Leptusa curvata, Assing, 2006

Assing, V., 2006, Six new species and additional records of Leptusa from northern Yunnan, China (Coleoptera: Staphylinidae, Aleocharinae), Linzer biologische Beiträge 38 (2), pp. 1157-1174 : 1157-1174

Leptusa curvata nov.sp. (Figs 58-67)

Holotype 3: China: N-Yunnan [C2005-01], Diqing Tibet. Aut. Pref., Zhongdian Co., Bitai Hai lake area, 29 km ESE Zhongdian / 27°43.65'N, 99°58.97'E, 3540 m, creek valley, devast. mixed forest, litter, moss, dead wood, 1.VI.2005, leg. M. Schülke [C2005-01] / Holotypus 3 Leptusa curvata sp. n. det. V. Assing 2006 (cAss). Paratypes: 1♀: China: N-Yunnan [C03-13], Zhongdian Co., 36 km ESE Zhongdian, overgrown rock hillside with old mixed forest, bamboo, dead wood, mushrooms, 27°40.9'N, 100°01.5'E, 3500-3550 m, 23.VIII.2003, leg. M. Schülke (cSch) ; 1♀: China (N-Yunnan), Zhongdian Co., 36 km ESE Zhongdian, 3500-3550 m, 27°40.9'N, 100°01.5'E (overgrown rock hillside with old mixed forest, bamboo, dead wood, leaf litter) 23.-24.VIII.2003, Wrase [13] (cSch) .

D e s c r i p t i o n: 2.1-2.4 mm. Habitus as in Fig. 58. Coloration: head reddish brown to dark brown; pronotum and elytra paler than head, rufous to reddish brown; abdomen blackish brown to black, with the anterior 2-3 segments and the apex slightly paler; legs and antennae reddish.

Head slightly wider than long; integument with distinct microreticulation and subdued shine; puncturation relatively sparse and very fine, barely noticeable; eyes moderately large, weakly protruding from lateral outline of head, approximately as long as postocular region in dorsal view (Fig. 59). Antenna with antennomere III distinctly shorter than II, IV subquadrate, V weakly transverse, VI-X of increasing width and increasingly transverse, X approximately twice as wide as long (Fig. 60). Penultimate joint of maxillary palpus approximately 2.5 times as long as wide.

Pronotum moderately convex in cross-section and strongly transverse, approximately 1.3 times as wide as head and almost 1.4 times as wide as long, maximal width in anterior half (Fig. 59); posterior angles obtuse, weakly marked; puncturation very fine and ill-defined, barely noticeable; microsculpture similar to that of head.

Elytra approximately as wide and at suture as long as pronotum; near posterior angles distinctly sinuate; puncturation moderately coarse and shallow, much more pronounced than that of head and pronotum; microsculpture shallow, but distinct (Fig. 59). Hind wings present, but apparently of reduced length.

Abdomen as wide as or slightly wider than elytra, maximal width at segment V; puncturation very fine and relatively sparse, especially on posterior tergites; microsculpture present, but rather shallow; tergite VII without sexual dimorphism, at posterior margin with palisade fringe; sternite VII without sexual dimorphism.

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Figs 58-67: Leptusa curvata : (58) habitus; (59) forebody; (60) antenna; (61) 3 tergite VIII; (62) 3 sternite VIII; (63) ♀ tergite VIII; (64) ♀ sternite VIII; (65) median lobe of aedeagus in lateral view; (66) apical lobe of paramere; (67) spermatheca. Scale bars: 58: 1.0 mm; 59: 0.5 mm; 60-64: 0.2 mm; 65-67: 0.1 mm.

3: posterior margin of tergite VIII almost truncate (Fig. 61); posterior margin of sternite VIII obtusely angled in the middle (Fig. 62); median lobe of aedeagus of highly distinctive morphology (Fig. 65), ventral process strongly curved in lateral view; apical lobe of paramere slender and with rather short setae (Fig. 66).

♀: posterior margin of tergite VIII of similar shape as in 3 (Fig. 63); posterior margin of sternite VIII distinctly convex (Fig. 64); spermatheca as in Fig. 67.

E t y m o l o g y: The name (Lat., adj.) alludes to the strongly curved ventral process of the aedeagus.

C o m p a r a t i v e n o t e s a n d s u b g e n e r i c a f f i l i a t i o n s:Based on external characters and especially the male primary and secondary sexual characters, the phylogenetic relations of this species to any of the described subgenera are uncertain. As was the practice with several other previously described species of doubtful

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subgeneric affiliations, a description of a new subgenus to accommodate this and the following species is here refrained from. At present, too little is known about the phylogenetics of Eastern Palaearctic Leptusa .

The new species is distinguished from its Chinese congeners particularly by the conspicuous morphology of the aedeagus, as well as by the combination of small size, compact body shape, a strongly transverse pronotum, and the very fine puncturation of the head and pronotum. For characters separating it from the extremely similar L. recta see the description in the following section.

Figs 68-73: Leptusa recta : (68) habitus; (69) forebody; (70) antenna; (71) 3 tergite VIII; (72) 3 sternite VIII; (73) median lobe of aedeagus in lateral view. Scale bars: 68: 1.0 mm; 69: 0.5 mm; 70- 72: 0.2 mm; 73: 0.1 mm.

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 localities are situated in the mountain range to the east-southeast of Zhongdian, northern Yunnan. The specimens were sifted from the forest floor in mixed forests at altitudes of 3500-3550 m.