11lIOl'ldlmne genera 
of the baSln.1Il\IOIvJng 36 characters. IS gIVen 
In Table 53 01 these characters, $IX (17%) 
are from lhe operculum Of shell, seven (19%) 
are Irom nonreproductive aspects 01 an? 
atomy. e'9ht (22%) are from the male repro?
ductive anatomy. and hfleen (42%) are from 
lhe female reprQducltve anatomy A m<lln)( Of 
percenl dillereoce between these taxa IS 
given In Table 54 and was constructed by 
Simply counltng differences between taxa 
pairs and dlvtdtng by the total I'H.IITlbef of 
characters shared by the two taxa In In?
stances where for a given character two taxa 
both share a character state and have a (il? 
lerent characte, slate (e g .. I . 2 versus I . 3). 
Ihe dillereoce IS scored as 0.5. A phenogram. 
based on SImple averaging of <Jifferences be? 
tween ta)(a. IS gIVen In Fig. 49, 
The phenogram (Fig 49) tndtcates lhat 
there are three groups 01 hUOrtd!mnes III the 
baSIn. each conStitUting a paIr of genera Two 
01 the groups COflSlsl of very Similar genera 
? 29% clillerence), the groups thernseWes 
linking at 46% difference. The ta)(a 01 the Ihtrd 
group, PaWscala and Coahuli/x. link al 41 % 
TABLE 52 list 01 10 morphological dt1tCfenccs botwooo Mc/l/511Oba and NymphopIlIIU5 
Mt!/l/511ObuJ 
I Operculum Wllh 35 whorfs 
2 Osphr-adlUt'l1 short 
3 Ccfl1rat 100Ih or rlldula wolh I paw or ba5a1 
..... 
4 Male gonad OVCflaps slomach 
5. Male gonad a SIngle lobed mass 
6 Penis v.,th StOglc glandular ndge 
7 Perwal lobe slender. WIth SIngle loki 
8 BoIstCf and VilIltral chitnncl poorly developed 
9 Bursa small (21% 01 pallial 0VIducf 1eng11\). 
dorsal 110 pall",1 ovK!uct. Wllh II shorl duct 
to Oponong 01 common 9(!f1<tal aperl\Jre al end of 
palkal OVIduct 
5 5-6 0 wtlorfs 
Osphr <idIom elongate 
3 PIllfS 
Malo gonad postCfIOf to stomach 
Male gonad bush-hkc 
t---3 glandular ndges 
PCl1lal)obe $lOUt v.ltt1 many loids 
Bolster and venIJai channel well?developed 
Bursa large (32'Iro 01 pallial oviduct longll\). poslCfIOf 
to pal~aI 0'IIduct. With II tong OUCI 
Opcnong 01 COiltnon geodal aperture taler1ll10 pal? 
I,al ovtO..tct 
106 HERSHLEA 
TABlE 503 Compaffoon 01 the SI. htlOfodlnlne genefll 01 Coallo Coenegas IIWOIvlng 36 ehamelers Pal 
Palodscald. Coah Co/Jhulil~ COd1J CCCtI/Icpna. Me",'h Me"'lhat.ma. Dot Ovrangonella. Me." 
MexPrtf1US 
Cha<acter PN COOh, C?N Me.,1t! Du, M, ,? 
ShO' 
"'-
3 0 0. ' 3 2 
a) plamspual (0) 
b) IT()ChoId.gIobose (1) 
c) OIIa!e-cono:; m 
djlumlorm (3) 
2 Sculplu.e 0.2 2 2 0.1 
al nbs (0) 
b) spwal cords (1) 
c) absent 121 
3 Apocal whorl rTlIC.oscu lpture 0 0 0 
a) poned (0) 
b) absent (1) 
, Shell WIth penostra.cal baods (0.1) 0 0 , , 0 , 
5 Shell aperture fla red (0. I) 0 0 0 0 0 
Elttemal Features 
6 T entacie collatK)l1 0 2 2 0 
al absent (0) 
bl~?hke( l ) 
t) Sputw!nlrra-hke (2) 
, Sna~ blInd. unpigmented (0.1) , , 0 0 0 0 , Mantle edge papUala (0. t I 0 0 0 , 0 0 
9 Pi)sotoon 01 operculum nucleus along long 
.= 0 0 
a) < 030 (0) 
bl ~030( l ) 
OoI)esIrve System 
10 OIgesttve gland tubercles as low swe\llogs 
(0. I) , 0 0 0 0 
" 
intestIne WIth anteno. loop (0. 1) 0 0 0 0 0 
" 
Caecal chamber edendS paslenOl" to 
stofnaCh (0. t) 0 0 
" 
0ngIn 01 basal cusps 01 Ce<1tral IOOIh of 
,...." 0 
a) Itom face 01 tooth (0) 
b) from lateral angles (1) 
Male ReproductIve Anatomy 
" 
Male 90fliKI morphology 2 2 0 0 0 
a) sompIe lobes (0) 
b) bush?l,ke (1) 
c) non-lobe<I mass (2) 
" 
Seminal vllSlCle cools ()f1 Slomadl (0. 1) 0 0 0 0 0 
" 
Prosune posterlOf to end of mantle ClMI)' 
(0. 11 0 0 0 0 0 
" 
PenIS Wllh slenc:ler penIal hlamenl 10 1) 0 , 1 0 0 
" 
Penlilllobe(sl 0 0 2 2 
al absenl (0) 
b) OOI!H1iIoe (11 
c) SImple (2) 
" 
Perr.i Clkaled (0. 11 0 0 0 0 
20 Pens WIth remllnal eve!SIbie papilla (0. 1) 0 0 0 
21 Penes WlIh speoahled gland(sl (0 1) 0 0 
CUAlAQ CIENEGAS HYDAOBIIOS 
'07 
TABlE 53 (Conl'nued) 
ChlUacler p., ""', 
"""" 
Mex,ff) 0." Me.~ 
Female ~oducl've At1alorn~ 
22 Female gonad overlaps slomach (0 'J 0 0 0 0 0 
23 Female gonad 0 2 2 0 
a) relat,vely IlUge. lobed (0) 
b) relatr.oely Large. nonlobed (1) 
c) ,elatlYely small . a mere thlCkerung of 
CMducI (2) 
" 
Aeptoduct,ve rrode 0 0 
a) ovopanly (0) 
b)oYC>Vt .. "pa"ty (1) 
25 Length 01 pallial oviduct 'I&ogth 01 body 0 0 
a) - OJ(} 
b) -OJ(} 
26 Length 01 bu,sa length 01 pallial (Mduc1 2 0 0 
a) < 0 20 (0) 
b) - 0.20 ~ 040(1) 
c) ' 040 (2) 
27 Albumen gland 0 0 2 2 
a) notmal sue (0) 
b) ,educed on s,ze I I) 
c) veoy redvced In Size (2) 
28 PosterIOr palhal CMdUCI 0 0 2 
a) Wfth bend (0) 
b) ... 111 SlI11j)Ie bend (1) 
c ) ... Ih ~x bend 'n mote lhan one 
plane (2) 
,. Normal semoal roceplacle present (0. I) 0 0 
30 Secondary sermnal ,eceplacle preSllflt 
(0. 1) , 0 0 0 0 0 
31 CMduct Wllhoul COIl (0. 1) , , 0 0 0 0 
'2. Spermal hecal duel 0 0 0 0 
a) long (0) 
b) shof1 (11 
33 01 OVOVNipafOUS taxa. anterlOf end 01 pal . 
.. ,"""'" 0 0 
3) w+lh shgP11 rruscular cod (0) 
b) ... 111 weIi.ooveioped nlU5O.lllU cool (I) 
" 
01 lalla w,Ih a tlOflTllIl semnaI 'eceplade. 
the semonal 'oceplacle opens onlO 0 0 
a) lhe oVlduel doreclly (01 
b) lhe oVIduct Via a spe,m duct (1) 
" 
01 lalla w,ff) a tlOImal semlflal receptacle. 
!he length ollha seminal 'OCepiacle.lenglh 
01 bursa 2 0 
a) < 03O(0) 
" 
OJ(} < 050 (1) 
oj 050 (2) 
,. OIlaJCa With a long spe,malhecal duel . !he 
OJlI!fWl9s 01 the spermathe(:al dud and 
paIIaI O\IOduet a,e 2 0 
a) separale (0) 
b) fOOned (1) 
c) separale bul w,lh an open channel 
between 1hem (2) 
Hl8 HERSHlEA 
TABlE 54 A matn. 01 percent O,He<ence belween P<lOfS o11he 6 1,llOndonone genera trom Cuat.o C.er.egas 
(based OIl (laI" trom fable 53) 
PaWSCal..l eo._ ~. 
Pa/udtscala 
" 
69 
""""', n 
"""-" MexllhalJma D,,,_ 
"",-
'-I ? ? Uh'um. 
C ocnHop,na 
O",angon.,lI, 
Me.,py.gua 
Palud,acil' 
CoahuUix 
I I I 
? 
., , , 
? 
, , , 
FIG. 49 Phenogram based OIl cMlance values 
dertved '.om Tables 53 and 54 
--
s.-....... Pol coati. ...... 
'. 
. , 
? 
FIG 50 Cladogram based 00 cNIfOCIe< slales 
~Sled In Table 55 Pal PaltJcjSC8/a Coah 
(;()ahu,"". Me.,p Mo .. py,gus-DlJ,angonella 
group, and Me.,1 MOI(,rhauma-CochIIOpfflB 
group Paludsca/a and Coohu,hJt share character?
stall!$ 5--1 (hence the ClfCIe eodoSong Ixlth laxa) 
difference. ThIS group links With the other lour 
gener<l at 75% difference 
An hypoitleSIS 01 the phyletIC retalloostups 
among HydrOO8 (HydrobunaeJ, the SIll Cua ?
lro C.enegas httOrlchnllloe genera. and Spur?
wmkl8. the only other North Amencan I.Uorl?
chnli1e known from erMe SOft?part anatomy 
M(mlhal?Jla Dutangone/la MeJl'PY'(JVS 
" " " 82 82 
" 
" " 
.. 
