Proceedings ofthe United StatesNational MuseumSMITHSONIAN INSTITUTION ? WASHINGTON, D.C.
Volume 124 1967 Number 3631Status of Genera Branchiobdella and Stephanodrilusin North America with Description of a New Genus(Clitellata: Branchiobdellida) 1
By Perry C. Holt 2Visiting Research Associate, Department oj Invertebrate Zoology-
Ill a previous paper (Holt, 1960), the status of one North Americanspecies of the branchiobdellid worms that had been assigned by anearlier worker to a non-American genus was clarified. An attempt ismade here to establish the generic affinities of the remaining NorthAmerican branchiobdellids that have been placed in Asiatic or Eu-ropean genera. There are three of these: Branchiobdella tetradontaPierantoni, 1906; Branchiobdellida americana Pierantoni, 1912; Stepha-nodrilus obscurus Goodnight, 1940. Since one of the areas of intrinsicinterest in the study of the branchiobdellids is a consideration of theirzoogeography, it is important to determine if these species are as-signed correctly and, hence, if there are defensible cases of multiconti-nental generic ranges among them.A brief reference has been made to this problem before and attentionhas been directed to the general relationships of the branchiobdellidfauna of North America to those of Asia and Europe (Holt, 1964). Itis not beyond credibility that representatives of the same genus mightoccur in eastern Asia and in eastern North America as is reputed to bethe case for one of the species I am considering herein: my studies
1 Supported by grant GB 372 from the National Science Foundation.2 Department of Biology, Virginia Polytechnic Institute, Blacksburg, Va.1
2 PROCEEDINGS OF THE NATIONAL MUSEUM V0L> 124indicate that this does not occur and that the distributional patternsof the branchiobdellids do not conform to those of their astacid hosts.The origin of the taxonomic problems I am involved with go backto the early days when the casual students of the branchiobdellidsheld such broad generic concepts that there was a tendency to assignany species not quite obviously distinguished by peculiarities of bodyform and ornamentation to the European genus Branchiobdella.Pierantoni (1912, p. 8), in the first monograph of the order, listed fivegenera, mostly separated by such characters of body form, though hewas aware of the distinctive difference (one testicular segment asopposed to two) between the genus Branchiobdella and the othergenera. In addition, he and perhaps others worked with materialrecovered from the bottoms of museum jars in which crayfish collec-tions were stored. Such material almost invariably is in such a poorstate of preservation that specific diagnoses or even generic assign-ments are difficult, doubtful, and often futile.Moore (1894) in his work on branchiobdellids during the time whenmany workers considered them leeches placed Leidy's speciesAstacobdella philadelphica (Leidy, 1851) in the European genusBranchiobdella and described as new members of this genus B.illuminata, B. pulcherrima, and B. instabilia. He quickly reassignedB. illuminata, establishing the new genus Bdellodrilus for it in hisexcellent treatment of its anatomy (Moore, 1895). Pierantoni (1912,pp. 21-22), who realized that these species have two testicular seg-ments, placed Branchiobdella pulcherrima and B. instabilia in Moore'sgenus Bdellodrilus. It remained for Ellis (1919, pp. 243-253) toestablish the genera Xironogiton, in which he placed Bdellodrilusinstabilia, and Xironodrilus, which includes B. pulcherrima. Ellis,however, did not have material that would allow him to deal withBranchiobdella tetradonta (Pierantoni, 1906, p. 3) and B. americana(Pierantoni, 1912, p. 14). The next important