A New Species Of Mud Shrimp, Upogebia Cortesi, From Pacific Costa Rica

4 Pages·2000·2.6 MB·English

by  A B Williams

PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
1 L3(l):13- 16. 2000.
A new species of mud shrimp, Upogebia cortesi, from Pacific Costa
Rica (Decapoda: Thalassinidea: Upogebiidae)
Austin B. Williamst and Rita Vargas
(ABW) National Marine Fisheries Service Systematics Laboratory, National Museum of
Natural History, Smithsonian Institution, Washington, D.C. 20560, U.S.A.; (RV) Museo de
Zoologfa, Escuela de Biologfa, Universidad de Costa Rica, 2060 Costa Rica (t: deceased
October 27, 1999)
—
Abstract. Upogebia cortesi, a new species of mud shrimp from the Pacific
side of Costa Rica is described and illustrated. The type series was dredged
m
parallel to shore in water of 30-40 depth. The species shares lack of a strong
proximal mesioventral spine on the merus of the second pereopod with several
members of the genus from the western hemisphere; moreover, the species
stands alone in having spineless articles on pereopods 1-5 except for fingers
of the chelae. The rostrum has no ventral spines. Similarities between this and
related species are emphasized in a partial abridgment of the key to upogebiid
species in the eastern Pacific.
Eight species of the family Upogebiidae Upogebia cortesi, new species
have been reported for the Pacific coast of Fig. 1
&
Costa Rica (Vargas Cortes 2000). Of — NW
these Pomatogebia cocosia (Williams Material. Costa Rica, side of Isla
Cabo Blanco, dredged parallel to coast, 30-
1986) and Upogebia vargasae Williams,
40 m, 16-17 May 1998: USNM 291186,
1997, were described based on material
UCRMZ
male holotype; 2220-06, male par-
from Costa Rica. During the 1998 Mollusk
USNM
atope; 291187, female ovigerous
Workshop organized by INBio at the "Re-
paratype.
serva Absoluta de Cabo Blanco", Peninsula —
Diagnosis. Rostrum with sides convex
de Nicoya, a dredge sample conducted be-
in dorsal view, obsolescent pair of spines
tween the mainland and Isla Cabo Blanco,
m on submedian anterior margin; projections
at 30-40 depth, yielded three specimens
to either side of rostrum slender and spine-
of a new species of Upogebia Leach, 1814,
like; no spine on postocular margin; ante-
described here. The substrate where the rior gastric region bearing many spines
specimens were obtained included calcare-
nearly hidden in patch of dense setae. Ab-
ous algae and rock fragments; at least 10 dominal sternites unarmed. Telson subrect-
species of brachyuran crabs and several angular, sides slightly crenulate. Merus of
mollusk species were also found in the sam- cheliped lacking subdistal dorsal spine and
ple. spines on ventral margin; carpus essentially
Specimens are deposited in the National spineless; palms spineless. Pereopods 2-5
Museum of Natural History, Smithsonian spineless; pereopod 2 without proximal me-
Institution, Washington, D.C. (USNM), and sioventral spine on merus.
—
in Museo de Zoologfa, Escuela de Biologfa, Description. Rostrum (Fig. \a,b) hori-
Universidad de Costa Rica, San Jose zontal in lateral view with tip slightly ex-
(UCRMZ), as indicated in the species ac- ceeding eyestalks; convex in dorsal aspect,
count. with pair of submedian obsolescent blunted
PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
14
Fig. 1. Upogebia cortesi, new species, male holotype, USNM 291187: a, Carapace and cephalic region,
lateral; b, Anteriorcarapace, dorsal; c, Cheliped, right lateral; d, Chela and carpus, right mesial; e, Right pereopod
2;f, Right pereopod 3; g, Right pereopod 4; h, Right pereopod 5; i, Telson, left uropod, and part of abdominal
segment 6, dorsal. Scale = 3 mm.
spines on anterior margin; 2 subdistal erect spines. Posterior region of carapace gla-
acute dorsal spines followed on each side brous. Shoulder lateral to cervical groove
by about 6 smaller marginal spines along bearing no spines below intersection with
either side of field of small spines on an- thalassinidean line, latter continuing to pos-
terior gastric region of carapace, spines on terior margin of carapace without interrup-
anterior part of field hidden in dense patch tion; postocular margin of carapace un-
of setae. Lateral ridge on either side of an- armed.
terior gastric region extended anteriorly to Abdominal sternites unarmed.
spine similar in size to dorsal spines on ros- Telson (Fig. 1/) subrectangular, wider
trum, ridge bearing crest of 18 spines, an- than long, posterior margin nearly straight,
terior 4 spines larger than succeeding smooth; transverse proximal ridge promi-
VOLUME NUMBER
113, 15
1
nent, rather broad, lateral ridge at each side Dr. Jorge Cortes, Curator of Cnidaria, Mu-
also rather broad; lateral margins almost seo de Zoologfa, Escuela de Biologfa,
imperceptibly crenulate. Universidad de Costa Rica, in recognition