.. 53 
29 
(see Oavls el al .? 1962). IS shown In Fig SO. 
The numbers indIcate presumed derived 
character states. listed In Table 55. used to 
deline ctades. Several 01 these Character 
states. relating to the lemale reproductive 
sys te m. ale Illustrated In rig . 51. "A ? 
represents an hypothetiCal ancestral hydro?
blld. With the female reproductive anatomy of 
HydroOla. 
In Hydrobta (Fig StAI. sperm pass along 
the Ciliated ventral channel 01 the pallial OVI?
duct, whICh connects With the lumen 01 the 
pallial oviduct via a narrow Sill. The ventral 
channel bifurcates at the posterior end of the 
mantle cavity: one branch leads to the bursa 
and the other IS the antenor end of the OVI' 
duel. ThiS groundplan of the female reproduc?
tive system IS found In all Hydroblinae, Nym?
phophlhnae and lithoglyphinae (DaVIS el a/ .? 
1982). 
DaVIS et al (1982) suggest that SpvrwmJoa 
(Fig 5\ 8) evolved Irom an ancestor With an 
Hydrobla.hke lemale reproductive system by 
haVing the ventral channel close 011 and parlly 
separate Irom the par~ar Oviduct (character 
state 1) As the eggs need to reach the albu?
men gland. a coonechon to the albumen 
gland from the OViduct formed (character 
state 2) ; and the duct from thai POint to the 
duct of the bursa became an extenslOl1 of the 
duct 01 the seminal receptacle (character 
slate 3) The ventral channel IS only parlly 
separated Irom the palhal oviduct. suggeshng 
that SpufWmkla IS only a slep removed Irom a 
snail With an Hydrobla-hke female reproduc?
tive system, Spurwlflkla has the adclltlOl1al 
denved lealule of holding egg capsule chains 
In the anterior end 01 the capsule gland 
(character stale 4) 
While In Paludlscala the ventral channel IS 
Slill only parlly separated from the pallial OVI' 
duct, In CoahulllJ' the channel has separated 
enllrely and conshtu tes a spermathecal duct 
(character slale 8) CoafJtJlllx and Paludl5Ca1a 
CUAlAO CIENEGAS HYOROBIIOS 109 
TABLE 55 Presumedly dl)flved c;haracle< Slales 00"'"'19 10 define clades as shown In F.g 50 
I Par11i11 separation at lhe venlral chaIV'IeIhom lhe palhal 0V1tIucI 
2 The OVIdUCI ef1lers lhe posIeflor po<1IOn at lhe albumen gland 
3 The duct 01 the semrnal receplade eiongales, ConnectIng 10 lhe wei 01 the bursa A sperm WCI 
comects the ovrcluct wrlh lhe duct ot lhe semrnal receptacle 
4 Egg capsule chaIns are retaIned Wllhon lhe a,,"enor end of l he capsule gland 
5 Loss o' eyes and pqnenl 
6 Loss 01 OVIduct COIls 
7 Loss 01 semnal receplacle 
8 Complete separallOO Ollhe ventral channel from lhe pallial 0VIduc1 ? ? 0mW'IQ a spennathocal dud 
9 Asstm1lIIOO of ovovlvlparrty lhe allfeoor pallial oYIduclls enlarged and rnocItlied Into a lhln.walled brood 
pouch. WIth lhe albumen gland reduced rn SLle. and wIth the development of a muscular Sphlncte< at lhe 
arnenor end of !he brood pouch. 
10 51'1111 ot duelIng Ihe ducl 01 the SI!mIflaI recep1acie snonens to open dllectly II'lIO 1t1e OViduct and a short 
dud forms between the bursa (or duet ot the bursa) and 0II0ducI 
, ~ ~~.o 
?? t,) ~." .. - J J ~ ~~ ~- .. ~ 
? .. 
? A o . 
~ B 
-><' - --I ." '><-
- ~ 
- ~ ~ ~~-? o. u .. 
? -~ C 
0 
FIG 5 1 Sct.emalrc draWIngs at the lemale reproductIve rTIQrPhoIogoes ot HydroI:?a (A). SpuiwlnkJa (BI_ 
CDahurltIi Ie). and Mellrrhauma (0) Lette,.".,.. as on earlier Irgures 
are considered closely related and spec.al?
'Zed: lhe evolution of these talla has .nvolved 
loss Of reductJOn 0/ morphologrcal features. 
either assocraled WIth the very small SIze 01 
the snatls (character states 6. 7) or aSSOCI?
ated With the unusual groundwater habllat 
shared by these ta.a (eharacler slale 5)_ Hy?
drol:>rold snarls WIth a presumed gloundwaler 
habllat are known from many parts 01 the 
wOIld and are frequently smail-SIzed. blInd, 
and WIthout body ptgfflenl (Boeters. t979-
Cllmo. 1974, Ponder. 1966) The bursa copu?
latfl ~ complell of Palud/scala and CoahUlhll 
(FIg. SIC) could have been derlVed from that 
01 Spurw,nkJa by loss of the semrnal recepla?
ele and elOf'l93tlOn 01 the sperm duct so as 10 
11 0 HEASHLER 
connect WlIh the ovlClucl al the openIOQ Into 
the albumen gland 
The remall"llng IOUf h1l0lldll1lf'lCs 01 Cualro 
Cli!negas aU have the female Iep!OOucl lve 
anatomy modilled as the result 01 the 
assumphon of ovovIviparity (character state 
9) In the Mexlpyrgus-Durangonella group, 
the orgaOlzatlOn of the bursa copulalnl( com?
plex IS basically as In Spvrw,nkJa' a short 
sperm duct COI"IOe(:ls the doct 01 the seminal 
rec;:eplacle Wltt'l Hle ovlClvct 
In [he f..,fex,lhauma-Coc:hhopna QfOlJP Wd ?
Ing IS d."erenl the seminal receplade opens 
""ecHy ... 10 the ovlducl and a short 00ct con?
nects the bursa (CocfWtapma) Of WC1 01 the 
b,,,sa (Me . .,thaum3, Fig. 510) and the OV!?
(tucI . These taxa share a puzzling mosaIC of 
maracla slates While the opel'llng at the 
seminal receptacle directly tnto the ovlduClIS 
also seen In Hydrobla (oot no! Spvrwtnkla ; 
see above) and IS arguably a prlm.llve 
character state suggesting a close reiatlOn?
stllP among these lalla, the spermathecal 
duct IS enllrely separate 110m the pal.al OVI?
duct. a Del'lVed character slate If1dIcatlng tha i 
Melli/haLma and Cochhopma evolved IrOm a 
$purwrnk.oa?!,ke ,nlermecliale II seems prob?
able !hal Ihe openlllg ollhe semnal recepla?
de oreCIly IflIO the oVIduct. Wllhlll the IrtlOfldl?
mne groundplan. IS a dEmvoo c::ond<bOfl and 
convergent WIth that 01 Hydrobla. Nole Ihal . 
among IIUondlfllnes. thiS c:ondtllO has 001'1' 
been found N1 McxI/Muma and CochIlOpma. 
whereas In other IIUortdlfllnes 110m vallOus 
parts 01 lhe WOfId lor which the analamy haS 
been Sludted. the seminal receplacle con?
nects wdh lhe 0\I1Ouc1 via a sperm o..tCt 10alils 
el aI . 1982) The IaUer. rrore Wldespl'ead 
condIllOIl IS probably the prt1TllNe one. The 
condJ11OIl seen .., Mexllhauma and CocIlIio?
pma could have been derl\led lrom lhal 01 
Spwwlfllua by a shorIeotng 01 the o..tCt 01 the 
5eIT\If1a1 receptacle. SO as to open 11'110 lhe 
OVIduct. and !he deYe1opmen1 01 a duet Irom 
the olilduct 1.0 lhe bursa or duel 01 lhe bursa 
(character sl ate 10) 
Ctlaracler stalas Ifom the lemale leproc:luc?
tlvO system have been emphaSlzoo In the 
phylehc analySIS because 01 the compleJl;Jly 01 
the syslem Irelallve to olt18r organ syslems In 
hydroblOld snails), WIth several organs and 
duets lunctlOf\B.lly 0I98(1IZOO 10 receNe and 
hold speml. fertltlZe eggs. and prO'o'1OO pas. 
sage lor the eggs or embryos through lhe 
pallal 0VIducI Prease COr'lVCfgences should 
be lrIIlkefy Ir'I such a system Vel Ihe phyletIC 
analySIs rocates lhat wllh the present data 
base. characl8l' states Irom the female repro?
duei lYe system carrnot always be conhdently 
scored as PIIIllItIYe or dorlVCd, the hypothe?
SiZed phylogeny IS therelore tentallve. An? 
alomlCal dala aro needed tor moro taxa to 
reline the phyletIC analySIS It, 101 Instance, 
hllOlldlnlf)e taJl;a 8(e toond thaI have lhe semo?
nal receptacle opening Irlto the oviduct as III 
McxJlhauma and Ccchbopma, but also WIth 
the ventral channel only partly separated Irom 
lhe palhal 0II1duc1 (as III SpufWlnkJa) thefl a 
rearrangemenl IS suggesled so Ihat Mox?
llhauma and Coch/lOplna are placed closer to 
"A- than Spul'Wlnklll. 
Convergence IS nol enillely unknown 
among features 01 the lemale reproducllV9 
system of hydroborcl snails. the PomatlOpSl' 
dae and LJllOfld!nrnae bolh have spel'mathe?
cal ducts, bul 01 separate ontogenetIC ongtns. 
