Ischnosoma vicinum, Kocian, Matúš & Schülke, Michael, 2016

Kocian, Matúš & Schülke, Michael, 2016, New species and records of Ischnosoma Stephens (Coleoptera, Staphylinidae, Tachyporinae) from China, Zootaxa 4105 (3), pp. 201-242 : 207-209

Ischnosoma vicinum sp. n.

Figs 2 , 9–12 , 54 .

Description. Body ( Fig. 2 ) blackish-brown. Posterior margins of pronotum, elytra and tergites slightly paler, reddish-brown. Legs, palpi and antenna brownish-yellow, with the middle antennomeres brownish. Pronotum, elytra and abdomen with blueish hue.

Head 0.65–0.73 mm broad; 0.52–0.58 times as broad as pronotum, broader than long. Eyes slightly longer than temples. Surface with distinct reticulate and undulate microsculpture. Antenna slender, 1.69–1.99 mm long. Antennomere X as broad as long or slightly longer than broad.

Pronotum 1.03–1.31 mm broad; 0.93–1.03 mm long; 1.2–1.3 times as broad as long, broadest in posterior half. Surface with distinct transverse microsculpture, finely and sparsely punctate. Posterior angles distinct. Lateral margin near lateral macropunctures with some additional small punctures and setae.

Elytra quadrangular, very slightly widened posteriad; along suture 0.86–0.98 mm long; 1.02–1.11 times as broad as pronotum; 0.9–0.95 times as long as pronotum. Surface with very fine transverse microsculpture. Sutural row with 9–13 punctures, discal row with 11–13 punctures, and lateral row with 11–14 punctures. Wings reduced.

Abdomen slightly tapering towards apex, densely puntate. Tergite VII without palisade fringe. Surface smooth with very fine transverse microsculpture.

Length of forebody 2.53–2.78 mm; total body length 5.0– 5.8 mm.

Male. Sternite VII in the middle of posterior margin broadly concave, without modified pubescence ( Fig. 9 ). Sternite VIII with posterior margin deeply triangularly concave in the middle, without setae in posterior portion, only anteriorly and in posterior angles with modified, thick and flattened setae. Medial area very sparsely punctate with short thin setae ( Fig. 10 ). Paramere and aedeagus see Fig. 11 .

Etymology. The specific name (Latin, adjective: near, neighboring) alludes to the similarity of this species with I. farkaci .

Type material. Holotype, male: "P.R. CHINA, Yunnan, E slope Cangshan at Dali, N25°40'13.2'', E100°07'54.8'', 11.V.2010, 2728 m, sifting05, V. Grebennikov" ( CAS).

Paratypes (3): " CHINA: NW-Yunnan, Bailakou pass, 3750 m, 28.V.–7.VI.2006, S.Murzin & I.Shokhin / Sammlung M. Schülke, Berlin", 1 ex. (cKoc); " CHINA: Yunnan ( CH 07-03), Dali Bai Auton. Pref., Diancang Shan W Dali, 25°41'49''N, 100°06'24''E, 2970 m, sifted at rock edges and under small shrubs, 28.V.2007, M. Schülke / Sammlung M. Schülke, Berlin", 2 exs. (cSch).

Distribution. Northwestern Yunnan ( Fig. 12 ): Diancang Shan and Haba Shan ranges.

Remarks. I. vicinum sp. n. is very closely related to I. farkaci Kocian. Both species differ from other species of the I. pictum group by the combination of the following characters: body dark coloured, blackish-brown to blackish, pronotum broad with conspicuous posterior angles, broadest in posterior fourth, elytra shorter than pronotum, humeral angles marked, head and pronotum with very conspicuous microsculpture. Lateral pronotal margins of both species often with some additional short setae besides long lateral setae. Posterior margin of male sternite VIII in both species very deeply triangularly concave. I. vicinum sp. n. differs from I. farkaci by generally smaller body, paler coloration and the modifications of the male sternite VIII (modified palisade setae only anteriorly and posteriorly), while in I. farkaci these setae are also present laterally.

Figures

FIGURE 12. Distribution of Ischnosoma vicinum sp. n. (square), Ischnosoma involutum sp. n. (triangle) and Ischnosoma gemellum sp. n. (circles) in China.

FIGURES 2 – 4. Habitus of Ischnosoma vicinum sp. n. (2); Ischnosoma yunnanum sp. n. (3); Ischnosoma zipapertum sp. n. (4).

FIGURES 9 – 11. Ischnosoma vicinum sp. n. Posterior portion of male sternite VII (9); posterior portion of male sternite VIII (10); aedeagus in ventral (left) and lateral view (11). Scale bars: 0.1 mm: a (Figs 9 – 10), b (Fig. 11).

FIGURES 54 – 57. Forebody. Ischnosoma vicinum sp. n. (54); I. foedum sp. n. (55); I. zipapertum sp. n. (56); I. gemellum sp. n. (57). Scale bar: 1 mm.