Geostiba (Sibiota) pambakica, Assing, 2016

Assing, Volker, 2016, A revision of Geostiba of the West Palaearctic region. XXIII. On the Sibiota species of the Caucasus region exclusive of Turkey (Coleoptera: Staphylinidae: Aleocharinae), Linzer biologische Beiträge 48 (2), pp. 1097-1117 : 1109-1111

Geostiba (Sibiota) pambakica nov.sp. ( Figs 42-52 , Map 2 )

T y p e m a t e r i a l: Holotype 6: " ARMENIA [6] - N Yerevan, NW Hrazdan, 40°38'07''N, 44°30'05''E, 2010 m, mixed forest, 27. VI.2016, V. Assing / Holotypus 6 Geostiba pambakica sp. n. det. V. Assing 2016" (cAss) . Paratypes: 16, 4♀♀: same data as holotype (cAss) ; 2♀♀: same data, but leg. Schülke ( MNB) ; 466, 3 ♀♀: " ARMENIA [5] - N Yerevan, NW Hrazdan, 40°40'07''N, 44°28'22''E, 2100 m, W-slope, sifted 26. VI.2016, V. Assing " (cAss) ; 16, 2♀♀: same data, but leg. Schülke ( MNB) ; 16, 1♀: " ARMENIA [8] - N Yerevan, NW Hrazdan, 40°33'45''N, 44°23'41''E, 2000 m, forest margin, 28. VI.2016, V. Assing " (cAss) ; 1♀: same data, but leg. Schülke.

E t y m o l o g y: The specific epithet is an adjective derived from Pambaki, the name of the mountain range where this species is probably endemic.

D e s c r i p t i o n: Body length 2.2-2.6 mm; length of forebody 0.85-1.05 mm. Coloration and other characters ( Fig. 42 ) as in G. unituber , except as follows:

Pronotum on average with less distinct impression on either side of midline.

6: elytra ( Fig. 43 ) with narrow, anteriorly slightly broader carina extending along whole suture, disc with usually extensive and more or less pronounced impression, punctation very fine, barely noticeably granulose; abdominal tergite VII ( Fig. 44 ) with a median pair of more or less pronounced, parallel carinae posteriorly; posterior margin of tergite VIII broadly convex; posterior margin of sternite VIII very obtusely angled in the middle; median lobe of aedeagus ( Figs 45-49 ) 0.22-0.23 mm long, without semi-transparent spines in internal sac; ventral process nearly straight in lateral view; paramere not distinctive.

♀: tergite VIII and sternite VIII with broadly convex posterior margins; spermathecal capsule ( Figs 50-52 ) with weakly dilated distal portion and conspicuously stout and short proximal portion.

C o m p a r a t i v e n o t e s: Though highly similar in external characters, G. pambakica is readily distinguished from the sympatric G. unituber by the presence of carinae (rather than one median tubercle) on the male abdominal tergite VII, by a slightly smaller median lobe of the aedeagus with a nearly straight ventral process (lateral view) and a somewhat shorter crista apicalis, as well as by the shape of the spermatheca (smaller; distal portion weakly dilated; proximal portion shorter and stouter).

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 specimens were collected in three localities in the Pambaki range ( Map 2 ), not far from the type locality of G. unituber (but at lower altitudes), by sifting litter and grass roots beneath bushes and in, or at the margin of, mixed deciduous forests at altitudes of 2000-2100 m.

Figures

Map 2: Distributions of the species of the G. carinicollis group: G. articarinata ASSING (black square), G. convergens ASSING (white square), G. uniplicata ASSING (black diamond), G. krzysztofi (ROUBAL) (white diamonds), G. carinicollis (EPPELSHEIM) (white circles), G. unituber nov.sp. (black circle), G. pambakica nov.sp. (white triangles), G. unicuneata nov.sp. (black star), G. meghruica nov.sp. (white star).

Figs 42-52: Geostiba pambakica nov.sp.: (42) male forebody; (43) male elytra; (44) median portion of male tergite VII; (45-49) median lobe of aedeagus in lateral and in ventral view; (50-52) spermatheca. Scale bars: 42-43: 0.2 mm; 44-52: 0.1 mm.