The ducl of the Pomallopsldae lorms as a bud 
Irom Ihe bursa (Oalils et al., 19761 while lhat 
01 Ihe LlltOflcllnlnae presumably forms as the 
ventral channel doses oft and separates from 
the pallial oVldUCI (DaIllS el al .. 1982). The 
orgaflizatoo 01 lhe bul5a copula lflx compIeJl; 
01 Mexllfiauma (Fig. 3081 IS. In fact. \llltually 
IdenIiCal to lhal 01 PomaIIOPSlS (DavIS. 1967, 
pl. 8) ThIs ITllSI be because of convergence, 
as MeXJlhauma lacks lhe folloWIng dlagnoshC 
pomallopslOC lea lures eyes In pronounced 
swellirgs at the bases 01 the tentacles. pres? 
ence 01 a pedal crease and suprapeclal fold. 
and basal cusps anSlflg Irom the lace 01 the 
central toolh of the radula (D aVIS. 1979). 
Ch alacter slales Involved with brooding 
young al6 unreliable, If) themselves, 101 do?
flmng dades as tho evoiuhon 01 OVOllllllpalily 
Involves Simple, lunchonally correlaled 
morphologICal changes (see below). and has 
OCCUlted !tCfalIVely among many groups of 
gast!opOOs (Fleller & Graham, 19621. Among 
hydrobolds, OVO\IIlIIpartly has evolved at least 
IW1CO: III lhe httorldllWl8S and In Polamopyr?
gus wtllch have an Hydrobla-tlke female r8-
productive syslem (Flet1er & Graham, 1962, 
fig 166H) Other chalaclcrs whose charaCIcr 
states could be scored as prlm,hv6 or derlVCd 
Wi th even less ronfldenoo, and hence we/e 
exclUded 110m thIS analySIs, Iflclude penIal 
form and gland Iype. lenglh 01 the Spel'mathe?
cal duct. and tenlacle o llallon pattern. 
The dala (summaflzed In lhe phenogram 
and claclogram) suggesl a polyphyletIC orrgm 
lor the endemic hydroblds 01 CUil lro Crene?
gas Of the llYe endemic genera each of 
thlee (N)'mphophIIus. MeXllhauma, MeJl;tpyr?
gus) IS more srm/af 10 a non?OfldemrC genus 
CUATRO CtENEGAS HYDRQBnDS 'n 
lound II'l the baSin than to the othel' endemIC 
taxa, suggesbng that the endemic hyaoblCl 
lalM'la may be comprised 01 at least lour sepa?
rate lineages. 
ORIGIN OF THE ENDEMIC SNAILS 
OF CUATRO CIENEGAS 
The Idea that the endemIC hydroblds of 
Cuatro CK!negaS are an anoent launa, WIth 
most laxa no! closely related 10 other hydro?
bids 01 the reQlOll . IS ptevalentll'lthe hleralure 
(MIndUey. 1969. 1977; Taylor. 1966) This 
hypothesis IS based on lhe supposed endem?
Ism of subfafTWhes 01 snruls that have diverged 
from a common ancestor. neoeSSllatJOg an 
angln datIng back to the Ter1lary penod based 
on the usual slow rate 01 freshwater snail 
evoluilOn (T<:iYIor. 1966). Does Inlormahon on 
Ihe geological history 01 the regtOll , coupled 
With the (above) resu lts of systemahc sludy of 
the snarlS. suppor1 thls hypotheSIS? 
1\ IS known from study of 10SStI plants Irom 
packrat mtddens tha t the Chlhuahuan Desert 
IS 01 recefll angln. the change lrom wood? 
lands to desert ha .... ng occurred dunng !he 
past 12.000 years (Van Oevender. 1916. 
1977; Wells. t977). There IS faunal and 
structural e\lldenCe that a number of Internal 
dramages 01 the Chlhuahuan Desert once 
IIltegrated WIth the RIO Grande system. and 
have Since been Isolated, perhaps due to 
decreased discharges aSSOCiated With r(l(:6I1t 
andlty (Mot-alka. 1977; Smith, 1981) The 
launa 01 these now-Isolated drall'lages rs 
characlerlzed by rel1c tualrsm and local 
endemism (Miller . 1977; MIlstead, 1960, 
Morafka. 1977) 
A good summary of the geological history 
01 the Cuatro Clenegas area a...:! ItS effec1s on 
IsolatIOn 01 the basin drainage IS grveo by 
Mlnckley (1969) While It IS known that the 
Sierra Madre Onenlale chain began to Iorm In 
the early Ter1 lary, the age of the Cuatro 
C~as Valley IS unknown It IS known. from 
a study 01 pollen from cores taken Irom the 
valley, that aQuatic enwonments have ex ?
ISted In the valley for at least 40,000 years 
(Meyer. 1912. 1913) The baSIn waters have 
had past COI"IIlE!dlOl'lS With the RIO Grande 
dfat~ VI3 lhe RIO Salado de NadaOores. 
which heads lust east 01 the valley The hsh 
launa 01 GuattO C.enegas has numerous RIO 
Grande elemenls (MlnckIey, 1977) 01 the 
snatIs, CtxMopna "OgrandenSlS. a sp8CteS 
WIth a RIO Grande dlslrrbullOl'l . IS Iound II'l the 
baSIll; and Nymphophlus. one 01 the endemic 
genera. has been fou...:! as a Iossd from 
Pietstocene-Holocene depositS alongSIde the 
RIO Monclova (a RIO Grande tllbutary), 70 km 
east 01 Cuatro CIE!negaS (J Landye. personat 
communlcahon. 198t) Waters from the 
southern RIO Nazas-Aguanaval system may 
have also connected With the Cuatro Ctefle?
gas drainage In the past (Conant 1917, 
Mlnckley. 1969) Two 01 the rron-endefTIIC 
genera 0I1he baSll'l. Dtxangonel/a a...:! Mex/$?
Itobla. are known hom the R,o Nazas?
Aguanaval dratnage. but not the RIO Grande. 
The above evtdence. suggesl lng that the 
waters 01 the baSIn have had a recent con?
nectlOllto ouIsIde dfarnage. coupled WIth the 
discovery 01 a lower level 01 endeflllSfl1 than 
once thought. WIth no endemtC subfamtlres 
and three 01 I .... e endemIC genera closely re-?
semblrng non-endemIC taxa found In the 
baSin. suggests thaI the endemic snails may 
be 01 a more recenl and local OIlgln than 
preYlOusIy thought 
The RIO GranDe drainage 01 Texas <W'ld 
MexICO. <W'ld alher waters of southwest Texas. 
do harbor IrllorlCllntne and nymphophrhne 
taxa. Genera lrom this area assrgne<l to the 
ltllondintnae. on !he baSiS of a perilS WIth 
stalked. spectalrzed glands (not glandular 
ndges). IncUde Texadma (peniS hgured II'l 
Andrews. 1917 82-83). Lt"ondlnop$ (An?
drews, t917_ 84). and Pyrgophorus (Fulling?
ton, 1978, frg 16) The dlshnctlve penrs type 
shared by MextSllobta and Nymphop/ltlus, 
With an eQ'lgate penlat hlament and small 
number 01 glandUlar ndges. IS seen In Fonte-?
lICe/fa (perilS dISCUssed In Gregg & Taylor. 
1965; hgured In Russell, 1971), recenTly 
found In a RIO Grande tnbutary not far Irom 
Cualro Clenegas (Lytle, 1972)_ AnatomtcaJ 
study 01 the above taxa IS needed to he1l 
determtne the onglll of the endemtc hy~()?
birds 01 Cuatro Clenegas 
I predICt that two 01 the endemIC genera 
Pa/udsscala and CoahtJI/tx. Will eventually be 
found hVlng II'l waters outsrde 01 the basrn 
(see below fo r diSCUSSion 01 possible 
Coahur/lx from Texas) MexICO IS undercot?
!ected for trash-water snails and most work?
ers have not employed the methOOs neces?
sary to ooIlecl hny snaIls Irom groundwater 
outlets This ptedlCllOfl IS SlJpported by the 
fact that of the three btll'ld. unJll9meo1ed 
crustacean genera Ol'lglnaJly descnbed from 
(and con5Idered endernrc 10) groundwater 
outlets III Guatro Crenegas, two. Mexswec:#(?
ella and Mexlslenasellus, were later diS' 
112 HERSHLEA 
covered Ifl cave waters In more southerly 
parts 01 MexICO \Argano. 1974, Holsinger. 
1973; Magrvez. 1972), The discovery of Dry?
goceras (?) sp, previously kno'M'l !rom a 
single sprlf'lg In southwest Texas, In Guatro 
C.enegas further atlesls 10 'he potential for a 
widespread dlslnbu!!on of groundwater?
dwelling taxa. 
Of the otOer three endemic genera, one, 
Nymphop/lllvs. may be relict as It has been 
found lossillzed outside the baSIn. and the 
other two could have evolved In \he baSin 
!rom the non-endemiC laxa thaI they closely 
resemble II IS now known that the rate 01 
evoluhol'1 of fresh-water snails can be QUite 
rapte! (DaVIS, 1979, 1981 ; Stanley. 1979) and 
thus one need notlnvoke an ancient 01'l91n for 
these endemIC genera 
The amount 01 diHerentiallOn seen among 
the snail genera 01 the baSin 15 shght (only 12 
specieS are known) ; no genus has more than 
two species. ard only one genus has sym?
patne congeners. Such mlnrmal dlllerenliatlOll 
does not SUPfJOrt Ihe Idea 01 an anctenl snail 
launa present In Ihe baSin lor tens 01 millions 
of years, aUhough perhaps In even such a 
long lime span 0f'Ie woukl nol expecl great 
differentiatIOn In SO small a baSIn With appar?
ently plastIC drainage patterns_ 
Members of the endemIC Cuatro C~negas 
snaillauna have been linked With those ol iWO 
Olher faunas and Ihese possIbilities are now 
discussed. Numerous peculiar-shelled snail 
taxa have been described from the Pliocene 
Pebas and olher formations from the Upper 
Amazon Valley In Peru (Boettger, 1878: Con?
rad, 1871 , 1874a, b: Gabb, 1869: de Greve. 
