r HARVARD UNIVERSITY •8? Library of the Museum of Comparative Zoology MUD SHRIMPS, UPOGEBIA, FROM THE EASTERN PACIFIC (THALASSINOIDEA: UPOGEBIIDAE) AUSTIN B. WILLIAMS MCZ LIBRARY FEB 2 1986 HARVARD UNIVERSITY SAN DIEGO SOCIETY OF NATURAL HISTORY MEMOIR 14 1986 MUD SHRIMPS, UPOGEBIA, FROM THE EASTERN PACIFIC (THALASSINOIDEA: UPOGEBIIDAE) AUSTIN B. WILLIAMS National Marine Fisheries Service Systematics Laboratory National Museum of Natural History Washington, D.C. 20560 SAN DIEGO SOCIETY OF NATURAL HISTORY MEMOIR 14 23 January 1986 SYNOPSIS The mud shrimp genus Upogebia found in the eastern Pacific between Alaska and the Galapagos Islands is reviewed. Four previously described species from this region are rec- ognized: U. longipollex (Streets) and spimgera (Smith) ranging from El Salvador to Ecuador; pugettensis (Dana), from Valdez, Alaska to Morro Bay, California; rugosa (Lockington), Gulf of California; and a fifth species from the western Atlantic, affinis (Say), has been taken once in San Francisco Bay. Fifteen species new to science are described: U. acanthops, Panama; burkenroadi, Sonora, Mexico; dawsoni, Gulf of California to Panama; galapagensis, Galapagos Islands; jonesi, Sonora, Mexico, to Panama; lepta, islands off southern California; maccraryae. El Salvador to Ecuador; macginitieorum, southern California bight; onichion, San Miguel Island off southern California; schmitti, Panama; temupollex, Ecuador; thistlei. Gulf of California to Ecuador; veleronis, Islas Tres Marias, Mexico, and Cape San Francisco, Ecuador; ramphida, Maria Madre Island, Mexico; cocosia, Cocos Island. All except U. affinis are illustrated. Keys are given for identification of all species of Upogebia known from the Western Hemisphere, 7 from the western Atlantic and 19 from the eastern Pacific. Mud Shrimps, Upogebia, from the Eastern Pacific (Thalassinoidea: Upogebiidae) Austin B. Williams' INTRODUCTION Mud shrimps of the genus Upogebia [Leach] in the eastern Pacific scarcely have been touched from a taxonomic point of view. Until now, five species have been recognized from the latitudes of Alaska to Peru. This range of over 9700 kilometers (6000 mi) encompasses seven zoogeographic provinces (Brusca and Wallerstein 1979) influenced by cold temperate to tropical current regimes. The literature concerning Upogebia in this region is rather limited. The species described are: Gebia pugettensis Dana 1852 (Puget Sound, Washington), redescribed in the genus Upogebia by Stevens ( 1 928) and de Man ( 1 929) from specimens collected in British Columbia; Ge- bia spinigera Smith 1871 (Gulf of Fonseca), rede- scribed in the genus Upogebia by Holthuis (1952) from Colombian material; Gebia longipollex Streets 1871 (Panama), poorly described, no type-speci- mens extant, and identity in doubt; Gebia rugosa Lockington 1878 (Gulf of California), briefly de- scribed, no type-specimens extant, but identity dis- tinctive: and Upogebia rostrospinosa Bott 1955 (El Salvador). De Saint Laurent and Le Loeuff(1979) pointed out the remarkable uniformity in morphology of the family Upogebiidae as a whole. They regarded the family as monogeneric, within which the subgenera recognized by de Man (1928) and others have no systematic value because of overlapping characters, but they continued to recognize certain clusters of taxa in a new attempt to evaluate relationships with- in the family. They pointed out that about 50 species were known at that time from the Indo-West Pacific. 13 from the eastern Atlantic, and 12 from the west- em hemisphere. Sakai (1982), in a revision of the Indo-West Pacific members of the family, recog- nized 45 species from that region. He also empha- sized the remarkable uniformity in morphology of the group. However, he subdivided it by placing 40 of the species in the genus Upogebia, further split into 3 subgenera, and erected two other genera, Wol- fogebia, to contain 4 subspecies having a median ' National Marine Fisheries Service Systematics Laboratory, National Museum of Natural History. Washington. D.C. 20560. carina on the anterior carapace, and the monotypic Tuerokayogebia, lacking lateral ridges on the ante- rior carapace. Though the richly developed Indo- Pacific fauna would appear to occupy a central po- sition in evolution and dispersal of the family, the seemingly depauperate western Atlantic and eastern Pacific harbor more species than thought heretofore. The elucidation of relationships within the family as a whole are beyond the scope of this paper, but the suggestions of de Saint Laurent and Le Loeuff (1979) are reinforced by a better understanding of the New World species. Three clusters of species occur in the western hemisphere (Table 1 ): ( 1 ) a large cluster of species with normal abdomen and tail fan but subdivided into a series which lacks a strong proximal spine on the merus of the second leg and another series which possesses this spine, (2) a form related to these that has a distinctive abdomen, and (3) a few species that have developed an opercular tail fan. There are 3 operculate species in the third cluster (1 Atlantic. 2 Pacific), and a single Pacific species with distinctive sixth abdominal segment in the second. All these species lack an epipod on the third maxilliped. The 22 species in the first cluster lack these modifications (6 Atlantic, 16 Pacific); 12 of these have a proximal spine on the merus of the second leg (4 Atlantic. 8 Pacific), 10 lack the meral spine (2 Atlantic, 8 Pacific), and 3 Pacific species in the latter group lack a postorbital spine as well. All of the 1 6 Pacific species in this first cluster have a rudimentary epipod on the third maxilliped (the Atlantic species remain to be studied). Mouthparts of species within the genus have a noteworthy similarity, as will be demonstrated with illustrations for representative species selected from the above mentioned groups. De Saint Laurent and Le Loeuff (1979) regarded the few New World operculate species as forming a link with the tropical Indo-Pacific "Calliadne" ele- ment in the genus. The more numerous remaining species are a distinct and relatively homogeneous endemic set, which at this time have an imperfectly understood relationship with the eastern Atlantic elements in the family. Though subgenera of Upo- Williams Table 1. Groupings within the genus Upogebia in the western hemisphere. A = western Atlantic distribution, P = eastern Pa- cific. First cluster; normal abdomen and tail fan Lacking strong proximal spine on merus of second leg U. annae Thistle, A U. brasiliensis Holthuis, A U. burkenroadi new species, P U. lepia new species, P U. maccraryae new species, P U. macginitieorwn new species, P U. onychion new species, P U. pugeltensis (Dana), P U. temupollex new species. P U. veleronis new species, P With strong proximal spine on merus of second leg U. acanthops new species. P U. affinis (Say), A (P. 1 introduction) U. dawsoni new species, P U. galapagensis new species, P U. jamaicensis Thistle, A U. jonesi new species, P U. longipollex (Streets), P U. noronhensis Fausto-Filho, A U. omissa Gomes Correa, A U. schmilti new species, P U. spimgera (Smith), P U. thistlei new species, P Second cluster; distinctive sixth abdominal segment U. ramphula new species, P Third cluster: with operculate tail fan U. cocosia new species, P U. operculata Schmitt. A U. rugosa (Lockington), P gebia have proved faulty in the past, Sakai (1982) has again split this unwieldy genus, and it is likely that there will be other subdivisions in the future. I hesitate to initiate such changes for the western hemisphere until at least all the New World species are studied, but it is evident that good distinctions can be made among some species groups. For that reason the sequence of species accounts that follow is not strictly alphabetical but is arranged in the three clusters, the largest first, the single species sec- ond, and the operculates last. The little information that is available on the bi- ology of Upogebia species occurring in the eastern Pacific is derived almost exclusively from study of the blue mud shrimp, U. pugettensis. That species forms male-female pairs which live in relatively per- manent U-shaped burrows, as much as 1 m deep, in anoxic soft muds or clay muds of tidal flats. For example, the burrows in Yaquina Bay, Oregon, are most frequent at lower tide levels. In some regions the substrate can be so honeycombed that water pours into an excavated burrow system almost as fast as mud can be removed. Upogebia pugettensis is a menace to young oysters in Puget Sound. The burrows cause leakage from dikes built to keep the oysters on mud flats covered with water at low tide, and bioturbation from the shrimps' activity smoth- ers spat. The mud shrimps pump water through their burrow systems in order to feed on plankton and suspended detritus (Johnson and Snook 1927; Smith et al. 1954; Ricketts and Calvin 1939, 1948, 1952. 