The identity of the freshwater crab Indochinamon manipurense (Alcock, 1909), with description of a new species of Potamiscus Alcock, 1909, from Manipur State, India (Decapoda, Brachyura, Potamidae)

Abstract

The identity of the potamid freshwater crab, Indochinamon manipurense (Alcock, 1909) from the state of Manipur in northeast India, is clarified based on an examination of the type specimens. The species is redescribed and a lectotype designated. Specimens from the same region previously referred to this species were compared to the types of I. manipurense and shown to belong to a new species of Potamiscus Alcock, 1909, instead. The new species, Potamiscus takedai sp. nov., can easily be separated from I. manipurense by the characters in the carapace, third maxilliped, male pleon, male gonopods, and female vulvae. Potamiscus takedai sp. nov. can be differentiated from congeners mainly by the strongly bent terminal segment of the male first gonopod and a relatively shorter distal segment of the male second gonopod.

Gurumon gurumayum, a new genus and new species of freshwater crab (Decapoda: Brachyura: Potamidae) from Arunachal Pradesh, northeastern India

“…With the discovery of the present new genus and species, India is now known to have 10 genera and 24 species of potamiscine crabs (cf. Mitra et al 2018Mitra et al , 2020Pati & Thackeray 2018;Mitra & Waikhom 2019;Pati et al 2020aPati et al , 2020bPati 2021;present study). The remaining four genera and 19 species of potamid crabs in India belong to Potaminae Ortmann, 1896 (cf.…”

Abormon, a new genus of freshwater crab (Crustacea: Brachyura: Potamidae) from northeastern India, with descriptions of two new species

“…Nauplius, 29: e2021014 introduction The diversity of potamid freshwater crabs in the northeastern region of India (Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim, and Tripura states) is very high and includes all known potamid genera (12 genera) and 29 of the 38 species now known from the country (Wood-Mason, 1871;1875;1876;Henderson, 1893;Rathbun, 1904;1905;Alcock, 1909;1910;Kemp, 1913;Bott, 1966;1970;Dutta, 1983;Ghosh and Ghatak, 1999;2000;Brandis, 2000;Roy et al, 2003;Ghosh et al, 2006;Yeo and Ng, 2007;Takeda et al, 2012;Absar et al, 2017;Mitra, 2017;Mitra et al, 2018;2020;Pati and Thackeray, 2018;Shaw et al, 2018;Mitra and Waikhom, 2019;Pati et al, 2019;2020a;2020b). Of these, three genera and 23 species (nearly 61 % of India's potamid fauna) are endemic to this area (Absar et al, 2017;Mitra, 2017;Mitra et al, 2018;2020;Pati and Thackeray, 2018;Mitra and Waikhom, 2019;Pati et al, 2019;2020a;2020b).…”

“…Many areas of northeastern India, however, remain poorly explored for freshwater crabs, and recent studies have substantially increased the number of known taxa (Absar et al, 2017;Mitra, 2017;2020;Mitra et al, 2018;Mitra and Waikhom, 2019;Pati et al, 2019;2020a;2020b). Despite this, more new taxa await description as many remote localities remain unsurveyed.…”

“…annandali (Alcock, 1909] [currently with 19 species: 11 from Yunnan Province, China; two from Myanmar, and six from northeastern India (see Ng et al, 2020;Pati et al, 2020a)]. Potamiscus, however, is clearly polyphyletic (see Shih et al, 2009;Chu et al, 2017;Zhang et al, 2020), with several groups, characterised by different carapaces, ambulatory legs, male pleons, male telsons, male gonopods, and female vulvae (see Ng et al, 2020;Pati et al, 2020a), but all are characterised by the exopod of the third maxilliped possessing at most a short flagellum. 11A); the relatively long male sternopleonal cavity, almost reaching to the imaginary line joining the anterior part of the cheliped coxae (Figs.…”