Cousya dimorpha, Assing, 2006

Assing, V., 2006, New species and records of Staphylinidae from Greece, with two new synonymies (Insecta: Coleoptera), Linzer biologische Beiträge 38 (1), pp. 333-379 : 338-339

Cousya dimorpha sp.n. ( Figs 10-21 )

Holotype 3: GR. [1] Flórina , 20 km SSW Flórina, Oros Vitsi, N-slope, 1850-1900 m, 40°38'32N, 21°22'46E, 22.V.2005, V. Assing / Holotypus 3 Cousya dimorpha sp. n. det. V. Assing 2005 (cAss). Paratypes: 733, 10♀♀: same data as holotype ( OÖLL, cAss) ; 433, 4♀♀: same data, but leg. P. Wunderle (cWun) .

D e s c r i p t i o n: Very small species, 1.9-2.4 mm (abdomen fully extended). Coloration: forebody uniformly dark brown to blackish; abdomen blackish with the apex slightly paler; legs brown; antennae dark brown, with the basal two antennomeres often slightly paler. Habitus as in Figs 10-11 .

Head approximately as wide as long; eyes moderately large and protruding from lateral outline of head, slightly shorter than postocular region in dorsal view; microsculpure distinct; puncturation very fine and sparse, barely noticeable. Mouthparts as in Fig. 12 . Antenna with antennomeres I and II of subequal length and about twice as long as wide; III much shorter than II and only slightly longer than wide; IV-X of increasing width and increasingly transverse; IV almost 1.5 times as wide as long; X approximately twice as wide as long; XI about 1.5 times as long as wide and slightly longer than the combined length of IX and X.

Pronotum transverse, approximately 1.25 times as wide as long and 1.25 times as wide as head; maximal width approximately in the middle; posterior angles weakly marked; microsculpture and puncturation similar to those of head; pubescence along midline directed posteriad.

Elytra with microsculpture and puncturation more pronounced than those of head and pronotum, surface matt. Width and length of elytra polymorphic. Macropterous specimens ( Fig. 10 ): elytra 1.3-1.4 times as wide and at suture approximately 1.1 times as long as pronotum; hind wings fully developed. Brachypterous specimens ( Fig. 11 ): elytra about 1.2-1.3 times as wide and at suture 1.0-1.1 times as long as pronotum. Hind wing development dimorphic, either fully developed or of reduced length and only slightly longer than elytra.

Abdomen subparallel, in macropterous specimens distinctly (0.8-0.9 x) narrower than elytra, in brachypterous specimens approximately as wide as elytra; tergites III-V with shallow anterior transverse impression; tergite VI without such impression; microsculpture distinct; puncturation fine and sparse; posterior margin of tergite VII with palisade fringe in both morphs; tergite VIII without appreciable sexual dimorphism, its posterior margin weakly convex in both sexes.

3: posterior margin of sternite VIII strongly convex and with long thin marginal setae, especially in the middle ( Fig. 13 ); median lobe of aedeagus and apical lobe of paramere as in Figs 14-17 .

♀: posterior margin of sternite VIII broadly convex, sometimes with shallow concavity in the middle, and with row of moderately stout modified marginal setae ( Fig. 18 ); spermatheca as in Figs 19-21.

E t y m o l o g y: The name (adjective) refers to the dimorphism of the wings.

C o m p a r a t i v e n o t e s a n d s y s t e m a t i c s: Cousya dimorpha is readily distinguished from its Western Palaearctic congeners by its small size, the distinctly transverse pronotum, the wing dimorphism, the relatively short antennae and maxillary palpi, as well as by the morphology of the genitalia. In body shape, as well as in the morphology of the mouthparts, the antennae, and the genitalia, C. dimorpha resembles species of the genus Zoosetha MULSANT & REY , from which it is distinguished by the much finer puncturation of head and pronotum. However, the character constellation of this species raises the question if Cousya MULSANT & REY and Zoosetha should really be considered distinct genera.

D i s t r i b u t i o n a n d b i o n o m i c s: The species is known only from the peak of the Oros Vitsi, a mountain inhabited by several species with restricted distributions or even local endemics: Pareudectus vitsiensis ASSING & WUNDERLE , an undescribed species of Coryphiodes BERNHAUER , Lathrobium vitsiense , Quedius bernhaueri , Geostiba torisuturalis , and an undescribed species of Tectusa BERNHAUER. The fact that C. dimorpha was not found on any of the neighbouring mountains suggests that the species may have a restricted distribution, too. The types were collected by sifting grass roots and moss on a north slope at an altitude of approximately 1900 m. Seven type specimens (13, 6♀♀) are macropterous, 22 (1433, 8♀♀) are brachypterous.

Figures

Figs 10-21: Cousya dimorpha sp.n. (10) forebody of macropterous specimen; (11) forebody of brachypterous specimen; (12) mouthparts; (13) 3 sternite VIII; (14-16) median lobe of aedeagus of three 33 in lateral and in ventral view; (17) apical lobe of paramere; (18) ♀ sternite VIII; (19-21) spermathecae of three ♀♀. Scale bars: 10-11: 0.5 mm; 12-21: 0.1 mm.