Tachyusa riftensis Pa, 2006

Pa ṡnik, Grzegorz, 2006, A revision of the World species of the genus Tachyusa Erichson, 1837 (Coleoptera, Staphylinidae: Aleocharinae), Zootaxa 1146, pp. 1-152 : 57-59

Tachyusa riftensis Pa ś nik, sp. n. ( Figs. 42–44)

Type material. Holotype: ♂: Afr. or. angl. [ Kenya], Nakuro 12, Rift Valley, Tachyusa leptothorax Fvl. syntype ( IRSNB) . Paratypes: 11♂ and 2♀♀: Afrique or. Anglaise [ Kenya], Nakuro (Rift­Valley), XII.1903, Ch. Alluaud ( MNHN) ; 3♂♂ and ♀: Afrique or. Anglaise [ Kenya], Nakuro (Rift – Valley), XII.1903, Ch. Alluaud ( ISEA) ; ♂: [ Kenya], Nakuro , A.O.A., L. Levasseur ( MNHN) ; ♀: Kenya, Camp l de l'Elgon, Mt. Elgon Vers' Est, 2100 m, Mission de l'Omo, C. Arambourg, P.A. Chappuis & R. Jeannel, 1932–33 ( FMNH) ; 2♂♂ and 2♀♀: Ethiopia: Arussi , 18 km E of Dighelli, under stones in dried up stream ( BMNH) .

Description. Body. Length 2.6–2.9 mm, convex, parallel­sided, glossy; body colour red, pronotum yellowish red, tergite 7 black, legs red, antennae brown with antennomeres 1–3 red.

Head circular in outline, convex, glossy, narrower than pronotum, widest across eyes; eyes large, moderately protruding from lateral contours of head, length of each, seen from above, subequal to that of postocular region; surface of head without microsculpture; puncturation fine and dense; pubescence short and sparse, directed inward. Antennae short, clearly increasing in width apically, antennomeres 2 and 3 subequal in length, antennomeres 4–5 longer than wide, antennomeres 6–10 as long as wide, antennomere 11 nearly conical.

Pronotum quadrate, convex, glossy, widest in apical third, lateral sides rounded in front, clearly concavely narrowed to obtuse hind angles; before base with small and shallow transverse impression; surface without microsculpture; puncturation relatively coarse, dense and asperate; pubescence at midline directed posteriorly.

Elytra elongate, wider than pronotum, lateral sides arcuate, at suture as long as pronotal length at midline; surface lacking microsculpture; puncturation fine and dense.

Abdomen widened posteriorly, bases of tergites 3–5 each with deep transverse impression, impressions with 7–8 longitudinal ridges connected by the short transverse ridges in the shape of honeycomb, tergal puncturation very fine and scattered, punctures very small and scarcely visible, surface without microsculpture; pubescence long and sparse, semierect.

Male. Aedeagus as in Figs. 42–43.

Female. Spermatheca as in Fig. 44.

Remarks. Tachyusa riftensis is closely related to T. leptothorax , from which it can be distinguished by the paler body colour, the longer elytra, the more convex pronotum and particularly by the shape of the aedeagus.

Etymology. The name riftensis refers to the type locality.

Distribution. The new species is known so far only from Ethiopia and Kenya.