paper in which thesespecies were considered was written by Clarence J. Goodnight (1940),who retained Pierantoni's generic assignments for them. Though hehad not seen anything he could identify as B. tetradonta, he did con-sider animals from Cleveland, N.Y., taken from Cambarus bartoniirobustus (Goodnight, 1940, pp. 28-29) as representative of B.americana. In the same paper (p. 55) he described the third species Iam dealing with here as Stephanodrilus obscurus. Stephanodrilus is ajunior synonym of Cirrodrilus Pierantoni (Yamaguchi, 1934, pp.191-192), and Yamaguchi's error in ignoring the law of priority byusing Stephanodrilus as the name of the Asiatic species, all of whichhe considered to be congeneric, was corrected by Goodnight (1940,pp. 55, 63) by reverting to the use of both of the Pierantonian names(Cirrodrilus and Stephanodrilus). For the present, basing the positionon Yamaguchi's descriptions, figures, and some Japanese materialthat he very kindly gave me a few years ago, I accept his decision
no. 3631 BRANCHIOBDELLIDA?HOLT 3
as to the generic unity of his Japanese worms. The correct name ofthe genus, then, must be Cirrodrilus Pierantoni, 1905, and notStephanodrilus Pierantoni, 1906. If Goodnight was correct in placinghis species from Fall River, Calif., in the Asiatic genus, its name mustbecome Cirrodrilus obscurus (Goodnight). One of the conclusions ofthe present paper, however, is that he was not correct and that S.obscurus must become the type of a new genus.Magmatodrilus, new genus 8Stephanodrilus.? Goodnight, 1940, p. 55. [In part.}Type-species.?Magmatodrilus obscurus (Goodnight, 1940), heredesignated by monotypy.Diagnosis.?Medium sized, stout branchiobdellid worms with twopairs of testes; unpaired nephridiopore on the dorsum of segment in;body terete; spermiducal gland with vasa deferentia entering entally;prostate absent; ejaculatory duct present; bursa large, enclosingprotrusible penis entally; spermatheca present, not bifid, with ectalduct and bulb invested with thick muscular covering.Distribution and affinities.?Magmatodrilus at this time standsas a monotypic genus known only from the type-locality of M.obscurus.Goodnight's (1940, p. 55) assignment of S. obscurus to Stephano-drilus (= Cirrodrilus) appears to rest upon the absence of a prostateand a mistaken belief that the anterior nephridia open by separatepores on the dorsum of segment in. In addition to Cirrodrilus, thegenera Xironodrilus, Xironogiton, Ankyrodrilus, and Branchiobdellahave paired nephridiopores, lack a prostate and, with the exceptionof Xironodrilus, the vasa deferentia enter the spermiducal glandalong its midlength rather than entally. Most genera that have acommon anterior nephridiopore also have a prostate gland. Theclosest relatives of Magmatodrilus, then, should be among thosegenera in which a prostate is absent and the anterior nephridiaopen by a common pore on the dorsum of segment in. There arethree (possibly four) such genera, including an unnamed one repre-sented by species from the southeastern United States and Mexico:Bdellodrilus, Caridinophila, and the Mexican genus. The prostateof Ceratodrilus (the fourth possible relative of Magmatodrilus) is aminute lobe or region of differentiated epithelial cells on the side ofthe spermiducal gland (Holt, 1960, pp. 57, 63). Leaving this questionfor the moment, Bdellodrilus illuminatus (the genus is monotypic)differs from Magmatodrilus in the possession of an eversible penis,in the entrance of the vasa deferentia along the midlength of the3 From magma (Greek, =lava) + drilos (Greek, =worm), masculine, "lava-worm" for the locality, springs in the lava beds of Shasta County, Calif., fromwhich topotypes were taken.
