Leptusa (Yunnaleptusa), Assing, 2008

Assing, V., 2008, Seven new species and additional records of Palaearctic Leptusa, primarily from Yunnan, China (Coleoptera: Staphylinidae: Aleocharinae), Linzer biologische Beiträge 40 (1), pp. 251-273 : 256-257

Yunnaleptusa nov.subgen.

Type species, here designated: Leptusa curvata ASSING 2006

D e s c r i p t i o n: Small species (ca. 1.8-2.5 mm). Head, pronotum, and abdomen with fine puncturation. Antennae of moderate length and with distinctly transverse preapical antennomeres. Pronotum distinctly transverse and much wider than head; posterior angles weakly marked. Elytra at suture of similar length as pronotum or only slightly shorter; humeral angles marked. Tarsi relatively short; metatarsomere I only slightly longer than II. Abdomen not distinctly parallel, widest at segment V; tergites III- V with moderately deep anterior impressions, tergite VI without such impression; tergites VII-VIII without distinct sexual dimorphism.

6: posterior margin of sternite VIII moderately projecting posteriad in the middle; median lobe of aedeagus strongly arched in lateral view; crista proximalis reduced; crista apicalis long and narrow; internal sac with relatively short straight flagellum, with weakly sclerotised apical structures, and without sclerotised basal structures; apical lobe of paramere relatively short, of conical shape, and with two long and two short setae.

♀: sternite VIII with convex posterior margin ; spermatheca with short duct; spermathecal capsule with long cuticular intrusion (see figure 67 in ASSING 2006).

E t y m o l o g y: The name is composed of Yunna (from Yunnan) and the generic name; the gender is feminine.

R e m a r k s: Since the Leptusa fauna of the Eastern Palaearctic region is rather poorly known, a description of subgenera at this stage seems generally problematic. For this reason, several species described in earlier papers ( ASSING 2002, 2004a, 2004b, 2006) which could not attributed to any of the existing subgenera were regarded as species of doubtful subgeneric assignment. An exception is here made for L. curvata ASSING , L. recta ASSING , and the two new species described below. They share numerous similarities, especially a synapomorphically derived morphology of the aedeagus, so that they are doubtlessly monophyletic. At the same time, they differ from other Eastern Palaearctic taxa so significantly that it seems justifiable to assign them to a distinct subgenus.

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 known distribution of the subgenus is confined to Yunnan province, China. The species are apparently inhabitants of the forest floor, as is suggested by the fact that they were sifted from the litter of various types of forest (coniferous, deciduous, and mixed forest). The altitudes range from 2730 to 3550 m.

Key to spec ies:

1 Antenna bicoloured, antennomeres I-III and XI pale reddish, antennomeres IV-X dark brown. Head and pronotum glossy, with extremely shallow, barely noticeable microsculpture. 6: sternite VIII posteriorly more strongly produced ( Fig. 16 ); median lobe shaped as in Figs 17-18 . Western Yunnan province: Gaoligong Shan ( Map 1 ) ............ .............................................................................................................. L. cultellata nov.sp.

- Antenna uniformly reddish or yellowish. Head and pronotum with pronounced microsculpture. 6: sternite VIII less strongly produced posteriorly; median lobe of aedeagus of different morphology. Northern and northwestern Yunnan province ..............2

2 Elytra at suture distinctly (ca. 0.7 ✕) shorter than pronotum. Small species, body length approximately 1.8 mm. 6: median lobe of aedeagus with basal part of ventral process curved in lateral view and with smaller proximal bulbus ( Fig. 24 ). Northwestern Yunnan province: Gaoligong Shan ( Map 1 ).................................... L. parvibulbata nov.sp.

- Elytra at suture approximately as long as pronotum. Larger species, body length>2.0 mm. 6: median lobe of aedeagus with basal part of ventral process either straight in lateral view or with larger proximal bulbus. Northern Yunnan ( Map 1 ).........................3

3 6: median lobe of aedeagus with basal part of ventral process curved in lateral view, subapically not distinctly angled (see figure 65 in ASSING 2006) ........... L. curvata ASSING

- 6: median lobe of aedeagus with basal part of ventral process straight in lateral view, subapically distinctly angled (see figure 73 in ASSING 2006) ..................... L. recta ASSING

Figures

Map 1: Distributions of the species of the subgenus Yunnaleptusa in China: L. curvata ASSING (filled circles), L. recta ASSING (open circle), L. parvibulbata nov.sp. (filled square), and L. cultellata nov.sp. (open square).

Figs 11-20: Leptusa cultellata nov.sp.: (11) habitus; (12) forebody; (13) antenna; (14) abdominal segments III-VII; (15) male tergite VIII; (16) male sternite VIII; (17-18) median lobe of aedeagus in lateral and in ventral view; (19) paramere; (20) apical lobe of paramere. Scale bars: 11: 0.5 mm; 12-16: 0.2 mm; 17-19: 0.1 mm; 20: 0.05 mm.

Figs 21-24: Leptusa parvibulbata nov.sp.: (21) habitus; (22) male tergite VIII; (23) male sternite VIII; (24) median lobe of aedeagus in lateral view. Scale bars: 21: 0.5 mm; 22-23: 0.2 mm; 24: 0.1 mm.