Geostiba (Sipalotricha) manca, 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 : 1049-1052

Geostiba (Sipalotricha) manca nov.sp. ( Figs 52-63 ; Map 3 )

T y p e m a t e r i a l: Holotype ♂: "N 41°51'26 E 42°47'23, Georgien Imeretien (53), Sairme S 1930 m 19.5.2018, Brachat & Meybohm / Holotypus ♂ Geostiba manca sp. n. det. V. Assing 2018" (cAss) . Paratypes: 1♂, 5♀♀: same data as holotype (cAss) ; 1♂, 1♀: "N 41°51'37 E 42°46'59, Georgien Imeretien (54), Sairme S 1890 m 19.5.2018, Brachat & Meybohm" (cAss) ; 3♂♂, 2♀♀: "N 41°51'50 E 42°47'20, Georgien Imeretien (55), Sairme S 1760 m 19.5.2018, Brachat & Meybohm" (cAss) ; 2♀♀: "N 41°52'47 E 42°46'02, Georgien Imeretien (56), Sairme S 1420 m 20.5.2018, Brachat & Meybohm" (cAss) .

E t y m o l o g y: The specific epithet (Latin, adjective: incomplete) alludes to the absence of a tubercle on the male tergite VII, one of the characters distinguishing this species from the similar and geographically close G. cingulata (EPPELSHEIM, 1878).

D e s c r i p t i o n: Body length 2.3-2.9 mm; length of forebody 1.0- 1.2 mm. Habitus as in Fig. 52 . Coloration: forebody reddish to dark-brown; abdomen usually reddish with segment VI and the anterior portion infuscate, rarely uniformly reddish or uniformly blackish; legs yellow; antennae pale-reddish to dark-reddish with the basal 2-3 antennomeres reddish-yellow.

Head ( Fig. 53 ) approximately as broad as long and of orbicular shape; punctation extremely fine and moderately dense; interstices with distinct, but shallow microreticulation. Eyes small, not protruding from lateral contours of head, and composed of 10-15 ommatidia. Antenna 0.7 mm long, strongly incrassate apically; antennomeres IV distinctly transverse, V-X of gradually increasing width and increasingly transverse, VIII-X nearly three times as broad as long, and XI nearly as long as the combined length of VIII-X.

Pronotum approximately 1.1 times as broad as long and 1.15 times as broad as head; punctation and microsculpture similar to those of head.

Elytra approximately 0.6 times as long as pronotum; punctation moderately dense and fine, more distinct than that of head and pronotum; interstices with shallow microsculpture and some shine. Hind wings completely reduced.

Abdomen slightly broader than elytra; punctation rather sparse and very fine; interstices with distinct, but shallow microreticulation and some shine; tergite VII without sexual dimorphism, its posterior margin without palisade fringe.

♂: tergite VII unmodified; tergite VIII ( Fig. 54 ) with weakly convex posterior margin; sternite VIII ( Fig. 55 ) with smoothly convex posterior margin and thin marginal setae; median lobe of aedeagus approximately 0.27 mm long and shaped as in Figs 56-57 ; apical lobe of paramere rather short, shape not distinctive.

♀: posterior margin of tergite VIII ( Fig. 58 ) convex; posterior margin of sternite VIII broadly convex, without median concavity, with rather long and stout marginal setae ( Fig. 59 ); spermatheca as in Figs 60-63.

C o m p a r a t i v e n o t e s: Geostiba manca is readily distinguished from G. cingulata , the only other Sipalotricha species known from Georgia, by the unmodified male tergite VII, the absence of a palisade fringe at the posterior margin of tergite VII (present in G. cingulata ), distinctly smaller eyes ( G. cingulata : eyes composed of approximately 30-40 ommatidia), less pronounced microsculpture of the forebody, more transverse antennomeres IV-X, and by the primary sexual characters.

The three geographically closest consubgeners in Northeast Turkey are G. euxina PACE, 1983, G. macronorum PACE, 2002, and G. soganlica ASSING, 2006, all of them described from Trabzon province. Geostiba manca is reliably distinguished from all of them by the primary sexual characters. For illustrations of G. cingulata , G. euxina, G. macronorum, and G. soganlica see ASSING (2001, 2005, 2006) and PACE (1983, 2002).

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 the region to the south of Sairme, Imereti, in the Lesser Caucasus, Southwest Georgia ( Map 3 ). The absence of previous records from the Lesser Caucasus suggests that the species may be locally endemic. The material was sifted from maple leaf litter, from litter in a mixed deciduous forest, from litter on a moist slope, and from debris near rocks (MEYBOHM pers. comm.). The altitudes range from 1420 to 1930 m.

Figures

Map 3: Distributions of species of the subgenus Sipalotricha in the Caucasus region, based on examined records: G. cingulata (black circles); G. manca (white stars).

Figs 52-63: Geostiba manca nov.sp.: (52) habitus; (53) head in lateral view; (54) male tergite VIII; (55) male sternite VIII; (56-57) median lobe of aedeagus in lateral and in ventral view; (58) female tergite VIII; (59) female sternite VIII; (60-63) spermatheca. Scale bars: 52: 1.0 mm; 53, 54-55, 58- 59: 0.2 mm; 56-57, 60-63: 0.1 mm.