1968; L. C. Thompson and Pritchard 1969; R. K. Thompson and Pritchard 1 969; Pritchard and Eddy 1979). So far as known, all members of the genus live in burrow systems, though substrates may vary. The large region covered in this paper is still rel- atively unexplored in many of its parts and, there- fore, other species of Upogebia will undoubtedly be added to those discussed here as studies progress. For example, specimens are not known from Peru southward. Nevertheless, it is evident that the geo- graphic ranges of the species treated (Fig. 1 ) conform reasonably well with shallow water zoogeographic provinces of the northeast Pacific as outlined by Brusca and Wallerstein (1979). One species (P. pugettensis) is limited to the cold Aleutian and Or- egonian provinces, 3 species (U. lepta, macginitieo- rum, onychion) are known only from the warm tem- perate California Province, 2 species (U. burkenroadi, rugosa) are known only from the Cor- tez Province (Gulf of California), 7 species ( U. acan- thops. longipollex, maccraryae, schmitti, spinigera, tenuipollex, cocosia) seem to be limited to the trop- ical Panamic Province, 3 species (U. dawsoni, jo- nesi, thistlei) range through Cortez, Mexican (sub- tropical) and Panamic provinces, 1 species (U. veleronis) seems to bridge the latter two provinces, still another (U ramphula) is confined to the Mex- ican Province, and a final species (U. galapagensis) is limited to the Galapagos Province. There is one occurrence of a western Atlantic species (U. affinis) in San Francisco Bay. Details of these distributions are set forth in the species accounts that follow. Material has been examined from the following collections: AHF - CAS - CICESE- ML NMS - SDSNH- SIO UABC - Allan Hancock Foundation, University of Southern California California Academy of Science Centra de Investigacion Cientifica y de Educacion Superior de Ensenada, B.C.N., Mexico Moss Landing Laboratory, California Natur-Museum Senckenberg, Frankfurt San Diego Society of Natural History Scripps Institution of Oceanography Universidad Autonoma de Baja Califor- nia Eastern Pacific Mud Shrimps 150° 135° 120° 105° 90° 75° I I I I .'.'.: . zr :"-:■ : rz T I I T-T ! I I I I I I I I ! I I I I I I 1 i I T | | I ! I ! I I I I 11. U. pugettensis _ rf60 12. U. schmitti IS. U. spinigera lk . U. tenuipollex 15. U. thistlei 16. U. veleronis 17. U. ramphula 18. U. cocosia Valdez V J 60° 45' 1. U. acanthops 2. U. burkenroadi 3. U. dawsoni h. U. galapagensis 5. U. jo?iesi 6. U. lepta 7. U. longipollex 8 . U. maccraryae 9. U. macginitieoru?n 19. U- rugosa 10. U. onychion 30° 15°- 0°- t30' Baja Califo -15* M I I I | I I I I | TTI X I | I I Li^F I I I I | | I i I I | I I I I | I I I I | i i i I i i i i I i i i i i 150° 135° 120° 105° 90° 75° Fig. 1. Distributional ranges from Alaska to Ecuador of 19 eastern Pacific species of Upogebia; inset shows detail for southern California and Gulf of California. Numbers for listed species are associated with appropriate range lines or restricted localities. USGS —U.S. Coast and Geodetic Survey USNM —U.S. National Museum of Natural His- tory Citations in synonymies are limited to descrip- tions or references that can be associated specifi- cally. Type-series of newly described species consist of a holotype and selected specimens designated as paratypes. Acknowledgments This study was begun in 1976, and had many interruptions before being brought to conclusion. Williams Help with it has come from many persons and or- ganizations. It was initiated when Anne B. McCrary, University of North Carolina-Wilmington, sent to me for identification specimens that she had col- lected in Ecuador. An attempt to identify this ma- terial lead me to the extensive collections in the USNM, including materials recently collected by C. E. Dawson, M. L. Jones, C. A. Child and others, in Central America. For loan of specimens, access to collections, and related information, I am especially indebted to J. S. Garth and J. Haig (AHF); D. D. Chivers and W. J. Light (CAS); A. Carvacho (CICESE); J. Fausto-Filho, Laboratorio de Ciencia do Mar, Fortaleza. Ceara, Brazil; K. M. Mawn (ML); M. Tiirkay (NMS); G. Pretzmann. Naturhisto- risches Museum Wien; S. L. H. Fuller and R. H. Gore, Academy of Natural Sciences of Philadelphia; the late G. E. Radwin (SDNHS); W. Newman, S. Luke, and D. Thistle (SIO); E. Campos G., Uni- versidad Autonoma de Baja California (UABC); and F. Nichols, United States Geological Survey (USGS). For help with field collection of specimens I am indebted to D. M. Dexter, J. Homziak. H. P. Wil- liams and my late wife Jean McN. Williams, and for a collecting permit, the Resources Agency of California, Department of Fish and Game. Other information was supplied by D. L. Adkison, Texas A&M University; J. Chapman. University of Cal- ifornia. Santa Barbara; R. W. Heard. Gulf Coast Research Laboratory; C. E. Jenner, University of North Carolina-Chapel Hill; D. Siegel-Causey. Uni- versity of Kansas, Lawrence; and G. E. Steyskal, United States Department of Agriculture, USNM. The many illustrations which greatly complement the text were skillfully executed by Keiko H. Moore and Maria M. Dieguez. Text was set on a word processor by Virginia R. Thomas, and critical com- ments on the manuscript were provided by B. B. Collette. R. B. Manning, I. Perez Farfante, and anonymous reviewers. SYSTEMATIC ACCOUNTS Family Upogebiidae Borradaile 1903 Diagnosis. — (Adapted from de Saint Laurent and Le Loeuff 1979.) Carapace compressed laterally, deeper than broad, poorly calcifed on posterolateral parts; cervical groove well-marked, crossing near midlength of dorsal line and running obliquely to anterior margin behind base of antennae; thalassi- nidean line (linea thalassinica) always present in an- terior region, sometimes absent or discontinuous in posterior region; gastric region continuous with ex- tensive, flattened rostrum projecting over base of eyestalks, and ornamented on about anterior % with usually spiniform tubercles and thick pile; antero- lateral margin either spineless, armed with single postocular spine, or series of spinules. Cristiform projection on lateral plate of epistome visible in lateral view below base of antenna. Abdomen elongate, depressed, pleura little de- veloped, second segment longest. First maxilla with coxal endite triangular, exite broad. First maxilliped with epipod reduced or ab- sent; exopod with flagellum; endopod with 2 arti- cles. Second maxilliped bearing short epipod usually pressed against coxa and fringed with setae; exopod with flagellum. Third maxilliped with or without rudiment of epipod; always with exopod; mesial border of endopod with thick fringe of setae; is- chium with crista dentata absent or reduced to row of fine spinules nearly invisible at base of setae, 1 hooked proximal spine on