Atheta specicola, Assing, 2018

Assing, Volker, 2018, A new Atheta species from the West Caucasus and a redescription of A. brevapicalis (Coleoptera: Staphylinidae: Aleocharinae), Linzer biologische Beiträge 50 (1), pp. 67-74 : 70-74

Atheta (" Alaobia ") specicola nov.sp. ( Figs 14-21 )

T y p e m a t e r i a l: Holotype ♂: " RUSSIA, NW Caucasus, (Krasnodarkij Kraj), Chernomorskiy Mts. rng., cave, NE Podgornoye, on bat excrements, 638 m, 44°07'51.4''N, 41°05'54.2''E, 26.V.2014 leg. A. Pütz / Holotypus ♂ Atheta specicola sp. n. det. V. Assing 2016" (cPüt). Paratypes: 30 exs.: same data as holotype (cPüt, cAss).

E t y m o l o g y: The specific epithet is a noun in apposition meaning cave inhabitant (from the Latin noun specus).

D e s c r i p t i o n: Body length 2.7-3.8 mm; length of forebody 1.4-1.8 mm. Coloration: head blackish-brown to black; pronotum dark-brown to blackish-brown; elytra dark-yellowish to yellowish-brown with the scutellar region distinctly and occasionally the postero-lateral portions indistinctly infuscate; abdomen blackish with the apex (posterior portion of segment VII and segments VIII-X) reddish-yellow to palebrown; legs dark-yellowish; antennae blackish, with the basal 2-3 antennomeres reddishyellow.

Head ( Fig. 14 ) transverse, approximately 1.1 times as broad as long, and distinctly wedge-shaped, dilated behind eyes, broadest posteriorly; punctation fine and rather dense; interstices with pronounced microreticulation. Eyes weakly convex, not distinctly projecting from lateral contours of head, slightly shorter than postocular region in dorsal view. Antenna 0.9-1.0 mm long; antennomere IV weakly transverse; antennomeres V-X of increasing width and increasingly transverse, X approximately twice as broad as long.

Pronotum ( Fig. 14 ) 1.20-1.25 times as broad as long and about 1.2 times as broad as head, small in relation to head; pubescence of type II (i.e., directed posteriad along midline and diagonally postero-laterad in lateral portions); punctation fine and rather dense; interstices with pronounced microreticulation.

Elytra ( Fig. 14 ) approximately 0.9 times as long as pronotum; punctation dense and fine, but more distinct than that of head and pronotum; interstices with microreticulation. Hind wings fully developed.

Abdomen narrower than elytra; punctation fine, rather dense on tergites III-VI, sparse on tergites VII-VIII; microsculpture shallow and transverse; posterior margin of tergite VII with palisade fringe.

♂: tergite VIII ( Fig. 15 ) transverse, posterior margin truncate, weakly serrate, and with a prominent tooth on either side; sternite VIII ( Fig. 16 ) transverse, much longer than tergite VIII, posterior margin strongly and convexly produced in the middle; median lobe of aedeagus ( Figs 17-19 ) 0.53-0.54 mm long; ventral process long and of distinctive shape.

♀: tergite VIII transverse, posterior margin smooth and more or less truncate in the middle; sternite VIII ( Fig. 20 ) slightly longer than tergite VIII and with broadly convex posterior margin; spermatheca as in Fig. 21.

C o m p a r a t i v e n o t e s: As can be inferred from the similarly derived morphology of the aedeagus, the similar modifications of the male and female tergites and sternites VIII, as well as from the similar shape of the spermatheca, A. specicola is closely related to A. trinotata (KRAATZ, 1856) and allied species. These species are currently assigned to the - most likely polyphyletic - subgenus Alaobia THOMSON, 1858. There is no unambiguous synapomorphy shared by the species of the A. trinotata group with the type species of Alaobia , A. scapularis (SAHLBERG, 1831). Thus, the subgeneric assignment of A. specicola should be considered doubtful and is indicated in quotation marks above.

Among the species of the A. trinotata group, the sexual characters of A. specicola are most similar to those of the widespread A. trinotata, from which the new species differs both by external (head wedge-shaped and larger in relation to pronotum; eyes distinctly smaller and less prominent; antennae shorter and with more transverse antennomeres IV- X and with yellowish basal antennomeres; elytra shorter) and sexual characters. In A. specicola , the ventral process of the aedeagus is more slender and of slightly different shape. For comparison, the median lobe of the aedeagus of a male of A. trinotata from Germany is illustrated in Fig. 22 . From A. spelaea (ERICHSON, 1939), a widespread caveinhabiting species of the A. trinotata group, with which A. specicola shares not only a similar habitat, but also a similar habitus and a similar shape of the spermatheca, the new species is distinguished by shorter antennae with more transverse preapical antennomeres, a more strongly wedge-shaped head, a smaller pronotum (in relation to head), a truncate posterior margin of the male tergite VIII (concave in A. spelaea), a posteriorly more strongly produced male sternite VIII, and above all the completely different shape of the ventral process of the aedeagus.

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 in the Chernomorskiy mountain range, Krasnodarksiy Kray, in the Northwest Caucasus. The specimens were collected from bat dung in a cave at an altitude of approximately 640 m.

Figures

Figs 13-22: Atheta brevapicalis from Armenia (13), A. specicola (14-21), and A. trinotata from Germany (22): (13, 20) female sternite VIII; (14) forebody; (15) male tergite VIII; (16) male sternite VIII; (17-19, 22) median lobe of aedeagus in lateral and in ventral view; (21) spermatheca. Scale bars: 14: 0.5 mm; 13, 15-22: 0.2 mm.