http://www.jstor.org Axiorygma nethertoni, a New Genus and Species of Thalassinidean Shrimp from Florida (Decapoda: Axiidae) Author(s): Brian Kensley and George M. Simmons, Jr. Source: Journal of Crustacean Biology, Vol. 8, No. 4, (Nov., 1988), pp. 657-667 Published by: The Crustacean Society Stable URL: http://www.jstor.org/stable/1548701 Accessed: 25/07/2008 14:20 Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/page/info/about/policies/terms.jsp. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/action/showPublisher?publisherCode=crustsoc. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission. JSTOR is a not-for-profit organization founded in 1995 to build trusted digital archives for scholarship. We work with the scholarly community to preserve their work and the materials they rely upon, and to build a common research platform that promotes the discovery and use of these resources. For more information about JSTOR, please contact support@jstor.org. JOURNAL OF CRUSTACEAN BIOLOGY, 8(4): 657-667, 1988 AXIORYGMA NETHERTONI, A NEW GENUS AND SPECIES OF THALASSINIDEAN SHRIMP FROM FLORIDA (DECAPODA: AXIIDAE) Brian Kensley and George M. Simmons, Jr. ABSTRACT Axiorygma nethertoni is described from material collected in about 30 m of water off the Key Largo area of the Florida Keys, and from 52-58 m in the Gulf of Mexico off the west coast of Florida. The genus is characterized by the possession of sexually dimorphic chelipeds, and by the absence of an appendix masculina in the male. The species burrows in sand flat areas around coral heads, with densities of up to 80/m2. The burrows, usually about 15 cm long, are often blocked by debris such as calcareous algal fragments. The species is considered to play an important role in the transfer of material across the sediment-water interface. The second author discovered the species described here while conducting a sabbati- cal research project on benthic microbial mats and submarine ground-water dis- charge off Key Largo, Florida (Fig. 1) (Sim- mons et al., 1985; Simmons and Love, 1987). Numerous pencil-sized holes, ringed by a cone of sediment, were observed and originally believed to be associated with the submarine ground-water discharge phe- nomenon. Sagittal core sections showed the holes to be unlined, to have extremely jag- ged and irregular walls, and to have the opening often occluded with flakes of Hal- imeda and/or other bits of sedimentary ma- terial (Fig. 2). The core sections suggested small dissolution channels rather than the work of an invertebrate. At the suggestion of Mr. Joe Dobarro (New Jersey Bureau of Shellfisheries, Bi- valve, New Jersey), the second author in- jected a mixture of ink and sea water into the holes, and eventually demonstrated that the holes were clustered, even though gen- erally abundant across the bottom where they occurred. The first suggestion that the holes were made by animals came from Mr. Guy Snyder. The second author then began covering the holes in 1-m quadrate areas with sediment, and observed their reap- pearance through time. A series of attempts was then made to obtain resin casts of the burrows, two of the more successful of which are illustrated (Fig. 3). Numerous attempts were made to collect the animals, with little success, until, on the last day and last dive of the sabbatical, 11 specimens were found beneath one of the instruments being used to collect submarine ground-water discharge. This paper had already been submitted for publication when Dr. Richard Heard (head of the Gulf Coast Research Labora- tory, Ocean Springs, Mississippi) drew the first author's attention to some axiids from the Gulf of Mexico, during a joint study of thalassinideans. These specimens, taken during the Bureau of Land Management's MAFLA (Mississippi-Alabama-northern Florida) and SOFLA (southern Florida) programs in the Gulf of Mexico off Florida, also proved to be the species described be- low. METHOD FOR OBTAINING RESIN CASTS While several types of resins were tried, the best casts were obtained with polyester resin such as is used for Fiberglas repair. The resin and hardener were carried underwater in separate bags. Collapsible and dispos- able hospital intravenous bags were suitable. Once the diver was ready, a predetermined amount of hardener was withdrawn with a 30-ml syringe and 14-16 gauge hypodermic needle and injected into the resin bag. The resin and hardener mixture were kneaded quickly for several seconds, and the mixture then