Ischnosoma acre Assing 2019, nov.sp.

Ischnosoma acre nov.sp. (Figs 1, 9-12, 17-19, 26-27, Map 1)

T y p e m a t e r i a l: Holotype ♂: " GEORGIA [44] - Imereti, S Bagdati, 42°00'50''N, 42°48'56''E, 270 m, deciduous forest margin, 21.VII.2019, V. Assing / Holotypus ♂ Ischnosoma acre sp. n. det. V. Assing 2019" (cAss). Paratypes 1♂: " N41°51'37 E42°46'59, Georgien Imeretien (54), Sairme S 1890 m, 19.5.2018, Brachat & Meybohm" (cAss); 1♂: " N42°00'50 E42°48'55, Georgien Imeretien (50), Baghdati 290 m 18.5.2018, Brachat & Meybohm" (cAss).

E t y m o l o g y: The specific epithet (Latin, adjective: acute) alludes to the 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 4.7-5.0 mm; length of forebody 2.1-2.2 mm. Habitus as in Fig. 1. External characters as in I. solodovnikovi SCHÜLKE, 2001 and I. molle ASSING & SCHÜLKE, 2017. Distinguished only by the male primary and secondary sexual characters.

♂: sternite VII (Figs 17, 26-27) with a cluster of moderately dense thin setae in posteromedian portion, posterior margin truncate; sternite VIII (Figs 18-19) with a cluster of moderately dense long and thin setae in postero-median portion, posterior margin shallowly triangularly excised; aedeagus (Figs 9-12) approximately 0.7 mm long; ventral process apically very acute in ventral view; internal structures shaped as in Figs 9-12.

C o m p a r a t i v e n o t e s: Based on the external and the male sexual characters, I. acre is undoubtedly closely allied to I. solodovnikovi from Northeast Turkey (Trabzon, Rize) and I. molle (Southwest Georgia: Adjara: western Meskheti Range). It is distinguished from these species as follows:

from I. solodovnikovi by smaller body size, longer and thin setae near the median portion of the truncate posterior margin of the male sternite VII, a shorter and less slender male sternite VIII with denser pubescence in the postero-median portion, and by a smaller aedeagus (I. solodovnikovi: 0.78-0.90 mm long; n = 6) with a significantly more acute apex of the ventral process (ventral view) and with less strongly sclerotized internal structures of different shapes (for comparison see Figs 15-16, 23-25, 30-31);

from I. molle by longer and less stout pubescence in the postero-median portion of the male sternite VII, a male sternite VIII with a smaller, less deep, and more triangularly shaped posterior margin (broadly concave in I. molle) and with a less distinctly delimited and less extensive cluster of much less dense and longer pubescence in the posteromedian portion, and a slightly smaller aedeagus with an apically more acute ventral process (ventral view) and with sclerotized internal structures of slightly different shapes.

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 specimens were found in two localities in the north slope of the Meskheti Range, Imereti region, Southwest Georgia (Map 1) at altitudes of 270-290 and 1890 m. They were sifted from chestnut leaf litter, from litter near rocks (MEYBOHM pers. comm.), and from leaf litter in a deciduous forest margin.