Priochirus (Euleptarthrus) curtidentatus

Wu, Jie & Zhou, Hong-Zhang, 2013, Taxonomy of the subgenus Euleptarthrus Jakobson (Coleoptera, Staphylinidae, Osoriinae, Priochirus) of China with descriptions of three new species, Zootaxa 3613 (2), pp. 165-175 : 168-170

Priochirus (Euleptarthrus) curtidentatus Wu & Zhou, new species

( Figs. 1–5 )

Type material. Holotype: CHINA: Xizang: 3, Mêdog (=Motuo), Baibung (=Beibeng), E Doxong Pass, Dayandong, 29.4283°N, 95.04982°E, 2890 m, 10.viii.2006, H.B. Liang coll. (IOZ-CAS). Paratypes: CHINA: Yunnan: 3, 3Ƥ, Tengchong, Mingguang, Zizhi, 25.80983°N, 98.6208°E, 2890 m, on log, 23.v.2006, H.B. Liang and P. Hu coll. (IOZ-CAS).

Description. Body length 12.7–13.6 mm. HL 1.00– 1.10 mm, HW 2.00– 2.05 mm, PL 2.30–2.35 mm, PW 3.05–3.35 mm, EL 2.60–3.00 mm, EW 2.70–2.95 mm.

Coloration. Head black with mouthparts dark brown. Pronotum and elytra black. Abdomen black except for posterior margin of 7th and whole of 8th segment rufous. Antennae brown. Femora black, tibiae brown, tarsi redbrown.

Head ( Fig. 1 ) strongly transverse, about twice as wide as long, sides distinctly contracted backward; frontal impression deep and cupulate, width of its anterior margin about 1/7 of head width; median sulcus narrow and deep, gradually contracted posteriorly with lateral margins fused before posterior margin of head; inner lateral teeth strongly curtate, inclined plane between clypeus and lateral teeth visible from above, outer lateral teeth apically rounded, lateral impression longitudinally depressed between inner and outer lateral teeth; frontal angle of head distinctly convex and rounded; vertex distinctly covered with fine coriaceous ground sculpture, with row of long setae along postero-lateral margin; eyes small, only occupying 2/5 length of head side length. Clypeus steep, anterior margin truncated, disc in center with two very close pairs of long setae; each basal-lateral side of clypeus with pair of long setae.

Mandibles ( Fig. 2 ) moderately symmetrical, strongly protruding, outer surface almost straight along basal 2/3, 1st dorsal tooth sharp and straightly elongate entad, 2nd dorsal tooth bluntly convex and introflexed, apical tooth very small with long seta close to its inner base, 1st and 2nd ventral teeth basally contracted to form bifurcate structure, behind which inner margin straight, 3rd ventral tooth small and triangular.

Mentum ( Fig. 3 ) trapeziform, lateral margin ventrally convex, not interrupted at frontal angle, anterior margin broadly depressed medially; median denticle distinctly projecting, shallowly emarginate at apex, with broad keel on ventral side; ventral surface rugose, in center with long median seta, basal impression oblong, shallow and bearing 3 setae, anterior 1/3 with distinct transverse ridge separating broad anterior impression; 4 anterior setae arranged in row, the inner two close to each other.

Antennae very long, weakly geniculate, posteriorly reaching middle of elytra, 1st segment baculiform, apically emarginate, dorsally without sulcus, 2nd smallest, slightly transverse, 3rd elongate and narrowed at base, more than 3 times as long as 2nd, 4th–10th longer than wide, but gradually decreasing in length, 11th elongate, bluntly pointed, about 1.5 times as long as 10th.

Pronotum distinctly transverse, anterior margin weakly sinuate, lateral sides slightly convex, posterior margin moderately protruding medio-posteriorly; superior marginal line only extending to post-lateral angle of pronotum; disc surface covered with distinct coriaceous ground sculpture, along marginal line with some setiferous punctures, above these punctures, in middle of lateral marginal area with two big setiferous punctures; median longitudinal sulcus very narrow, distinctly expanding at posterior end to form fovea.

Protibiae crenulate externally, with 14–21 denticles, 2nd distinctly smaller than 3rd.

Elytra almost quadrate, sides slightly convex posteriorly, surface covered with coriaceus ground sculpture; along lateral margin sparsely scattered several small setiferous punctures.

Abdomen cylindrical, weakly broadened posteriorly; 3rd–6th segments densely punctuate in basal half, unpunctuated region with indistinct coriaceous sculpture; 3rd segment with only one row setae: along posterior margin, 4-6th segments with two rows of setae: one along basal and the other along posterior margin, posterior setae longer and denser than basal; punctures on 7th segment smaller than on 3rd–6th segments, occupying almost whole dorsal surface, both 7th and 8th segments densely covered by setae, except for glabrous median part.

Male aedeagus almost membranous ( Figs. 4, 5 ) with median lobe moderately bulbous at base, slightly constricted and squarely curved behind basal orifice, posterior part baculiform, broadly sclerotized on dorsal side; parameres thin and slightly curved with their basal parts protruding ventrally and connected to each other below basal orifice, in dorsal view this protruding structure anteriorly truncated; basal orifice round and distinctly emarginate distally.

Remarks. The new species is similar to P. (E.) longicornis in the shape of lateral teeth and frontal impression on head, but can be easily distinguished from the latter by distinctly larger body size and black color, and more distinct 2nd dorsal tooth on mandible.

Distribution. Known from Yunnan and Xizang, at elevation of 2890 m.

Etymology. The species name is formed from the Latin adjectives ‘ curtatus ’ (curtate) and ‘ dentatus ’ (denticulate) to indicate the distinctly curtate inner lateral teeth of head.

Figures

FIGURES 1 – 5. Priochirus curtidentatus sp. nov. 1, dorsal view of head and prothorax; 2, dorsal view of left mandible (broken line indicating unobserved part); 3, mentum (wrinkles and rugae on surface not shown); 4, ventral view of male aedeagus; 5, lateral view of male aedeagus. Scale bars: 0.25 mm.