withdrawn with a 60-cc syringe and 15-cm spinal tap needle. The mix- ture was forced into a burrow until resistance was en- countered, or until resin began to flow back out of the hole. Family Axiidae Huxley, 1879 Axiorygma, new genus Diagnosis. -Carapace not carinate poste- rior to cervical groove. Eyestalks elongate, subequal to rostrum in length. Antennal aci- cle elongate. Pereiopod 1: male having ro- bust chelipeds subequal in length, chela dif- fering on left and right sides, proximodorsal propodus of left and right chela bearing 2 657 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 8, NO. 4, 1988 Fig. 1. Study area off Key Largo, Florida, and collection sites in the Gulf of Mexico. clusters of slender distally feathered setae, merus distally inflated; female having slen- der nonrobust chelipeds subequal in length and similar. Pleopod 1 in male absent; con- sisting of single slender article in female. Pleopod 2 similar in male and female, hav- ing appendix interna, lacking appendix masculina in male. Outer uropodal ramus having suture in distal half. Type species. -Axiorygma nethertoni, new species, by present designation. Etymology. -The generic name is a com- bination of the prefix Axi-, derived from the family name Axiidae, plus orygma, from Greek meaning a tunnel or mine. Gender feminine. Remarks.--Generic definitions in the fam- ily Axiidae continue to be unclear or vague, even while new genera are described. A phy- logenetic reassessment of the family is ob- viously needed, along with a reexamination of the characters having value in defining the genera. Nevertheless, a consensus con- cerning these supposed generic characters is emerging (see Kensley and Gore, 1981, Ta- ble 1). Four species ofaxiids have been recorded from Florida (Abele and Kim, 1986): Ax- iopsis hirsutimana (Boesch and Smalley), A. oxypleura (Williams), A. serratifrons (A. Milne Edwards), and Coralaxius abelei Kensley and Gore. None of these bears much resemblance to the present species. Of the 17 or so genera and subgenera of the Axiidae, the present material seems most similar to Axiopsis Borradaile, 1903. This similarity is seen in the distribution of ex- opods, epipods, and branchiae, in the ab- sence of pleopod 1 in the male, in the elon- gate antennal acicle, in the presence of a uropodal suture, and in the keeled and spi- nose telson. Two features, however, sepa- rate Axiorygma not only from Axiopsis, but from all the other axiid genera. These fea- tures are the sexually dimorphic chelipeds, and the absence of an appendix masculina in the male. Axiorygma nethertoni, new species Figs. 4-7 Type Material. -Holotype USNM 211440, 3 CL 5.8 mm; allotype USNM 211441, ovigerous 2 CL 6.0 mm; paratypes USNM 221442, 4 5$ CL 5.1, 5.1, 5.6, 5.8 mm, 4 ovigerous 22 CL 5.0, 6.1, 6.2, 6.6, nonovigerous Y CL 5.6 mm; Key Largo National Marine Sanctuary, Florida, in 30 m. Additional Material. -Southwest Florida (Gulf of Mexico), BLM-SOFLA Stations: station 4B, S CL 3.8 mm; 26?46'N, 83?32'W, 55 m, medium sand, 5 April 1981.-Station 16C, D, 3 66 CL 3.3 mm, 4.1 mm, 4.5 mm; 25?45'N, 83?1 1'W, 53.7 m, fine sand, 9 November 1980.-Station 16D, $ damaged, $ CL 5.6 mm; 25?45'N, 83?11'W, 53.7 m, fine sand, 28 April 1981.-Station 20A, 2 55 CL 4.0 mm, 4.0 mm; 25?17'N, 82?09'W, 658 KENSLEY AND SIMMONS: NEW THALASSINIDEAN SHRIMP FROM FLORIDA A Fig. 2. A, sagittal section of resin-impregnated top of core, showing debris blocking entrance to burrow, scale = 30 mm; B, close-up of carbonate material (possibly fragment of Halimeda) blocking resin flow into burrow. Total resin penetration in this burrow was -2 cm. Pointer is pencil tip. 659 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 8, NO. 4, 1988 A& I Fig. 3. Resin casts of burrows of Axiorygma nethertoni, new genus, new species. A, 15-cm cast of burrow ending in old coral fragment; B, 15-cm cast of burrow with possible side burrows near vermetid and other shell fragments. Scales = 30 mm. 22.7 m, coarse sand, 27 April 1981.-Station 22E, 8 CL 4.9 mm, Q CL 5.0 mm; 25?17'N, 83002'W, 52.2 m, fine sand, 26 April 1981.