1938; Pllsbfy, 1944). Some of these taxa 
have not only been placed In the Hydroblldae, 
but have also been conSidered elosely related 
to some of the Cuatro Clenegas endemic !a.a 
(Kadoisky. 1980; ParodlZ. 1969). These taxa 
Include T ropIdebora (Pllsbry, 1944), Similar 10 
Nymphophllus; and Eubora Kadolsky. 1980 
( Ebara Conrad. 187 1), Similar to Mexl?
lhauma However. examlnallan 01 types 01 the 
Pebas ta.a shows thaI they cannot be hydro. 
bllds as they have a slphanal notch (Fig 52), 
or an otherwise peculiarly-angled aperture 
unknown In ~Vlng hydrobllds. Slmltanlies be?
tween Peba.s and Cuatro Clenegas taxa mUSt 
therelore be due to convergerce 
The Edwards AqUifer In southwest Texas 
harbors one oIlhe world's most dIVerse sub?
terranean aQUatIC faunas (longley. 1981) In? 
eluded In this fauna are a number 01 hny, 
blind, unpgmented snails (Karne., 1978) In-
eluding specle5 wrth lamelli form COSlae on the 
shell Ihal were aSSIgned to Paludlsca/a (Ful?
IU'l910n, 1978, IIg 17). AlcOhOl specimens of 
these specieS, stored at Southwest Texas 
Stale UrliverSlty, were sludled dUring Jan?
uary. 1982. These snails diller from Paludls?
cala In at least seven features, With the 
female reproductIVe anatomy stili uosludled 
1) the shell IS much smarter (length 1.1 mm) 
and has only 3.3-3 5 whorfs; 2) strong spirat 
Imes, not seen in Paludlscala, run between 
lhe costae (Fullington, 1978, IIg 17); 3) the 
aperture IS greatly flared all around, 4) the 
operClJlum has a slight Inlernal swelling or 
peg, not known lor any other North American 
hydroblOld: 5) the Inteshne has an antenor 
loop; 6) the penIS has neither lobes nor spe?
Cialized glands; 7) Ihere IS no ctervdlum. 
These differences rule out there being Palu?
dlscala. The Shell 01 these snails IS mUCh 
more Similar to that 01 Lanzala Bruslna. 1906 
(hgured In Bole, 1970, fig 6). a European 
hydrobhne 
While Paluc/lscala may not eXISl in the wat? 
ers Of the Edwards Aquller. It IS POSSIble that 
CoahUlI,x does. The type of Horalra mlCfa 
(Pilsbry & FerriSS, t 9(6). descflbed trom 
stream dflft (probably washed out 01 a spnng) 
of the Guadalupe River. New Braunfels. 
Te.as, is remarkably Similar to Coahuilix 
hubbsl. With simitar slight apertural flaflflQ 
Horatra fTIICr'a IS also reported f'Om the ar1e?
sian well at San Marcos, Te~as. and a sub?
terranean stream In Marliiou Cave, near Fort 
Payne , Alabama (Hubflcht . 1940). Un?
deSCribed Horalia are reported from Sala?
manderCave, TravIS County. Texas (Reddell , 
1965) and Roanng Sprtngs. Real County. 
Texas (Taylor, 1974) 
EVOLUTION OF OVOVIVIPARITY 
IN HYDRQBIOID SNAilS 
It has been suggested that the mltial step Ifl 
the evofullOl'l 01 ovoYIVlpanty in hydrobIOId 
snails Invotves a Simple morphologIC change 
separatlOl'l of the ventral channel 'rom the 
pallial oviduct to torm a spermathecal duct. 
thus keeplllg separate lhe functions of receiv?
Ing sperm and stonng embryos (DaVIS et ai , 
1982). The need for such a prerequIsite IS 
suggested by there bemg numerous laxa 
worldwide whICh lack Ihls separahon. only 
one (Polamopyrgus) IS known to brood 
young. $pu(Wlffkla and LJlfondmops are ap?
parent mtermedlales In the evolutIOn ot 
CUATRO CIENEGAS HYDROBIIDS 
"' 
fIG 52 HoIoIype (NYSM 9193) 01 Eubora bella (COnrad, 1871) The shell IS 7 58mm long Note !he 
SfPhOnaI notch on !he basal v.aw (lower fl11I9n.ocalooo) 
ovoVlvlparlly, as they have spermalhecal 
ducls (although thai ot the lormer IS slltl con?
nected antenorly to the pallial oviduct) and, 
wtllie lhey do not brocld young, Ihey hold egg 
capsules Ifl lhe anlenor end 01 the pallial 
oviduci belore dePOSiting them 00 the sub?
strate (DaVIS et ai, 1982) The hnondinmes of 
Cuatro C.enegas Incklde taxa lhal have lur?
lher modllicatlon of the female reproductIVe 
syslem associated with Ihe assumphon 01 
OVOVlvlpanty 
01 the SIX htlorldlnlne laxa 01 Cualro C.ene?
gas, two, CoahUllix and Paludlscala, are egg 
layers, but do not hold egg capsules III lhe 
antenor pallial OViduct. The other lour share 
leatures associated wllh the evolution ot 
OVOVIVIpanty Irom a Spurwmkta-like conditIOn. 
An have an enlarged pallial oviduct (to 58% at 
the body lenglh, lor Spurwmkla It IS 40%, 
DaVIS el af, 1982) that orten ovt!rlaps par1 01 
the stomach, and thai bends posterlOfty 10 
varymg degrees (Spurwmkla has a sllghl pos-
tenor bend at the pallial oviduct), Mexlpyrgus 
represenls lhe pinnacle 01 thiS trend as the 
length 01 the brood pouch IS vastly tJ1Cl'eased 
by a senes 01 COlts lhat are progreSSIVely 
dorsal to one another Whereas egg !aymg 
hydroblOlds have a thld<. walled, glandular 
pal hal oviduct WIth a sht-like central lumen, 
the OVOVllllpafOUS h1torldlOlnes all show at 
least some reductlOl'l 10 the Size 01 the albu?
men gland. WIth the other (much larger) sec? 
\Ion 01 the pallial oviduct modil led IOtO a Ihln, 
walled, non-glandular brood pouett These 
leatures ooliectlVely Increase the amount 01 
space available In !he pallial OI/Iductlor hold? 
Ing embryos In additIOn, all 01 these taxa 
have the antenor end of the brood pouch 
musculanzed. giVIng It the ability to Streich as 
large SiZed embryos are released. and per?
haps the ability to control timing 01 embryo 
release. QvovIVip3rous snails may not need 
great egg prodUCIIOl'l at anyone lime and thiS 
may explain why lemale gonads 01 three 01 
114 HEASHLER 
the lou! OVOVIVlpalOUS taxa are unusually 
small. filling only a por1lon of the length 01 the 
dogestlve gland al all times 01 the year 
The ovovIviparous Cualro CICneg3S hy ?
dfobllds appear to represent two dltterent 
brooding strategies. each represented by two 
laxa 01 the Silme clade. CochllOplna and 
Mexlthauma brood a relatively large number 
of similar-SIzed embryos, with orlly a two- and 
four-Iokl range In embryo shell lengths. re?
spectIVely. Ourilngonella and Mexlpyrgus 
brood relatively fewer young with a greater 
(live- and eghHokl. respectIVely) range of 
embryo shell lengthS The laner two genera, 
perhaps hoIdH'lg embryos for long time pen?
ods (hence the great range in ent>ryo shell 
lengths), may require a very long brood 
pouch. and they do. In lael, have a greater 
complexity of pallial OViduct COIling than the 
other two genera. It IS not known why the 
antenor end of the brood pooches 01 Coch? 
/1OpHla and MeJilthauma IS much more re?
lIected and musculanzed than In Duran? 
gonella and MeX!pyrgus: the lorme, two tal(a 
do not release relallvely large young. but per? 
haps they release numeroos young at the 
same lime, necessitating greater stretching of 
the brood pouch. 
Thus the evolution of ovovlvlpanty In these 
Irttondrmnes has rnvolved modilicatlOlls 0 1 the 
female reproductive analomy 10 Increase the 
amount 0 1 space available for holding em? 
bryos. and 10 allow and control the release of 
large-SIzed embryos Some of these brooding 
fealures parallel those deSCribed for other 
fresh?water gaStropodS. The two broodrng 
strategies outlined above were described lor 
species of the centhlacean Setmsulcospra 
(DaVIS. 1969b) The great deIIelopment of 
postenor pallial oviduct COiling In MeX!PYrgus. 
while unique among hydrobrord sna~s. IS par?
alleled by that seen In several Villlparrdae 
(Rohrbach. t937) 
ACKNOWLEDGMENTS 
My CO?adv,sorS. Drs Steven M Stanley 
and George M DaVIS. prOVided constant 
encouragement and hnanclal support dunng 
tenure of thiS Pl"Ojecl Dr . DaVIS suggested the 
protect to me, shared hiS knowledge 01 hytlro?
btotd snmls With me. and proV1ded the space 
and faclhbes at the Academy 01 Natural Sci?
ences of Ph~adclph,a necessary for compto?
lion 01 the prOje(:t Without hrs Interest and 
suppor!. the pro,ect would not have been 
completed 
I thank the Mel(tCan government for provid?
