A new genus of freshwater crab, Karkata gen. nov., with two species, K. ghanarakta sp. nov. (type species) and K. kusumbha sp. nov., and two new species each of Pilarta Bahir and Yeo, 2007 (P. aroma sp. nov. and P. punctatissima sp. nov.)...
moreA new genus of freshwater crab, Karkata gen. nov., with two
species, K. ghanarakta sp. nov. (type species) and K. kusumbha
sp. nov., and two new species each of Pilarta Bahir and Yeo, 2007
(P. aroma sp. nov. and P. punctatissima sp. nov.) and
Cylindrotelphusa Alcock, 1909 (C. breviphallus sp. nov. and C. longiphallus
sp. nov.), are described from Kerala, India. Additionally, C.
granulata (Pillai, 1951) comb. et stat. nov. is recognised as a
distinct species. Karkata gen. nov. is distinguished from other
Indian gecarcinucid genera by a suite of carapace and gonopod
characters, including a moderately arched, smooth carapace, the
presence of a prominent suture between male thoracic sternites 2,
3 and 3, 4, the absence of a flagellum on the third maxilliped
exopod, a very short terminal segment of the male first gonopod
(G1), and a short distal segment of the male second gonopod (G2).
Karkata ghanarakta sp. nov. is differentiated from K. kusumbha sp.
nov. by the shape of the G1 subterminal segment and its live
colouration. Pilarta punctatissima sp. nov. is distinct among the
congeners mainly by its densely punctate carapace, densely setose
anterolateral and posterolateral margins of the carapace, stouter
G1 terminal segment, and relatively long G2 distal segment
whereas P. aroma sp. nov. can be separated from P. anuka Bahir
and Yeo, 2007 by its relatively smooth carapace, deep H-shaped
groove, relatively long G1 terminal segment, and almost straight
outer margins of the G1 terminal and subterminal segments.
Cylindrotelphusa breviphallus sp. nov. is differentiated from C. longiphallus
sp. nov. and C. steniops (Alcock, 1909) by its stout G1, with
a stout, short terminal segment. Cylindrotelphusa longiphallus sp.
nov. is distinguished from the congeners by its shallow, narrow
cervical grooves and relatively slender ambulatory legs. An identification
key to the species of Karkata, Pilarta and Cylindrotelphusa is provided.