Ischnosoma barbigerum, Assing & Schülke, 2017

Assing, Volker & Schülke, Michael, 2017, On the Ischnosoma fauna of Georgia (Coleoptera: Staphylinidae: Tachyporinae), Beiträge Zur Entomologie = Contributions to Entomology (Beitr. Entomol.) 67 (2), pp. 195-206 : 201

publication ID 10.21248/contrib.entomol.67.2.195-206

publication LSID

persistent identifier

taxon LSID

treatment provided by


scientific name

Ischnosoma barbigerum

spec. nov.

Ischnosoma barbigerum spec. nov.

( Figs 11–18 View Figs 11–23 , 37 View Fig , Map 1 View Map 1 )

Type material: Holotype : “N 42°49'02 E 42°01'52 (10), Georgien Svaneti , Jvari ca. 20 km N 600 m, Brachat & Meybohm 25.6.2017 / Holotypus  Ischnosoma barbigerum sp. n. det. V. Assing 2017” (cAss).

Etymology: The specific epithet (Latin, adjective: bearded) alludes to the characteristic clusters of dense setae on the male sternite VIII.

Description: Body length 4.3 mm; length of forebody 2.0 mm; length of antenna 1.3 mm. Elytra with sutural series composed of 5–7 moderately coarse punctures. Based on external characters ( Fig. 11 View Figs 11–23 ) indistinguishable from the geographically close I. acutum .

: sternite VII ( Figs 12 View Figs 11–23 , 33 View Figs 24–35 ) with an extensive cluster of dense pale short setae in postero-median portion and near posterior margin with modified short and stout setae; sternite VIII ( Figs 13–14 View Figs 11–23 ) with moderately concave posterior margin, in postero-median portion with a transverse cluster of very dense long setae not arranged in palisades, anterior to this cluster with dense shorter and paler setae; aedeagus ( Figs 15–18 View Figs 11–23 ) 0.7 mm long, apex of ventral process subapically abruptly narrowed in ventral view and very acute in lateral view; basal internal structures distinctly, apical internal structures weakly sclerotized; parameres regularly tapering apicad and with 10–11 setae each.

Comparative notes: Ischnosoma barbigerum is readily distinguished from the externally similar I. acutum , the only other representative of the I. spelaeum group recorded from Svaneti, by the shape and chaetotaxy of the male sternite VIII and by the completely different shape of the apex of the ventral process of the aedeagus. It differs from I. caucasicum , which it most resembles in the chaetotaxy of the male sternite VIII, by slightly smaller body size, smaller eyes, shorter antennae, a male sternite VII with an extensive postero-median cluster of dense short setae, a male sternite VIII with a narrower posterior cluster of shorter and less dense setae and with less stout long black setae on either side of the posterior median setae, and by a more slender aedeagus with a less broad ventral process (ventral view), with a much more slender and acute apex of the ventral process (lateral view), and with internal structures of different shapes. For illustrations of I. caucasicum see Figs 19–23 View Figs 11–23 .

Distribution and natural history: The type locality is situated to the north of Jvari, Svaneti region, Georgia ( Map 1 View Map 1 ). The holotype was sifted from leaf litter near a stream in a mixed deciduous forest ( Fig. 37 View Fig ) at an altitude of 600 m (MEYBOHM pers. comm.).