Ing the necessary pcrmrts lor collectrng Iresh?
water snails In therr coon try FleldWQfk In 
Cuatro CIOOegaS was aided by Or CurtiS 
Dunn. Mr Daniel Bereza and numerous local 
townspeople. Including Pepc Lugo. Hector 
RUlz. RefUQlO Gualardo. Benusllano GuaJar?
do, Gerardo Sauceda and Modesto de Ia 
Garza. The people 0 1 Cuatro Clenegas. par? 
tlcularly the familIeS of AntoniO PalacIOS and 
Modesto de la Garza. made my stay there 
pleasant. 
Or. W. l. Mlnckley and Mr. J Jerry Landye 
lent me aerral photographs 0 1 Cuatro Ciene?
gas and spent lime diSCUSSing Ihe area and 
launa With me Or Irving Kornheld diSCussed 
aspects of the prOject With me and lent the 
bol( core sampler Or Glenn Longley per?
milled me to study hrs specimens of hydro?
blold snails from Itle Edwards AqUiler 
The follOWIng InsbtutlOOS lent me matenal 
that was 01 use In the study. Academy of 
Natural Sciences of Philadelphia (ANSP), 
Field Museum of Nalural HISlory (ChICagO). 
New Vork State Museum (NVSM). and 
Smithsonian Insl ltulroo (USNM). Financial 
support came from SIgma XI. the Natronal 
Capital Shell Club. the Theodore Roosevelt 
Memorial FUnd. the Geotoglcal SocIety of 
Amenca. and the Nalronal InSlrtutes of Health 
(grant no. TMP-11373 10 Dr. DaVIS). A Jessup 
Scholarship partly supported my stay at the 
Academy 01 Natural Scrences of Philadelphia 
Research for thrs paper was done In partial 
fullillment for a Doctor o f Philosophy degree 
al Johns HopkinS Unlverslly, Baltimore, Mary?
land. I thank Drs. G. M DaVIS, w. F Pondel, 
and F. G. Thompson. and an anonymous 
reviewer for therr comments on the manu?
SCript. 
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8t'Id process Freeman. San FrancISCO. 332 p 
TAYLOR. 0 W . 1966. A femarkable Srl8l1 i auna 
trom Coahu.la. MexICO. Ve/<gef.9 152-228 
TAYLOR. 0 W . 1974. The Tertiary gaslr(lpOd 
~as found h~lng A/ChN fur MoNuskenk?
t*1de. 107' 93-96 
TAYlOR. D W & MINCKLEY. W L .? 1966. New 
world lor bIOlogiStS PoollC Dosoovery. 19 18-
22 
THOMPSON F G. 1968. The aqua/lCsnllJlsoifhe 
famlr Hydroblldae oi petIIIIsular F/onda Urov8f' 
SIt'( 01 Florida. Gameswle. 268 p 
THOMPSON F G, 1977. The hydrobild sllall 
genus MarsICnlJ &Jte/Jf1 01 the Florida Stare 
Museum. ~I Soence. 2f 113- 158 
THOMPSON. F G., 1979. The syslernabc .eta 
Iionsh.ps 01 !he hydrobid snail genus Nym?
p/lopIIJlus Taylor 1966 and lhe Slalus 01 the 
sub/amily Nymphophillnae Ma/acologJCal ~ 
View. 12 41-50 
THOMPSON. F G a McCALEB. J. E. 1978. A 
new /reshwa1er sna~ Irom a SPflng In easlem 
Alabama Ameflcan M,dland Natural'st 100 
35Q-358 
VAN OEVENDER. T R, 1976 The biola oIlhe hot 
deser1S 01 North AmerICa dutlng the last 9iBC". 
lion Ihe packrat midden record. An1etlcan 
OualemaryAssoClaI,l()rl Abslr8C/s Icx 1976meet? 
'ng. p 62-67 
VAN DEVENDER T R, 1977. Holocene wood? 
lands ,n Southweslern deserts. ScJenC(J. 198 
169-192 
VERMEIJ G J & COVleM. A P, 1978 CoevoIu? 
loon 01 Ireshwaler gaSlropodS and lhe" pred?
alors AmeflCan Na11Jf8llst. 112 833-843 
WEBB. R G & LEGLER. J M . 1960. A new 
sot1She~ lurlie (gel"lUS Trl()t'ly~) hom Coahuila. 
Me~1CO I.ifwerSi/y 01 /(WlSllS. ScJlJOC6 Bulle/1ft, 
40 21-30 
WELLS. P V 1977 [-1974"[. PosHllOClai oro91n 01 
lhe present Olohuahuan Desert less Ihan 11.500 
years ago T.aosactoons or me Symposa.m on 
the BooIogIC8I Resources of lhe Chlhuahuan 
Oesert Reg.on. United Slales and MexICO 
NaIlOn<ll Pa,I< 5en'ICe Transactrons and Pra. 
ceedmgs SerIeS. 3 67- 83 
APPENDIX 1 
CoIIectIOfl Iocalmes tor I," SII)(!y Locahll8S 1-
100 afe shown In Fog 3 1 Laguna Chunoce 
(SOUIhel1'Vl'lOSlollhe lIvee Posos BonIIOS). 19 5 km 
SSW 01 Cualro Coenegas along Ihe hoghway 2 
small seep leedlng the moddle 01 lhe IIvee Posos 
Borlilos 3 Roo Chunnce. 100 m downstream from 
Laguna Chunnce 4 RIO Chuflnce. wide pool a.ea 
1 ()(X) m downsl.eam from Laguna Chuflnce 5 RIO 
Chuflnc8. very 18<90 pool a.ea due E 01 Laguna 
Grande 6 Small pool at NW edge 01 (5) 7 Small 
pool In marshy area. N 01 (5) 8 Small pool ., 
marshy area. W 01 (7) 9 Laguna Grande. playa 
lake termrnus 01 Roo Ch.mnce 10 Posos de Ia 
Becerra. 4 km S 01 the lip 01 Sl(!ffa de San Maroos 
along lhe highway 11 SI.eam /rom cool spnngs al 
los Choceros 12 Sma_ Spring leedlng slream at 
los Choceros 13 Siream al Los ChlCefOS. below 
warm waler II'IIIow from canal lrom Poses de 1a 
Becerra 14 Small spring. 224 km S 01 tiP 01 Soen-a 
de San Maroos along !he hlghwav. al SE corner 01 
lhe spnngheld 15 Small spnng. 3 m W 01 (14). 
feeding same st.eam 16 Small SPflng. 40 m N 01 
(14) 17 SrnaMsprlng 146mNoI( 16) 18 Large 
116 HERSHlER 
sprong. 130mNoI(l7) 19 L,lfgtlsprong. jUStWoI 
marsh lermlnus 01 (181 20 large spflng. 10 m Wei 
(19) 21 large sp!1f1{1. 25 m NW 01 (20) 22 Juan 
SanIo5 Laguna. NW 01 (2 1) 23 Small sP"OQ. 62 m 
NoIllS) 24 SmallspllnghoietnoOUflow). 31Om 
NNE 01 (23) 25 Small spnng, 52 m NNW 01 (24) 
26 Sma. spong. 88 m N 01 (25) 27 Sm3R spmg. 
165m NNW 01 (26) 28 Small Spring at SE comer 
01 vegelaled a rea, 24 m N o. (27) 29 Sma" sprong 
(11owIng NI. atxluI 300 m W 01 (28) 30 North 
Spring, 960 m S 01 lip ot Sll'rra de San MarC05 
along !he tughway 31 Small spong. 57 m W 01 
(30) 32 Small spring 27 m N at (3 1) 3J Small 
spnno. 54 m N of (32) 34 Small spong. 60 m NW 
01 (33) 3S Smell spring. 328 m N 01 (JO) 36 Small 
spnng. 300 m NW 01 (22) 37 Large cold spnng. 
800 m S. 1 km N ot top ot Sierra de Sar1 Marcos 38 
Large cold sprong, about 50 m W 01 (37) 39 SmiJM 
sp"ng hole (no outflow) , 10 m S 01 (38) 40 Small 
sprong. aoo m S. 1 6 km W of tiP 01 Soerra de San 
Marcos. 41 large spo-oog. 800 m S. 1 2S kin W 01 
lip 01 SIen a de san Mar<:os 42. large spong. due 
W 01 JUflcbon 01 streams Irom (4 1) and (43) 43 
large spong. 800 m S , 1.22 km Wei lip oI5oef.a de 
San Malcos 44 RIO Ga.abatal. due W 01 (42) 45 
Small spnng. due W o. (42) 46 large spr..-.g 
230 m NE 01 (43) 47 Small sprong. JUS! W 01 marsh 
ICfmonVS 01 (46) 48 l arge spong. 800 m S. 400 m 
W 01 1., 01 SIerra de San Marcos 49 l arge spnng. 
700 m S 01 lIP 01 SIerra de San Marcos along lhe 
hoghway 50 RIo MesqUlles. 200 m upstream !rom 
JUf1C11Of1 WIth spn<lgs from the west 5\ Small 
spong. \00 m S 01 RIO IIfIesqo.llles al house 01 Toerra 
BIanca_ 52 Small sprIng. Jusl N at hpay. 320 m 
NE 01 tIP 01 Sierra de San Marcos 53 Roo Mes? 
qUltes at lhe hoghway. 93 km SSW 01 Cualro 
Ctenegas 54 Roo Mesqulles. where smaN marshy 
slream branches 011 Ihe Motarral area 55 Sman 
Slream branching Irom ~54) . due E 01 (76) 56. 
