Two new freshwater crabs of the genus Ptychophallus Smalley, 1964 (Crustacea: Decapoda: Brachyura: Pseudothelphusidae) from Panama, with notes on the distribution of the genus

—Two new species of freshwater crabs of the genus Ptychophallus Smalley, from Panama, P. uncinatus and P. kuna, are described and illustrated. The addition of these two species means the genus now includes 13 species, all of which are distributed in Panamd and Costa Rica. The species are distinguished primarily by differences in characters of the male first gonopod. A sunmiary of the geographic distribution of the species in the genus is presented. The systematics of the genus Ptychophallus Smalley, 1964a, were reviewed by Rodriguez (1982, 1994) who found that a number of characters of the male first gonopod in species of this genus were homologous with those of Hypolobocera Ortmaim, 1897 and Neostrengeria Pretzmann, 1965. These characters are the presence of a caudal crest, a lateral lobe, and a central papilla on the spermatic channel. Rodriguez (1982) considered Ptychophallus to be transitional between Andean and Central American Pseudothelphusidae because species of this genus present a fusion of the cephalic and caudal borders forming a mesial process, a morphological characteristic present in all pseudothelphusids species from Central America (including Mexico), but absent in species of Hypolobocera and Neostrengeria from South America. Species of Ptychophallus are distinguished primarily by characteristics of the third maxilliped and male first gonopod. The exognath of the third maxilliped is 0.6 to 0.7 as long as the ischium. The male first gonopod has a prominent apex that is bent cephalically and is joined to the gonopod by a narrow peduncle; the lateral projection is large, and usually divided into two lobes; and the caudal ridge extends longitudinally on the distal half of the caudal surface. A study of freshwater crabs in the National Museum of Natural History, Smithsonian Institution, Washington D.C. (USNM), revealed two new species of Ptychophallus from Panam^, bringing to 13 the total number of species currently recognized in this genus. This number excludes P. campylos Pretzmann, 1965, a species that was originally briefly described, without illustrations (Pretzmann 1965). This species was listed by Pretzmann (1971), and he (Pretzmann 1972) subsequently added details with illustrations and photographs. Rodriguez (1982:80) indicated in a footnote that based on the information provided by Pretzmann (1965, 1971, 1972), P. campylos could not be separated from P. tristani (Rathbun, 1896); however, Rodriguez did not formally synonymize Pretzmann's taxon with Rathbun's and excluded P. campylos from his treatment of Ptychophallus species. The type of P. campylos, deposited in the Naturhistorisches Museum, Vienna, needs to be examined in order to properly evaluate the validity of Pretzmann's taxon. The terminology used for the morpholo554 PROCEEDINGS OF THE BIOLOGICAL SOCIETY OF WASHINGTON gy of the male first gonopod follows that of Smalley (1964b) and Rodriguez (1982). The abbreviations cb and cl stand for carapace breadth (measured at the widest point) and carapace length (measured along the midline), respectively. Color nomenclature used follows Smithe (1975). Family Pseudothelphusidae Rathbun, 1893 Tribe Hypolobocerini Pretzmann, 1971 Genus Ptychophallus Smalley, 1964a Ptychophallus uncinatus, new species Figs. 1, 2, 5 Material.—Holotype: 6, cl 16.4 mm, cb 26.5 mm, Rio San Pedro, Bocas del Toro, Panamd, Jan 1978, leg. B. L. Gordon (USNM 276164). Paratype: S (juvenile) cl 9.5 mm, cb 15.2 nun, same locality as holotype (USNM 276165). Type locality.—Rio San Pedro, Bocas del Toro, Panama. Diagnosis.—First male gonopod with very broad lateral projection divided into 2 subequal lobes by deep depression on caudal surface and lateral notch; distal lobe with crest-like flange; distocaudal ridge short and narrow, with lateral crest; subapical mesial process with triangular base and hook-like projection; central papilla of spermatic channel robust, swollen. Description of holotype.—Carapace (Fig. 1) with narrow, deep cervical groove curving posteriorly euid not reaching lateral margin. Anterolateral margin with shallow sinus just posterior to anteroextemal orbital angle; rest of margin with papillae. Postfrontal lobes wide, delimited anteriorly by transverse depression; median groove narrow, deep, with incision on upper margin of front. Surface of carapace in front of postfrontal lobes flat and inclined smteriorly. Upper border of front thin, marked with row of tubercles; lower margin sinuous in frontal view. Surface of front between upper and lower borders high and slightly excavated. Upper and lower orbital margins each with row of tubercles. Surface of carapace covered with small papillae; limits between regions demarcated. Third maxilliped (Fig. 2E) with merus of endognath regularly curved, with shallow depression on distal part of external margin; exognath approximately 0.6 times length of ischium of third maxilliped. First pereiopods absent in holotype. In paratype, right cheliped slightly larger than left. Merus with 3 crests as follows: upper crest with rows of tubercles, internal lower crest with rows of teeth, and external lower crest with few tubercles. Carpus with 4 tubercles on internal crest and prominent blunt spine distally. Palm of both chelipeds smooth, moderately swollen. Fingers of chelae not gaping when closed, tips crossing, with rows of tubercles on dorsal side. Surface of walking legs (pereiopods 2-5; Fig. 1) with rows of minute setae. Dactyls each with 5 rows of large spines slightly diminishing in size proximally, rows arranged as follows: anterolateral and anteroventral rows each with 5 spines, external row with 5 spines plus 2 proximal papillae, posteroventral row with 4 spines, and posterolateral row with 5 spines. First male gonopod (Fig. 2A-C) wide in caudal view. Lateral projection very wide, divided in 2 subequal lobes by deep depression on caudal surface and lateral notch; distal lobe with crest-like flange directed distally; proximal lobe almost rounded; margins with minute setae; distocaudal ridge short and narrow, with lateral crest, reaching only to middle of deep depression dividing lateral projection. Subapical mesial process with triangular base and hook-like projection; apical mesial process triangular (Fig. 2C, D). Apex bent cephalolaterally, with fleld of spines directed cephalolaterally; caudal border of apex with shallow notch near middle, eind deep notch near lateral side; central papillae of spermatic channel robust, swollen (Fig. 2B, C, D). Color.—In alcohol, the dorsal side of the carapace is light brown (near 239, Ground Cinnamon). The walking legs are Buff (124). The chelae are True Cinnamon (139) VOLUME 112, NUMBER 3 555