Lobrathium digitatum, Assing, 2010

Assing, Volker, 2010, On the Lathrobiina of Taiwan (Coleoptera: Staphylinidae: Paederinae), Beiträge Zur Entomologie = Contributions to Entomology 60 (2), pp. 301-361 : 351-353

Lobrathium digitatum sp. n. ( Figs 203-210 )

Type material:

Holotype ♂: " Taiwan, Chiai Hsien, Yushan N. P., Ta-Ta Ghia , 2750 m, 27.IV.1990, A. Smetana [ T27 ] / Holotypus ♂ Lobrathium digitatum sp. n., det. V. Assing 2010" (cSme) . Paratypes: 1 ♂, 1 ♀: same data as holotype (cAss) ; 1 ♂: " Taiwan, Chiai Hsien, Yushan N. P., Mun-Li Cliff, 2700 m, 27.IV.1990, A. Smetana [ T28 ]" (cAss); 1 ♀: " Taiwan, Chiai Hsien, Yushan N. P., Mun-Li Cliff, 2700 m, 13. V.91, A. Smetana [ T79 ]" (cSme); 2 ♀ ♀: " Taiwan, Nantou Hsien, Yushan N. P., Mun-Li Cliff, 2700 m, 18. V.91, A. Smetana [ T86 ]" (cSme); 1 ♀: " Taiwan, Chiai Hsien, Alishan, Sister Ponds, 2180 m, 26.IV.1990, A. Smetana [ T24 ]" (cSme); 2 ♀ ♀: " Taiwan, Kaohsiung Hsien , Kuanshan trail above Kaunshanchi Riv., 2550 m, 22.VII.1993, A. Smetana [ T160 ]" (cSme) .

Description:

Body length: 6.0-8.0 mm. Habitus as in Fig. 203 . Coloration: body, including antennae, darkbrown to blackish-brown; legs reddish-brown to brown.

Head oblong, 1.05-1.10 times as long as broad; posterior angles practically obsolete, broadly rounded ( Fig. 204 ); punctation well-defined, very dense (interstices narrower than punctures), and relatively coarse; median dorsal portion and frons with sparser punctation; interstices without microsculpture; eyes relatively large, slightly more than half the distance from posterior margin of eyes to posterior constriction in dorsal view. Antennae of similar morphology as that of L. stimulans , but somewhat less slender, with antennomeres II and III shorter ( Fig. 205 ).

Pronotum approximately 1.2 times as long as wide, or nearly so, and about as wide as head ( Fig. 204 ); punctation somewhat coarser and less dense than that of head; midline more or less narrowly impunctate; interstices without microsculpture.

Elytra short, but of rather variable length, 0.65-0.75 times as long as pronotum ( Fig. 204 ); humeral angles practically obsolete; punctation dense, coarse, irregular, and partly confluent; interstices without microsculpture; lateral parts without fine submarginal line. Hind wings completely reduced. Legs moderately slender, metatibia 1.2-1.3 mm long.

Abdomen 1.10-1.15 times as broad as elytra; punctation fine and dense; interstices with shallow microreticulation; posterior margin of tergite VII without palisade fringe.

♂: posterior margin of tergite VIII weakly convex; sternite VII posteriorly somewhat depressed, posterior margin weakly concave; sternite VIII with distinct median impression, this impression with two clusters of numerous peg-setae, posterior excision moderately deep and broadly Ushaped ( Fig. 206 ); aedeagus of characteristic morphology, apically with two finger-shaped processes ( Figs 207-208 ).

♀: posterior margin of tergite VIII indistinctly angled in the middle ( Fig. 209 ); sternite VIII broader than long, approximately as long as tergite VIII, posteriorly weakly produced, posterior margin weakly concave in the middle ( Fig. 210 ); segments IX-X not particularly slender; tergite X of ovoid shape, acute basally, reaching anterior margin of tergite IX, and broadly convex apically.

Comparative notes:

This species is distinguished from all the preceding representatives of the L. stimulans group by the absence of the fine submarginal line of the elytra, the less broad head, the somewhat coarser punctation of the head and pronotum, the broader impression of the male sternite VIII with more numerous peg-setae, the conspicuous morphology of the aedeagus, the posteriorly weakly produced female sternite VIII, and the apically broadly convex female tergite X.

Etymology:

The specific epithet is an adjective derived from the Latin noun digitus (finger) and refers to the shape of the apical lobes of the aedeagus.

Distribution and natural history:

The type specimens were collected in the Yushan (Chiai and Nantou Hsien), the Alishan (Chiai Hsien), and the Kuanshan (Kaohsiung Hsien), southern central Taiwan, at altitudes of 2180- 2700 m. They were collected from moss and vegetation at the edge of small ponds, by sifting moss, leaf litter, and other debris in an old coniferous forest, in a primary, mainly coniferous forest with lush undergrowth, and in a mixed forest. The specimens from the Alishan and the Kuanshan are all females, so that the possibility that they in fact refer to other species cannot be ruled out with certainty.

Figures

Figs 203-210: Lobrathium digitatum sp. n.: habitus (203); forebody (204); male sternite VIII (205); aedeagus in lateral and in ventral view (207-208); female tergite VIII (209); female sternite VIII (210). Scale bars: 203-204: 1.0 mm; 205-210: 0.5 mm.