Tetartopeus bimaculatus (LI, TANG & ZHU 2007)

Assing, V., 2011, On some East Palaearctic Tetartopeus species (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 43 (2), pp. 1179-1197 : 1190-1191

Tetartopeus bimaculatus (LI, TANG & ZHU 2007) ( Figs 39-51 )

Lobrathium bimaculatum LI, TANG & ZHU 2007: 261 f.

Tetartopeus bimaculatus: ASSING (2010b) .

C o m m e n t: The illustrations of the male sexual characters provided in the original description, which is based on a single male holotype from Guizhou, are schematic and unsuitable for an identification of this species. It was only after Liang Tang (Shanghai), one of the authors, kindly sent photographs of the primary and secondary sexual characters of the holotype that an interpretation was possible.

M a t e r i a l e x a m i n e d: Taiwan: 65 exs., Ilan Hsien, Chyr Duan, 1100 m, 11.IV.1990, leg. Smetana (cSme, cAss, cSch) ; 1, Ilan Hsien, Shen-Mi Lake, 24°23'N, 121°44'E, 1110 m, 9.V.1995, leg. Smetana " (cSme). China: 1, Zhejiang, Tianmu Shan , leg. Reitter [" Typus Lathrobium tienmuschanensis O. Scheerpeltz " ( NHMW); 1, China, SW-Hunan, SW Huitong, 7.XI.1993, Guangping env., 400 m, leg. Schillhammer ( NHMW); 7 exs. [2 teneral], SW-Hunan, SW Huitong, Guangping env., 350 m, 4.XI.1993, leg. Schillhammer ( NHMW); 1, Yunnan, Baoshan Pref., Gaoligong Shan, road to Kambaiti pass, 22.5 km NW Tengchong, 25°11'N, 98°20'E, 1930 m, creek bank with vegetation, 29.VIII.2009, leg. Wrase (cAss).

D i a g n o s i s: Body length 5.8-6.8mm;lengthofforebody 3.2-3.7 mm. Coloration: body blackish, postero-external angles of elytra with yellowish to reddish-yellow spot of variable size; middle and hind legs yellowish; forelegs in mature specimens almost always somewhat darker; antennae dark-brown, with the basal 1-2 and the apical 1-3 antennomeres paler reddish.

Elytra polymorphic, approximately as long as pronotum or nearly so, rarely shorter, in specimens from mainland China, and approximately 0.9 times as long as pronotum in material from Taiwan ( Fig. 39 ); punctation dense and usually defined.

: posterior margin of tergite VIII convexly produced in the middle ( Fig. 40 ); posterior margin of sternite VII weakly concave in the middle; sternite VIII without distinct clusters of black setae, posterior margin with pronounced V-shaped incision ( Figs 41-42 ); aedeagus ( Figs 43-45 , 48-51 ) 0.9-1.0 mm long; ventral process usually weakly angled approximately in the midde (lateral view), moderately broad basally and very slender apically in ventral view, apex of ventral process distinctly hooked (lateral view); dorsal plate apically convex (dorsal view); internal sac with large sclerotized spines.

: posterior margin of tergite VIII produced and distinctly angled in the middle ( Fig. 46 ); sternite VIII distinctly longer than tergite VIII, posterior margin produced, in the middle almost truncate ( Fig. 47 ).

I n t r a s p e c i f i c v a r i a t i o n: The length of the elytra, the size and colour of the pale posterior spot on the elytra, and even the shape of the ventral process of the aedeagus are subject to rather pronounced variation. The elytra are distinctly shorter in specimens from Taiwan and from Yunnan than in material from the remaining Chinese localities. The elytral spots are darker (pale reddish) and much larger (occupying approximately one third of the elytra surface) in the specimen from Yunnan, whereas in the material seen from other localities they are pale yellow and confined to the extreme postero-lateral angles. The ventral process of the aedeagus is subapically slightly more slender in males from Taiwan ( Fig. 44 ) and less distinctly angled in the middle in the male from Yunnan ( Fig. 48 ). However, since no additional distinguishing characters were found and in view of the similar general morphology of the aedeagus, particularly the internal structures in lateral ( Figs 43-44 , 48 ) and in dorsal view ( Figs 49-51 ), the observed differences are attributed to intra- rather than interspecific variation.

C o m p a r a t i v e n o t e s: Both in external and sexual characters, T. bimaculatus is most similar to T. pallipes , but distinguished by the usually somewhat darker coloration of the forelegs (in T. pallipes of similar coloration as the yellowish middle and hind legs), the morphology of the aedeagus (larger; ventral process stouter, bent in the middle, and apically distinctly hooked), and by the slightly different shape of the posterior margin of the female sternite VIII ( T. pallipes : more convex in the middle). Specimens from Taiwan are additionally distinguished from T. pallipes by the shorter elytra.

D i s t r i b u t i o n a n d n a t u r a l h i s t o r y: The species is currently known from mainland China (Guizhou, Zhejiang, Hunan, Yunnan) and Taiwan. The material from Taiwan was collected at the edge of a pond by pushing Carex tufts into the water (SMETANA pers. comm.). The male from Yunnan was found on a vegetated stream bank. Two specimens collected in November are teneral.

Figures

Figs 39-47: Tetartopeus bimaculatus (LI, TANG & ZHU) from Taiwan (39-41, 44-47) and from Hunan (42-43): (39) forebody; (40) male tergite VIII; (41-42) male sternite VIII; (43-44) aedeagus in lateral view; (45) aedeagus in ventral view; (46) female tergite VIII; (47) female sternite VIII. Scale bars: 39: 1.0 mm; 40-47: 0.5 mm.

Figs 48-51: Tetartopeus bimaculatus (LI, TANG & ZHU) from Yunnan (48-49), Taiwan (50) and from Hunan (51): (48) aedeagus in lateral view; (49-51) aedeagus in dorsal view. Scale bar: 0.5 mm.