4 PROCEEDINGS OF THE NATIONAL MUSEUM V0L - 1Z4
spermiducal gland, and in the primitive bifid character of the sperma-theca. Caridinophila unidens (another monotypic genus) from YunnanProvince, China, lacks a spermatheca, has a peculiar almost sphericalspermiducal gland (Liang, 1963, pp. 564, 569), and cannot be con-sidered in any way close to Magmatodrilus. The unnamed groupof species from Mexico, Georgia, and South Carolina resemblesMagmatodrilus in the absence of a prostate, in the entrance of thevasa deferentia at the ental end of the spermiducal gland, and inthe large size of the copulatory bursa, but differs in the facies (sizeand shape) of the jaws and most importantly in the presence of aneversible penis instead of the protrusible one of M. obscurus. Thelatter point requires further comment: the penes of Bdellodrilusilluminatus, Ceratodrilus, Oedipodrilus, Branchiobdella, and perhapsthose of Cirrodrilus and Ankyrodrilus are eversible, i.e., the penisitself is turned inside out in copulation; those of other genera areprotrusible, i.e., the bursal atrium everts and carries to the outsidea cone-shaped muscular penis papilla that does not itself evert.Material in museum collections, however, rarely contains animalswith everted or protruded penes, and conclusions as to the func-tioning of the organ frequently, as in the case of Magmatodrilus,rest on inferences from the structure of the uneverted or unpro-truded penis. In brief, Magmatodrilus also is related to Ceratodrilusbut differs in the lack of body ornamentation (peristomial and bodytentacles or projections), in the presence of a rudimentary or vestigialprostate in Ceratodrilus, and in the presence of a protrusible insteadof an eversible penis in Magmatodrilus. Further study may unite thespecies of the unnamed southeastern genus with Magmatodrilus, butfollowing the criteria previously used (e.g., Holt, 1953, 1960, 1965;Hoffman, 1963; Liang, 1963), Magmatodrilus must be considered aseparate genus. Magmatodrilus obscurus (Goodnight)Figures 1-4Stephanodrilus obscurus Goodnight, 1940, p. 55.Diagnosis.?Jaws subrectangular in en face view, dental formula6/5; prosomites of segments i-iv, viii raised (supernumerarymuscles present); spermiducal gland with large anterior deferentlobe, shorter posterior one, gland long and looped at ental end ofbursa; bursa large, extending to dorsal margin of segment vi;spermathecal bulb clavate or bulbose, without ental process, wrinkledand often appearing in sections to be diverticulate. Average size of10 measured animals 2.8 mm in length.Type-locality.?Fall River, Shasta County, Calif. (Goodnight,1940, p. 55). Additional topotypical material: Thousand Springs
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3631 BRANCHIOBDELLIDA?HOLT 5(head of Fall River) on Thousand Springs Ranch, 4 Fall River Mills,Shasta County, Calif.; collectors, Perry C. and Virgie F. Holt.Disposition of material.?Holotype, USNM 20568; 2 topotypes,USNM 45696; 11 topotypes, PCH 1818, in my collection at theVirginia Polytechnic Institute.Cambarincola philadelphica (Leidy)Cambarincola philadelphica (Leidy), 1851, p. 209.Branchiobdella americana Pierantoni, 1912, p. 14.?Hall, 1914, p. 190.?Good-night, 1940, pp. 28-29.Pierantoni (1912, p. 14) described Branchiobdella americana onthe basis of material in the possession of the Hamburg Museum.In the summer of 1966, Professor Richard L. Hoffman of RadfordCollege visited the Zoologische Staatsinstitut und Zoologische Museumat Hamburg and inquired as to the existence of this material. ThroughDr. Hoffman's good offices, Dr. M. Dzwillo lent me this material,consisting of the syntypes. I am grateful to both of these scholars.The material itself, upon which Pierantoni based his diagnosis ofB. americana, is macerated badly and must have been so when heexamined the material and described B. americana as follows:Prostomio intero, poco slargato a ventosa, capo ben distinto dal corpo; corocinadi papille circumboccali presente; superficie ventrale del corpo non appiatta,corpo non rigonfio nella regione mediana, quasi cilindrico.Ventosa terminale poco prominente.Clitello poco visibile.Lunghezza mm. 5 circa.Mascella disugali; la dorsale (Fig. 6B nel testo e 7A della tavola) provvedutadi un grosso dente mediano e di due paia di dentelli laterali rivolti in basso; laventrale di due grossi denti (Fig. 6C nel testo e 7B della tavola) con medianialquanto divaricati e sol paio di dentelli laterali. Questo due mascelle nelladisposizione dei denti si corrispondo in modo che i dente della mascelle ventraleingranano negli spazii che intercedo fra i denti e dentelli consecutivi nella dorsale,il che avviene di frequente nella specie a mascelle disuguaii.La spermateca in questa specie non e molto sviluppata e si presente in formadi ampolla o fiasco collo corto, sensa processo terminale.L'atrio e poco rigonfio.Nel complesso dei caratteri questa specie si avvicina alia Br. pentodonta ....Habitat: Su varie specie di Cambarus.Nota.?Esemplari riferibili a questa specie ho riconosciuto sovente nel ma-teriale del Museo di Amburgo, e tutti provenieti dell' America del Nord; diquesti esemplari alcuni erano registrati come viventi su Cambarus viridis Hay.,altri su Cambarus latimanus Fabr., altri Cambarus Hayi Fosc. (Texas), altri suCambarus rusticus Gir., altri su Cambarus immunis Hay., e su Cambarus sp.(Raleigh, N. Car.). E quindi da ritenere che sia una specie frequento nel NordAmerica.
