Geostiba (Sibiota) breviflagellata, Assing, 2018

Assing, Volker, 2018, A revision of Geostiba of the West Palaearctic region. XXVI. New species and additional records, primarily from the Caucasus region (Coleoptera: Staphylinidae: Aleocharinae), Linzer biologische Beiträge 50 (2), pp. 1033-1054 : 1041

Geostiba (Sibiota) breviflagellata nov.sp. ( Figs 15-21 )

T y p e m a t e r i a l: Holotype ♂: "N 41°57'24 E 42°46'10, Georgien Imeretien (51), Sairme N 630 m 18.5.2018, Brachat & Meybohm / Holotypus ♂ Geostiba breviflagellata sp. n. det. V. Assing 2018" (cAss) . Paratypes: 3♂♂, 2♀♀: same data as holotype (cAss) ; 1♂: "N 42°00'50 E 42°48'55, Georgien Imeretien (50), Baghdati 290 m 18.5.2018, Brachat & Meybohm" (cAss) .

E t y m o l o g y: The specific epithet (adjective) alludes to the short flagellum in the internal sac of the aedeagus, one of the characters distinguishing this species from the similar and geographically close G. bituberculata (EPPELSHEIM, 1878).

D e s c r i p t i o n: Body length 2.4-3.0 mm; length of forebody 1.0- 1.2 mm. Coloration: body, including antennae, reddish to dark-reddish; legs yellow. Eyes strongly reduced, without ommatidia and pigmentation. External characters as in G. bituberculata, except as follows:

Large ♂: elytra with pronounced sutural carinae, these carinae broad anteriorly and strongly tapering posteriad ( Fig. 15 ); tergite VIII with a pair of posteriorly converging carinae in postero-median portion; medial lobe of aedeagus approximately 0.28 mm long and shaped as in Figs 16-19 ; internal sac with short flagellum.

♀: spermatheca as in Figs 20-21.

I n t r a s p e c i f i c v a r i a t i o n: The male secondary sexual characters are more or less reduced in small males.

C o m p a r a t i v e n o t e s: Geostiba breviflagellata differs from other species of the G. bituberculata group recorded from the Lesser Caucasus as follows:

from G. bituberculata by a smaller aedeagus (G. bituberculata: approximately 0.33 mm) with a broader ventral process, a differently shaped crista apicalis, and a much shorter flagellum;

from G. batumiensis by less strongly impressed male elytra with shorter, anteriorly broader and posteriorly less sharp sutural carinae, more pronounced carinae on the male tergite VII, a smaller aedeagus ( G. batumiensis : approximately 0.32 mm), and a shorter and less slender spermatheca;

from G. zerchei PACE, 1996 (male unknown) by more strongly reduced eyes (G. zerchei: eyes composed of few ommatidia).

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: Thespecimenswerecollected in two localities in the Imereti region, Lesser Caucasus, Southwest Georgia. They were sifted from leaf litter in a mixed deciduous forest with chestnut, beech, and rhododendron (type locality) and from chestnut litter at the base of a slope (MEYBOHM pers. comm.). The altitudes range from 290 to 630 m.

Figures

Figs 15-21: Geostiba breviflagellata nov.sp.: (15) male forebody; (15-19) median lobe of aedeagus in lateral and in ventral view; (20-21) spermatheca. Scale bars: 15: 0.5 mm; 16-21: 0.1 mm.