SfnalJ spnng. J20 m S 01 RIo Me5Qtllles at Ihe 
highway 57 Sma" spnng. 370 m S at lop 01 $rerra 
de san Marcos along dIrt rood OIl Ihe east SIde 58 
Small Spmg. due E ot (59) 59 Sman sprIng. due E 
01(60) 60 SmalIspnng.670mSoIllpolSrerrade 
San Marcos along dort rOOd 61 Small spong. due E 
01 (62) 62 Small sprong. 150m NE 01 (63) 63 
Large spnng. \ 12 km S 01 lIP 01 lhe Siena de San 
Marcos along dll1 road 64 Small spnng 40 m S at 
(63) 65 Smab sprong. 72 m S 01 (64) 66 SmaH 
spnng. 60mSor(65) 67 SmaUsprrng. t 4 kmSoI 
lip 01 Sterra de San MarcO$ along dort rood 68 
Small sprong. I 6 km S 01 top at SIerra de San 
Marcos along dirt road 69 Small spnng. due W at 
(70) 70 La'ge spong. 400 m E. 60 m S at (68) 71 
Stream Hom (70). 130 m above mash 72 Small 
spong. 27 km S 01 lop of Soerra de San Marcos 
along dlf1 rood 73 Mojarral Wesl Laguna. abool 
200 m N 01 (76) 74 Slream draanlf19 marsh r:kle W 
01 (73) 75 Slream dralnlf1Q (73) 76 Mqarral Easl 
Laguna. 10 211m S 01 CUalrO Oenegas along Ihe 
I\rghway. 14 km 5 01 highway n Srnal sprong 
le?Itng SW comer 01 (76) 78 Pools 30 m d0wn?
stream I,om (55) 79 Large sprIng 241m 5 or Itp 
01 S.crra de San Mafoos along (lift road. 900 m E 01 
rood 80 Large spong (re<:1!IV1flQ !tow Irom 79). 
lOOmSoI(79) 81 L05Aemotos. northernspnng. 
500 m S 01 (80) 82 Los Remqos. middle spong 
83 l O$ Remotos. soothem spring 84 Los Re?
motos. large pool fecetvlng Iflflows f,om (8 1). (82). 
and (63) 85 Large spnng. 1 2 km S 01 (83) 86 
Large sprIng. 400 m S 01 (85) a7 l arge spong. 
115 m SEat(96j88 Largesprlng. about l_2kmS 
01 (86) 89 Largespnng. abouI l OOmSoI ~88) 90 
Large spring. 60 m SW 01 (a9) 91 Large sprong. 
2OO m SoI(90) 92 Largespnng.aboul200m N ot 
(95) 93 Large spnng. due E 01 (90) 94 Large 
sp!"lng. due SE 01 (98) 9S Laguna ESCObedae. 
672 km S 01 lIP of SIerra de San Marcos along dirt 
road. I km E at road 96 Large 6Pftng. 6 9 km S 01 
lip 01 SIerra de San Marcos along dirt ,oad 97 
Laguna Tio G.andodo. 93 km S of np 01 Sierra de 
San Marcos along dirt road 98 Lar{/!! spnng. 
107 km S 01 hp at SIerra de San Marcos along dirt 
road 99 Laguna An1eqo 100 Smalle< spong. due 
W 01 (99) 10 1 $anla Tec::1a Laguna ( ~ La Tecla). 
22 2 km S 01 lip ot Soerra de San Marcos along dirt 
road. I 6 km S? of road 102 $po"tng alongSIde !he 
RiO SaladO de Nadadores. 304 km N 01 Sac? 
ramenlo. Coahuila 103 RIo Salado de NadaOOfes. 
al Ca,mo de Ia Montana. 3 S4 km E 01 Socramf!f1to. 
Coahuila 
APPENDIX 2 
The malenal collected by lhe author and ex?
amined dunng Ih,s study IS itsted below by Sj)e(:1e5 
For each species. lhe lois are lisled In order 01 
locality number ( I - IOO). wllh lhe calalog ourrbe<s 
and dales 01 ooIecfIOn IoIiowIng AU of lhe malenal 
IS deposl1ed Ifl lhe Department of Malacologv allhe 
Academy 0 1 Nalural Sciences 01 Philadelphia 
(ANSP) The 1r"llIIalietler A reters 10 specwnens Nl 
alcohol Other catalog n......tlers reler to dry sheI 
"''' I Nymphop/ltItJS rnondileyr I A9879?A. 23 Mar 
1979. A9879?E. 17 Dec 1981. A9878?1. 19 Dee. 
1981 3 A987a-G. 23 Mar 1979 5 A9879?6 . 16 
May 1980 10 A9878-H. 4 Aug 1979 13 Ase77?B. 
2 June 1979 A9878-A, 17 Nov 1980, A9878?E. 9 
Feb 1981 18 A9878-D. 13 June 1979 3IJ A9878-
F. 9 Apr 1979 37 A9878-6. I I July 1980 38 
A9877,C. 12Apr 1979 A9877?F. 18 July 1980 40 
A9877?A. 27 May 1981 41 A9S79-G. 17 Feb 
1981 42 A9879?D. lOAf)< 1981 43. A987a..c.8 
July 1979 53' 355196. Ase77?D. 26 Ju~ 1979 
A9876. 23 AfJf 1979 64 A9879?F. 4 June 1981 
71 A9879?C. I May 1981. A9879?H. 12 Dec 1961 
76 A9877?H. 7 May 1979. 355197. A9877-E. 7 Apr 
1981 79 A9877'(>. 3 Apr 1979 97; 3S519S. 
A9879-J. 21 May 1979 
2 Nymphoptr,lus acarrnalus 98 holotype 
355255, 2(l Dec 1981 paralypes 355256. 2(l Dec 
1981 101 1\9929?8. 13 July 1980. A9929-C. 26 
May, 1981 
3 Mex'SI/0bf8 mananfr<ilr 14 A9888?E. 2S Nov 
CUAlAO CIENEGAS HYDROBIIDS 119 
1980 '6 A9887-e. 11 -14 June 1979. A9866-K 5 
June 1980, A9888.J. 27 Nov 1980 ,7 A9887?L 7 
Dec 1980 2S A9687?G. 11 Feb 1981 27 A9888? 
I. 14 Feb 1981 28 A9687?L. 17 Jan 1981 29 
A9S88-B 7 ~ 1919 3. A9881?A 18 May 1981 
36 A9887?K. 20 June 1981 38 A9886-', 8 Jan 
1981 . A9687-H. 16 JM 1981 . A9887-F 5 Feb 
1981 43 A9886-M. 13 July 1979 51 tnorype 
355205. 13July 1979, paralypes A9887?0, 20 Ap< 
1979.355204. A9888-L 13 July 1979 52, A9886. 
D, 21 June 1981 57 A9886.(;, 15 June 1981 59 
A9886?B. 19 June 1981 64 A98f16.N. 31 May 
1979. A9687-E. 30 May 1961 A9886-G. 4 June 
1981 A9886?L. 21 June 1961 65 A9886-H,31 
May 1979. 355206. A9OO8?F. 28 PIC< 1981 67 
A98S6?F. A9S87.J. 30 Apr 1981 68 A9889--K, 2 
May 1981 72 A98B7?C. 19 May 1979 74 A9888? 
C. 5 Apr 1980 77 A9886?J. 16 June 1981 
4 COMu/,,( hubbsi ,6 A9892?A. 11_ 14 June 
1979. A9892-M 5 Jan 1980: A98B2-H. 27 Nov 
1980 18 A!}892?C. 19 Dec 1981 24 A9892.J, 14 
Dec 1981 31 A98920. 18 May 1981 33 A9892? 
B. 21 May 1981 3S 355210. 9 May 1981 38 
A9893-G, 8 Jan 1981 58 A9892?N 17 Jan 1981 
61 A9892?L 18 June 1981 64 A9893?B.26Ap< 
1981, A9892?G. 4 June 1981. A9892?K 2 1 June 
1961 A9892-E, 130ec 1981 66 A9892?l 28Apr 
1981 67 355209. A9893?A. 30 PIC< 1981 68 
A9692?F . 1 May 1981 
5 Coa/IuJIIx landyet 16 A9894-M 27 NaY 1980 
17 A9894-1. 1<1 June 1979 24 A9894-A. 13 Feb 
1981 28 A9694-l 7 Apr 1979, A9894-G, 17 Jan 
1981 31 A9694-F, 18 May 1981 38 A9894?E.8 
Jan 1981 59 A9894-H. 19 Jan 1981 63 A9894. 
K 16 Apf 1981 64 hololype A9894-N 29 Apr 
1981 paratypes 355211. 27 Apr 1981 65 A9894. 
B, 26 Apr 1961 61 A9894?J. 30 Apr 198 1 69 
A9894-G 6 May 1981 
6 CodIJtopona rtlI/lefl 38 A9884?E. 5 Feb 1981 
38 A9684.J, 3 Sept 1978. A9884-C, l O~ 1981, 
355200. A9884 K. 5 Jan 1981 41 A9884?0.17 
Feb 1981 42 A9684?C. 10PlC< 1981 43 A9884. 
B. 8 July 1979 SO A9884?1. 1 5epI 1978 53 
A9884?F, 23 Apr 1979 SS A9884?G.7 May 1979 
97 A9884-H. 2 1 May 1979 
7 Coc/lIJcpIna nograndensls 101 A9665-D. 10 
July 1979, A9885?E, 13 July 1980. 35S2Q2 28 May 
1981 Ia:!' 355201. A9865-A. 25 May 1981 '03 
A9685-B A9865?C. 24 July 1979 
8 Me",1havmB qW(/npaludlVm I A9883 23 
Ma. 1979 355198 A9861?F. 2S Aug 1980 '0 
A9880-E 9 Apr 1979. A9881?C. 4 Aug 1979 ' 8 
A9880?0. 13 June 1979 20 A9860-G 2Q June 
1979 22 A9880?B. 3 Ap. 1979 JO A9880-1,23 
Ma. 1979 42 A9881?E, 10 Apt 1981 49 A9881-
D. 23 Feb 1981 50 A9880-C. 1 SepI 1978 
A9880-F , 26 Feb 1981 n A96fIO.A.1May l98 1. 