4 I am indebted to Mrs. Vincent Meyer, wife of the owner of Thousand SpringsRanch, for her hospitality and permission to collect on the ranch house grounds.269-566?67 2
b PROCEEDINGS OF THE NATIONAL MUSEUM V0L - 124This description of B. americana could apply to several species of thebranchiobdellids. The range, all provinces of North America ("etutti provienti dall America del Nord"), can apply to no species thatI know. The one clue as to the identity of the species in Pierantoni'sdescription is in the description and illustrations of the jaws, and thiscould apply to several species of the genus Cambarincola, includingthe widespread C. philadelphica.Among the syntypes, the only recognizable specimen belongs to C.philadelphica (Leidy, 1851, p. 209), conforming in all diagnosticcharacters to the topotypical material (Hoffman, 1963, p. 342) that is inmy collection (PCH 695). Branchiohdella americana Pierantoni isreduced hereby to synonomy as Cambarincola philadelphica (Leidy)and Pierantoni's specimen "V 2914" has been labeled as the lectotypeof B. americana and returned to the Hamburg Museum.Branchiohdella tetradonta PierantoniBranchiohdella tetradonta Pierantoni 1906, p. 3; 1912, p. 12.?Ellis 1912, p. 190.
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Goodnight 1940, p. 28.Pierantoni (1906, p. 3) treats this species as follows:Questa nuova specie e molto affine alia Br. pentadonta di Whitman, di cui misono estesamente occupato nel mio citato lavoro. . . . Gli esemplari studiatifurono rinvenuti su Aslacus klamathensis (del fiume Klamath) di California,faciente parte delle collezione del Museo di Vienna.Caratteri esterni.?Ha forma sottile ed allungata, quasi cilindrica, con capooviodale, provvisto di due laolra, l'uno dorsale, l'altro ventrale.E anche questa una piccola specie, non oltrepassando i 2 mm. di lunghezza eavendo una grossezza di non oltre 1/5 di mm. La ventosa posterior non e moltoslargata, ed ha la forma di una piccola coppa. I pori genitali sono poco visibili. IIclitello occupa il 7? segmento dopa il capo.Caratteri interni.?Le du mascelle (Fig. 8) sono provviste ciascuna di quattrodentelli uguali, e sono esattamenete simili fra loro.La spermateca e fatta ad ampolla, con breve condotto di uscita.Lo spermascecco e molto evidente; l'atrio e slargato sacciforme; il pene prov-visto di rigonfiamento a forma di bulbo, e sprovvisto, come in tutte le piccolespecie, di uncinetti e di guaina chitinosa.Gli ovari sono bene sviluppati, e grosse le uova che ricolmano la cavita del 7?segmento postcefalico.Diagnosi riassuntiva.?Corpo allungato, capo poco rigonfio, bocca provvistadi due labra. Mascelle simili e provvista di quattro dentelli uguali ciascuna.Spermateca in forma di ampolla, atrio sacciforme.Dimensioni: Lunghezza 2 mm. grossezza 1/5 mm.Habitat: A stacus klamathensis: fiume Klamath (California).This is all that has been recorded concerning B. tetradonta. Pierantoni(1912, p. 12), Ellis (1912, p. 190), and Goodnight (1940, p. 28) do nomore than cite the original description with no indication that anyadditional material other than that on which Pierantoni based hisdescription had been seen.