-Station 28E, 1 6 CL 5.3 mm, 1 ovigerous $ CL 5.9 mm; 24047'N, 83013'W, 58.6 m, fine sand, 4 August 1981. BLM MAFLA Stations: station 2104, 2 S& CL 4.9 mm, 5.3 mm, e CL 5.0 mm; 26?25'N, 83?23'W, 53 m, coarse sand, 29 May 1975. Description. -Male: carapace smooth, ros- trum narrowly triangular, apex very slightly upturned, with 5 pairs of lateral teeth, lat- eral margins extending onto carapace as dis- tinct entire carina, reaching midway to cer- vical groove; median carina entire, reaching anteriorly to about midlength of rostrum; submedian carinae entire, starting well pos- terior of level of anterior carapace margin; cervical groove well defined; outer orbital angle rounded; anterior margin with anten- nal emargination, then sloping posteroven- trally to cervical groove; small branchioste- gal tooth present; ventral margin entire; posterior submarginal carina terminating at dorsolateral notch. Middorsal length of ab- dominal somites 2-6 subequal, all somites smooth; somite 1 shorter, ventrally pro- duced into acute forwardly directed tooth, anterolateral margin with flange articulating with posterolateral carapace extension; pleural ventral margins of somites 2-5 evenly convex; somite 6 with small tooth at posteroventral angle, posterolateral mar- gin concave to accommodate uropodal base. Eyestalk relatively elongate, reaching to apex of rostrum; cornea well pigmented, barely wider than eyestalk. Antennular peduncle of 3 articles, basal 660 KENSLEY AND SIMMONS: NEW THALASSINIDEAN SHRIMP FROM FLORIDA 661 S 0 in 1) V V V VS 0 ;-4 crt E rn a) 0r VO a) u w d, r- Z IZ) (13 bl a, (Z) h, Ob -4 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 8, NO. 4, 1988 A Fig. 5. Axiorygma nethertoni, new genus, new species: A, anterior carapace of female; B, telson and right uropod. article reaching to cornea of eye, with distal spine on outer margin; articles 2 and 3 sub- equal in length; flagella subequal to carapace in length, inner slightly longer than outer. Antennal peduncle of 5 articles, article 1 short, with ventrodistal tooth; article 2 dis- tolaterally produced into elongate tooth, with elongate acicle between it and article 3; latter articulating obliquely on article 2, with slender distal tooth; article 5 about half length of article 4, both unarmed; flagellum more than twice length of antennular fla- gella. Mouthparts as illustrated. Distribution of epipods, exopod, and branchiae: maxilliped 1 with broad bilobed epipod; maxilliped 2, exopod, epipod plus reduced podobranch; maxilliped 3, exopod, epipod plus reduced podobranch, 2 arthro- branchs; pereiopod 1 with epipod plus re- duced podobranch, 2 arthrobranchs; pe- reiopod 2 with epipod plus reduced podobranch, 2 arthrobranchs; pereiopod 3 with epipod plus reduced podobranch, 2 ar- throbranchs; pereiopod 4 with epipod, 2 ar- throbranchs; pereiopod 5 with setobranch. Maxilliped 3, basis articulating obliquely on coxa, with slender mediodistal tooth; is- chium with 2 or 3 teeth on mesial margin, strongly dentate crest on inner surface reaching beyond distal articulation of arti- cle; mesial margin of merus bearing 5 teeth, 2 distal teeth longest; carpus subequal to propodus in length, with small mesiodistal tooth and row of elongate setae on mesial margin; both propodus and dactylus bearing dense fringe of elongate setae. Pereiopod 1, chelae unequal, smaller che- la subequal to carapace plus rostrum in length, larger chela about 1.5 times carapace plus rostrum length; ischium with 1 or 2 distal teeth on posterior margin; merus dis- tally inflated, with 3 or 4 teeth on proximal half of posterior margin; carpus half length ofmerus, unarmed; propodus of both chelae with 2 tufts of 40-50 fine very slender non- 662 KENSLEY AND SIMMONS: NEW THALASSINIDEAN SHRIMP FROM FLORIDA J Fig. 6. Axiorygma nethertoni, new genus, new species: A, antenna; B, antennule; C, mandible, with palp detached; D, maxilla 1; E, maxilla 2; F, maxilliped 1; G, maxilliped 2; H, maxilliped 3, with dentate crest on inner surface of ischium; I, pleopod 1, 2; J, pleopod 2, 6. 663 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 8, NO. 4, 1988 Fig. 7. Axiorygma nethertoni, new genus, new species: A, right pereiopod 1 6; B, left pereiopod 1 S; C, left pereiopod 1 $; D, pereiopod 2; E, pereiopod 3; F, pereiopod 4; G, pereiopod 5. 