Tangius indicus Yin & Li

Yin, Zi-Wei & Li, Li-Zhen, 2013, A new species of Tangius from north India (Coleoptera, Staphylinidae, Pselaphinae), ZooKeys 346, pp. 23-27 : 24-27

Tangius indicus Yin & Li sp. n. Figs 1, 2 A–F, H–K, M–N

Type material

(6 ♂♂, 3 ♀♀). Holotype: INDIA: ♂, labeled 'INDIA, Meghalaya, Khasi Hills, 28.X, Mawphlang, 1800 m, Besuchet-Löbl, 78. / Holotype [red], Tangius indicus sp. n., det. Yin & Li 2013, MHNG’. Paratypes: INDIA: 4 ♂♂, 3 ♀♀, same label data as holotype [1 ♂ totally disarticulated and preserved in Euparal on plastic boards; 1 ♂ with left antenna and abdomen missing]; 1 ♀, labeled 'INDIA: Darjeeling, distr., 13 km N. Ghoom, 1500 m, 15.X.1978, I. Löbl, Bes. nr. 15, litter’. Each paratype bear a type label as 'Paratype [yellow], Tangius indicus sp. n., det. Yin & Li, 2013, MHNG’.

Description.

Male (Fig. 1A). Length 2.91-2.97 mm. Surface almost glabrous. Head trapezoidal, slightly transverse, HL 0.61-0.62 mm, HW 0.64-0.65 mm; clypeus covered with sparse short setae anteriorly; Antennomeres II–X (Fig. 2A) each subcylindrical, apical antennomeres nearly oval, enlarged. Each eye composed of about 35 facets. Pronotum about as long as wide, PL 0.62-0.63 mm, PW 0.61-0.62 mm; roundly expanded at lateral margins; pronotal apex and base narrowed and truncate. Elytra (Fig. 2I) wider than long, EL 0.79-0.81 mm, EW 1.00-1.03 mm; inner two ba sal foveae close; discal suture extending to less than half elytral length. Hind wings fully developed. Metaventrite (Fig. 2J) with posterior margin narrowly and deeply notched medially. Protrochanters (Figs 2B, E) with small ventral denticle at middle; mesotibiae (Figs 2C, F) with broadly concave mesal margin before triangular preapical spine; metatrochanters (Figs 2D, H) with blunt ventral projection near apex; all femora with ringed sulcus near base. Abdomen slightly wider than long, AL 0.81-0.83 mm, AW 1.03-1.07 mm; sternite IX (Fig. 2K) nearly oval. Aedeagus (Figs 2M, N) length 0.57 mm; median lobe asymmetric, apex rounded, with sharp, weakly-sclerotized projection at right side; dorsal lobe well-sclerotized, slender, curved rightwards near apex.

Female (Fig. 1B). Identical to male except antennomeres shorter, and mesotibiae lacking distal concavity and preapical tooth.. Measurements: BL 2.73-2.81 mm, HL 0.51-0.52 mm, HW 0.53-0.54 mm, PL 0.53-0.54 mm, PW 0.52-0.54 mm, EL 0.66-0.68 mm, EW 1.00-1.03 mm, AL 0.91-0.95 mm, AW 1.06-1.07 mm.

Comparative notes.

The new species is closely allied to Tangius 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 Tangius indicus , and the mesotibiae being broadly concave just before the preapical denticle (Fig. 2G), while Tangius glabellus has asymmetric, transversely trapezoidal antennomeres VII–X, and the mesotibiae with straight mesal margins (Fig. 2G). The females of Tangius indicus have relatively longer antennomeres than those of female Tangius 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 Tangius 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.