Lathrobium celere, 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 : 27-29

Lathrobium celere sp. n.

( Figs 1-10 )

Type material:

Holotype : “ CHINA: W-Sichuan (15), Daxue Shan , Hailuogou Glacier Park, Camp 2, 2550- 2700 m, 29.35.16N, 102.01.53E, 30.-31.V.1997, M. Schülke / Holotypus  Lathrobium celere sp. n., det. V. Assing 2012” (cAss). Paratypes: 1 : “China: Sichuan, Daxue Shan , Gongga Shan Mt. , Hailougou [sic] Glacier Park, 102.04E, 29.36N, river valley ca. 1 km above Camp 1, 2100 m, 28.& 31.V.1997, leg. A. Pütz ” (cAss); 1 : “ CHINA: Sichuan, Gongga Shan, Hailuogou, for. above Camp 2, 2800 m, 29°35N, 102°00E, 5.VII.1998, A. Smetana [C75] / 1998 China Expedition, J. Farkač, D. Král, J. Schneider & A. Smetana ” (cSme) .

Etymology:

The specific epithet (Latin, adjective: quick, hurried) alludes to the long legs.

Description:

Species of conspicuously slender habitus ( Fig. 1 ) and of moderate to moderately large size, with pronounced sexual size dimorphism. Body length 9.5-10.0 mm (), 7.8 mm (); length of forebody 4.3 mm (), 3.85 mm (). Coloration: body dark-brown to blackish-brown, elytra partly more or less extensively paler brown; legs reddish to pale reddish-brown; antennae reddish.

Head ( Fig. 2 ) distinctly oblong, 1.10-1.12 times as long as broad; punctation coarse and moderately dense, sparser in median dorsal portion; interstices silk mat, with fine but very distinct microreticulation. Eyes weakly convex and relatively large, more than one third the length of postocular region in dorsal view and composed of approximately 50 ommatidia. Antenna approximately 2.4 () and 2.0 mm () long, respectively.

Pronotum ( Fig. 2 ) slender, 1.25-1.30 times as long as broad and about 1.02 times as broad as head; punctation slightly finer and less dense than that of head; impunctate midline moderately broad; interstices without microsculpture.

Elytra ( Fig. 2 ) short, approximately 0.55 times as long as pronotum; punctation fine, sparse, shallow, and often weakly defined. Hind wings completely reduced. Legs slender, metatibia nearly as long as pronotum. Protarsi

without appreciable sexual dimorphism, moderately dilated in both sexes.

Abdomen with moderately fine and moderately dense punctation, that of tergite VII noticeably sparser than that of anterior tergites; interstices with fine and shallow microsculpture, somewhat glossy; posterior margin of tergite VII without palisade fringe; tergite VIII without sexual dimorphism, posterior margin indistinctly pointed in the middle in both sexes.

: sternites III-VI unmodified; sternite VII moderately transverse, with unmodified pubescence, and with broadly and weakly concave posterior margin ( Fig. 3 ); sternite VIII ( Fig. 4 ) approximately as long as broad, symmetric, pubescence unmodified except for the somewhat shorter setae in anterior median portion, posterior excision small and of almost semi-circular shape, median portion of sternite with cluster of (gland?) pores ( Fig. 5 ); aedeagus ( Figs 6-8 ) 1.3-1.4 mm long, compact, with short, stout, and apically acute ventral process; dorsal plate small, with strongly sclerotized apical and weakly sclerotized basal portion; internal sac without sclerotized structures.

: sternite VIII 1.1 mm long, distinctly oblong, and with strongly convex posterior margin ( Fig. 9 ); tergite IX with very short and undivided median portion and with long postero-lateral processes; tergite X flat and approximately 4 times as long as tergite IX in the middle ( Fig. 10 ).

Comparative notes:

This highly distinctive species differs from all other geographically close congeners by numerous external characters alone: the pronounced sexual size dimorphism, the slender habitus and long legs, the distinctly oblong and silk-matt head, and the absence of a sexual dimorphism of the protarsi. In addition, it is characterized by conspicuous sexual characters, particularly the shape and chaetotaxy of the male sternite VIII, the morphology of the aedeagus (shape of ventral process and of dorsal plate), as well as by the morphology of the female tergites IX and X. The presence of a cluster of pores, most likely gland openings, in the median portion of the male sternite VIII appears to be unique among East Palaearctic Lathrobium species. Shared derived characters suggesting closer phylogenetic affiliations with other described species recorded from China were not found.

Distribution and natural history:

Lathrobium celere is probably endemic to the Gongga Shan, where it was collected in three localities at altitudes of 2100-2800 m. Remarkably, only singletons were collected in these localities, which, together with the slender habitus and the long appendages, suggests that the species lives in a special, cryptic habitat and not in the leaf litter layer.

Figures

Figs 1-10: Lathrobium celere sp. n.: habitus (1); forebody (2); male sternite VII (3); male sternite VIII (4); median portion of male sternite VIII (5); aedeagus in lateral and in ventral view (6-8); female sternite VIII (9); female tergites IX-X (10). Scale bars: 1-2: 1.0 mm; 3-4, 6-10: 0.5 mm; 5: 0.2 mm.