Neostrengeria fernandezi, Campos, Martha R., 2017

Campos, Martha R., 2017, Two new species of freshwater, cave-dwelling crabs of the genus Neostrengeria Pretzmann, 1965, from Colombia (Crustacea: Decapoda: Pseudothelphusidae), Zootaxa 4247 (2), pp. 157-164 : 158-161

Neostrengeria fernandezi n. sp.

( Figs. 1 , 2 )

Holotype. Male (cl 16.1 mm, cb 30.0 mm), ICN-MHN-CR 3172, Municipio Pauna, Las Cacas cave, elevation 2000 m, Boyacá Department, Colombia, 5°43’8.4”N 74°02’21.0”W, 8 May 2016, leg. N. Valdivieso.

Paratypes. Three females (cl 25.0, 23.4 and 15.7 mm, cb 43.8, 42.7 and 27.5 mm), ICN-MHN-CR 3173. Same data as for holotype.

Diagnosis. Male first gonopod bent distally towards cephalic side, wider in mid-distal portion; mesial side with convex expansion, deep notch subdistally; lateral lobe oblong, external margin rounded, internal margin concave, separated from accessory lobe by deep notch; accessory lobe narrow, elongated, slightly sinuous, semiacute distally; accessory lobe shorter than lateral lobe; apex outline oblong in distal view, with prominent, acute mesial projected spine; mesial lobe rounded; mesio-caudal projection of spermatic channel awl-shaped with proximal internal spine, 3 tiny spinules distally. Exognath of third maxilliped between 0.56, 0.62 length of ischium of endognath.

Description of the holotype. Carapace ( Fig. 1 A) with cervical groove nearly straight, narrow, shallow anteriorly, deep, wide posteriorly, ending some distance from lateral margin; anterolateral margin with shallow sinus posterior to antero-external orbital angle, with 4 papillae anterior of cervical groove, lateral margin with series of low, rounded papillae; posterior margin smooth; postfrontal lobes oval, delimited anteriorly by 2 depressions; median groove shallow, without incision on upper border of front; front with upper border rounded, not demarcated, slightly bilobed in dorsal view, surface of front between upper, lower borders narrow, excavated, lower border sinuous in frontal view, fringed with tubercles, protruding more than upper border in dorsal view; orbital margins each with row of rounded tubercles; eyes large, filling the orbits ( Fig. 1 B); dorsal surface of carapace smooth, covered by small papillae, regions distinctly marked. Third maxilliped with external margin bearing rounded lobe after mid portion, followed by subdistal depression; exognath 0.62 length of ischium ( Fig. 2 F). Efferent branchial channel open, nearly subquadrate ( Fig. 1 B).

First pereopods heterochelous ( Fig. 1 A, B), right cheliped larger than left; merus with 3 crests: upper crest with rows of semi-acute tubercles, internal lower crest with row of 12 acute teeth, increasing in size distally, external lower crest with row of blunt tubercles; carpus with 4 acute spines, distal one prominent; palms of both chelipeds smooth, dorsal surface covered by rows of low tubercles, palm of larger cheliped strongly swollen, fingers strongly gaping when closed, smaller cheliped slightly swollen, fingers not gaping when closed, outer, inner surfaces of fingers of both chelae with rows of small tubercles, fingers with large subtriangular teeth. Walking legs (second to fifth pereopods) slender, dactyli each about 1.2 times as long as propodi, with 5 longitudinal rows of large spines diminishing in size proximally. Spines, papillae on each dactylus arranged as follows: antero-lateral row, anteroventral row each with 5 spines, 1 proximal papilla; external row with 5 spines, 2 proximal papillae; postero-ventral row, postero-lateral row each with 3 spines.

Male first gonopod wider in mid-distal portion, bent distally towards cephalic side in lateral, mesial views; mesial side forming convex expansion with deep notch subdistally; marginal suture slightly sinuous, rounded distally, proximal portion forming rounded lobe with conspicuous long setae; lateral lobe oblong, external margin rounded, internal margin concave, with caudal surface slightly excavated, separated from accessory lobe by deep notch; accessory lobe narrow, elongated, slightly sinuous, semi-acute distally; accessory lobe shorter than lateral lobe ( Fig. 2 A-D); apex outline oblong in distal view, with prominent, acute mesial projected spine; mesial lobe rounded; mesio-caudal projection of spermatic channel awl-shaped with proximal internal spine, 3 tiny spinules distally; spermatic channel with conspicuous rows of spinules ( Fig. 2 E).

Color. The alcohol-preserved holotype is mottled brown (near Raw Umber, 223; Smithe (1975)) on the dorsal side of the carapace. The walking legs are mottled brown (near Cinnamon Brown, 33) dorsal, light brown (near Mikado Brown, 121C) ventrally. The chelae are brown (near Mars Brown, 223A) dorsal, light brown (near Mars Brown, 223A) ventrally. The ventral surface of the carapace is mottled brown (near Cinnamon, 39).

Habitat. The specimens were collected in a small underground lagoon located at 184 m depth with respect to the surface in a cave in the middle of a protected Andean forest. They were collected using trawl nets.

Etymology. The species is dedicated to Professor Juan Carlos Fernández of Buenos Aires University, Argentina, an exceptional researcher who has contributed to the training of many researchers.

Remarks. Comparison with descriptions and material of other species reveals that Neostrengeria fernandezi sp. n. is most similar to Neostrengeria lindigiana (Rathbun, 1897) . The main distinguishing character between the two species is the form of the first gonopod. The male first gonopod of N. lindigiana has been described and illustrated by Campos (2005: 191, fig. 54; 2014: 510, fig. 192). The mesial side of this new species forms a convex expansion and deep notch subdistally, whereas in N. lindigiana the expansion and the subdistal notch are absent, and has a mesial side sinuous from subdistal to distal portion. The lateral lobe in N. lindigiana is foliose, semicircular, rounded distally, whereas in N. fernandezi it is oblong with external margin rounded and internal margin concave. The accessory lobe in N. lindigiana is spatulate and distal rounded, whereas in N. fernandezi it is elongated, sinuous, and semi-acute distally. The mesial lobe in N. lindigiana is triangular, whereas it is rounded in N. fernandezi . The apex outline in N. lindigiana is oval in distal view with a caudo-cephalic rounded expansion and prominent, mesial directed cephalic spine; the mesio-caudal projection of the spermatic channel is bifid with wide blunt papillae. In contrast, in N. fernandezi the apex outline is oblong in distal view with prominent, mesial projected acute spine, and the mesio-caudal projection of spermatic channel is awl-shaped with internal proximal spine and three spinules distally. The specimens were collected in a cave at 184 m depth, but, except for a female (cl 23.4 mm, cb 42.7 mm) that presents a partially unpigmented cornea, they do not exhibit characteristics of hypogean species, such as greatly elongated pereopods, peduncle of the eyes that is reduced and does not fill completely the orbits, or depigmentation of the carapace.

Figures

FIGURE 1. Neostrengeria fernandezi new species, holotype male, ICN-MHN-CR 3172. A, dorsal view of carapace; B, ventral view of carapace.

FIGURE 2. Neostrengeria fernandezi n. sp., holotype male, ICN-MHN-CR 3172. A, left first gonopod, caudal view; B, same, lateral view; C, same, cephalic view; D, same, mesial view; E, same, detail of apex, distal view; F, left third maxilliped, external view.