Lathrobium aspinosum, Assing, 2013

Assing, Volker, 2013, On the Lathrobium fauna of China III. New species and additional records from various provinces (Coleoptera: Staphylinidae: Paederinae), Beiträge Zur Entomologie = Contributions to Entomology 63 (1), pp. 25-52 : 35-37

Lathrobium aspinosum sp. n.

( Figs 44-51 )

Type material:

Holotype : “ CHINA: W-Sichuan 1999, Ya’an Prefecture , Tianquan Co., E Erlangshan Pass, 2900 m, 9 km SE Luding, 29°52N, 102°18E, Gesiebe, 20. VI., leg. M. Schülke / Holotypus  Lathrobium aspinosum sp. n., det. V. Assing 2012” (cSch) . Paratypes: 1 : “ CHINA: W-Sichuan 1999, Ganzi Tibet. Aut. Pref., Luding Co., W Erlangshan-Pass, 2600 m, 7 km SSE Luding, 29°51'N, 102°15'E, Laubstreu , Pilze , 29. VI., leg. M. Schülke ” (cSch); 1 : “ CHINA: W-Sichuan 1999, Ganzi Tibet. Aut. Pref., Luding Co. , W Erlang Shan Pass, 2900 m, 29°51N, 102°17E, Weiden + Moos, Blockhalde, 21. VI., leg. M. Schülke ” (cSch, cAss); 1: “ CHINA: W-Sichuan, Ya’an Prefecture, Tianquan Co. , E Erlang Shan Pass / 2900 m, 22.VI.1999, 29.52.36N, 102.17.82E, leg. A. Pütz ” (cPüt) .

Etymology:

The specific epithet (Latin, adjective: without spines) refers to the absence of long sclerotized spines in the internal sac of the aedeagus.

Description:

Species of moderately large size, without evident sexual size dimorphism. Body length 8.4-9.5 mm; length of forebody 3.5-4.0 mm. Habitus as in Fig. 44 . Coloration: body dark-brown to blackish; legs and antennae reddish.

Head ( Fig. 45 ) as broad as long or weakly transverse, more or less distinctly dilated posteriorly; punctation moderately coarse and moderately dense, sparser in median dorsal portion; interstices with distinct microreticulation. Eyes weakly convex, slightly more that one fourth the length of postocular region in dorsal view and composed of approximately 50 ommatidia. Antenna approximately 2 mm long.

Pronotum ( Fig. 45 ) moderately slender, approximately 1.25 times as long as broad and about 1.05 times as broad as head; punctation similar to that of head; impunctate midline rather narrow to moderately broad; interstices without microsculpture.

Elytra ( Fig. 45 ) short, 0.51-0.55 times as long as pronotum; punctation shallow, moderately dense, and rather weakly defined. Hind wings completely reduced. Protarsi with pronounced sexual dimorphism.

Abdomen with fine and dense punctation, that of tergite VII only slightly sparser than that of anterior tergites; interstices with fine microsculpture; posterior margin of tergite VII without palisade fringe; tergite VIII without sexual dimorphism, with weakly convex posterior margin.

: protarsomeres I-IV strongly dilated; sternites III-VI unmodified; sternite VII ( Fig. 46 ) strongly transverse, symmetric, and with moderately modified short and dark setae in postero-median impression, posterior margin weakly concave in the middle; sternite VIII ( Fig. 47 ) noticeably transverse, posteriorly with weakly defined cluster of weakly modified dark setae on either side of middle, and with shallow, broadly V-shaped posterior excision; aedeagus ( Figs 48-49 ) approximately 1.5 mm long, symmetric, and with slender, subapically weakly curved (lateral view), and apically acute ventral process, dorsal plate with very long and distinctly sclerotized apical portion and with very short basal portion; internal sac with dark membranous basal structures and with weakly sclerotized apical structure.

: protarsomeres I-IV moderately dilated, much less so than in male; sternite VIII ( Fig. 50 ) 1.1-1.2 mm long, weakly oblong, and convexly produced posteriorly; tergite IX with median portion undivided and short, posterior processes long and slender; tergite X more than twice as long as tergite IX in the middle ( Fig. 51 ).

Comparative notes:

The morphology of the aedeagus suggests that L. aspinosum belongs to the L. ensigerum group, which previously included three species from the Emei Shan (ASSING et al. 2013) and with which the new species shares the long and large dorsal plate and the presence of an apical internal structure of the aedeagus. It is distinguished from the other representatives of this group by much larger eyes with more numerous ommatidia, the less slender head, the shapes and chaetotaxy of the male sternites VII and VIII, as well as by the morphology of the aedeagus. For illustrations of the species of the L. ensigerum group from the Emei Shan see ASSING et al. (2013).

Distribution and natural history:

The species was discovered in three geographically close localities near the Erlang Shan Pass in western Sichuan, where the specimens were sifted at elevations of 2600- 2900 m.

Figures

Figs 44-56: Lathrobium aspinosum sp. n. (44-51) and L. appendiculatum sp. n. (52-56): habitus (44, 52); forebody (45, 53); male sternite VII (46, 54); male sternite VIII (47, 55); aedeagus in lateral view (48); apical portion of aedeagus in ventral view (49); female sternite VIII (50); female tergites IX-X (51); aedeagus in latero-ventral view (56). Scale bars: 44-45, 52-53: 1.0 mm; 46-51, 54-56: 0.5 mm.