A9881-H. 12 Dec. 1981 76 A988().H 9 May 1979 
A9882. 26 July 1979 A9881 -A. 10 Apr 1981 97 
355199 23 May 1981 98 A9881 ?G. 20 Dec 1981 
99 355257. 10 Apr 1981 100 A9881?B. 10 PIC< 
1981 10 . A9880-J, 28 Mar 1981 
9 Durangonella ooahtl,/ae 2 A9922.J . 13 Oec 
1961 4 A9922-1 15 May 1960 S A9922?G, 16 
May 1980,A9924 B, 19 Nov 1980 6 A9922K,17 
Mey 1980. 355244, A9928?K 8 Ocl 1980 7 
A9922-H, 20 May 1980 8 A9922-L. 27 May 1980 
9 A9922?0.29Mar 1979. A99i2 B, 16May1979 
A9922-C. 30 May 10June 1980 A9922?E. 23 Aug 
1980. A9922-f. 10 Oct 1980. 355249, 22 Oct 
1980 12 A9924?L 19 Dec 1960. 13 35S250 
A9923?B. 13 Noll 1900 '4 A9923-E. 2S Nov 
1980: 355246. A9928-M. 27 Nov 1000 16 A9926-
M. 9 June 1979 A9928-J. 27 Nov 1980; A9925?E, 
6 Dec:: 1980 17 A992J?C. A9928 B. 10 June 1979, 
A9927?K. 7 Dec 1980 '8 A9923-K, 15Jan 1900 
A9927?L. 19 Oec 1981 23 A9927?A. 8 Feb 1961 
A9927-J. 11 Feb 1961 24 A9926?t. 8 Feb 1981 
A99241. 13 Feb 1981 A9928?C, 14 Dec 1981 25 
A9926?K8Feb 1981 26 A9928-H. 14 Dec 1981 
27 A9927?F 8 feb 1961 A992J?B. 14 Feb 1981 
28 A9924-N. 7 Apr 1979 A9926?F. 13 July 1979 
A9924?C, 17 Jan 1961 29 A9927-D. 14 Feb 
1981 30 A9925-A. 28 Jan 1980 31 A9928-1. 18 
May 1981 35 A9922?A. A9924-G. 9 May 1981 37 
A9926?H. 11 July 1980; A9925-K 7 Feb 1981 38 
A9923-D. 15 May, 1979. A9923?F, 18 July 1980 
A9924?F. 8 Jao 1981 3SS251, 20 Jan 1981. 
A9926?G. 5 Feb 1981 A9923?C. 5--6 Jan 1981 
A9927?H. 16 Jan 1961 . Am3-H A9926.J. 6 Feb 
198 1 41 AmS-G, 17 Feb 1981 43 A9924 M, 7 
Juty 1919. Am7-' 13JuIy 1979. 355245, A 19928? 
L, 17 Feb 1981 45 A9928-N. 10 APf 1981 48 
A9925-l .23 Feb 1961, A992S-J, 5May 198149 
A9925-F. 23 Feb 1981 50 A9925-C. A9925?I. 1 
Sepl 1978.51 355247. A9928-N, 20 Apf 1979 
52' A9924?D. 21 Jan 1981 56 A9928-F , 18 Mar 
1981 . A992S-B. 19 Mar 19$1 58 A9924-A. 17 
Jan 1981 59 A9923.J. 19 Jal1 1981 61 A9927? 
M 18 Jan 1981 62 A9927?N. 15 June 1981 6J 
A9926?C. 8 Jan 1979 64 A992S?B. A992S?D. 31 
May 1979. A9928?A. 21 Jan 1981 A9926-L 27 
Apr t981 A9928-G, JO May 1981 65 A9923?A. 
22 May 1979 A9924-H 31 May 1979. 355248. 
A9923?l. 4 Apf 1980. "9923- ' 24 July 1980 
A9923?J, 1 Oct 1900 72 A9927?E. 19 May 1979 
73 355252. A9926-0. 5 Apr 1980 74 A9926-A. 2 
May 1979: A992S?H . 12 Apr 1980 75 A9925?M. 4 
May 1979 77 A9924-E. 16 Jan 1981 
10 Me,,!pytgtJS chunnceanus I A99Q9?H 23 
Mar 1979. 3S5230, 15 Sept 1980. A9907?1 20 
Sepl 1980. A9909-1 13 Mar 1981 S A9908?I. 16 
May 1980.A9907?H. 24 SepI 1980.355231 50d 
1980 10 A9909-C A991 I A. 27 Oel 1980 
344232, 29 Oct 1980.A9909?D,3 10c:11 980 11 
355233. 2 Nov 1980, A9901. 10 Nov 1980 13 
A9911 ?F. 8 Nov 1980 18 35S220, A9912?1. 12 
JUl1e 1980, 355216. A9912?E. 12 Au9 1980. 
A9911 -H.8Dec 1980 19 A9911.J. 10Dec 1980 
20 A9910?G. 26 June 1980 355234. 10 Dec 1980 
A9907?E,11 Dec 1960 21 JSS214 A9912?C.29 
Apr 1961 22 A9907-B, 3 Apr 1979.355241. 16 
Dec 1980 A9907?C.18Dec 1980 30. A9911-G. 9 
Apr 1979.A9907?F.20Aug 1980.355222,A9914. 
18 Dec: 1980 37 355213 A9912 6. 30 Dec:: 1980 
38 355236. 1 Jan 1981 A991o.H 5-8Jan 1961 
'20 HERSHLER 
A9911 S. A9911?0 , A9911 E . 16 Feb 1981 
A991 0?J, 21 May 1961 43 A9910-J. 7 July 1979, 
AGG1 1-G. 16FeIl 196\ 44 Agg" .1, IOApJ 1961 
46A99O&J 19 Feb 1961 . 3553212. A991 2-A. 20 
Feb 1981 4 7 355227.23 Feb 1961 48 A9895 
23 Feo 1961. 355235. 24 Feb 196 1 A9B97. 5May 
1981 49 A989E1 , 23 Feb 1981 .355242. 24 Feb 
1981 A9907-G. 5 May 1981 50 355218. A9920. 
2fiFeb. 1961 53. A9909?E. 23 Apr 1979. A9909-F. 
6 Ma! 1981 S>4 A9909?G.8Mar 1981 65 A99Q9. 
A. 31 May 1979 67 A99IQ-E. 4 May 1961 , A9910-
D. SMay 1981 7'0 A9910-F . 1 May 1981 A9909-J , 
2 May 1981 71 A9910-A, 4 May 1979, 355240, 
A9910-6. 25 Mar 1981. A9905. 5 May 1981 . 
A991 o-C . 4 May 1981, A9907?A. 12 Dec 1981 73 
355219. A9912?H. " Mar 1981 76 ' A9906. 16 
Ma. 1981 , 355239, 17 Maf 1981 78 A9907-0 . 9 
Apr 1981: 355215. A9912-0. 29 ApI" 1961 79 
A99OO. 6 May. 1981, 355237, A9906-f. 8 May. 
1981 81 355223. A9915. 11 May 1981 82 ' 
355226, A9918, 11 May 1981 83. A9902, 9 May 
1981 , 355243, 11 May 1981 84 A9908?A, 12 May 
1981 85 A9908?C. 14 May 1961 86 A9896. 14 
May 19t1l 87 A9909-6 . 16May 198\ 88 344229. 
A.9921 . 17 May 1981 89 A99Q8?B. 17 May 1981 
90 356225. A991 J. 17 May 1981 91 A99Q8?G. 18 
May 1981 92 A9908?H. 20 May 1981 93 1\9904, 
22 May 1981 94 A9908?E. 22 May 1981 95 
35522 1. A9913. 20 May 1981 96 355218. 
A9912G. 20 Dec 1981 97 355224 A9916. 23 
May 1981 98 A9907?J 20 Dec 1981 99 355217. 
A9912?F. 10 Apr 1981 100 A9908-D. 10 Apr 
1981 101 A9903. 28 May 1981 
"'" I SheI shape 
al p1arosporal 
bl trocl'lolcl1Jlobose 
clovale-conoc: 
dl tumlofm 
2 . Maxomum shejl d,menslOn 
al 2 rrm 
b) ' 2rrm 5mm 
cl :2:5rrm 
3 Shell scu1plure: 
a) ooIabral nbs 
b) spiral cords 
c) absent 
4 Apcal...norl rTIIO'OSCu~lure 
a) wnn"led. poned 
b) absenl 
5 Shell ... ,lh penOSlracal bands 
6 Shell aperture flared 
E.lema! leatures 
7 Tentacle ClloallOn 
a) absent 
b) Hyaoboa-hke 
c) Spunw?.<a-hke 
8 Anmal blond. unpoQme!11ed 
9 Mantle edge papollale 
11 Orygoc:eras? sp 67 355254. A9929-A. 19 
Dec 1981 
12 PaltJdsc.!la CiflarrtNJ 2 A9890?D. 13 Dec 
1961 16 A9690-K. 11 June 1979 Age90?H. 5 Jan 
1960. A9889?K. 27 Nov 1980 17 A9890?J. IOJan 
1979 18 A9891.J . 19 Dec 1981 23 A9889-N 
A9891?D. 11 Feb 1981 24 A9691?H. 13 Feb 
1961. A9889?M. 14 Doc. 1981 25 A9891-K. 11 
Feb 1981 26 A9889-G. 14 Doc. 1981 27 A9891? 
l. 11 Feb 1981 28 A988()-B. 17 Jan. 1981 31 
A9691 ?E. 11 May 1981 32 A9690-L. 16May 1961 
33 A9689?A. 21 May 1961 35 A9889?1. 9 May 
1961 38 A9880-H. 16 Jan 1981 . A9690?I. 8 Jan 
198 1 56 A9889?L. 18 May 1981 57 A9890?M. 15 
Jan 1981 58 A9889-C. 17 Jan 1961 59 A9889. 
