Atheta (Dimetrota) bispinosa, 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 : 349-351

Atheta (Dimetrota) bispinosa nov.sp. ( Figs 28-44 )

T y p e m a t e r i a l: Holotype 3: " ARMENIA [4] - N Yerevan, NW Hrazdan, 40°41'40''N, 44°29'16''E, 2500 m, W-slope, sifted, 26.VI.2016, V. Assing / Holotypus 3 Atheta bispinosa sp. n. det. V. Assing 2017" (cAss). Paratypes: 10833, 94♀♀ [partly slightly teneral]: same data as holotype (cAss, cFel, cVog, cWun, MHNG, MNB, NHMW); 122 exs.: same data, but leg. Schülke (MNB); 1♀: " ARMENIA [AR16-01] N Yerevan, W Hrazdan, 2020 m, 40°31'13''N, 44°30'38''E, grassy slope with scattered oak, litter and roots, sifted, 26.VI.2016, leg. M. Schülke" (MNB); 13, 1♀: " ARMENIA [2] - N Yerevan, W Hrazdan, 40°32'02''N, 44°33'16''E, 2130 m, litter sifted, 25.VI.2016, V. Assing" (cAss); 1♀: " ARMENIA [3] - N Yerevan, W Hrazdan, 40°30'28''N, 44°34'12''E, 1870 m, forest, sifted, 25.VI.2016, V. Assing" (cAss); 1233, 10♀♀: " ARMENIA [5] - N Yerevan, NW Hrazdan, 40°40'07''N, 44°28'22''E, 2100 m, W-slope, sifted, 26.VI.2016, V. Assing" (cAss); 11 exs.: same data, but leg. Schülke; 333, 2♀♀: " ARMENIA [6] - N Yerevan, NW Hrazdan, 40°38'07''N, 44°30'05''E, 2010 m, mixed forest, 27.VI.2016, V. Assing" (cAss); 3 exs.: same data, but leg. Schülke (MNB); 733, 9♀♀: " ARMENIA [7] - N Yerevan, NW Hrazdan, 40°38'06''N, 44°27'37''E 2110 m, litter sifted, 28.VI.2016, V. Assing" (cAss); 4 exs.: same data, but leg. Schülke (MNB); 2 exs.: " ARMENIA [AR16-08] N Yerevan, NW Hrazdan, 40°33'45''N, 44°23'41''E, 2000 m, mixed deciduous forest margin, litter sifted, 28.VI.2016, leg. M. Schülke" (MNB); 2♀♀: " ARMENIA [11] - 50 km NW Sisian, Jermuk, 39°50'02''N, 45°40'21''E, 2110 m, oak forest, 30.VI.2016, V. Assing" (cAss); 2 exs.: same data, but leg. Schülke (MNB); 2♀♀: same data, but "[11a]... 3.VII.2016 " (cAss); 833, 6♀♀: same data, but "[11b]... 12.VII.2016 " (cAss, MNB); 1♀: " ARMENIA [12] - 40 km NW Sisian, Vorotan P., 39°42'36''N, 45°40'30''E 1960 m, dry oak forest, 30.VI.2016, V. Assing" (cAss); 1♀: " ARMENIA [16] - 30 km NW Sisian, 39°46'33''N, 45°56'05''E, 2960 m, grassy slope, sifted, 2.VII.2016, V. Assing" (cAss); 233, 1♀: " ARMENIA [23] - WSW Kapan, Meghri Pass, 39°07'00''N, 46°09'38''E, 2520 m, litter & roots, 6.VII.2016, V. Assing" (cAss); 1♀: " ARMENIA [28] - WSW Kapan, S Meghri Pass, 39°06'10''N, 46°10'47''E, 2310 m, oak litter, 6.VII.2016, V. Assing" (cAss); 233: " ARMENIA - Aragazotn, Byurakan env., 40°23'42''N, 44°18'40''E 1930 m, 26.V.2016, leg. A. & J. Müller" (cAss); 333,

1♀: " ARMENIA, above Jermuk , sifting of plant leavings near snow residues, 2400 m, 39.839053N, 45.693496E, 21.V.2015, M. Kocian lgt." (cKoc); 1♀: " ARMENIA, Goris, E slope, deciduous forest, leaf litter sifting, 1700 m, 25.V.2015, 39.516611N, 46.322847E, M. Kocian lgt." (cKoc); 1♀: " ARMENIA, Goris env., above Verishen, sifting, 1880 m, 26.V.2015, 39.558515N, 46.316772E, M. Kocian lgt." (cKoc); 333: "N 41°48'37 E 43°31'04 (4), GEORGIA: Samzche- Dschawach., Timotesubani 1144 m, Brachat & Meybohm, 13.V.2016 " (cAss); 13: "N 42°47'53 E 42°38'01 (17), GEORGIA: Ratscha, Lentekhi 10 km W, 1100 m, Brachat & Meybohm, 20.V.2016 " (cAss) .

E t y m o l o g y: The specific epithet (Latin, adjective) alludes to the pair of long sclerotized spines in the internal sac of the aedeagus.

