Leptusa (Yunnaleptusa) hamulata, Assing, 2010

Assing, V., 2010, Three new species of Leptusa from Yunnan, with a catalogue of the Leptusa species recorded from China and Taiwan (Coleoptera: Staphylinidae: Aleocharinae), Linzer biologische Beiträge 42 (2), pp. 1155-1167 : 1158-1160

Leptusa (Yunnaleptusa) hamulata nov.sp. ( Figs 10-14 )

T y p e m a t e r i a l e x a m i n e d Holotype [slightly teneral]: " China (Yunnan), Nujiang Lisu Pref., Gaoligong Shan E pass 20 km NW Liuku , 3000 m (creek valley with devast. prim. for., ferns, litter/moss sift.), 25°58'49''N, 98°41'48''E, 3.IX.2009, D. W. Wrase [25] / Holotypus Leptusa hamulata sp. n. det. V. Assing 2010" (cAss).

D e s c r i p t i o n: Small species, 2.4 mm. Habitus as in Fig. 10 . Coloration (note that the holotype is slightly teneral): head dark-brown; pronotum and elytra pale-brown; abdomen pale-brown, with segment VI somewhat infuscate; legs dark-yellowish; antennae reddish, with antennomere XI dark-yellowish.

Head ( Fig. 11 ) weakly transverse; punctation moderately dense, fine, and shallow; interstices without distinct microsculpture. Eyes moderately small, weakly projecting from lateral contours of head, approximately as long as postocular portion in dorsal view. Antenna moderately incrassate apically; antennomeres IV-V approximately as long as wide, VI very weakly transverse; VII-X of gradually increasing width and increasingly transverse; X less than twice as wide as long.

Pronotum ( Fig. 11 ) relatively weakly convex in cross-section, 1.32 times as wide as long and 1.38 times as wide as head, maximal width approximately in the middle; lateral margins evenly convex in dorsal view; posterior angles weakly marked; punctation very dense, shallow, and ill-defined; surface only with subdued shine.

Elytra slightly broader than, and approximately as long as pronotum ( Fig. 11 ); posterior margin near external angles strongly sinuate; punctation much coarser than that of head and pronotum. Hind wings present.

Abdomen subparallel, slightly narrower than elytra, widest at segments V/VI; punctation fine, sparser on posterior than on anterior tergites; microsculpture very shallow; tergite VII without sexual dimorphism; posterior margin of tergite VII with palisade fringe.

: sternite VII unmodified; tergite VIII without median tubercle, posterior margin concave in the middle ( Fig. 12 ); sternite VIII distinctly longer than tergite VIII, posteriorly obtusely produced in the middle ( Fig. 13 ); median lobe of aedeagus ( Fig. 14 ) 0.34 mm

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long, strongly arched in lateral view and with long apical portion; internal structures of distinctive shape.

E t y m o l o g y: The specific epithet is an adjective derived from the Latin noun hamulus (small hook) and refers to the shape of the apical internal structure of the aedeagus.

C o m p a r a t i v e n o t e s: Based on the male primary and secondary sexual characters, L. hamulata probably belongs to Yunnaleptusa . The shape of the median lobe of the aedeagus differs somewhat from that of the other species of the subgenus, but the internal structures are of rather similar general shape and arrangement. The new species is readily distinguished from all other representatives of Yunnaleptusa by the conspicuous shape of the aedeagus (long apical portion; shape of the internal structures) and by the slender antennomere V. In addition, it is easily separated from L. parvibulbata and L. zhemomontis by the much longer elytra, the presence of hind wings, the more pro-

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nounced palisade fringe at the posterior margin of the abdominal tergite VIII, as well as by the relatively smaller (in relation to head and elytra), less convex, and less shiny pronotum.

D i s t r i b u t i o n a n d b i o n o m i c s: Leptusa hamulata is known only from the type locality in the Gaoligong Shan, western Yunnan province, close to the border with Myanmar. The slightly teneral holotype was sifted from litter and moss in a degraded primary forest at an altitude of 3000 m, together with a specimen of L. cultellata and a female of a probably undescribed species.

Figures

Figs 10-14: Leptusa hamulata nov.sp. (holotype): (10) habitus; (11) forebody; (12) male tergite VIII; (13) male sternite VIII; (14) median lobe of aedeagus in lateral view. Scale bars: 10: 1.0 mm; 11: 0.5 mm; 12-14: 0.1 mm.