Spiralothelphusa gibberosa, a new freshwater crab (Brachyura: Gecarcinucidae) from Thrissur district, Kerala, India

Abstract

A new species of freshwater crab, Spiralothelphusa gibberosa n. sp. is described from rice fields near Kizhoor in Thrissur district of Kerala in southern India. The new species is easily differentiated from its congeners by its first male pleopod (G1), which has a long, less strongly twisted terminal segment and distal portion of subterminal segment in addition to a setose hump on the outer margin of the non-twisted portion. Key to the species of the genus Spiralothelphusa Bott, 1968, is provided. We recognized S. wuellerstorfi (Heller, 1862), as a new record to Maharashtra based on specimens wrongly identified as S. hydrodroma (Herbst, 1794), by Pati & Sharma (2014).

Description of a new species of Spiralothelphusa Bott, 1968, and redescription of Spiralothelphusa wuellerstorfi (Heller, 1862) (Decapoda: Brachyura: Gecarcinucidae)

“…11A) (vs almost straight postorbital cristae, each sloping posteriorly towards the anterolateral margin in the male holotype; Figs 9A, 13). This intraspecific variation raises doubt on the consistency or reliability of the shape of the postorbital cristae as one of the key characters for separating the species of Spiralothelphusa as used by Pati & Sudha Devi (2015). The smaller male paratype (ZSI-FBRC INV/2257) has a relatively broader telson, i.e., the medial length of the telson is almost equal to its proximal width (Fig.…”

“…We also thank Dr Peter Ng (ZRC) for providing some literature and his notes. Figure 7I was from Pati & Sudha Devi (2015) published in Zootaxa by the Magnolia Press, reproduced herein by the first author (SKP) with the right to use. Dr Peter Dworschak (former curator of Crustacea collections in NHMW) is thanked for providing information on the syntypic material of Spiralothelphusa wuellerstorfi, while Dr K.A.…”

“…Spiralothelphusa Bott, 1968, a freshwater crab genus of the family Gecarcinucidae Rathbun, 1904, was previously known from six species: S. fernandoi Ng, 1994, and S. parvula (Fernando, 1961) from Sri Lanka; and S. gibberosa Pati & Sudha Devi, 2015, S. hydrodroma (Herbst, 1794, S. senex (Fabricius, 1798), and S. wuellerstorfi (Heller, 1862) from India (Ng & Tay 2001;Pati & Sudha Devi 2015;Pati & Thackeray 2018). In carapace morphology, Spiralothelphusa most resembles Oziotelphusa Müller, 1887 (see Ng & Tay 2001), the only other genus with representatives from both India and Sri Lanka .…”

New records of two species of freshwater crabs (Decapoda: Gecarcinucidae) from Kerala, India, with notes on their distribution

“…Considering the small spatial scale of endemism in freshwater crabs (Klaus et al, 2014), more isolated and poorly studied areas need to be investigated. Furthermore, many new taxa await descriptions as evident from the recent discoveries (Pati and Sharma, 2013;Pati and Sudha Devi, 2015a;2015b;Kumar et al, 2017;Pati et al, 2017).…”