Kerala has the highest known diversity of freshwater crabs among the Indian states, and many more species are likely to be added to the state, especially from the Western Ghats. The present specimens from the Western Ghats of Kerala add two more species records to Kerala: Oziotelphusa wagrakarowensis (Rathbun, 1904) and Vanni nilgiriensis (Roux, 1931). Although O. wagrakarowensis was reported from the Indian states of Andhra Pradesh, Karnataka, and Maharashtra, it has not been recorded from Kerala previously. The present record of O. wagrakarowensis also constitutes the first reliable report of the species from the Western Ghats. The other species, V. nilgiriensis, was previously known from the Western Ghats of Karnataka and Tamil Nadu. Kerala now includes 37 species of gecarcinucid crabs with the addition of these two new records whereas the Western Ghats of India currently has 59 species.

The mangrove crab, Parasesarma bengalense (Davie, 2003), was previously reported in an ecological study from the Coringa Wildlife Sanctuary of Andhra Pradesh on the east coast of India. No specimen, however, is readily available to confirm the identity of P. bengalense from the Coringa Wildlife Sanctuary. The present study confirms the presence of P. bengalense in Indian waters for the first time based on the collections from Kerala and Maharashtra in the west coast of India (Arabian Sea). The distributional range of P. bengalense is now extended to the Arabian Sea because the species was previously known only from the Bay of Bengal and the Andaman Sea. India now has 918 species of marine brachyuran crabs and six species of Parasesarma De Man, 1895, including the present new record. The west coast of India is home to 465 brachyuran species whereas Kerala and Maharashtra coasts now contain 180 and 131 marine crab species, respectively. Parasesarma bengalense can be distinguished among the Indian species of Parasesarma except for P. bidens (De Haan, 1835) mainly by the presence of a prominent epibranchial tooth with a distinct notch. Parasesarma bengalense is distinct from P. bidens mainly by its male cheliped, which has a greater number of dactylar tubercles and a lesser number of teeth on the transverse crests of the palm.

A new species of the hitherto monotypic gecarcinucid freshwater crab genus, Arcithelphusa Pati & Sudha Devi, 2015, is described from the Western Ghats, in the Wayanad district of Kerala, India. Arcithelphusa tumpikkai sp. nov. can be easily distinguished from the only congener, A. cochleariformis Pati & Sudha Devi, 2015, mainly by its relatively broader carapace, the presence of a short flagellum on the exopod of the third maxilliped, and the relatively less stout male first gonopod, with a sharply bent and relatively long terminal segment. The diagnosis for Arcithelphusa is emended to include the new species, which can be useful in distinguishing it from the closely related genus Cylindrotelphusa Alcock, 1909. The state of Kerala now has 38 species of gecarcinucid crabs, including the present new species.

The Zoological Survey of India, Western Regional Centre, Pune (ZSI-WRC) contains 1887 specimens of mostly unstudied marine brachyuran crabs. The present systematic study on the marine crabs of ZSI-WRC reports 62 species in 44 genera, 18 families and nine superfamilies. Of these, four genera and 13 species are new distributional records within India. We also record three species for the first time from the Indian waters: Metopograpsus cannicci Innocenti, Schubart & Fratini, 2020 (Grapsidae MacLeay, 1838), Varuna yui Hwang & Takeda, 1986 (Varunidae H. Milne Edwards, 1853), and Ilyograpsus paludicola (Rathbun, 1909) (Macrophthalmidae Dana, 1851). The record of Varuna yui is significant as it is the first time it has been found from the western Indian Ocean. The subfamily Ilyograpsinae Števčić, 2005, has likewise not previously been reported from India. The taxonomy of the poorly known menippid crab, Sphaerozius scaber (Fabricius, 1798), is clarified with the designation of a lectotype, and its taxonomy is discussed. Sphaerozius scaber can be distinguished from the only congener S. nitidus Stimpson, 1858, by its prominently tuberculated carapace, palm and carpus of the chelipeds, and the strongly curved male first gonopod, with the distal part gently tapering into a truncate tip. Sphaerozius scaber is a new addition to the west coast of India. With the inclusion of the present new records, India is now known to have 939 species of marine brachyuran crabs in 375 genera of 63 families.