inner surface, occasion- ally a secondary smaller spine. Chelipeds equal, symmetrical, and sub- to fully chelate, rarely simple; fixed finger nearly always more slender than dactyl; merus with 2 fringes of long plumose setae ventrally. Second legs with merus as conspicuously setose as that on cheliped; propodus slightly broadened; dactyl short, both densely setose on margin; legs 3 and 4 not so conspicuously setose, dactyls more or less spatulate and bearing comb of stiff setae ventrally; leg 5 with extremity subchelate. Pleopod 1 absent in male, Particulate and simple in female; pleopods 2-5 foliaceous, endopod about V2 as long as exopod, without appendix interna; pleo- pod 2 without appendix masculina in male. Uro- pods with no division on exopod. Genus Upogebia [Leach 1814] Figure 2 Upogebia [Leach 1814]:400. -Hemming 1958:143, name no. 1034. — Sakai 1982:8 (complete syn- onymy). Diagnosis. —Anterior region of carapace with me- dian dorsal furrow (often indistinct and obscured by setae) posterior to rostral tip; lateral ridge sep- arated from ornamented part of anterior carapace by longitudinal groove; anterolateral margin with or without spines; first leg chelate, subchelate or simple (adapted from Sakai 1982). Eastern Pacific Mud Shrimps abdominal segments „,,„ rostrum e antennule antenna Fig. 2. Schematic drawing of Upogebia. A. Animal in lateral view; B. Coxa and associated articles of legs 1-3 in ventral view: c. Carpus; eg. Cervical groove; eh. Cheliped; ex, Coxa (sometimes spined); d. Dactyl; e. Eye; en. Endopodite; ex Exopodite; i. Ischium; m. Merus (sometimes spined proximally); p. Propodus; pi. Pleuron (sometimes bearing spinules); pr. Protopodite; ps. Postorbital spine; st. Stemite (sometimes bearing spinules); tl. Thalassimdean line. Key to Known Eastern Pacific Species of Upogebia 1. Telson with distal margin conspicuously wider than proximal margin 2 Telson essentially rectangular or somewhat narrowed distally 3 2. Telson with proximal raised area on either side near base of submesial longitudinal rib unarmed. Cocos Is. U. cocosia, n. sp. p. 55 Telson with proximal raised area on either side near base of submesial longitudinal rib bearing 1 or more small spinules. Gulf of California U. rugosa (Lockington) p. 58 3. Abdomen with lateral margin of segment 6 bearing acute, hooked, anterolateral process; chelae with fingers equal, pre- hensile edges finely and evenly toothed. Islas Tres Marias U. ramphula, n. sp. p. 52 Abdomen with lateral margin of segment 6 sinuous or somewhat lobed but lacking anterolateral process; chelae almost al- ways with fingers unequal, prehensile edges not evenly toothed 4 4. Merus of leg 2 lacking proximal mesioven- tral spine _.._ _ _... 5 Merus of leg 2 bearing proximal mesioven- tral spine 1 2 5. Postocular spine absent or at most obso- lescent (tiny) 6 Postocular spine present and well devel- oped 8 6. Merus of chelipeds bearing well developed distodorsal spine; merus of leg 3 bearing cluster of proximoventral spines. Ecua- dor U. tenuipollex, n. sp. p. 45 Williams Merus of chelipeds lacking distodorsal spine or with spine tiny; merus of leg 3 bearing few obsolescent proximoventral spines _ 7 7. Chelipeds slender, carpus with only 1 strong spine dorsally; fixed finger tapering, slen- der, and nearly as long as dactyl. Gulf of California U. burkenroadi, n. sp. p. 12 Chelipeds robust, carpus with more than 1 strong spine dorsally; fixed finger stout at base, tapered beyond stout middle tooth to short rather thick point, shorter than dactyl. Southern California U. macginitieorum, n. sp. p. 30 8. Leg 3 with spineless merus 9 Leg 3 with merus ventrally or proximolat- erally spined (sometimes inconspicuous- ly) 10 9. Short fixed finger of chelae with rather slen- der, laterally compressed tip. Alaska to Morro Bay, California U. pugettensis (Dana) p. 35 Short fixed finger of chelae with broad tip flattened on prehensile edge and cor- neous. San Miguel Island, California U. onychion, n. sp. p. 33 10. Rostrum long and slender, exceeding edge of cornea by distal part bearing terminal spines and 3 marginal spines; antennular peduncle with conspicuous slender ven- tral spine on basal article distally and also on short second article. Baja Cali- fornia Norte U. lepta, n. sp. p. 22 Rostrum short, exceeding cornea by distal part bearing terminal spines and at most 1 marginal spine; antennular peduncle not conspicuously spined ventrally 1 1 1 1 . Chelipeds with lower margin of ischium smooth, lacking any evidence of spines; dactyl of cheliped with elongate, cor- neous distal patch, subdistal prehensile tooth reduced or absent. Mexico, Ecua- dor U. veleronis, n. sp. p. 50 Chelipeds with small ventral spine on is- chium; dactyl of chela with short cor- neous tip preceded by noticeable pre- hensile tooth. El Salvador to Ecuador U. maccrarvae, n. sp. p. 25 12. Eyestalks with cornea normally rounded distally 13 Eyestalks obliquely truncate distally and bearing short subterminal spine mesial to reduced, triangular cornea. Panama U. acanthops, n. sp. p. 10 13. Abdominal segments 1 and/or 2 spined ventrally on sternites or edge of pleura 14 Abdominal segments 1 and/or 2 lacking ventral spines 1 5 14. Merus of leg 4 bearing ventral spines; ab- dominal segments 1-2 with sternites lacking spines but margin of pleura and bases of pleopods sometimes bearing de- ciduous spinules; surface of uropods and telson without spinules. El Salvador to Ecuador U. spinigera (Smith) p. 41 Merus of leg 4 spineless; abdominal seg- ments 1-2 almost always bearing spines or spinules (often many) on sternites, margin of pleura, and bases of pleopods; dorsal surface of uropods and telson often strewn with numerous spinules. Central America U. longipollex (Streets) p. 24 1 5. Chelae with spines proximal to fixed finger on ventral keel of palm _ 1 6 Chelae with no spines directly on ventral keel of palm (but mesial surface of palm may bear spines) 1 7 16. Projection on either side of rostrum set apart by shallow incision; chela with no- ticeable tooth at midlength of dactyl on cutting edge. Atlantic; Massachusetts to Fig. 3. Upogebia acanthops new species, a. Cephalic region, lateral; b. Anterior carapace, dorsal; c. Mandible; d. e, Maxilla 1, 2;f, g. h. Maxilliped 1. 2, 3; Cheliped, i. lateral,/ mesial; k. I, in. n. Legs 2-5; o, Abdominal segments 1-2. basal articles of pleopods. lateral; p. Telson and left uropods. USNM 213194. 9 Holotype. Scales = 1 mm; O = a, b. h. i. j. k. I, in. n, o. p;0 = e;O =f, g; = c.d. Eastern Pacific Mud Shnmps 10 Williams Brazil. Pacific; one occurrence in San Francisco Bay U. affinis (Say) p. 12 Projection on either side of rostrum set apart by deep incision; chela with large tooth proximal to midlength of dactyl on cutting edge. Gulf of California, Central America U. jonesi, n. sp. p. 19 17. Merus of leg 4 bearing ventral spines 18 Merus of leg 4 spineless (sometimes ob- solescent on one side) 19 18. Shoulder flanking cervical groove bearing about 3 granules; fixed finger of chela greater than Vi length of dactyl. Central America to Ecuador U. spinigera (Smith) p. 41 Shoulder flanking cervical groove bearing well developed spines; fixed finger of chela less than '/: length of dactyl. Pan- ama U. schmitti, n. sp. p. 40 19. Chelipeds with coxa unspined 20 Chelipeds with coxa drawn into ventral spine. Gulf of California and Central America ... U. dawsoni, n. sp. p. 14 20. Carpus of chelipeds unspined at anterior ventrolateral corner. Galapagos Islands U. galapagensis, n. sp. p. 17 Carpus of chelipeds with spine (often small) at anterior ventrolateral corner. Gulf of California to Ecuador U. thistlei, n. sp. p. 47 Key to Known Western Atlantic Species of Upogebia (Adapted from Thistle 1973) 1 . Telson essentially rectangular or somewhat narrowed distally 2 Telson with distal margin conspicuously wider than proximal margin. Gulf of Mexico