Lathrobium depravatum, 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 : 45-46

Lathrobium depravatum sp. n.

( Figs 92-97 , 112-113 )

Type material:

Holotype : “ CHINA: JIANGXI prov., Wuyi Shan Nat. Res., Huangganshan [sic], (1800-2050 m), 5.vi.2001, Hlaváč & Cooter lgt / Holotypus  Lathrobium depravatum sp. n., det. V. Assing 2012” (cAss) . Paratype : same data as holotype (cAss).

Etymology:

The specific epithet is the past participle of the Latin verb depravare (to deform) and refers to the asymmetries of the male and female sexual characters.

Description:

Species of relatively small size, without sexual size dimorphism; body length 6.2-6.5 mm; length of forebody 3.2 mm. Coloration: body reddish-brown with slightly darker head; legs and antennae reddish.

Head ( Fig. 92 ) distinctly oblong, 1.12-1.14 times as long as broad; punctation rather coarse and moderately dense, sparser in median dorsal portion; interstices with distinct fine microreticulation, silk-matt. Eyes small, approximately one fourth as long as postocular region in dorsal view and composed of approximately 40 ommatidia. Antenna 1.7 mm long.

Pronotum ( Fig. 92 ) slender, approximately 1.35 times as long as broad and approximately as broad as head; punctation similar to that of head; impunctate midline moderately broad; interstices without microsculpture.

Elytra ( Fig. 92 ) short, approximately 0.55 times as long as pronotum; punctation rather shallow and weakly defined. Metatibia with weak sexual dimorphism; protarsi with weakly pronounced sexual dimorphism.

Abdomen slender; punctation moderately fine and not particularly dense, that of tergite VII somewhat sparser than that of anterior tergites; microsculpture fine and shallow, interstices rather glossy; posterior margin of tergite VII without palisade fringe; tergite VIII with sexual dimorpism.

: protarsomeres I-IV moderately strongly dilated; metatiba with small ventral dilatation at apical third; tergite VIII weakly transverse, posterior margin truncate; sternites III-VI unmodified; sternite VII ( Fig. 93 ) without appreciable modifications, except for the weakly concave posterior margin; sternite VIII ( Fig. 94 ) distinctly transverse, strongly asymmetric and with conspicuous chaetotaxy, with extensive median impression, this impression with a cluster of numerous strongly modified short and stout black setae, posteriorly with two pronounced clusters of strongly modified long black setae, these clusters of different shapes and in asymmetric position, posterior excision large, deep, and strongly asymmetric; aedeagus ( Fig. 95-96 ) 1.1 mm long, strongly asymmetric, and of highly distinctive morphology; ventral process asymmetric and apically divided into two lobes of different shapes; dorsal plate very large, asymmetric, and apically divided into two lobes of different shapes; internal sac with long and curved sclerotized spine and with additional apical spine of characteristic shape.

: protarsomeres I-IV nearly as dilated as in male; tergite VIII ( Fig. 112 ) oblong and with weakly concave posterior margin; sternite VIII ( Fig. 97 ) 0.9 mm long, oblong, and asymmetric, posterior margin convexly produced in the middle and on either side of this convex projection with concave excision of different shape and in asymmetric position; tergite IX conspicuously short and asymmetric, median portion short and undivided, but partly with median suture, postero-lateral process short, but of different lengths, the left process distinctly shorter than the right one; tergite X broad, nearly flat in cross-section, slightly more than twice as long as tergite IX in the middle ( Fig. 113 ).

Comparative notes:

Lathrobium depravatum is one of the most distinctive species known from China. Externally, it is characterized particularly by the distinctly oblong head. The most conspicuous male sexual characters are the modified metatibiae, the remarkable shape and chaetotaxy of sternite VIII and the intricate morphology of the aedeagus. Even the female is characterized by unique sexual characters, particularly the asymmetric shape of the posterior margin of sternite VIII and the asymmetric and conspicuously short tergite IX. Synapomorphies suggesting closer affiliations with any of the geographically close congeners were not found.

Distribution and natural history:

Lathrobium depravatum is probably endemic to the Wuyi Shan. The specimens were found in the Huanggang Shan in Jiangxi province, at an altitude of 1800-2050 m. Lathrobium cornigerum and L. wuyicum were collected in the same sample.

Figures

Figs 87-96: Lathrobium barbiventre sp. n. (87-91) and L. depravatum sp. n. (92-96): forebody (87, 92); male sternite VII (88, 93); male sternite VIII (89, 94); aedeagus in lateral and in ventral view (90-91, 95-96). Scale bars: 87, 92: 1.0 mm; 88-91, 93-96: 0.5 mm.

Figs 97-102: Lathrobium depravatum sp. n. (97) and L. cornigerum sp. n. (98-102): female sternite VIII (97); forebody (98); male sternite VII (99); male sternite VIII (100); aedeagus in lateral and in ventral view (101-102). Scale bars: 98: 1.0 mm; 97, 99-102: 0.5 mm.

Figs 103-113:Lathrobium wuyicumsp. n. (103-111) andL. depravatum sp. n. (112-113): habitus (103); forebody (104); male sternite VII (105); male sternite VIII (106); aedeagus in lateral and in ventral view (107-108); female tergite VIII (109, 112); female sternite VIII (110); female tergites IX-X (111, 113). Scale bars: 103-104: 1.0 mm; 105-113: 0.5 mm.