E. 19 June 1981 60 A9889?B. 19 Jan 1961 61 
A9690?C. 18 Jan 1981 62 A9890?A. 15 Jan 
1981 63 355207. A98911 . 16 Api 1981 64 
A9689?J. 31 May 1979. A9889?F. 26 Apr 1981 ' 
A9890?F . 13 Dec 1981 65. A9889?H. 31 May 
1979; 3552(18. 24 July 1960. A9891?1. 26 Apr 1961 
66. A9891?A. 26 Apr 1981 67 A9S90?E. 30 Apr 
1981 68 A9691 ?B. I May 1981 69 A9891-G. 6 
May 1981 72 A9B91?F. 19 May 1979 
APPENDIX 3 
f,"y-one characters and their cI'oarilCtl!f stales 
are used ,n Ih,s s ludy 10 d'SI<n9u;sh between 
genera and geoenc; groups 01 HydlObolllae T (I the 
nght are relerences 10 publocat()ns ,n wInch the 
varIOUs character slales have been bgured '"H"" 
,ndocates a logu'e WlItun Ih,s paper 
H. f'9S 1SA-G. I-I< 
H. FOSS 4 . 9 . 27 
H. Fig 37 
H. Fog 33 
H. '. 19 H. '. 27 H. '. 32 H. Fig II Thompson. 1977. IIg 4 
H. Fig 39A 
H. Fog 37 
6oelers. 1974. logs 9-11 Bole, 1970. log 
H. Fog 40A 
, 
Dav,s . 1966. IIg 2 . Hershler 8. Dav,s, 1960. IIg lA 
Dav,s el aI . 1982. log 5 H. Fogs 29A. B 
H. Fog 3OA. 31A 
CUAlAQ CIENEGAS HYDAOBIIDS 121 
10 Osphrao..n elongate ( 0 JO 04 tho ctencl!um 
-", II NuIT'tlef of open;ulum who!1s 
" . 
bl ?4 
12 POS!toon 01 nucleus 01 operrulum aIorlg 115 long 
,m 
a) 31)'\, 
b) .-30" .. 
DtgestIve syslem 
13 OIgeshve gland w,lh roduood Ilbe<des 
14 ln1es1one WIlh antenor loop 
15 Caecal chamber e~tends posleno. 10 stomach 
16 O"g.n 01 oosal cusps 04 cenl.alloo1t1 01 radula 
al trom lace 01100lh 
bl from Lal(lfal angles 
17 Number 01 p," 's 04 basal cusps on cenl,ai l001h 
04 ,a(lula 
all-2 
b) ~3 
18 Cenlrat wsp of lato'al tOOlh 
al mas5lVU 
b) small 
Male ,eproductlve anal0my 
19 Male gonad morphology 
al s>mpIe lobes 
b) bush?llke 
c) Single un-1ob6d mass 
20 Male gonad e Xlends onl0 stomach 
21 Semonal vesocle coohng 
a) on slomach 
b) postenor to stomach 
22 Po5I1oon of prostalo 
al enlt'ety poslonor 10 end 01 mantle C8VIty 
b) overlaps m8l111e cavny 
23 AntClIOl yas deloll:ms 
a) exItS hom antellOl' t,p 01 pn;15lale 
b) cx,.ts Irom poslCOOl' por100n 01 prOSUlle 
24 Peros WIth slender penial Itlamefll 
25 Pen'" ohaled 
26 Penrs Wllh le ,m,nal eve,sobic papilla 
27 Penoallobets) 
,' ?b)~hke 
c)som~ 
d) Wllh l!lIds 
28 Gland(s) 0 1 pens 
a) absent 
b) lafge. spec.ahzed 
C) sma~ on glandular rodges 
29 or snaolS hailing glandular rodges on !he penrs 
a ) < 4 ,idges 
b ) ~ 4 ridges 
Female reproduct,ve anatomy 
JO Reproduclwe modo 
a) O\IIP3"ty 
b ) oYOYMparoly 
Dav.s & Pons da SIIYa. 1984 log 6 
H. Fog 358 
H Fog 58 
H. F. 358 
H F. 58 
H. F. 
"" H F. 17C. 
H F. 7A 
H F. 16C. 
H. Fog 
"" 
Boete<s, 1974, t.g 3 
Davos & Pons da S,lva. 
H. Fogs 126. C 
H. Fog 28D 
H. Fog 6B 
H Fog 12A 
Dav,s & Groor. 1980. log 9A. 
H Fog 31A. 
H Fog 17C 
H. Fog 17C 
Dav,s & Greer. 1980. fig 9A 
1984 log 14 
H.Fog 17C OavtSelaJ 1982 log 14A. 
H. Fog 31A 
H, Fog 31A. 
Dav,s. 1967. pi 25, log 4 
H. Fog316 
H. Fogs 350, 446 
H. Fogs 350 44A 
H. Fogs 250,316 
H. Fogs I7D,2IC 
H. Fog 35D 
H. Fog 8A 
H, Fogs 170 2IC,44A 
H Fogs 86 C BoeIOfS. 1914, logs 6,7, Thompson. 
1968. togs 42-47 
H. Fogs 88. C, 130. Thompson 1977. hgs SA 7A. 
llC. 13 
Thompson. 1968. logs 42-47 
HERSHLER 
31 Female gonad rTIOfphologv 
3) .e\3lwety 13108 k:Ibed 
b) le\3hYe/y lafge. tTI?1obed 
C) reIattYeIy smaI. 3 me<e Ihockenong at end 01 
""""" 32 Female gonad e ~Iends onIO 5I()ma(:tl 
33 0vduCI wolhoul a)II 
34 lenglh 01 pallal ovodUCI1eng1h of body 
3) 030 
b) 030 
3S Po5ter"IOf palll3l OVIducl 
3) Wlihoul beOO 
b) WIth shorI bend 
C) ...-,ttl lOng bend. codong 111 t plane 
,,""""""?
<I) 1IOITf\3' .... ed 
b) ,educed on sue 
el .educecl 10 a glandula' smear 
37 01 D\IO\IIII!Pa' ous laxa . capsule gland 
a) WlIh 1 tissue <egIOf' 
b) WlIh 2 t,ssue 'eo;JlOOS 
c) Wl1h 3 ' Issue feglOOS 
38 length 01 bufsa lenglll 01 pallial 0\IIdud 
3) 020 
b) 020 040 
el040 
39 Posoklrl ~ busa 
a) posteoor 10 paIIl3l 0\IIdud 
b) overlapped by pallial oYIduct 
40 Normal semonal feGeplacie Pfesenl 
'" Seoond3ry senun;ll ,eceplacie Pfesent 
42 01 snaols w"h a normal semonalleceptade. the 
Ier1gth 01 the semonal receptacle length 01 bur?
~. 
a) ' 030 
b) ' 030 050 
c) 050 
.t.3 01 snaoI5 WIIh a nonnal senWlII receptacle. 
OJ)i!i-og 01 SI'lfTWlIII recepl3Cle onto 
., """"" 
bl spflfm duel 
"" 01 sna~s With a normal selT\lnal receptaC.le the 
sernnaI receptacle '5 
a) oYf!f1apped by the btM"sa 
b) lateral 10 the bursa 
<15 Female W1th 
<I) cikated ventral chaIvleI rnsroe!he paIIaI eM 
.... 
bl ~1tlfaI duel 
~ 01 soaoI5 With II Cl'-ated verlbal channel 
/II pallal 0YIduc1 opens al ante<Of bp 
bl pallial OIItduc, opens Ia'e , /I.y 
47 01 StIIIIIs. Wllh a Ciliated vent,aI channel 
al boISler weakly developed 
b) boIsler weI-deveIoped 
48 01 snaoIs WlIh .. spennalhecat duel. the duel IS 
-, """ 
bI ""'" 49 01 S03IIs Wllh ? shOO spermathecat duct . the 
.... . 
a) musculafLZed 
b ) noo?muscularl1ed 
H Fog 41A 
H. Fog , 78 
H. Fog 30A 
H Fog 30A 
H. Ftg 178 
H. Fog 178 
H. Fog 30A 
H. Fog 178 
H. Fogs 30A 36A 0iI'IIS et aI . 1982. log l OA 
H. Fog 43 
H Fog 178 
H Fog 26A 
H. Fog 36A 
HefShlel & DavIs. 1980. hg 2 
H Fog 178 
H. Fog 22A 
H. Fog 300 
H Fog 178 
H Fogs 7A. 8 
H Fog 148 
H Fog 78 
H Fog 22A 
H. Fog 42B 
H. Fogs 26B C 
H. Fog 30B 
H. FlO 306 
H. Fog 42C 
H. Fog 428 
H. Fog 30B 
H Fog 78 
H Ftg 30A 
H. Fog 140 
H. Fog 7E 
H Fig 14C 
H Fog 70 
H. Fog 30A 
H. Fog 26A 
H Fog 42?1 
H. Fog 26A 
CUATRO CIENEGAS HYOR08110S 
50 01 sn.I$ WIlt! a long spennalhccal duel. Itle 
operwogs 04 !he 5PC<malhecal duel arcl pit'" 
""""" ~. 
a)sepatalc 
bI_ 
c) 5Cp/I.alc, bul Wllh an open channel between 
,,-
51 01 CIo'OVMP8l(llJS snaIls, Ihe anlCl'IOf pa~1 ()VI-
""" "'" a) a sllghl muscula. loop 
b) a weI-deveIoped muswlaf loop 
H. f'!js 36f G 
H, Fog 22F 
H, F'!j 30E 
H, F'!j 41B 
H F'!j 26E