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3631 BRANCHIOBDELLIDA?HOLT 7Dr. Robert P. Higgins of Wake Forest College unsuccessfullyattempted to locate the types of B. tetradonta in the NaturhistorischesMuseum, Vienna, for me. They apparently are lost and, without them,it is impossible to identify this species. I am grateful to Dr. Higgins.In the summer of 1964, my wife and I took two collections (PCH 1815,1816; USNM 35698, 35699) from the Klamath River, one about fourmiles east of the village of Klamath River and the other at BurbellResort about 10 miles north of Yreka, and a third (PCH 1817;USNM 35697) from the Shasta River about eight miles north ofYreka, all in Shasta County, Calif. Previous attempts in 1960 tocollect branchiobdellids near the mouth of the Klamath in Californiaand from just below and around the shores of Klamath Lake in Oregonwere unsuccessful. All of the hundreds of specimens obtained nearYreka and the village of Klamath River belong to Xironogitonoregonensis Ellis, 1919; moreover, Pierantoni's (1906) illustration ofthe jaws of B. tetradonta (his fig. 8) could be one of the jaws of X.oregonensis. Uncertainty is introduced, however, by his statementsabout size (X. oregonensis normally exceeds 2 mm in length), shape(the species of Xironogiton are flattened), and the penis with hooksand a chitinous sheath. In addition, his not-too-clear drawing (hisfig. 7) shows male reproductive organs more like those of Cambarincola,which does not have a chitinous sheath (I know of no branchiobdellidthat does) nor penial hooks (which are present in at least one as yetundescribed species of the recently established genus OedipodrilusHolt, 1967, and in some European species of Branchiobdella) . It ispossible that Pierantoni was dealing with small, extended, and mac-erated specimens of Xironogiton oregonensis; it is also possible that hewas working with a collection containing specimens of Cambarincolaor Oedipodrilus: species of both genera occur in the Coastal Range ofOregon, but not, as far as I know, in the Klamath River in California.There is grave doubt as to the type-locality. The Klamath River is alarge stream of some length in Oregon and California, and it is nowwell known that not all parts of the same stream contain the samebranchiobdellids (Hobbs, Holt, and Walton, 1967). Before I wasaware of the existence of the very small village of Klamath River, Ifirst read "fiume Klamath" to mean simply the river. This is still thereasonable interpretation, but it is possible that translation of theoriginal locality data made the name of the fishing camp into thatof the river. It is, finally, possible that Pierantoni's material waslabelled incorrectly. Unless the original material is found (an unlikelyevent), restudied, and a lectotype designated, the status of Branchiob-della tetradonta must remain forever uncertain and the name regardedas a nomen inquirendum. I regard it as such.
