Leptusa (Neopisalia) migrituber, Assing, 2017

Assing, Volker, 2017, On the Leptusa fauna of the Caucasus region (Coleoptera: Staphylinidae: Aleocharinae), Linzer biologische Beiträge 49 (2), pp. 1049-1074 : 1067-1068

Leptusa (Neopisalia) migrituber nov.sp. ( Figs 9-13 , 17-20 , Map 7 )

T y p e m a t e r i a l: Holotype 3: "N 42°54'41 E 43°00'34 (20), Georgien Svaneti , Ushguli Nordhang 2190 m, Brachat & Meybohm 30.6.2017 / Holotypus 3 Leptusa migrituber sp. n. det. V. Assing 2017" (cAss) . Paratypes: 1533, 11 ♀♀: same data as holotype (cAss, MNB) ; 533, 2 ♀♀: "N 42°56'22 E 43°02'22 (21) Georgien Svaneti , Ushguli - Shkara 2200 m, Brachat & Meybohm 30.6.201 [recte 2017]" (cAss) .

E t y m o l o g y: The specific epithet is a noun in apposition composed of the Latin adjective migrus (minute) and tthe Latin noun tuber (tubercle). It alludes to the minute tubercle on the male tergite VII.

D e s c r i p t i o n: Body length 2.2-2.9 mm; length of forebody 1.0- 1.2 mm. Coloration: body reddish-brown, with the preapical abdominal segments more or less distinctly infuscate; legs yellowish-red; antennae reddish.

Head ( Fig. 9 ) of orbicular shape; punctation very fine and moderately dense, barely noticeable in the pronounced microreticulation. Eyes small, composed of less than 20 ommatidia with pigmentation, and approximately one-fourth as long as postocular region in dorsal view. Antenna relatively long, distinctly incrassate apically; antennomere IV weakly transverse; antennomeres V-X of increasing width and increasingly transverse; antennomere X approximately twice as broad as long.

Pronotum ( Fig. 9 ) distinctly transverse, 1.25-1.30 times as broad as long and usually 1.25-1.30 times as broad as head; maximal width approximately in the middle; posterior angles obtusely marked; punctation rather dense and fine, but more distinct than that of head; interstices with pronounced microsculpture.

Elytra ( Fig. 9 ) moderately short, approximately 0.8 times as long as pronotum; punctation more distinct than that of head and pronotum; interstices with distinct microsculpture. Hind wings completely reduced.

Abdomen broader than elytra; punctation fine and moderately dense, sparser on posterior than on anterior tergites; interstices with distinct microsculpture composed of transverse meshes; posterior margin of tergite VII with narrow rudiment of a palisade fringe; posterior margin of tergite VIII concave in the middle; tergites VII and VIII with sexual dimorphism.

3: tergite VII with or without minute median tubercle posteriorly ( Fig. 10 ); posterior margin of tergite VIII ( Fig. 17 ) with distinct median concavity, margin of this concavity with setiferous tubercles; posterior margin of sternite VII broadly concave; sternite VIII ( Fig. 18 ) with posterior margin angularly produced in the middle; median lobe of aedeagus ( Figs 11-12 ) 0.41-0.45 mm long and of distinctive shape; paramere ( Fig. 13 ) longer than median lobe, apical lobe moderately long and slender.

♀: posterior margin of tergite VIII ( Fig. 19 ) with median concavity less pronounced than in male, margin of this concavity without tubercles; posterior margin of sternite VIII ( Fig. 20 ) weakly, obtusely produced in the middle; spermatheca not distinctive, similar to that of L. svanetica .

C o m p a r a t i v e n o t e s: Among micropterous Neopisalia species, L. migrituber is characterized particularly by the posterior concavity of tergite VIII, by the modifications of the male tergite VII and the male sternite VII, as well as by the morphology of the aedeagus. It is additionally distinguished from the geographically close L. svanetica by larger body size, longer elytra with distinct microsculpture, larger eyes with more ommatidia, the shape of the pronotum ( L. svanetica : pronotum less transverse, more convex in cross-section; maximal width close to anterior angles), and by distinctly denser punctation of the abdomen. The new species differs from L. xanthopyga , which it somewhat resembles in the shape of the aedeagus, by much shorter elytra, its coloration ( L. xanthopyga : body bicolored; pronotum reddish, strongly contrasting with the blackish head and elytra), by the shapes of tergite VIII and sternite VII ( L. xanthopyga : posterior margins without distinct concavity), and by the shape of the median lobe of the aedeagus and its internal structures. According to the original description of L. khnzoriani PACE, 1982 (type locality: Glola in the east of Racha, Georgia, close to the border with Ossetia), this species has an aedeagus of similar shape as that of L. migrituber , but is distinguished by reddish-yellow coloration, elytra with an elevated suture and a large impression on either side of the suture, oblong median tubercles on the male tergites VII and VIII, and a much smaller aedeagus (according to the illustrations approximately 0.32-0.33 mm) ( PACE 1982). Moreover, according to an illustration provided by PACE (1989), the distal cuticular invagination of the spermatheca is very small and shallow in L. khnzoriani .

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: Thespecimenswerecollected in two localities in Ushguli mountain, Svaneti region, Georgia ( Map 7 ). They were sifted from leaf litter in a forest composed of dominant birch, aspen, rowan, and rhododendron, and beneath birch trees near a stream in a meadow (MEYBOHM pers. comm.) at altitudes of 2190 and 2200 m, respectively.

Figures

Map 7: Distributions of species of the subgenus Neopisalia in the Caucasus region: L. gibbera (black circles), L. subnivalis (white circles), L. migrituber (white diamonds), L. svanetica (black diamond), L. substricta (white star), L. triangulata (black star), and L. sica (black triangles).

Figs 9-16: Leptusa migrituber nov.sp. (9-13) and L. triangulata nov.sp. (14-16): (9, 14) forebody; (10) male tergites VI-VII; (11-12, 15) median lobe of aedeagus in lateral view; (13, 16) paramere. Scale bars: 9-10, 14: 0.5 mm; 11-13, 15-16: 0.2 mm.

Figs 17-27: Leptusa migrituber nov.sp. (17-20), L. triangulata nov.sp. (21-23), and L. longalata nov.sp. (24-27): (17) male tergite VIII; (18) male sternite VIII; (19, 21) female tergite VIII; (20, 22) female sternite VIII; (23) spermatheca; (24) forebody; (25-26) median lobe of aedeagus in lateral and in ventral view; (27) paramere. Scale bars: 17-22, 24: 0.2 mm; 23, 25-27: 0.1 mm.