and Caribbean U. operculata Schmitt 2. Merus of leg 2 lacking proximal mesioven- tral spine 3 Merus of leg 2 bearing proximal mesioven- tral spine 4 3. Merus of chelipeds with distodorsal spine beyond level of postocular spine; merus of legs 2-4 elongate, that of leg 2 with small ventral spine at proximal 'A length; shoulder lateral to cervical groove smooth. Caribbean U. annae Thistle Merus of chelipeds with distodorsal spine at about level of postocular spine; legs 2-4 of normal length, that of leg 2 spineless ventrally; shoulder lateral to cervical groove bearing about 5 obsolescent spines or tubercles. Brazil U. brasiliensis Holthuis 4. Abdominal segments 1 and/or 2 lacking ventral spines 5 Abdominal segments 1 and/or 2 spined ven- trally on sternites or edge of pleura. Pan- ama to Brazil U. oniissa Gomes Correa 5. Postocular spines 0-2 6 Postocular spines 4-5. Caribbean U. jamaicensis Thistle 6. Chelae with spines proximal to fixed finger on ventral keel of palm. Massachusetts to Brazil U. affinis (Say) Chelae with no spines proximal to fixed finger on ventral keel of palm. Fernando do Noronha U. noronhensis Fausto-Filho Upogebia acanthops new species Figure 3 Material examined.— -Panama. USNM - 2 1 3 1 94 (Holotype) 9, Fort Kobbe Beach, 8°53'45"N, 79°34'35"W, < 1 m, 0-90 m offshore, 30%o S. C. E. Dawson, 29 June 1979, Nox-fish. Diagnosis. — Postocular spine present. Eyestalk obliquely truncate distally, reaching level posterior to base of subterminal rostral spines; bearing short, subterminal spine mesial to reduced, triangular cor- nea. Abdominal segments 1 and 2 with corneous spinules on margin of pleura. Telson essentially rect- angular. Cheliped with 1 spine on ventral margin of ischium; merus with 2 superior subdistal spines. Merus of leg 2 with strong proximal mesioventral spine, that of leg 4 bearing ventral and ventrolateral spines plus few spinules. Description. — Rostrum short, broadly triangular and slightly deflexed; pair of moderate subapical spines followed on each side by 2 spines of almost equal size, these in turn merging with field of spines and tubercles diminishing over approximately an- terior % of anterior dorsal part of carapace and an- gling toward sides posteriorly; gastric part posterior to this smooth; ornamented part separated from and flanked on each side by posteriorly divergent ridge Eastern Pacific Mud Shrimps 11 bearing similar crest of about 12 spines decreasing from strongest on lateral rostral process to obsoles- cence posteriorly; all spinose area interspersed with dense tufts of setae. Cervical groove deep and con- tinuous, 2 small spines on shoulder lateral to it be- low thalassinidean line, latter continuing to posterior margin. Postocular spine present. Abdomen broadly and smoothly arched dorsally; dense fine setae in band on posterior margin of seg- ments 3 and 4 and in dense tracts on pleura of segments 3-5, scattered setae elsewhere; pleura of segment 1 narrowly rounded posterolaterally. those of segments 2-5 broadly rounded, margins on seg- ments 1 and 2 bearing corneous spinules; segment 6 rectangular, wider than long, lateral margin sin- uous, narrow oblique marginal incision anterior to posterolateral lobe near insertion of uropods. Telson rectangular, sides slightly converging dis- tally, distal margin somewhat convex and densely fringed with setae, transverse ridge at proximal Vi fairly prominent. Eyestalk reaching level posterior to base of sub- terminal rostral spines; longer than deep, upper and lower margins parallel, distal margin oblique and bearing short, subterminal spine mesial to narrowly triangular, anterolaterally directed cornea. Antennular peduncle reaching about to end of an- tennal peduncle, its proximal 2 articles together about as long as terminal article; flagella unequal, lower thinner ramus slightly longer than upper thicker one. Antennal peduncle with about l h its length extend- ing beyond tip of rostrum; article 2 bearing almost obsolescent subdistal ventral spine; scale moderate, oval, with distal seta and another at anterodorsal angle. Mouthparts as figured; maxilliped 3 with epipod. Epistomial projection rather broad in lateral view, bearing 2 spines at anterodorsal angle. Right cheliped only present. Ventral margin of ischium bearing single moderate spine. Merus with row of 4 moderate spines on proximal l h of ventral margin, 2 superior subdistal spines reaching level of ocular spine. Carpus trigonal, shallow longitu- dinal groove laterally and acute spine closely pre- ceded by smaller acute spine at ventrolateral corner; mesiodorsal crest of 10 almost uniform small spines behind prominent spine on anterior margin, all di- rected forward; somewhat smaller spine below latter on middle of distomesial margin and between these a still smaller intermediate spine; distoventral spine strong. Palm oval in cross section, length including fixed finger about 2.1 times maximal height; long fine setae, rather ragged in 3 dorsal rows and longest in ventral tract; dorsal crest of low, forwardly di- rected spines flanked laterally by spineless crest and more remotely on mesial surface by crest of obso- lescent teeth ending in tooth-tipped inner condyle of dactyl, small tooth below lateral condyle; mesio- proximal surface bearing granular vertical ridge; fixed finger %-% length of dactyl, slightly curved and ta- pered to slender tip, bearing 5 teeth on prehensile edge; dactyl slightly curved and stouter than fixed finger, corneous slender tip preceded by strong tooth on prehensile edge and then row of about 5 calcar- eous teeth ending in strong tooth near toothless proximal space; 2 rows of tubercles mesially and few tubercles proximally on dorsal and lateral sur- face. Leg 2 reaching about to end palm of cheliped; carpus with tiny subdistal ventral spine; elongate merus with hooked superior, subdistal spine, me- sioventral spine strong. Leg 3 with slender pointed dactyl extending beyond rostrum; merus with clus- ter of spines ventrolaterally and row of spinules dis- tally on mesiodorsal crest; 1 ventral spine on is- chium; coxa with oviducal opening guarded by spine laterally. Leg 4 with ventral and ventrolateral spines, few spinules on merus, a ventral distolateral spine on ischium. Subchelate leg 5 reaching base of che- liped, merus spineless. Two arthrobranchs arranged in biserial rows of undivided (entire) lamellae on maxilliped 3 and legs 1-4. Pleopods with basal articles spinulose, first pleo- pods vestigial, lacking distal articles. Uropod with spine on protopod overhanging base of endopod; straight distal margin of endopod ex- ceeded by curved margin of exopod, both rami with minute scattered distal spines and dense fringe of setae; endopod with low, median longitudinal rib and less prominent lateral rib having shallowly con- cave margin except for rounded, proximal shoulder; exopod with 3 ribs, mesial strongest one bearing slender spine proximally, intermediate rib longer, lateral rib least evident of all, slightly curved out- ward but shallowly concave proximally. Measurements (mm). — Length anterior carapace 9.0, length carapace 13.0, length right chela includ- ing fixed finger 7.4, height right chela 3.5. Known range.— Confined to type-locality. Remarks. — This species resembles U. spinigera of the eastern Pacific in that it possesses a spiny merus on leg 4, small spines flanking the cervical groove, and 2 strong spines at the base of the uropods. It also resembles certain other specimens of that species as well as U. longipollex in that it possesses corneous 12 Williams spinules on the pleura of abdominal segments 1 and 2 and on the bases of the pleopods. However, pos- session of spined eyes, double dorsal spines on the merus of leg 1, and the deep posterolateral incision on abdominal segment 6 set it apart as a distinct member of the genus. Name. — The specific name is a noun in apposi- tion derived from the Greek "acantha," thorn or prickle, and "ops," the eye, in reference to the small distal spine near the cornea of each eye. Upogebia affinis (Say) Gebia affinis Say 1818:241. Upogebia affinis. -Hay and Shore 1918:408, pi. 29, fig. 9.