Eyestalk stout, horizontal, shorter than of his life-long efforts to advance knowl-
rostrum; lower margin slightly convex; cor- edge of the—marine fauna from Costa Rica.
nea narrower than diameter of stalk and di- Remarks. Upogebia cortesi, new spe-
rected laterally. cies, shares with several eastern Pacific and
Antennular peduncle (Fig. \a) reaching western Atlantic members of the genus a
to about base of terminal article of antennal second pereopod on which the merus bears
peduncle, combined length of proximal 2 no proximal mesioventral spine (see keys to
articles subequal to length of terminal arti- species in Williams 1986, 1993). The ab-
cle. dominal sternites and pleura bear no ventral
Antennal peduncle (Fig. \a) with distal spinules.
article and distal half of penultimate article The species stands alone, however, with
extending beyond tip of rostrum; moderate respect to several other characters. The ros-
compressed scale bearing obsolescent an- trum with rounded anterior margin has no
teroventral spine. ventral spines. The anterior gastric region
Maxilliped 3 bearing epipod. and rostrum bear an extremely dense patch
Epistomial projection rather broad in lat- of setae obscuring spines on this surface.
eral view, bearing prominent, acuminate The pereopods are virtually spineless. This
apical spine. condition is most easily demonstrated by
Chelipeds (Fig. \c,d) lacking spine on emendation of the key to species of the
ventral margin of merus. Carpus trigonal, eastern Pacific (Williams 1986) in which
with barely perceptible longitudinal lateral the comparative relationship to other spe-
groove, obsolescent spine at anterior ven- cies in the region becomes apparent. Al-
trolateral corner. Chela length about 2.7 though the new species has spineless pereo-
times chela height. Fixed finger slender, pods, it appears to be related to U. tenui-
with extended tip. Dactyl thick, longer than pollex Williams, 1986 which has a well de-
fixed finger, drawn to corneous tip, and at veloped distodorsal spine on the merus of
midlength bearing small tooth on occlusive the cheliped and a cluster of spines on the
edge opposing tip of fixed finger. merus of pereopod 3.
Pereopod 2 (Fig. \e) reaching about to
distal edge of cheliped palm; pereopods 2— Emended part of Williams (1986:7-10)
4 (Fig. If-h) spineless. Pereopod 5 of usual key distinguishing U. cortesi, new species,
form, with cleaning brush on propodus. and U. tenuipollex
Uropods (Fig. 1/) with acute spine on
protopod above base of mesial ramus; both 4. Merus of pereopod 2 lacking proximal
rami slightly exceeding telson, and with mesioventral spine 5
distal margins smooth. Merus of pereopod 2 bearing proximal
—
Measurements (in mm). Male holotype, mesioventral spine 12
anterior carapace length 6.1, carapace 5. Postocular spine absent 6a
Postocular spine present and well de-
length 9.1, length of chela including fixed
veloped 8
finger 4.1, mid-length height of chela 1.8;
6a. Merus of cheliped and pereopod 3
male paratype, same, 4.8, 7.8, 3.8, 1.8; fe- spineless U. cortesi, new species
male ovigerous paratype, same, 5.4, 7.9, Merus of cheliped and pereopod with
4.2, 1.5. — spines 6
Known range. Known only from the 6. Merus of chelipeds bearing well devel-
type locality. — oped distodorsal spine; merus of pereo-
Etymology. The species is named for pod 3 bearing cluster of proximoventral
16 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON
spines U. tenuipollex Literature Cited
Williams Merus of chelipeds lacking
Leach, W. E. 1814. Crustaceology. In Edinburgh En-
distodorsal spine or with spine tiny; cyclopaedia, 2nd edition, 7:383-437, plate 221.
merus of pereopod 3 bearing few ob- New York: Samuel Whiting and John L. Tiffany.
&
solescent proximoventral spines .... 7 Vargas, R., J. Cortes. 2000. Biodiversidad marina
de Costa Rica: Crustacea: Decapoda (Penaeo-
idea, Sergestoidea, Caridea, Astacidea, Thalas-
—
Acknowledgments sinidea, Palinura) del Pacifico. Revista de
Biologia Tropical 47 (in press).
Williams, A. B. 1986. Upogebia, from the eastern Pa-
This study was made possible, in part, by —
cific (Thalassinoidea: Upogebiidae). Memoir
RV
Short-Term Visitor grant awarded to by of the San Diego Society ofNatural History 14:
the Office of Fellowships and Grants, 1-60.
Smithsonian Institution, Washington, D.C. . 1993. Mud shrimps, Upogebiidae, from the
We thank Michael Vecchione for critical western At—lantic (Crustacea: Decapoda: Thal-
assinidae). Smithsonian Contributions to Zo-
reading of the manuscript and Keiko Hira- ology 544:1-77.
tsuka Moore for preparing the illustrations. . 1997. Two new species and a range extension
This is a contribution of the Museo de of mud shrimps, Upogebia from Pacific Costa
Rica and Mexico (Decapoda: Thalassinidea:
Zoologia, Escuela de Biologia, Universidad —
Upogebiidae). Proceedings of the Biological
de Costa Rica. Society of Washington 110:617-623.