A new species of Tangius from north India (Coleoptera, Staphylinidae, Pselaphinae)

Abstract Tangius indicus sp. n. (Batrisitae: Batrisini) is described and illustrated from the Indian States of Meghalaya (Khasi Hills, type locality) and West Bengal (Darjeeling). Specimens of the new species are similar to those of the recently described T. glabellus Yin & Li from Tibet, Southwest China, and can be separated only by minor differences of the male features.


Introduction
The batrisine genus Tangius Yin & Li (Yin et al. 2012) was recently established for a single species T. glabellus Yin & Li, from southeast Tibet (= Xizang A. R.). Characters distinguishing it from the allied genera Dendrolasiophilus Nomura, Maajappia Nomura, and Songius Yin & Li were described.
When visiting the Natural History Museum of Geneva, Switzerland (May, 2013), the first author sorted a small series of north Indian Tangius specimens out of the large pselaphine collection. A second species of the genus, closely allied to T. glabellus, was recognized based on differences in male characters. In this paper we describe the new species, provide illustrations of its major diagnostic features, and distinguish it from the previously described T. glabellus.

Material and methods
The type series is housed in the Muséum d'histoire naturelle de la Ville de Genève, Switzerland (MHNG -G. Cuccodoro).
The collection data of the referred material are quoted verbatim. A slash (/) is used to separate different labels. Authors' notes are included in '[]'.
Comparative notes. The new species is closely allied to T. glabellus in sharing similar body size, general habitus, including the unusual head shape, and aedeagal structure (Figs 2L, M). Males of these two species can be best separated by the subcylindrical antennomeres VII-X in T. indicus, and the mesotibiae being broadly concave just before the preapical denticle (Fig. 2G), while T. glabellus has asymmetric, transversely trapezoidal antennomeres VII-X, and the mesotibiae with straight mesal margins (Fig. 2G). The females of T. indicus have relatively longer antennomeres than those of female T. glabellus.
Distribution. North India: Meghalaya, West Bengal. Biology. One female paratype was collected from sifted litter, as inferred from the label data. Members of this genus are supposed to be inquilines of ants as they exhibit obvious morphological adaptions to myrmecophily, e.g. smooth body surface, compressed antennae, reduction of foveae, etc. The type series of T. glabellus was collected from the colony of an unidentified ant nesting under a fallen tree.
Etymology. The specific epithet refers to the country where the type series were collected.