Ischnosoma cuspidatum, Assing, 2019

Assing, Volker, 2019, New species and additional records of Ischnosoma from Georgia (Coleoptera, Staphylinidae, Tachyporinae), Linzer biologische Beiträge 51 (2), pp. 773-788 : 776-777

Ischnosoma cuspidatum nov.sp. ( Figs 2 , 47-51, Map 2 )

T y p e m a t e r i a l: Holotype ♂: " N42°12'19 E45°27'45, GG Kakheti Lechuri N, 830 m 9.5.2019, Brachat & Meybohm (2) / Holotypus ♂ Ischnosoma cuspidatum sp. n. det. V. Assing 2019" (cAss).

E t y m o l o g y: The specific epithet (Latin, adjective: acute) alludes to the sharply acute apex of the ventral process of the aedeagus in ventral view.

D e s c r i p t i o n: Body length 4.3 mm; length of forebody 1.9 mm. Habitus as in Fig. 2 . Coloration: body reddish, with the antero-median portions of tergite IV-VI slightly darker; legs dark-yellow; antennae pale-reddish.

Eyes ( Fig. 47 ) slightly longer than postocular region in lateral view, composed of some 40-50 ommatidia. Antenna 1.45 mm long.

Pronotum 1.15 times as broad as long and 1.83 times as broad as head; disc with moderately dense micropunctation, mostly without microsculpture (nearly obsolete traces of microsculpture visible only near anterior margin).

Elytra 0.82 times as long as pronotum, without microsculpture; sutural and lateral series each composed of six punctures.

Abdomen with rather coarse and dense punctation, punctures somewhat sparser in postero-median portions of tergites; posterior margin of tergite VII without palisade fringe.

♂: sternite VII ( Fig. 48 ) weakly transverse, with a distinct cluster of dense setae in postero-median portion; sternite VIII ( Fig. 49 ) distinctly oblong, in postero-median portion with a cluster of moderately dense and rather short setae, posterior margin strongly concave; aedeagus ( Figs 50-51 ) 0.68 mm long; ventral process apically extremely acute in ventral view; parameres with numerous setae in apical half.

C o m p a r a t i v e n o t e s: Ischnosoma cuspidatum is distinguished from I. major, its geographically closest micropterous congener (see map 2 in ASSING & SCHÜLKE 2017) by slightly larger body size, the (near) absence of microsculpture on the pronotum and the elytra, a male sternite VII with a truncate posterior margin and with a less extensive cluster of setae in the postero-median portion, a more slender male sternite VIII with a more deeply concave posterior margin and a distinct cluster of dense setae in the postero-median portion, and by a more acute and differently shaped apex of the ventral process of the aedeagus. For illustrations of I. major see KOCIAN (1997).

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 to the north of Lechuri in the southern slopes of the Greater Caucasus, Kakheti region, Northeast Georgia ( Map 2 ). The holotype was sifted from leaf litter in a stream valley with deciduous forest at an altitude of 830 m (MEYBOHM pers. comm.).

Figures

Map 2: Confirmed distribution of Ischnosoma myops (black circles) and type locality of I. cuspidatum (white star).

Figs 1-8: Ischnosoma acre (1), I. cuspidatum (2), I. convergens (3-4), I. parallelum (5-6), and I. myops (7-8): (1-3, 5, 7) habitus; (4, 6, 8) head and pronotum in lateral view. Scale bars: 1-3, 5, 7: 1.0 mm; 4, 6, 8: 0.5 mm.

Figs 47-51: Ischnosoma cuspidatum: (47) head and pronotum in lateral view; (48) male sternite VII; (49) male sternite VIII; (50-51) aedeagus in lateral and in ventral view. Scale bars: 47: 0.5 mm; 48-51: 0.2 mm.