Krishnamon, a new genus for the cavernicolous crab Telphusa austeniana Wood-Mason, 1871 (Decapoda: Brachyura: Potamidae) from Meghalaya state, northeastern India

摘要

Telphusa austeniana Wood-Mason, 1871 is a poorly known potamid crab described from a single female specimen from Meghalaya state, northeastern India, and its position in Tiwaripolatnon Bott, 1970 has been questioned. Its systematic position is now clarified based on the examination of the female holotype and a male specimen recently collected from a cave near the type locality. The species is transferred from Tiwaripotamon to a new genus, Krislatamon gen. nov. on the basis of the differences in the structures of the epigastric cristae, male pleon, male sixth pleonal somite, male telson, gonopods, and vulvae. The geographic distributions of the two genera are some 1,000 km apart. The new genus has affinities with Doimon Yeo & Ng, 2007, and Indochinamon Yeo & Ng, 2007, but can be distinguished mainly by its extremely slender and elongated ambulatory legs. While Arislutanton austenimen (Wood-Mason, 1871) comb. nov. is now recorded from limestone caves, it does not, however, possess the troglomorphic features of an obligaic troglobite.