Geostiba (Sibiota) articarinata, Assing, 2016

Assing, Volker, 2016, A revision of Geostiba of the West Palaearctic region. XXII. Two new species from Jordan and the Caucasus, and additional records (Coleoptera: Staphylinidae: Aleocharinae), Linzer biologische Beiträge 48 (1), pp. 221-228 : 223-225

Geostiba (Sibiota) articarinata nov.sp. ( Figs 1-7 )

T y p e m a t e r i a l: Holotype 3: " RUSSIA, NW Caucasus, ( Krasnodarskij Kraj ), Lagonakskij Mts. rng., Matazyk Mt., 9 km S Guamka, sift., 1082 m, 44°09'05.0''N, 39°54'33.3''E, 21.V.2014, leg. A. Pütz / Holotypus 3 Geostiba articarinata sp. n. det. V. Assing 2016" (cAss).

E t y m o l o g y: The specific epithet is an adjective composed of the Latin adjectives artus (narrow) and carinatus (carinate). It alludes to the narrow sutural carinae of the elytra.

D e s c r i p t i o n: Body length 2.7 mm; length of forebody 1.2 mm. Coloration: body reddish-brown; legs yellowish; antennae pale-reddish with the basal three antennomeres yellowish.

Head ( Fig. 1 ) approximately as long as broad; punctation extremely fine, barely noticeable; interstices with microreticulation. Eyes small, with weak pigmentation, and composed of approximately 10 ommatidia, not protruding from lateral contours of head. Antenna distinctly and gradually incrassate apically, antennomere X approximately twice as wide as long.

Pronotum ( Fig. 1 ) 1.07 times as broad as long and nearly 1.2 times as broad as head, without sexual dimorphism; interstices with distinct microreticulation.

Elytra ( Figs 1-2 ) with moderately pronounced sexual dimorphism, 0.65 times as long as pronotum. Hind wings absent.

Abdomen broader than elytra; punctation very fine and sparse, barely noticeable; interstices with distinct microreticulation and only subdued shine; tergite VII with sexual dimorphism; posterior margin of tergite VII without palisade fringe.

3: elytra ( Fig. 2 ) with narrow carina extending along whole suture, disc with shallow impressions near postero-lateral angles, punctation very fine, very weakly granulose; abdominal tergite VII ( Fig. 3 ) with posteriorly convergent carinae forming a broad "V" in posterior half; posterior margin of tergite VIII ( Fig. 4 ) distinctly concave in the middle; posterior margin of sternite VIII broadly convex; median lobe of aedeagus ( Figs 5-6 ) 0.25 mm long, with small crista apicalis and crista proximalis, and without semitransparent spines in internal sac; paramere ( Fig. 7 ) with relatively stout apical lobe.

♀: unknown.

C o m p a r a t i v e n o t e s: Regarding its external and male sexual characters, G. articarinata is most similar to G. convergens ASSING, 2011 (West Caucasus: region to the south of Mount Fisht), from which it differs by darker coloration, a less transverse pronotum without modifications in the male ( G. convergens : male pronotum with an oblong impression on either side of the middle and with coarser punctation), much narrower, less strongly elevated, and contiguous sutural carinae on the male elytra, and a smaller aedeagus ( G. convergens : 0.3 mm) with smaller crista apicalis and crista proximalis. For illustrations of G. convergens see ASSING (2011).

D i s t r i b u t i o n a n d n a t u r a l h i s t o r y: The type locality, Matazyk Mountain, is situated in the northwestern Caucasus to the south of Guamka. The specimen was sifted at an altitude of approximately 1080 m.

Figures

Figs 1-7: Geostiba articarinata nov.sp.: (1) male forebody; (2) male elytra; (3) male abdominal tergite VII; (4) male abdominal tergite VIII; (5-6) median lobe of aedeagus in lateral and in ventral view; (7) paramere. Scale bars: 1: 0.5 mm; 2-7: 0.1 mm.