iDdrroiue^j foitby, l r ?fi PROC. BIOL. SOC. WASH. 102(2), 1989, pp. 394-400 FRESHWATER CRABS ASSOCIATED WITH CAVES IN SOUTHERN MEXICO AND BELIZE, WITH DESCRIPTIONS OF THREE NEW SPECIES (CRUSTACEA: DECAPODA) Gilberto Rodriguez and Horton H. Hobbs, Jr. Abstract.— Records of nine freshwater crabs frequenting subterranean hab- itats in Belize and Mexico are reported. Three of them are described as new: Potamocarcinus leptomelus, a troglophile from Veracruz; Odontothelphusa monodontis, also a troglophilic species, from Tabasco; and Typhlopseudo- thelphusa hyba, a troglobite, from Chiapas. The remaining crabs are troglo- philes, one of which occurs in Belize, and the others, two of which because of inadequate material cannot be fully identified, were found in caves in the states of Chiapas, Guerrero, Oaxaca, and Tabasco, Mexico. A study of several collections of cave- dwelling crabs, kindly donated to the Smithsonian Institution by James R. Red- dell, has prompted us to record additions to his list of Brachyura known to occur in subterranean habitats in Mexico, Guate- mala, and Belize (Reddell 1981). His list includes three troglobites and six others that are probable troglophiles. Subsequently, one troglobitic form, Typhlopseudothelphusa acanthochela Hobbs (1986), was described from Blind Crab Cave, 12 km SW Millio- nario, Cayo District, Belize, and a troglo- philic one, Pseudothelphusa mexicana Al- varez-Noguera (1987), from La Jolla [sic, Joya?] Cave in the State of Guerrero, Mex- ico. Records of the occurrence of eight ad- ditional species, two of which cannot be ful- ly identified because of inadequate material, are reported herein from spelean waters of Belize and Mexico. All of the "Material" cited herein is de- posited in the National Museum of Natural History, Smithsonian Institution (USNM). Other abbreviations employed are: cl = car- apace length, and cb = carapace width. Pseudothelphusidae Ortmann, 1893 Potamocarcinus leptomelus, new species Fig. la-h Material.—Mexico: Cueva del Tuknel, Mahoilca, Porvenir Zongolica, Veracruz, 31 Dec 1986, Steve and Lori Robertson, male holotype, cl. 13.3 mm, cb. 21.1 mm (USNM 230080). Description. — Cervical groove narrow, almost straight, very shallow, reaching mar- gin of carapace. Postfrontal lobes obsolete, their position marked by slight depressions; median groove absent except for notch on upper margin of front. Surface of carapace between postfrontal lobes and front sloping gently ventromesially. Front low, of equal height throughout, bilobed in dorsal view, upper margin defined by series of irregularly placed papillae; lower margin V-shaped in median part, straight in lateral parts. Dorsal margin of orbits sinuous. Lateral orbital an- gle forming papillated tooth, followed by deep notch; rest of anterolateral margin cov- ered by small, irregularly placed, conical pa- pillae. Surface of carapace covered by very