Atheta (Atheta) hamulata, Assing & Vogel, 2017

Assing, Volker & Vogel, Jürgen, 2017, On some Athetini from Armenia and adjacent regions (Coleoptera: Staphylinidae: Aleocharinae), Linzer biologische Beiträge 49 (1), pp. 341-368 : 345-347

Atheta (Atheta) hamulata nov.sp. ( Figs 17-27 )

T y p e m a t e r i a l: Holotype 3: " ARMENIA [9] - S Martuni, Sulema Pass, 39°57'58''N, 45°14'13''E, 2340 m, near stream, 29.VI.2016, V. Assing / Holotypus 3 Atheta hamulata sp. n. det. V. Assing 2017" (cAss). Paratypes: 3333, 4♀♀ [partly teneral]: same data as holotype (cAss, cVog, MNB); 633: " ARMENIA [9a] - S Martuni, Sulema Pass, 39°57'58''N, 45°14'13''E, 2340 m, rocky slope, 29.VI.2016, V. Assing" (cAss, MNB); 1♀: " ARMENIA [20a] - 35 km NW Sisian, 39°41'01''N, 45°46'46''E, 2080 m, bushes nr. stream sifted, 3.VII.2016, V. Assing " (cAss); 13: " ARMENIA [39] - 25 km SW Kapan, 39°04'01''N, 46°16'10''E, 2150 m, near stream, sifted, 10.VII.2016, V. Assing " (cAss); 13: " ARMENIA [AR16-33] WSW Kapan, S Meghri Pass, 39°05'56''N, 46°09'47''E, 2090 m, stream valley, litter near stream sifted, 8.VII.2016, leg. M. Schülke " ( MNB) .

E t y m o l o g y: The specific epithet is an adjective derived from the Latin noun hamulum (small hook) and alludes to both the shape of the distal portion of the spermatheca and the shapes of the internal structures of the aedeagus in lateral view.

D e s c r i p t i o n: Body length 3.2-4.5 mm; length of forebody 1.7-2.1 mm. Coloration: body black; legs with blackish femora, pale-brown tibiae, and dark-yellowish tarsi; antennae black; maxillary palpi black with pale-brown palpomere IV.

Head ( Fig. 17 ) 1.05-1.09 times as broad as long; punctation fine, moderately dense in lateral portions and sparse in median portion of dorsal surface; microsculpture pronounced and composed of isodiametric meshes. Eyes slightly longer than distance from posterior margin of eye to posterior constriction of head. Antenna ( Fig. 18 ) 1.3-1.4 mm long; antennomeres IV-X weakly transverse, X less than 1.5 times as broad as long, and XI nearly as long as the combined length of VIII-X.

Pronotum ( Fig. 17 ) 1.23-1.30 times as broad as long and 1.20-1.25 times as broad as head, broadest in anterior half; punctation very fine and moderately dense; microsculpture similar to that of head, composed of isodiametric meshes; pubescence directed anteriad along midline and predominantly diagonally postero-laterad and transversely laterad in lateral portions (type I).

Elytra ( Fig. 17 ) 1.03-1.10 times as long as pronotum; punctation very dense and fine, more distinct than that of head and pronotum; interstices with isodiametric microreticulation. Hind wings fully developed.

Abdomen narrower than elytra; tergites III-V with, tergite VI without anterior transverse impressions; punctation rather dense and distinct on tergite III, gradually becoming sparser towards posterior tergites, sparse and very fine on tergites VII-VIII; microsculpture shallow, but distinct, composed of transverse meshes ( Fig. 19 ); tergite VIII subject to moderate sexual dimorphism.

3: posterior margin of tergite VIII truncate and not distinctly crenulate in the middle, laterally angled, but without tooth ( Fig. 20 ); sternite VIII ( Fig. 21 ) longer than tergite VIII and with strongly convex posterior margin; median lobe of aedeagus approximately 0.5 mm long and shaped as in Figs 22-24 .

♀: posterior margin of tergite VIII ( Fig. 25 ) weakly concave in the middle, laterally not angled; sternite VIII ( Fig. 26 ) distinctly transverse and slightly longer than tergite VIII, posterior margin without distinct concavity in the middle; distal portion of spermatheca simply curved, proximally with a hook-shaped process; proximal portion of spermatheca with relatively few coils ( Fig. 27 ).

C o m p a r a t i v e n o t e s: Amongthespeciesof Atheta sensu strictu, A. hamulata is characterized by relatively small body size, a uniformly black body, relatively massive antennae with a rather long antennomere XI, and by the primary and secondary sexual characters, particularly the shape and internal structures of the median lobe of the aedeagus and the shape of the spermatheca. It is distinguished from the dark-coloured, relatively small, and widespread A. ebenina MULSANT & REY, 1873 by even darker coloration (particularly of the elytra and the legs), even smaller size, a longer and more slender antennomere XI, finer punctation of the forebody, the shape of the male tergite VIII ( A. ebenina : posterior margin broadly, distinctly concave and crenulate), the shape of the aedeagus, and the shape of the spermatheca.

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 known distribution is confined to few localities in South Armenia. The specimens were sifted from debris and litter in moist habitats, mostly near small streams, at altitudes of 2080-2340 m. For a photo of the type locality see ASSING (2016c: figure 8). Some of the specimens from the type locality are teneral. The sex ratio is strongly biased in favour of males (5.7: 1).

Figures

Figs 17-27: Atheta hamulata: (17) forebody; (18) antenna; (19) median portion of tergite VII; (20) male tergite VIII; (21) male sternite VIII; (22-23) median lobe of aedeagus in lateral and in ventral view; (24) internal structures of aedeagus in ventral view; (25) female tergite VIII; (26) female sternite VIII; (27) spermatheca. Scale bars: 17-18: 0.5 mm; 20-27: 0.2 mm; 19: 0.1 mm.