-Schmitt 1935:196. -Williams 1965:103, fig. 60.-1984:191, fig. 133. -Thistle 1973:23 (key). Material examined. — USA: California. USNM — 213285, 2 <5, 2 9. middle section of San Francisco Bay. R Tang. Red Rk., S 48D E Brothers Lt. N 1 3D E, Lft. Tang. Marine I.. N 4 1 D W (trian- gulation bearings off Pt. San Quentin), 12.5 fm, CS5532. Albatross sU. 5824A. 18 December 1912, sledge trawl, gooey mud. Remarks. — This small collection of Upogebia la- belled as one of the Albatross collections from San Francisco Bay seems identical with U. affinis of the western Atlantic. The specimens may represent an introduction of the kind discussed by Carlton ( 1979), that is 1) of fouling or ballast-dwelling organisms on ships, or 2) nestling invertebrates on and among oysters imported from the western Atlantic. Carlton did not list this species from San Francisco Bay, and to my knowledge no other specimens of this species have been taken there. Adequate descriptions of U. affinis may be found in references cited in the abbreviated synonymy. The known natural range of the species is from Cape Cod, Mass., to the state of Sao Paulo. Brazil. Upogebia burkenroadi new species Figure 4 Material examined. —Mexico: Sonora. SDNHS-3985 (Holotype) 3, 3986 (Paratype) 9, La Libertad [29°55'N, 1 1 2°43'W], collector and date not recorded. Diagnosis. — Postocular spine minute. First and second abdominal segments lacking ventral spines. Telson essentially rectangular. Cheliped with merus bearing tiny, obsolescent subdistal spine on curved dorsal margin. Merus of leg 2 with tiny subdistal dorsal spine but lacking mesioventral proximal spine. 2 obsolescent spines ventrolaterally. Description. —Rostrum triangular, slightly down- turned: tip slightly exceeding eyestalks in female, but extending beyond eyestalks by Vi their length in male; dorsal pair of strong subapical spines followed on each side by 2 spines somewhat smaller in length; dorsal % of carapace anterior to cervical groove bearing hairlike tufts, its surface spiny anteriorly to tuberculate and angling toward sides posteriorly, gastric Vi posterior to this smooth; ornamented an- terior part separated from and flanked on each side by posteriorly divergent ridge bearing similar crest of about 1 2 to 16 spines decreasing from strong on lateral rostral process to obsolescent posteriorly. Cervical groove deep and continuous, shoulder lat- eral to it smooth; thalassinidean line continuing to posterior margin of carapace. Postocular spine mi- nute. Abdomen broadly and smoothly arched dorsally; pleura of segment 1 narrowly rounded posterolater- ally, those of 2-5 broadly rounded, pleural margin and sterna of segments 1-2 unarmed; dense fine plumose setae in tracts on pleura of segments 2-6; segment 6 rectangular, wider than long, with lateral margin sinuous, notch anterior to posterolateral lobe continuous with oblique groove and lunate dorsal impression. Telson rectangular, a little wider than long but broadest proximally, angle on anterolateral margin interlocking with groove on central rib of uropodal endopod; distal margin slightly biconvex and dense- ly fringed with setae; transverse proximal ridge fairly prominent and continuous with low lateral ridges at each side; median groove obsolescent. Eyestalks stout, cornea narrower than diameter of stalk and directed anterolaterally. Antennular peduncle reaching to about proximal 'A of terminal article of antennal peduncle, its prox- imal 2 articles together about as long as terminal article; flagella unequal, lower thinner ramus some- what longer than thicker upper one. Antennal peduncle with about V: its length ex- tending beyond tip of rostrum; article 2 bearing ob- solescent subdistal ventral spine; scale moderate, oval. Mouthparts as figured for U. pugettensis; maxil- liped 3 bearing epipod. Epistomial projection rather broad in lateral view, unspined. Chelipeds essentially equal. Merus with row of 1- 3 scattered, obsolescent, spiniform tubercles on ven- Eastern Pacific Mud Shrimps 13 Fig. 4. Upogebia burkenroadi new species, a. Cephalic region, lateral; b. Anterior carapace, dorsal; Cheliped, c. lateral, d, mesial; e. f. g, h. Legs 2-5; i. Telson and left uropods. SDNHS 3985. $ Holotype; mouthparts and g from 3986. 9 Paratype. Scales = 1 mm; O = a, b. c, d, e. f, h, i; • = g. tral margin; minute subdistal dorsal spine reaching level of tiny postocular spine. Carpus trigonal, a shallow longitudinal groove laterally; no spine at anterior ventrolateral corner; mesiodorsal crest of obsolescent granules behind prominent spine on an- terior margin; comb of 3 spines remotely lateral to this on anterior margin and 1-3 obsolescent tuber- cles below it on distomesial margin; distoventral spine slender but strong. Palm oval in cross section, length including fixed finger about 3 times maxi- mum height; 3 dorsal rows and 1 mesiodorsal row of scattered sparse setae. Fingers relatively straight; fixed finger about % length of dactyl, slightly curved and tapering to slender tip reaching beyond level of strong subdistal dactylar tooth, bearing about 3 teeth on proximal prehensile edge. Dactyl stouter than fixed finger, its curved upper surface smooth; slight- ly bent tip corneous on prehensile edge and preceded by strong tooth, that in turn by a more or less straight raised edge capped by row of about 8 teeth, smaller and close-set distally but with proximalmost larger tooth remote, toothless proximally. Leg 2 reaching to distal 'A palm of cheliped; carpus toothless; merus with tiny subdistal dorsal spine but lacking mesioventral, proximal spine. Leg 3 with slender pointed dactyl extending beyond rostrum; merus with cluster of obsolescent spines ventrolat- erally. Leg 4 with spineless merus. Subchelate leg 5 reaching base of cheliped. Two arthrobranchs arranged in biserial rows of undivided (entire) lamellae on maxilliped 3 and legs 1-4. Uropod with acute small spine on protopod over- hanging base of endopod; straight distal margin of endopod exceeded by curved margin of exopod, dis- tal margin of exopod on adult female with few ob- N Williams solescent granules but distal margins otherwise smooth and bearing dense fringe of setae; endopod with low, median longitudinal rib and less promi- nent lateral rib having shallowly concave margin except for rounded, proximal shoulder; exopod with 3 ribs, mesial one strongest, intermediate rib longer, lateral rib least evident of all, slightly curved out- ward but shallowly concave proximally. Measurements (mm). — Male holotype, length an- terior carapace 6.4, length carapace 9.4, length chela including fixed finger 6. 1 , height chela 2. 1 . Paratype female, same, 7.7, 1 1.5, 7.3, 2.4. Known range.— Confined to type-locality. Remarks. — Upogebia burkenroadi, represented by- only two known specimens, resembles U. tenuipol- lex in the disposition of spines on legs 1 and 3. and in possession of a postocular spine, though having all of these much less well developed. It also resem- bles U. macginitieorum which usually lacks the postocular spine and has much more robust chelae with shorter fixed fingers, but U. burkenroadi lacks bands of setae on the posterior margin of the terga of segments 3-4, whereas they are present in U. macginitieorum. Name. —The species is named for Martin D. Bur- kenroad, one of the chief architects of currently ac- cepted decapod crustacean classification, and a stu- dent of Upogebia in California and Mexico. Upogebia dawsoni new species Figure 5 Material examined.