Vol. 60, 2021
(update: 2021.02.05; 02.19)
Description of a New Genus with Two New Species of Freshwater Crab (Decapoda: Brachyura: Gecarcinucidae) from the Southwestern Ghats, India
Smrithy Raj1,2, Appukuttannair Biju Kumar1, and Peter K.L. Ng3,*
of Aquatic Biology and Fisheries, University of Kerala, Kariavattom,
Thiruvananthapuram – 695581, Kerala, India. E-mail:
Received 24 October 2020 / Accepted 29
A new genus of freshwater crab, Rajathelphusa gen. nov. and two
species, R. ala sp. nov.
(type species) and R. muni
sp. nov., are described from the Kerala part of the Western Ghats
biodiversity hotspot, India. The new genus is superficially similar to Arcithelphusa and Cylindrotelphusa from the same
hotspot, but can easily be distinguished by the following suite of
carapace and gonopod characters: an inflated carapace with distinct
epigastric and postorbital cristae; the third maxilliped exopod has a
long flagellum; male sternites 2 and 3 separated by a shallow median
groove while sternites 3 and 4 are completely fused, demarcated by
shallow oblique grooves; a male first gonopod that is almost straight
with a short distal conical distal segment; and a male second gonopod
that is as long as the first gonopod with a long and slender distal
segment. The two new species can be differentiated from each other by
the lateral margins of male pleonal somite 6 and the structure of the
male first gonopod.
Key words: Taxonomy, New freshwater crab, Gecarcinucoidea, Kerala, Idukki, Arcithelphusa, Cylindrotelphusa.
Citation: Raj S, Kumar AB, Ng PKL. 2021.
Description of a new genus and two new species of freshwater crab
(Decapoda: Brachyura: Gecarcinucidae) from the southwestern Ghats,
India. Zool Stud 60:0q. doi:-.