664 KENSLEY AND SIMMONS: NEW THALASSINIDEAN SHRIMP FROM FLORIDA A Fig 8. Axiorygma nethertoni, new genus, new species: A, posterodorsal part of propodus of $ pereiopod 1, showing position of setal tufts; B, single propodal seta. Scale = 0.2 mm. branching setae of varying length on round- ed proximal shoulder, setae proximally smooth, becoming distally setulose, setules longest distally; larger chela, dactylus more than half length of propodal palm; cutting edge of propodal fixed finger with flattened proximal area, large tooth at about mid- length followed by several small teeth, be- coming crenulations distally; dactylar cut- ting edge bearing flattened basal tooth, broad concavity followed by rounded tooth in dis- tal third, remainder of cutting edge finely crenulate. Smaller chela, dactylus subequal to propodal palm; cutting edge of propodal fixed finger with large tooth in proximal third, bounded by smaller teeth or finer crenulations; dactylus with three-fourths of cutting edge straight, finely crenulate, distal fourth formed by flexed apically acute tip. Pereiopod 2 extending anteriorly to mid- length of chela of pereiopod 1; ischium with small subdistal tooth; merus with 3 or 4 spines on posterior margin becoming dis- tally progressively larger, bearing numerous elongate ventrodistal setae; carpus un- armed, slightly shorter than chela; fingers of chela slightly more than half length of pro- podal palm, cutting edges finely spinulose, with tufts of distal setae. Pereiopod 3, ischium about one-fourth length of merus; carpus half length of merus; propodus 1.5 times length of carpus, with single posterodistal spine; dactylus with 5 small spines near posterior margin. Pereiopod 4 slightly shorter than pereio- pod 3, propodus with posterodistal cluster of stiff grooming setae and single subdistal spine; dactylus with 7 small spines on me- sial surface. Pereiopod 5 shorter than pe- reiopod 4; propodus with dense cluster of stiff grooming setae on posterodistal sur- face; dactylus with posterior margin twisted 665 JOURNAL OF CRUSTACEAN BIOLOGY, VOL. 8, NO. 4, 1988 into almost dorsal position, bearing nu- merous setae. Pleopod 1 absent. Pleopods 2-5 bira- mous, endopod bearing appendix interna. Outer margin of outer uropodal ramus with 7-10 teeth, ending at larger articulating spine at start of distal suture; 6 or 7 teeth along suture; distal margin bearing elongate fringed setae. Inner uropodal ramus with 4 teeth along outer margin, distal tooth ex- tending beyond distal margin of ramus; 4 teeth on low longitudinal middorsal ridge; distal margin bearing elongate fringed setae. Telson with lateral margin bearing 3 teeth and small articulating spine between second and third teeth; posterolateral margin evenly convex, bearing elongate fringed setae; 3 submarginal spines at about posterolateral angle; posterior margin with single median tooth; dorsal surface with arc of 4 teeth at about midlength. Female: similar to male, with following exceptions: median carina of carapace finely crenulate in anterior half. Pereiopod 1, che- lipeds subequal, similar, slender, hardly more robust than pereiopod 2; lacking tufts of fine setae on propodi; ischium with 2 teeth on posterior margin; merus not in- flated, with single tooth on anterior margin in distal half, 3 teeth on posterior margin; carpus unarmed; fingers of chela about two- thirds length of propodal palm, latter par- allel-sided, fixed finger with about 9 low teeth on cutting edge; dactylus with cutting edge entire to very finely crenulate, with transparent subapical spine on outer margin reaching just beyond dactylar apex. Pleopod 1 consisting of single slender article bearing setae along both margins. Etymology. -The species is named for Mr. John Netherton, diver extraordinary, who has contributed in many significant ways to the collection of this new species, as well as to the measurement and understanding of submarine ground-water discharge in deep coral reef ecosystems. Ecological Notes. -Burrows of Axiorygma nethertoni were observed in the Florida Keys from Elliott Key in Biscayne National Park to Alligator Reef south of Key Largo Na- tional Marine Sanctuary. Based on the den- sity and distribution of burrows, it would seem that this species is very abundant in the sand flat areas around coral heads at depths of >27 m off the Florida Keys. The distribution of holes has an unusual pattern: hole-density generally ranged between ~ 50- 80/m2 in depths between 30.3-37.9 m (100- 125 ft), between -20-40/m2 in depths be- tween 25.8-30.3 m (85-100 ft), and then ended abruptly at 25.8-27.3 m (85-90 ft). In one survey off Conch Reef(l 7 July 1985), hole-density averaged 52 + 15/m2 at 30.3 m, 27 ? 