Geostiba (Tropogastrosipalia) reducta, 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 : 1035-1038

Geostiba (Tropogastrosipalia) reducta nov.sp. ( Figs 1-5 ; Map 1 )

T y p e m a t e r i a l: Holotype ♂: "RU - Krasnodar area, Tuapse distr., Olginka env., Saray Gora , 250 m, leaf litter, 18.V.2017, leg. Gontarenko / Holotypus ♂ Geostiba reducta sp. n. det. V. Assing 2018" (cAss) . Paratypes: 1♂: same data as holotype (cAss) ; 1♂: " Krasnodar area, Tuapse distr. , Olginka env., h ~50, 19.05.017, leg. Salnizkaya M.O. / under stone near stream" (cGon) .

E t y m o l o g y: The specific epithet is the past partiple of the Latin verb reducere and alludes to the minute cristal process of the aedeagus.

D e s c r i p t i o n: Body length 2.7-3.2 mm; length of forebody 1.15-1.25 mm. Coloration: head reddish to blackish; pronotum reddish to dark-brown; elytra yellowishred to yellowish-brown; abdomen reddish to brown with segments V-VI and the anterior portion of VII more or less extensively blackish; antennae reddish to brown with the basal two antennomeres paler. Head and pronotum with sparse and very fine punctation and with microreticulation. Posterior margin of abdominal tergite VII without palisade fringe.

Large ♂: pronotum ( Figs 1-2 ) distinctly oblong, approximately 1.2 times as long as broad, posterior margin truncate, in the middle indistinctly concave; elytra ( Figs 1-2 ) with extensive and somewhat diagonal impressions, sharply edged lateral margins, and short, but strongly elevated sutural carinae; abdomen with anterior tergites unmodified, tergite VII ( Fig. 3 ) with pronounced postero-median spine; median lobe of aedeagus ( Figs 4-5 ) 0.27 mm long, with minute cristal process.

♀: unknown.

I n t r a s p e c i f i c v a r i a t i o n: In the two paratypes, the male secondary sexual characters are somewhat reduced. The pronotum is 1.08-1.10 times as long as broad and has the posterior margin convex, the sutural carinae and the impressions of the elytra are much less pronounced, and the postero-median spine of tergite VII is of much smaller size (only weakly indicated in one of the paratypes).

C o m p a r a t i v e n o t e s: Only three species of the subgenus Tropogastrosipalia SCHEERPELTZ, 1951 were previously known from the Greater Caucasus: Geostiba svanetica ASSING, 2017, G. gibberiventris ASSING, 2017, and G. tiflisensis PACE, 1996 ( ASSING 2017c). Geostiba reducta is distinguished from all of them by a much smaller cristal process of the aedeagus. From G. svanetica ( Georgia: Svaneti), the geographically closest species, it additionally differs by a distinctly oblong male pronotum, the modifications of the male elytra, unmodified anterior tergites of the male abdomen, and a more pronounced postero-median spine on the male tergite VII. For illustrations of G. svanetica, G. gibberiventris, and P. tiflisensis see ASSING (2017c).

D i s t r i b u t i o n: The type specimens were collected in two localities in the Saray Gora near Ol'ginka (44°12'N, 38°53'E), to the northwest of Tuapse, Krasnodarskiy Kray, in the northwestern extension of the West Caucaseus ( Map 1 ). Two specimens were sifted from leaf litter at an altitude of 250 m, one was found under a stone near a stream at an altitude of only 50 m.

Figures

Map 1: Distributions of the species of the subgenus Tropogastrosipalia in the Caucasus region, based on examined records: G. reducta (black star); G. defecta (black diamond); G. svanetica (white square); G. gibberiventris (black square); G. tiflisensis (white diamonds); G. artvinensis (white circles); G. pontica (black triangle); G. solodovnikovi (white triangle); G. priva (white star); G. khnzoriani (black circles).

Figs 1-6: Geostiba reducta nov.sp. (1-5) and G. defecta (6): (1) male forebody in dorsal view; (2) male forebody in lateral view; (3) male tergites VI-VII in lateral view; (4-5) median lobe of aedeagus in lateral and in ventral view; (6) habitus. Scale bars: 6: 1.0 mm; 1-3: 0.5 mm; 4-5: 0.1 mm.