D e s c r i p t i o n: Body length 3.5-4.6 mm; length of forebody 1.5-2.0 mm. Coloration: body black, with the elytra sometimes partly indistinctly paler blackish-brown; legs with the femora yellowish-brown to brown and the tibiae and tarsi dark-yellowish; antennae blackish; maxillary palpi blackish with palpomere IV yellowish.

Head ( Figs 28-29 ) approximately as long as broad or weakly transverse; punctation fine and moderately dense, barely visible in the pronounced microreticulation. Eyes slightly longer than distance from posterior margin of eye to posterior constriction of head. Antenna ( Fig. 30 ) 1.15-1.40 mm long; antennomeres IV weakly oblong, V-VI approximately as long as broad or weakly transverse, VII-X weakly transverse, X distinctly less than 1.5 times as broad as long, and XI approximately as long as the combined length of IX and X.

Pronotum ( Figs 28 , 39 ) relatively weakly transverse, 1.15-1.20 times as broad as long and approximately 1.25 times as broad as head, broadest in anterior half; punctation dense and fine, though slightly more distinct than that of head; microsculpture pronounced and composed of isodiametric meshes; pubescence directed anteriad along midline and predominantly diagonally postero-laterad and transversely laterad in lateral portions (type I).

Elytra ( Fig. 28 ) approximately as long as pronotum (or nearly so); punctation dense and fine; interstices with isodiametric microreticulation. Hind wings fully developed. Metatarsomere I approximately as long as metatarsomere II; mesotibial seta nearly twice as long as width of mesotibia in the middle.

Abdomen narrower than elytra; tergites III-V with, tergite VI without shallow anterior transverse impressions; punctation rather dense and distinct on tergites III-V, sparser and very fine on tergites VI-VIII; microsculpture distinct, composed predominantly of long transverse meshes ( Fig. 40 ); tergite VIII subject to moderate sexual dimorphism.

3: tergite VIII ( Fig. 41 ) strongly tapering posteriad, posterior margin truncate or weakly concave in the middle, laterally distinctly angled; sternite VIII ( Fig. 42 ) strongly tapering posteriad and with strongly convex posterior margin; median lobe of aedeagus ( Figs 31- 33 ) approximately 0.5 mm long and with short ventral process; internal sac with a pair of long sclerotized spines and other structures of characteristic shapes ( Figs 34-35 ).

♀: tergite VIII ( Fig. 43 ) weakly tapering posteriad, posterior margin truncate or weakly concave in the middle, laterally not angled; posterior margin of sternite VIII with broadly convex posterior margin and a row of modified long and stout marginal setae ( Fig. 44 ); spermatheca ( Figs 36-38 ) with slender distal and proximal portions, maximal extension approximately 0.3 mm.

C o m p a r a t i v e n o t e s: In habitus, coloration, and other characters, A. bispinosa resembles the widespread and common A. putrida (KRAATZ, 1856) , but differs by a relatively larger and less transverse pronotum, on average shorter elytra, less pronounced lateral angles of the posterior margin of the male sternite VIII, a larger median lobe of the aedeagus with a less marked crista apicalis (lateral view), a differently shaped ventral process (lateral view), and internal structures of different shapes, as well as by the more slender and proximally not distinctly dilated spermatheca. For illustrations of the primary sexual characters of A. putrida see BRUNDIN (1954).

C o m m e n t: When making the name Dimetrota available, MULSANT & REY (1873) included two species, Homalota laetipes MULSANT & REY, 1873 (today a junior synonym of Atheta vaga (HEER, 1839)) and H. tristicula MULSANT & REY, 1873 (now a synonym of Atheta cadaverina (BRISOUT DE BARNEVILLE, 1860)) , without designating a type species. BLACKWELDER (1952) subsequently designated Homalota tristicula as the type species. Apparently unaware of this, BRUNDIN (1954) followed the concept of previous authors in his revision of Dimetrota, an interpretation that has been adopted by most subsequent authors, too, and that does not include A. cadaverina and allied species. As a result, the species currently included in Dimetrota (for the Palaearctic species see SCHÜLKE & SMETANA 2015) clearly form a polyphyletic group.

The two new species assigned to Dimetrota in the present paper, A. bispinosa and A. senticollis , belong to Dimetrota sensu BRUNDIN (1954) and are not closely related to A. cadaverina .

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: This species was found in several localities both in North and South Armenia, as well as in two localities in Georgia. The vast majority of specimens (> 320 specimens) was collected in the type locality, a grassy west slope with scattered willow at an altitude of 2500 m ( ASSING 2016b: figure 41), by sifting leaf litter and roots. The remainder was sifted from litter and grass roots in forests, forest margins, bush habitats, and alpine grassland at altitudes of 1100-2960 m. Some of the specimens are more or less distinctly teneral.

Figures

Figs 28-38: Atheta bispinosa: (28) forebody; (29) median dorsal portion of head; (30) antenna; (31- 33) median lobe of aedeagus in lateral and in ventral view; (34-35) internal structures of aedeagus in ventral view; (36-38) spermatheca. Scale bars: 28, 30: 0.5 mm; 29, 31-38: 0.1 mm.

Figs 39-44: Atheta bispinosa: (39) median portion of pronotum; (40) median portion of tergite VII; (41) male tergite VIII; (42) male sternite VIII; (43) female tergite VIII; (44) female sternite VIII. Scale bars: 0.2 mm.