Orientogidiella, Sidorov & Reddy & Shaik, 2018

Sidorov, Dmitry, Reddy, Yenumula Ranga & Shaik, Shabuddin, 2018, Groundwater amphipods (Crustacea, Malacostraca) of India, with description of three new cavernicolous species, Zootaxa 4508 (3), pp. 403-426 : 404-406

Orientogidiella , new genus

Type species. Bogidiella indica Holsinger, Ranga Reddy, and Messouli, 2006 , here designated.

Generic diagnosis. Amphipods with obvious troglomorphic traits (anophthalmy and depigmentation), slender habitus, small head, well-developed but irregularly rounded inter-antennal lobe. 1 Antenna I longer than antenna II, about 33–35% as long as body. Antenna II lacking aesthetascs. Mandibles well-developed, each with strong incisor, lacinia mobilis and spine row; molar process reduced and with short setae; palp 3-articulate, distal article narrow, bearing 1 apical seta. Outer plate of maxilla I with 6 or 7 apical serrate spines; inner plate bearing 2–4 apical plumose/naked setae; palp 2-articulate (normal) or 1-articulate (reduced), bearing 2 apical setae. Both plates of maxilla II sparsely setose with naked setae. Other mouthparts (labrum, paragnath and maxilliped) normal, without obvious peculiarities. Gnathopods relatively small, with prominent propodi; palmar angles of both gnathopods indistinct but with mid-palmar spines; propodi with stiff, tiny notched setae along inner and outer faces of palmar margin; dactyli with shallow serration accompanied by thin setae on inner face, and nail indistinctly demarcated. Coxal plates shallow (wider than deep), plates V–VII indistinctly lobate. Pereopod V short , about 70% as long as pereopod VI and 35% as long as pereopod VII, with stocky carpus (article 5) armed with conspicuous groups of strong spines; pereopod VI armed similar to pereopod V. Coxal gills present on pereonites II–VI. Pleopods I–III similar, without inner rami. Second and/or first uropod sexually dimorphic; inner ramus with apical modified spine in males. Uropod III and telson typical of bogidiellids.

Etymology. The generic epithet Orientogidiella is derived from the combination of Orient (from Latin noun, Oriens ) meaning the East with ' gidiella ꞌ a part of the closely related genus Bogidiella . Gender feminine.

Composition and geographic distribution. Both Orientogidiella indica ( Holsinger, Ranga Reddy, and Messouli, 2006) comb. n. and Orientogidiella reducta sp. n. inhabit the freshwater subterranean environment of the southeastern Indian peninsula.

Remarks. In a previous publication, Sidorov et al. (2016), being of the opinion that Bogidiella indica belonged to the niphargoides -group, had expressed doubts about the reliability of the morphological features proposed by Holsinger et al. (2006: 53), i.e. reckoning the special structural features of pereopod V for designating the indica -group (group E). However, having carried out a comparative morphological analysis of 114 described bogidiellid species in 37 genera, and in particular for B. indica (the former monotypic representative of the indica - group) versus Orientogidiella reducta gen. n., sp. n., described herein, we agree with the rationale of the taxonomic criteria suggested by Holsinger et al. (2006) for the indica -group of species. Based on the structurally unique pereopod V of this group, we propose here a new genus, Orientogidiella gen. n., to accommodate both species. This taxonomic decision warrants a new combination for nomenclatural consistency: Orientogidiella indica ( Holsinger, Ranga Reddy, and Messouli, 2006) comb. n.

Orientogidiella gen. n. is distributed in the coastal belt along the Eastern Ghats (Ghats orientales) at altitudes ranging from ca. 19 to 710 m above sea level. Taking into account the Chidambaram specimen of Bogidiella sp. sensu Holsinger et al. (2006), which belongs to the same genus, the distribution of Orientogidiella gen. n. extends from 18° N l. towards the south 11° N l. exclusively along the present coastline, but not extending deeper than 100 km into the interior of the continent (see also discussion in Holsinger et al. 2006). Although, we could not confirm our findings with molecular data, we are of the opinion that the species of Orientogidiella gen. n., sharing unique phenotypic features, inhabit a common territory along the east coast of India for about 1000 km.