Tetragonomenes sylvestris Ando & Yuan, 2021

Ando, Kiyoshi & Yuan, Cai-Xia, 2021, Nine new species of Cnodalonini (Coleoptera: Tenebrionidae) from Hainan Island with additional records of other Tenebrionidae, Zootaxa 4965 (2), pp. 321-338 : 328-329

Tetragonomenes sylvestris Ando & Yuan , sp. n.

( Fig. 16 )

Type material. Holotype: ♀, China, Hainan Is.: Mingfeng Valley, Mt. Jianfengling , Jianfeng Township , Ledong County, 18˚44′N/108˚50′E, Alt. ca. 1,000 m, Ɨ南省乐东s尖峰•尖峰岭ṅNjẅ, 19–20.VII.2017, Local collec- tor leg. ( HBUM).

Description. Body length: 9.2 mm in ♀ (n = 1). Proportions ♀ (n = 1): IE/TD 2.67; PW/PL 1.35; EL/EW 1.84.

Female. Elongate, subparallel-sided, shiny. Colour reddish brown; distal six antennomeres darker; dorsal surface metallic blue, with slight greenish sheen; pronotum with violet sheen anteriorly; mouthparts and gula yellowish.

Head hexagonal, moderately convex; mCG scarcely sinuate; clypeus feebly convex in middle, finely microsculptured, almost truncate at apex in median three-fourths, with punctures large and piligerous, dense and coarse, becoming smaller along anterior margin; frontoclypeal suture fine, obscurely rounded at posterior corners; genae weakly convex, 1.11 times as wide as long, finely punctate; frons strongly convex, with punctures coarse and dense, nearly as large as on posterior portion of clypeus and not piligerous; eyes moderately convex, transverse in dorsal view, with inner ocular sulci broad, very deep and long, running along lateral margins of frons; tempola feebly and evenly convergent posteriad, with punctures coarse and dense, slightly smaller than on frons. Antennae reaching middle of pronotum; distal six antennomeres distinctly dilated and clavate, with dense sensory pores; 11th oval. Ultimate maxillary palpomere small, weakly securiform. Mentum obtrapezoidal, tenuously elevated in posterior two-thirds of middle, and broadly depressed at both sides of the elevation, densely with very long setae. Submentum scutellate, coarsely punctate, with some long setae.

Pronotum transversely quadrate, widest behind middle, scarcely microsculptured; disc distinctly convex forwards, steeply declined laterally, weakly depressed but not sulcate along lateral margins; punctures piligerous and dense, slightly larger than on frons; anterior margin weakly emarginate though slightly produced in median half, very finely beaded laterally; lateral margins moderately rounded, roundly narrowed forwards from the widest point and sinuate before base, finely beaded; basal margin weakly bisinuate, distinctly beaded; anterior corners obtusely rounded, posterior ones rectangular, both corners not produced. Scutellum transverse, large and flat, 1.30 times as wide as long, sparsely punctate.

Elytra elongate, subparallel-sided, widest at apical third, with lateral margins very weakly beaded, almost invisible seeing from above; striae tenuous, weakly impressed throughout; strial punctures coarse and rather dense, be- coming somewhat sparser anteriorly, and smaller on apical declivity; intervals weakly convex, never costate, finely and sparsely punctate; humeral calli narrow, moderately humped; epipleura oblique, unevenly depressed, finely and sparsely punctate, reaching middle of 5th abdominal ventrite.

Prothoracic hypomera weakly depressed, rather sparsely and very coarsely punctate. Prosternum convex, coarsely punctate and scarcely rugose, tenuously beaded at apex; prosternal process elongated linguiform, strongly adunc posteriorly, rounded at apex, with distinct and U-shaped sulcus in middle. Mesoventral ridge weak, V-shaped, gently oblique forwards, without clear anterior angles. Metaventrite distinctly convex, moderately and finely punctate. Abdomen moderately convex; basal three ventrites with large and sparse piligerous punctures, apical two ventrites also with punctures denser than those on basal three ones.

Legs slender, rather short. Profemora dilated towards basal two-fifths; meso- and metafemora so towards apical third. Tibiae scarcely incurved, with inner margins sparsely pubescent in apical two-thirds in protibiae or apical half in meso- and metatibiae. Tarsi rather robust, each ultimate tarsomere distinctly longer than the preceding tarsomeres combined.

Male. Unknown.

Distribution. China (Hainan Is.).

Etymology. The specific epithet is named after “live in the forest”.

Differential diagnosis. The new species is very similar to Tetragonomenes subcostata ( Fairmaire, 1893) from Borneo, but is different from the latter in having deeper and longer inner ocular sulci; clypeus truncate at apex instead of emarginate at apex in the latter; punctures on head much coarser. Pronotum densely and coarsely punctate, with lateral margins scarcely undulate, roundly narrowed forwards from the widest point, while those in the latter, evenly narrowed forwards from the widest point. Elytra with strial punctures coarser; intervals weakly convex, not costate on 4th, 5th, and 6th ones. Prosternal process elongated linguiform instead of cuneiform in the latter; punctures on metaventrite and abdomen distinctly larger and sparser.

Figures

FIGURES 14–21. Tenebrionidae spp. 14. Tetraphyllus hlaicolus sp. n., holotype; 15. Androsus pullus sp. n., holotype; 16. Tetragonomenes sylvestris sp. n., holotype; 17. Taichius caeruleopunctatus sp. n., holotype; 18. Hemicera (Hemicera) viridula sp. n., paratype; 19. Euhemicera hirtipes sp. n., holotype; 20. ditto, venter, showing femoral pubescence and tibial emargination; 21. venter of Euhemicera gebieni (Kaszab, 1941) from Taiwan.