Geostiba (Sibiota) frischi, Assing, 2019

Assing, Volker, 2019, A revision of Geostiba of the West Palaearctic region. XXVII. New species from Georgia and Kyrgyzstan, and additional records (Coleoptera, Staphylinidae, Aleocharinae), Linzer biologische Beiträge 51 (2), pp. 717-730 : 727-728

Geostiba (Sibiota) frischi nov.sp. ( Figs 24-33 )

T y p e m a t e r i a l: Holotype ♂: " Kyrgyzstan: Issyk-Kul, NE Karakol: SE Ak-Bulak (Turgenaksu River), 2080 m (Picea schrenkiana -forest) N 42°34'40'' E 078°53'12'', 27.06.2011, leg. J. Frisch / Holotypus ♂ Geostiba frischi sp. n. det. V. Assing 2019" (MNB). Paratypes: 3♀♀: same data as holotype (MNB, cAss).

E t y m o l o g y: This species is dedicated to Johannes Frisch (MNB), who collected the type material all three species described from Kyrgyzstan in the present paper.

D e s c r i p t i o n: Body length 2.3-2.7 mm; length of forebody 1.1 mm. Habitus as in Fig. 24 . Coloration: body reddish-yellow with yellow legs. Eyes weakly pigmented and small (though of somewhat variable size), approximately as large as antennomere I in cross-section or slightly larger, composed of approximately 5-8 ommatidia ( Fig. 26 ). Antenna 0.6-0.7 mm long. Head and pronotum with extremely fine and sparse punctation and with more or less pronounced microreticulation. Elytra ( Fig. 25 ) approximately 0.55 times as long as pronotum and with moderately pronounced sexual dimorphism. Hind wings completely reduced. Posterior margin of abdominal tergite VII with very narrow and indistinct rudiment of a palisade fringe. Tergite VIII with very weakly pronounced sexual dimorphism.

♂: head and pronotum with pronounced microreticulation and nearly matt ( Fig. 25 ); elytra ( Figs 25-26 ) near suture distinctly elevated, this elevation broader and more pronounced anteriorly than posteriorly and with rather coarse granules; abdominal tergite VII ( Fig. 27 ) in postero-median portion with a pair of short and narrow oblong tubercles (not carinae); posterior margin of tergite VIII truncate in the middle; sternite VIII strongly convex posteriorly; median lobe of aedeagus ( Figs 28-29 ) 0.35 mm long, with long crista apicalis; internal sac without spines; paramere ( Fig. 30 ) 0.45 mm long, with short and stout apical lobe.

♀: head and pronotum with less pronounced microreticulation and some shine; posterior margin of tergite VIII weakly convex; posterior margin of sternite VIII weakly concave in the middle, with rather long marginal setae; spermatheca ( Figs 31-33 ) with strongly dilated distal portion and with short untwisted proximal portion.

C o m p a r a t i v e n o t e s: Based on several - presumably synapomorphic - similarities (median lobe of aedeagus with long crista apicalis, long crista proximalis, and with strongly bisinunate basal portion in lateral view; short and stout apical lobe of the paramere; spermatheca with short and untwisted proximal portion), G. frischi is closely allied to G. kirghisica from Northwest Kyrgyzstan. It is distinguished from this species by the strongly elevated and granulose sutural portion of the male elytra, the presence of short tubercles rather than carinae on the male tergite VII, a posteriorly truncate male tergite VIII (G. kirghisica: posterior margin distinctly concave in the middle), a ventral process of the aedeagus with a longer and more slender apical portion (lateral view), and a spermatheca with a strongly dilated distal portion. For illustrations of G. kirghisica see ASSING (2008).

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 is situated in the extreme east of Kyrgyzstan. The specimens were sifted in a Picea schrenkiana forest at an altitude of 2080 m.

Figures

Figs 24-33: Geostiba frischi: (24) male habitus; (25) male forebody in dorsal view; (26) male forebody in lateral view; (27) male abdominal segments VI-VIII; (28-29) median lobe of aedeagus in lateral and in ventral view; (30) paramere; (31-33) spermatheca. Scale bars: 24: 1.0 mm; 25-27: 0.5 mm; 28-33: 0.1 mm.