— Mexico: Baja California Norte. AHF-2566-01, 1 0.60 length of cut- ting edge of dactyl; palm of chela posterior to base of fixed finger spineless mesially; ischium with 1 spine on ventral margin. Legs slender; leg 2 with merus 5:4 times width and bearing mesioventral spine; merus of leg 4 lacking ventral spines. Description.— Rostrum rather narrowly triangu- lar and almost straight; pair of moderate subapical spines followed on each margin by 3 spines smaller in size and these in turn merging with field of spinous tubercles diminishing over anterior % of anterior dorsal part of carapace and angling toward sides posteriorly; gastric part posterior to this smooth; ornamented part separated from and flanked on each side by posteriorly divergent ridge bearing similar crest of about 10 spiniform tubercles decreasing from strongest on lateral rostral process to obsolescence posteriorly; all spinose area interspersed by dense tufts of setae. Cervical groove deep and continuous, no spines (rarely obsolescent) on shoulder lateral to it. Postocular spine present. Abdomen broadly and smoothly arched dorsally, scattered setae on segments 3-6 with denser tracts on pleura of segments 3-5; pleura of segment 1 nar- rowly rounded posterolaterally, those of 2-5 broadly rounded; segment 6 rectangular, slightly wider than long, pleura formed into shallowly bilobed anterior lobe and posterior lobe adapted for articulation of uropods, dorsally marked with obsolescent sinuous groove at side. Telson rectangular, slightly wider than long, par- allel sided; very slightly biconvex distally and dense- ly fringed with setae; anterior transverse ridge fairly sharp. 18 Williams Fig. 6. Upogebia galapagensis new species, a. Cephalic region, lateral; b. Anterior carapace, dorsal; c, Mandible; d. e. Maxilla 1. 2\f, g, h, Maxilliped 1, 2, 3; Chehped. /. lateral,;, mesial; k. 1. m, n. Legs 2-5; o, Telson and right uropods. USNM 213223, 9 Holotype; mouthparts from CAS 2073. Scales = 1 mm; O = a. b. i. j, k, I, m, n, o\ • = h; □ = e, f. g; = c. d. Eastern Pacific Mud Shrimps 19 Eyestalk reaching level of penultimate rostral spine, moderately thickened; cornea rather large though not dilated, directed anteroventrally. Antennular peduncle reaching proximal l A of ter- minal article in antennal peduncle, its proximal 2 articles together about as long as terminal article; flagella unequal, lower thinner ramus Va longer than upper thicker one. Antennal peduncle with l h its length extending beyond tip of rostrum; article 2 bearing nearly erect subdistal ventral spine; scale small, oval, bearing minute anterior spine. Mouthparts as figured for U.jonesi; maxilliped 3 bearing epipod. Epistomial projection rather broad in lateral view, bearing 1 or 2 spines, sometimes asymmetrical. Chelipeds essentially equal. Ventral margin of is- chium bearing slender hooked spine. Merus with superior, subdistal spine reaching level of ocular spine, row of 5 or 6 irregularly spaced, moderate spines on ventral margin. Carpus trigonal, a shallow longitudinal groove laterally; with mesiodorsal crest of small spines and a strong spine all directed for- ward; 3 or 4 much smaller spines laterally on an- terior margin, and below anterodorsal spine on me- siodistal margin a smaller intermediate spine followed by a stronger median spine; distoventral spine strong but slender. Palm oval in cross section, length including fixed finger about 4 times maximal height; hand with rows of long silky setae, densest in 3 mesiodorsal rows and longest in ventral tract; proximal dorsal crest of small spines originating near articular condyle of carpus flanked laterally by lon- ger spineless crest; with or without row of (or scat- tered) small spines on mesial and/or lower surface, lunate crest on proximomesial surface, and irregular row of about 3 spines on distomesial margin, dor- salmost spine near dactylar condyle largest; fixed finger '/:-% length of dactyl, blunt tipped, rather slender distally, broadening proximal half with row of 4-5 low teeth on prehensile edge; dactyl slightly curved and stouter than fixed finger, corneous and rather blunt to moderately slender tip sometimes immediately preceded by worn or obsolescent tooth, with variable crest of low teeth running along nearly proximal 2 h of prehensile edge to end in slightly larger, rounded tooth anterior to shallow, basal notch; teeth opposed to tip of fixed finger usually slightly enlarged. Leg 2 reaching beyond midlength palm of che- liped; carpus with tiny subdistal dorsal and still smaller ventral marginal spine; elongate merus with superior, subdistal spine directed almost straight distally, mesioventral proximal spine strong, straight and slightly reflexed. Leg 3 with slender, pointed dactyl extending beyond rostrum; merus with 3 spines along lower margin. Leg 4 spineless, not quite reaching tip of rostrum; all 3 articles bearing tracts of long setae. Leg 5 reaching base of cheliped, merus spineless. Two arthrobranchs arranged in biserial rows of undivided (entire) narrow lamellae on maxilliped 3 and legs 1-4. Uropod with slender spine on protopod over- hanging base of endopod; straight distal margin of endopod exceeded by curved margin of exopod, both rami with minute, scattered, distal spines and dense fringe of setae; endopod with strong, median lon- gitudinal rib and less prominent lateral rib having shallowly concave margin except for rounded, prox- imal shoulder; exopod with 3 ribs, mesial strongest one with spiniform tubercle proximally, interme- diate rib longer but weaker; lateral rib least evident of all, slightly curved outward but shallowly concave proximally. Measurements (mm). — Holotype female, length anterior carapace 7.4, length carapace 10.4, length right palm with fixed finger 5.3. height palm 1.8. Known range. — Galapagos Islands. Remarks. — Upogebia ga/apagensis most closely resembles U. thist/ei, from which it differs in having more slender chelae which lack a small spine at the anterior ventrolateral corner of the carpus and in having generally more slender fingers. Similarities to U. spinigera and U. longipollex are given in the remarks on U. thistlei. Name. —The specific name "galapagensis" refers to the island origin of the material studied. Upogebia jonesi new species Figure 7 Material examined.— Mexico: Baja California Norte. AHF-2537-01, 1 9, off Consag Rock, 31°06'30"N, 114°28'152"W, 21 fm, Velero III sta. 1069-40, 1 February 1940; 2546-01 (Paratype 4013) 1 2, off Punta Willard, Bahia San Luis Gonzaga, 30-40 fm, mud, Velero ///sta. 1061-40, 30 January 1940. Sonora. AHF-2543-01, 1 2, off Punta Rocosa, 31°18'35"N, 113°37'55"W, 11 fm, mud, sand, Ve- lero III sta. 1074-40, 3 February 1940. 20 Williams Fig. 7. Upogebia jonesi new species, a. Cephalic region, lateral; b. Anterior carapace, dorsal; c. Mandible; d, e. Maxilla 1, 2;f. g, h, Maxilliped 1. 2, 3; Cheliped, i, lateral, j, mesial; k. I. in. n, Legs 2-5; o. Telson and left uropods. USNM 213195, 9 Holotype; mouthparts from USNM 21398. Scales = 1 mm; O = a, b; • = o; D = /', /, k, I, m. n; = h; A =/; A = e, g; ir = d\ ® = c. Eastern Pacific Mud Shrimps 21 Costa Rica. USNM-213198, 2 6, 1 9 (ovig.), Golfo de Ni- coya, University of Delaware and University of Cos- ta Rica (UDUCR), sta. 15-2-1000, 12 July 1980; 213199, 1 c5. 1 9, Golfo de Nicoya UDUCR, sta. 30- 3-1000, 1 October 1980; 213200, 1 juv., Golfo de Nicoya, UDUCR, sta. 29-3-1 000, 27 January 1981; 213201, 13, Golfo de Nicoya, UDUCR, sta. 29-4- 1000, 4 April 1981. Panama. USNM-213195 (Holotype) 2 (ovig.). Pilot House Beach, Naos Is., lower end of beach transect, 27°C, 25%c S, M. L. Jones, sta. 245-1, 8 January 1978; 213196 (Paratype) 1 6, same; 213197 (Paratypes) 1 6, 1 2 (ovig.), S side Perico Is., M. L. Jones, sta. 266- 2, 22 July 1978. Diagnosis. — Postocular spine present and acute. First and second abdominal segments lacking ven- tral spines. Telson essentially rectangular. Cheliped with mesial row of 2-3 spines on palm proximal to base of fixed finger; more than half length of dactyl beyond large tooth on cutting edge. Second leg with prominent mesioventral spine on merus. Projection to either side of rostrum fairly acute at tip. Description.