8 PROCEEDINGS OF THE NATIONAL MUSEUM V0L - mTo summarize: Steyhanodrilus obscurus Goodnight, 1940, is desig-nated the type of a new genus, Magmatodrilus; Branchiobdella tetra-donta Pierantoni, 1906, unidentifiable and the types unavailable ishence regarded as a nomen inquirendum; Branchiobdella americanaPierantoni, 1912, is reduced to synonomy with Carnbarincola phila-delphica (Leidy, 1851). Many thousands of specimens of branchiobdel-lids from all parts of North America have been examined, none belongto the genus Branchiobdella, and the conclusion is reached that nospecies of this genus is endemic to North America. There are, then,no known cases of intercontinental generic ranges among thebranchiobdellids. Literature CitedEllis, Max M.1912. A new discodrillid from Colorado. Proc. U.S. Nat. Mus., vol. 42,no. 1912, pp. 481-486, text figs. 1-5.1919. The branchiobdellid worms in the collections of the United StatesNational Museum, with descriptions of new genera and newspecies. Proc. U.S. Nat. Mus., vol. 55, no. 2267, pp. 241-265,pis. 10-13.Goodnight, Clarence J.1940. The Branchiobdellidae (Oligochaeta) of North American craj^fishes.Illinois Biol. Monogr., vol. 17, no. 3, pp. 1-75, pis. 1-111.Hall, Maurice C.1914. Descriptions of a new genus and species of the discodrillid worms.Proc. U.S. Nat. Mus., vol. 48, no. 2071, pp. 187-193, text figs. 1-3.Hobbs, Horton H., Jr.; Holt, Perry C; and Walton, Margaret1967. The crayfishes and their epozootic branchiobdellid and ostracodassociates of the Mountain Lake, Virginia, region. Proc. U.S.Nat. Mus., vol. 123, no. 3602, 84 pp., 22 figs.Hoffman, Richard L.1963. A revision of the North American annelid worms of the genus Carn-barincola (Oligochaeta: Branchiobdellidae). Proc. U.S. Nat. Mus.,vol. 114, no. 3470, pp. 271-371, text figs. 1-79.Holt, Perry C.1953. Characters of systematic importance in the family Branchiobdellidae(Oligochaeta). Virginia Journ. Sci., vol. 4, no. 2, pp. 57-61.1960. The genus Ceratodrilus Hall (Branchiobdellidae, Oligochaeta) withthe description of a new species. Virginia Journ. Sci., vol. 11,no. 2, pp. 53-77, pis. i-iv (figs. 1-16).1964. The distribution of the branchiobdellids: Some zoogeographical prob-lems. American Zool., vol. 4, no. 4, abstr. 260.1965. On Ankyrodrilus, a new genus of branchiobdellid worms (Annelida).Virginia Journ. Sci., vol. 16, no. 1, pp. 9-21, figs. 1-14.1967. OecUpodrilus oedipus, new genus and species (Annelida, Clitellata:Branchiobdellida). Trans. American Microsc. Soc, vol. 86, no. 1,pp. 58-GO.Leidy, Joseph1851. Contributions to helminthology. Proc. Acad. Nat. Sci. Philadelphia,vol. 5, p. 209.
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3631 BRANCHIOBDELLIDA?HOLT 9Liang Yan-Lin1963. Studies on the aquatic Oligochaeta of China, 1: Descriptions of newnaids and branchiobdellids. Acta Zool. Sinica, vol. 15, no. 4,pp. 560-570, text figs. 1-4.Moore, J. Percy1894. On some leech-like parasites of American crayfish. Proc. Acad.Nat. Sci. Philadelphia (for 1893), pp. 419-428.1895. The anatomy of Bdellodrilus illuminatus. Journ. Morph., vol. 10,no. 2, pp. 497-540, pis. xxviii-xxxii.PlERANTONI, UmBERTO1906. Nuovi discodrilidi de Giappone e della California. Ann. Mus. Zool.R. Univ. Napoli, vol. 2, pp. 1-9, pi. 5.1912. Monografia dei Discodrilidae. Ann. Mus. Zool. R. Univ. Napoli,vol. 3, pp. 1-28, text figs. 1-20, pi. 5.Yamaguchi, Hideji1934. Studies on Japanese Branchiobdellidae with some revisions on theclassification. Journ. Fac. Sci., Hokkaido Imp. Univ., ser. 6,vol. 3, no. 3, pp. 177-219, text figs. 1-17, pis. xii-xiii.
Fig. |
Fig.2
Figures 1-3.
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Magmatodrilus obscurus: 1, upper jaw; 2, lower jaw; 3, body in lateral aspect.
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Figure 4.
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Magmatodrilus obscurus, lateral view of male reproductive system (adl= an-terior deferent lobe, b= bursa, ejd=ejaculatory duct, sg=spermiducal gland, vd=vasdeferens).
U.S. GOVERNMENT PRINTING OFFICE: 1907