9 at 28.8 m, 4 + 4 at 27.3 m, and no holes at 25.8 m. Measurements off French Reef and Ajax Reef showed similar distributions. In depths of - 30 m, the holes were more dense around coral heads, but became less dense and finally disappeared, as one moved onto open sandy areas. However, at depths of -38 m, this latter type of distribution was not as marked and holes were more evenly distributed across the bottom. The holes of this species were not found under coral heads. The material from the west coast of Flor- ida in the Gulf of Mexico was collected with a modified Reineck box core (0.09 m2) and was taken in a depth range of 52.2-58.6 m, deeper than the SCUBA-collected material from the Florida Keys. The substrate varied from coarse to fine sand. The geographic range, and the maximum depth at which this species occurs, are at present unknown. The density of holes off the keys suggests that this species is impor- tant in the transfer of material across sedi- ment-water interfaces in coral reef ecosys- tems. ACKNOWLEDGEMENTS We are grateful to Drs. Fenner A. Chace, Jr. (Smith- sonian Institution) and Austin B. Williams (National Marine Fisheries Service) for their comments and crit- icisms on this paper, and to Dr. Richard Heard for providing the material from the Gulf of Mexico. The second author is grateful to Mr. John Netherton, Dr. Kenny Elliott, Messrs. Guy Snyder and John Strain (United States Coast Guard) for their assistance in the deep diving efforts to collect the specimens described here; to Gene Shinn, United States Geological Survey, Fisher Island Station, Miami, Florida, for discussing details of the resin technique; to Mr. Dave Westphal, Manatee Bay Marine, Key Largo, for providing resins, hardeners, and other technical support and sugges- tions; to NOAA's Marine and Estuarine Management Division for financial support under contracts NA83AAA02762 and NA84AAA03722, and for per- mits to work in the Key Largo National Marine Sanc- tuary; to Dr. Stephen Cofer-Shabica for a permit to work off Ajax Reef in Key Biscayne National Park; to 666 KENSLEY AND SIMMONS: NEW THALASSINIDEAN SHRIMP FROM FLORIDA NOAA's National Undersea Research Program in Wil- mington, North Carolina, for valuable ship time and logistic support; and to the U.S. Geological Survey, Water Resources Division in Reston, Virginia, and At- lanta, Georgia, for sabbatical support during which time these specimens were collected. LITERATURE CITED Abele, L. G., and W. Kim. 1986. An illustrated guide to the marine decapod crustaceans of Florida. Part 1.- State of Florida, Department of Environmental Regulation, Technical Series 8: i-xvii, 1-326. Kensley, B., and R. H. Gore. 1981. Coralaxius abelei, new genus and new species (Crustacea: Decapoda: Thalassinidea: Axiidae): a coral-inhabiting shrimp from the Florida Keys and the western Caribbean Sea. -Proceedings of the Biological Society of Wash- ington 93: 1277-1294. Simmons, G. M., Jr., G. B. Hall, A. T. Mikell, and F. G. Love. 1985. A comparison of biogeological properties of a deep-water marine stromatolite an- alog with those from ice-covered Antarctic fresh- water lakes.-Geomicrobiological Journal 4: 269- 283. ,and F. G. Love. 1987. Water quality ofnewly discovered submarine ground water discharge into a deep coral reef habitat.--In: R. A. Cooper and A. N. Shepard, eds., Science applications of current div- ing technology on the U.S. continental shelf. NOAA Symposium Series, Undersea Research 2: 155-163. NOAA Undersea Research Program, Rockville, Maryland. RECEIVED: 27 January 1988. ACCEPTED: 4 May 1988. Addresses: (BK) Department of Invertebrate Zool- ogy, National Museum of Natural History, Smithson- ian Institution, Washington, D.C. 20560; (GMS) De- partment of Biology, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0794. ANNOUNCEMENT "Aspects of decapod crustacean biology," A. A. Fincham and P. S. Rainbow, eds., has been published (1988) in the Symposia of the Zoological Society of London 59: i-xv, 1- 375. This work contains the proceedings of a symposium held at the Zoological Society of London on 8th and 9th April 1987. Among the subjects included in the 16 chapters are: life history strategies, evolution in larval forms, the megalopa in majid crabs, hormones in larvae, phylogeny of the brachy- uran megalopa, larval sensory biology, ontogeny of anomuran eyes, stock size estimation using larvae, rhythmic behavior, physiological ecology of burrowing decapods, ecophys- iology in rock pools, photoecology of pelagic decapods, trace metals, ecophysiology in mangrove swamps, environmental influences on Nephrops and fishery management, and lobster population biology. Copies of this work, at approximately US$ 100.00, may be obtained from Oxford Uni- versity Press, Walton Street, Oxford X2 6DP, England, or Oxford University Press, 16- 00 Pollitt Drive, Fair Lawn, New Jersey 07410. 667