— Rostrum almost equilaterally tri- angular in dorsal view and densely setose, flanked by somewhat shorter, subacute lateral projection at each side; tip rounded, slightly exceeding eyestalks, nearly horizontal in lateral view, ventral border spineless and curved gently upward to tip; lateral borders bearing about 4 small conical teeth; surface behind rostrum armed with small conical teeth an- teriorly but grading to tubercles posteriorly and an- gling toward sides; central gastric region smooth; ornamented area separated from and flanked on each side by posteriorly divergent ridge bearing crest of about 12 elements decreasing from strongest on lat- eral rostral process to obsolescence posteriorly. An- terolateral margin bearing prominent, slender post- ocular spine. Shoulder lateral to cervical groove not prominent; thalassinidean line extending to poste- rior margin of carapace. Abdomen with first 2 segments lacking spines or spinules on sterna, pleura and bases of pleopods; segment 6 rectangular, its dorsal surface with ob- solescent, obliquely curved groove to either side, lateral margin with angled lobe behind middle. Tel- son rectangular. Eyestalk clearly exceeded by rostrum; cornea nar- rower than eyestalk, directed anterolaterally. Antennular peduncle with articles unspined. An- tennal peduncle with small distoventral spine on basal article; rather prominent, slender, distoventral spine on article 2; scale unspined. Mouthparts as figured; maxilliped 3 bearing epi- pod. Extension of epistome in lateral view bearing sin- gle slender spine. Chelipeds essentially equal, slender to moderately robust; coxa armed with small spine; ischium with prominent, slender, curved ventral spine; merus with ventral row of 4 or 5 slender spines of irregular length and a strong subdistal dorsal spine. Carpus with strong, slender anteromesial spine preceded by low mesiodorsal crest bearing 2 spines and flanked laterally by 2 small spines; moderate lateral spine on anterior margin, 2 strong spines on anterior mar- gin mesially, and slender anteroventral spine. Palm more or less compressed but convex on lateral sur- face, about twice as long as deep; bearing mesio- dorsal crest of about 12 small acute, anteriorly di- rected spines; lateral to these a spineless crest; subdistal dorsal spine and lateral distal spine near base of dactyl; row of 2 acute anteriorly directed spines proximal to base of fixed finger. Fixed finger less than l h length of dactyl, drawn to slender point, low tooth at midlength. Much longer grooved dactyl gently curved to simple, slender, corneous tip; pre- hensile edge obscurely toothed. Legs 2-5 with usual setose tracts; merus of leg 2 with very strong proximal spine and well developed subdistal dorsal spine; merus of 3 with 2 or 3 spines on ventral border; 4 with spineless merus. Two arthrobranchs arranged in biserial rows of undivided (entire) narrow lamellae on maxilliped 3 and legs 1-4. Uropod exceeding telson, small acute spine on protopod lateral to articulation of endopod; smaller spine proximally on inner rib of exopod. Measurements (mm). — Holotype female, length anterior carapace 5.1, length carapace 7.6, length chela including fixed finger 3.6, height chela 1.4. Paratype male, same, 4.2, 6.1, 3.6, 0.6. Variation. —Chelae of small specimens from Cos- ta Rica are relatively more slender than those of larger specimens from Panama, but in other respects both sets of specimens seem identical. Known range.— Mexico to Panama. Remarks. — Upogebia jonesi seems to be a Pacific counterpart to the western Atlantic U. affinis. though it is apparently a smaller species and has fewer me- sial spines on the palm proximal to the fixed finger of the chelipeds than the latter. This comparison should be qualified because our knowledge of vari- ation in the widespread U. affinis needs study. Name. — The species is named for Meredith L. 22 Williams Jones, Department of Invertebrate Zoology, U.S. National Museum of Natural History, under whose leadership the NMNH Panama Survey of the Canal Zone fauna was conducted during the 1970s, when many specimens of Upogebia were collected. Upogebia lepta new species Figure 8 Material examined. —USA: California. AHF-2536-01 (Paratype 4130) 1 $, V: mi SW Ribbon Rock, Santa Catalina Is., 33°26'05"N, 118°34'50"W, 51-56 fm, Velero III sta. 1312-41,4 May 1941; 2540-01 (Paratypes 4131) 1 <3, 9 9 (1 ovig. frag.), plus assorted frags, of several specimens, 1 mi SW Ben Weston Pt., Santa Catalina Is., 33°20'55"N, 11 8°30'25"W, 45-49 fm, Velero III sta. 1316-41, 17 May 1941. Mexico: Baja California Norte. USNM - 2 1 3270 (Holotype) <5, Los Coronados Is. [32°25'N, 117°15'W], 73-91 m (40-50 fm), S. A. Glassell, 4/11/28 [11 April 1928]; 2137 (Paratype) <5, same. Diagnosis. — Postocular spine present. Rostrum with extremity distinctly exceeding that of eyestalks. Abdominal segments 1 and 2 lacking ventral spines. Telson essentially rectangular. Cheliped with fixed finger about half as long as dactyl; palm with lunate row of spines on mesial surface; ischium with small spine on ventral margin. Leg 2 without proximal mesioventral spine on merus; merus of leg 4 lacking ventral spines. Description. —Rostrum narrowly triangular, straight; tip exceeding pair of small, subapical dorsal spines, latter followed on each side by 4 spines of about equal size; central dorsal rostral surface dense- ly pilose but almost spineless, merging with less pi- lose field of spiniform tubercles and tubercles di- minishing over approximately 3 A of anterodorsal carapace and angling toward sides posteriorly; gas- tric part posterior to this smooth; ornamented part separated from and flanked on each side by poste- riorly divergent ridge bearing similar crest of about 9 elements decreasing from spines on lateral rostral process to obsolescence posteriorly. Cervical groove deep and continuous, rather sharp shoulder lateral to it; thalassinidean line continuing to posterior margin of carapace. Postocular margin bearing spine. Abdomen broadly and smoothly arched dorsally; pleura of segment 1 narrowly rounded posterolater- ally, those of 2-5 broadly rounded, margins un- spined; fine setae in posterolateral tracts on pleura of segments 3-4; segment 6 rectangular, slightly wider than long, lateral margin with slight shoulder at midlength and margins convergent thereafter. Telson rectangular, sides slightly lobed proxi- mally, posterior margin very shallowly biarcuate and densely fringed with setae; transverse anterior ridge obsolescent, continuous with low lateral ridges at each side, median groove obsolescent. Eyestalk far shorter than long rostrum, reaching level of third dorsal spines on rostral margin; some- what constricted at midlength between dilated base and good sized subglobular, terminal cornea. Antennular peduncle reaching to between base of and about midlength of terminal article of antennal peduncle, its proximal article about as long as sec- ond plus terminal article together and bearing prom- inent distoventral spine, short second article with similar sized ventral spine; flagella unequal, lower thinner ramus decidedly longer than thicker upper one. Antennal peduncle with about % its length ex- tending beyond tip of rostrum; article 2 spineless distally; scale moderate, more or less rhomboid in outline. Mouthparts as figured for U. pugettensis; maxil- liped 3 bearing epipod. Epistomial projection quite broad in lateral view, bearing single, slender anterodorsal spine. Chelipeds essentially equal, rather slender. Ven- tral margin of ischium bearing 1 short spine. Merus with variable number of spines on ventral margin (4-9); short subdistal dorsal spine (if present) reach- ing level of postocular spine. Carpus trigonal, an obsolescent longitudinal groove laterally, no spine at anterior ventrolateral corner; mesiodorsal crest with forwardly directed uniform small or obsoles- cent spines behind prominent spine on anterior margin, or with only 1 or 2 prominent spines in anterior part of row; anterior spine flanked by re- mote cluster of 3 sharp spines on anterodorsal mar- gin and followed below on distomesial margin by 1 moderate spine; distoventral spine moderate. Palm oval in cross section, length including fixed finger about 2.5-2.8 times maximal height; inconspicuous setae in dorsal rows, longer in ventral tract, some setae along low lateral ridge, and tufts distally; lat- eral dorsal crest of mostly low spines running 2 h length of palm, becoming obsolescent distally but ending near prominent spine near base of dactyl; mesiodorsal crest bearing 1 or 2 spines proximally, becoming obsolescent through about % its length, but reappearing distally as a thin low crest, entire except for outlying spine at its proximal end, then Eastern Pacific Mud Shrimps 23 Fig. 8. Upogebia lepta new species, a. Cephalic region, lateral; b. Anterior carapace, dorsal; c. Peduncular articles (part) of antennules and antenna; Cheliped, d. lateral, e, mesial;/ g. h, i. Legs 2-5; j, Telson and left uropods. AHF 2540-01, Paratypes. Scales = 1 mm; O = d. e, f, g\ • = a, b, h, i, j; ▲ = c. becoming obsolescent again near acute spine below mesial condyle of dactyl; mesial surface of palm bearing lunate row of spines, low and more closely spaced in anterior part below above mentioned dis- tal ridge, more widely spaced and prominent proxi- mally but disappearing anterior to granular area on mesioproximal surface: lateral condyle of dactyl un- armed. Fixed finger short, stout, and bearing 1 tooth at proximal l h of prehensile edge. Dactyl slightly curved, setose, stouter than fixed finger, and tapered to corneous slender tip; dentate dorsal crest varying from erect at proximal end to obsolescence at mid- length; similar less developed crest laterally; pre- hensile edge beyond basal lobe sharp and entire ex- cept for low proximal tooth and low tooth near middle opposing tip of fixed finger. Leg 2 reaching about to distal Va palm of cheliped; carpus bearing slender, subdistal dorsal and ventral spine; elongate merus with slender subdistal dorsal spine. Leg 3 with slender pointed dactyl extending beyond rostrum; merus with cluster of obsolescent spines proximoventrally. Leg 4 with spineless me- rus. Subchelate leg 5 reaching base of cheliped. Two arthrobranchs arranged in biserial rows of undivided (entire) lamellae on maxilliped 3 and legs 1-4. Uropod with tiny spine on protopod overhanging base of endopod; straight distal margin of endopod exceeded by curved margin of exopod, both rami with dense fringe of setae distally; endopod with rather prominent median longitudinal rib and lat- eral rib having shallowly concave margin except for rounded, proximal shoulder; exopod with 3 ribs, mesial strongest one bearing small spine proximally, intermediate rib longer, lateral rib least evident of all, slightly curved outward but shallowly concave proximally. Measurements (mm). — Holotype male, length an- 24 Williams terior carapace 3.8, length carapace 6.2, length chela including fixed finger 3.7. height chela 1.3. Paratype male, same, 3.2, 5.2, 2.4, 1.0. Known range. —Confined to Santa Catalina Is- lands, California, and Los Coronados Islands, Baja California Norte. Remarks. — Upogebia lepta belongs to the cluster of species which lacks a proximal mesioventral spine on the merus of leg 2. It is relatively more slender than any other species in the eastern Pacific. The shape of the rostrum somewhat resembles that of U. dawsoni, including the small size and disposition of marginal teeth, although the ornamented part of the anterior carapace is more extensive than in the latter. Upogebia dawsoni, however, is a member of the cluster having a proximal spine on the merus of leg 2. Name. — The name is from the Greek "leptos," thin, small, slender. Upogebia longipollex (Streets) Figure 9 Gebia longipollex Streets 1871:242. — Lockington 1878:108; 1878:300 (listing). Upogebia (Upogebia) longipollex. — Borradaile 1903: 543. -De Man 1928:23, 35. 39. 51. Upogebia spinigera. — Holthuis 1952:3 (part, syn- onymy). Upogebia rostwspinosa. — Bott 1955:50 (part). Material examined. — El Salvador: NMS — 2117 (part, Paratype of U. rostwspinosa Bott) 1 9, Puerto El Triunfo, Peters. Panama. USNM — 213156, 1 juv., Aguadulce on Golfo de Parita, 8°13.2'N, 80°29.1'W, tidal flats E of town and S of Estero Aguadulce, 0-2 ft, low tide, sandy mud, large rock outcrops, M. L. Jones et al., 24 April 1971, hand net, poison, sieve (with specimens of U. spinigera); 213157, 1 9, San Carlos, [8°29'N, 79°57'W], under rock in sand at 1.9 ft. L. G. Abele, 4 August 1 969; 213158,19, ovig., Venado, 1 2 April 1941; 213159, 4 9, Venado Beach about [ h way to Venado Is., W side connecting sandbar, 0-2 ft, low tide, cobble and rock tidepools, 30.5°C, 26%c, Daw- son and party, 1505, 4 November 1971. ichthyo- cide; 213160, 1 9, Venado Beach, about % way to Venado Is., tidepools and streams either side con- necting sandbar, 0-2 ft, rocks, sandy silt, 28°C, 30.2%o, C. E. Dawson, 1523, 16 January 1972, ichthyocide; 213161, 1 9, ovig., Venado Beach along sandbar to Venado Is., 0-0.6 m, ebb-flood tide, rock, sand, shell and marl, 32°C, Dawson and party, 1 7 April 1972, 1537. ichthyocide; 213162, 1 <3, Venado Beach along sandbar to Venado Is., 0-0.8 m, ebb- flood tide, small rocks, sand and silt, 32°C, 34%o, Dawson and party, 1607, 4 April 1973, ichthyocide; 213163, 2 9, Fort Kobbe Beach ofTSW end, 0-0.75 m, low flood tide, rock, sand-muddy inshore, tide- pool among sparse mangrove inshore, 29.5°C, 30%o, Dawson and party, 1587, 3 November 1972, ich- thyocide; 213164, 1 (3. 1 9 ovig., Farfan Point, 8°56'N, 79°34'W, 0-1 m, ebb-flood tide, tidepools, mainly sand, some rock and silt, 35°C, 33%o, Dawson and party, 1609, 6 April 1973, ichthyocide, (taken with U spinigera); 213165, 1 <5, Farfan Point, 8°56'N, 79°34'W, 0-6 ft, deep tidepool, low flood tide, sandy mud, 27%o, Dawson and party, 1506, 5 November 1971, ichthyocide; 213166, 15 6, 20 9, sorted plus 20 unsorted jaws and frags., Naos Is., rock pile on E side of causeway 0-3 ft, rocks, silty sand to gravel, low tide, C. E. Dawson, 1522, 15 January 1972, ichthyocide (all of these have 3 internal spines on carpus and no spines on merus of P4. there were 3 U. spinigera in the collection); 213167, 3 9, NE end of causeway to Naos Is., 8°56'07"N, 79°32'47"W, 0-2 in, low flood tide in tidepools, rocks, sand-grav- el. C. E. Dawson, 1527,18 March 1972, ichthyocide (taken with U. spinigera); 213168, 2 6, rockpile on E side Naos Is. causeway, 0-1 m, low flood tide, sand, sandy marl, small rocks, Dawson and party, 1605, 3 April 1973, ichthyocide; 213169, 1 <5, 3 9, NE end of Naos Is. causeway, 8°56'07"N, 79°32'47"W, 0-6 cm, gravel-sand, low tide, 32°C, Dawson and party, 1 604, 3 April, 1973, ichthyocide; 2 1 3 1 70, 2 9, NE end Naos Is. causeway, 8°56'07"N, 79°32'47"W, 0-6 cm, gravel, sand, cobble, low tide, 30.5°C, 23V C. E. Dawson, 1661, 11 November 1973, ichthyocide; 213171,2 5, 69(1 ovig.), Naos Is., Scout Beach, 0-1 .0 m, low flood tide, rocks, fine mud and sand, Dawson and Overstreet, 1753, 8 January 1978, ichthyocide ( 1 S atypical); 213172, 1 9, Naos Is., causeway, rock pile and sand, canal side, 0-0.13 m, C. E. Dawson, 1772, 21 July 1978; 213173, 2 9, San Francisco Reef near Panama City, S. F. Hildebrand, 18 February 1937; 213174, 11 <5, 7 9 (4 ovig.), 5 undet. juvs., Panama reef off French Fort, 8°57'N, 79°3 1 '40"W, rock, sandy silt and grav- el, tide pools, low tide, 33.2°C, 30%o, 0-3 ft, Dawson, Dawson and McCosker, 1498, 9 July 1971, Chem- fish; 213175, 1