Atheta (Microdota) dimorpha, Assing, 2006

Assing, V., 2006, Six new species of micropterous Atheta and Apimela from northern Yunnan, China (Coleoptera: Staphylinidae, Aleocharinae), Linzer biologische Beiträge 38 (2), pp. 1143-1156 : 1143-1156

Atheta (Microdota) dimorpha nov.sp. ( Figs 27-36 , 45-48 )

Holotype Ƌ: China: N-Yunnan [C2005-08], Diqing Tibet. Aut. Pref., Deqin Co., Baima Shan , Eside , pass 12 km SE Deqin, 4085 m / 28°23.86'N, 98°59.04'E, small creek valley, Rhododendron, Salix, leaf litter, moss, dead wood, sifted, 10.VI.2005, leg. M. Schülke [C2005-08] / Holotypus Ƌ Atheta dimorpha sp. n. det. V. Assing 2006 (cAss). Paratypes: 6 exs.: same data as holotype (cSch, cAss) ; 3 exs.: China: N-Yunnan [C2005-06], Diqing Tibet. Aut. Pref., Deqin Co., Baima Shan , pass 25 km SE Deqin, 4225 m, / 28°19.38'N, 99°05.47'E, small creek valley, Rhododendron, Salix, leaf litter, moss, dead wood, sifted, 8.VI.2005, leg. M. Schülke [C2005-06] (cSch, cAss) ; 1 ex.: China: N-Yunnan [C2005-07], Diqing Tibet. Aut. Pref., Deqin Co., Meili Xue Shan , E-side, 12 km SW Deqin, 2890 m, 28°25.30'N, 98°48.47'E / small creek valley, mixed forest with bamboo, leaf litter, moss, dead wood, sifted, 9.VI.2005, leg. M. Schülke [C2005-07] (cSch) .

D e s c r i p t i o n: 2.1-2.6 mm. Habitus as in Fig. 27 . Coloration: head and pronotum brown to blackish brown, with the head usually slightly darker than pronotum; elytra brown; abdomen blackish brown, with the apex (posterior margin of segment VII, segments VIII-X) distinctly paler, yellowish; legs yellowish brown; antennae dark brown, with the basal 3-4 antennomeres yellowish to yellowish brown.

♀: head not depressed; pronotum with weaker microsculpture and with very fine puncturation ( Fig. 29 ); posterior margin of tergite VII more weakly concave; tergite VIII with almost truncate posterior margin ( Fig. 47 ); sternite VIII slightly longer than tergite VIII, its posterior margin in the middle weakly concave and with long modified marginal setae ( Fig. 48 ); spermatheca as in Fig. 36 .

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E t y m o l o g y: The name (adj.) refers to the pronounced sexual dimorphism, especially of the pronotum.

C o m p a r a t i v e n o t e s: The species is readily distinguished from all other Chinese representatives by the remarkably small (in relation to head) and weakly trans-

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verse pronotum, by the conspicuous puncturation and microsculpture of the male pronotum, as well as by the primary sexual characters.

D i s t r i b u t i o n a n d b i o n o m i c s: ThelocalitiesaresituatedintheBaima Shan and the Meili Xue Shan in Deqin County, northern Yunnan. The specimens were sifted from the forest floor in mixed forests at altitudes of 2890-4225 m.

Figures

Figs 27-36: Atheta dimorpha: (27) Ƌ habitus; (28) Ƌ forebody; (29) ♀ forebody; (30) head in lateral view; (31) antenna; (32-33) median lobe of aedeagus in lateral view; (34) ventral process of median lobe of aedeagus in ventral view; (35) apical lobe of paramere; (36) spermatheca. Scale bars: 27: 1.0 mm; 28-29: 0.5 mm; 30-31: 0.2 mm; 32-36: 0.1 mm.

Figs 37-48: Atheta detruncata (37-44) and A. dimorpha (45-48): (37) ♀ habitus; (38) ♀ forebody; (39) head in lateral view; (40) antenna; (41, 47) ♀ tergite VIII; (42, 48) ♀ sternite VIII; (43) posterior margin of ♀ sternite VIII; (44) spermatheca; (45) Ƌ tergite VIII; (46) Ƌ sternite VIII. Scale bars: 37: 1.0 mm; 38: 0.5 mm; 39-42, 45-48: 0.2 mm; 43-44: 0.1 mm.