Ischnosoma parallelum, 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 : 787-788

Ischnosoma parallelum nov.sp. ( Figs 5-6 , 35-37, 43-45 , Map 3 )

T y p e m a t e r i a l: Holotype ♂: " GEORGIA [36a] - Adjara, SE Batumi, Machakhela Nat. Park , 41°30'34''N, 41°49'04''E, 170 m, 17.VII.2019, V. Assing / Holotypus ♂ Ischnosoma parallelum sp. n. det. V. Assing 2019" (cAss) . Paratypes: 2♂♂: same data as holotype (cAss) ; 1♀: " GEORGIA [33] - Adjara, SE Batumi, Machakhela Nat. Park , 41°28'55''N, 41°51'29''E, 680 m, 16.VII.2019, V. Assing" (cAss) ; 1♂: same data, but "[33a]" (cAss) ; 1♀: " GEORGIA [37] - Adjara, SE Batumi, Machakhela Nat. Park , 41°28'47''N, 41°51'31''E, 700 m, 17.VII.2019, V. Assing" (cAss) .

E t y m o l o g y: The specific epithet (Latin, adjective) alludes to the more or less subparallel apico-lateral lamellae of the median lobe of the aedeagus.

D e s c r i p t i o n: Habitus as in Fig. 5 . Eye rudiments ( Fig. 6 ) minute, approximately as large as antennomere I in cross-section or slightly larger, composed of 0-5 ommatidia, often with additional degenerated rudiments of ommatidia. In size, proportion, coloration, and other external characters practically identical to I. convergens .

♂: shape and chaetotaxy of sternite VII unmodified ( Fig. 43 ); sternite VIII ( Fig. 44 ) with sparse pubescence, posterior margin weakly concave; median lobe of aedeagus ( Figs 35- 37 , 45 ) on average slightly larger than that of I. convergens ; apico-lateral lamellae subparallel, weakly converging apicad at most; pair of apical sclerites longer and more slen- der, median pair of sclerites larger, and basal membranous structure larger than in I. convergens .

C o m p a r a t i v e n o t e s: Ischnosoma parallelum is distinguished from the otherwise practically identical I. convergens only by the morphology of the aedeagus: the orientation of the apico-lateral lamellae, the longer and more slender apical internal structures, the larger median internal structures, and the larger basal internal structure. Based on the available males, these differences are constant.

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: Thetypespecimenswerecollected in three localities in the Machakhela National Park in the extreme west of the Shavsheti range, Adjara region, Southwest Georgia. The highly restricted distribution of I. parallelum is separated from that of I. convergens by the Acharistskali river valley ( Map 3 ).

The specimens were sifted from leaf litter or washed from soil obtained in a deciduous forest margin with rhododendron undergrowth and in stream valleys with deciduous forests (alnut, hazelnut, alder, chestnut) at altitudes of 170-600 m, in two localities together with I. myops .

Figures

Map 3: Distributions of Ischnosoma convergens (black circles) and I. parallelum (white circles).

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 40-46: Ischnosoma convergens (40-42), I. parallelum (43-45), and I. myops (46): (40, 43) male sternite VII; (41, 44, 46) male sternite VIII; (42, 45) apical portion of median lobe of aedeagus in ventral view. Scale bars: 40-41, 43-44, 46: 0.2 mm; 42, 45: 0.1 mm.

Figs 32-39: Ischnosoma convergens (32-34), I. parallelum (35-37), and I. myops (38-39): aedeagus in lateral and in ventral view. Scale bar: 1.0 mm.