Tribasodites tubericeps, Li & Yin, 2021

Li, Qi-Qi & Yin, Zi-Wei, 2021, Four new species of Scydmaeninae and Pselaphinae (Coleoptera: Staphylinidae) from Yunnan, China, Zootaxa 4920 (1), pp. 114-122 : 120-121

Tribasodites tubericeps sp. nov.

( Fig. 4 )

Type material (15 exx.). Holotype: CHINA: Ƌ, labeled ‘ Yunnan, Lincang, Mt. Tangli , 24°01'18''N, 99°14'20''E, 1758 m, 2020.ii.25, with Odontotermes termites, sifted, Ji-Shen Wang leg.’ ( SNUC) . PARATYPES: CHINA: 6 ƋƋ, 8 ♀♀, same label data as holotype ( SNUC) .

Diagnosis. Male. Body length 2.38–2.44 mm; with simple antennae, vertex with greatly raised sub-triangular projection in deep central cavity, pronotum with three spines on each discal carina, aedeagus sub-triangular, median lobe with greatly constricted basal capsule, ventral lobe broad, dorsal lobe strongly curved downwards, with a pointed apex. Female. Body length 2.48–2.63 mm; genital complex transverse, with short lateral lobes.

Description. Male. Body ( Fig. 4A ) length (combined length of head, pronotum, elytra and abdomen) 2.38–2.44 mm. Coloration red-brown, mouthparts and tarsi paler. Head ( Fig. 4B, C ) slightly wider than long, subtriangular, length from anterior margin of clypeus to head base 0.47–0.50 mm, width across eyes 0.47–0.53 mm; vertex with large sub-triangular projection in deep central cavity, anterior margin of cavity also greatly raised to same level as projection; frons depressed between moderately raised antennal tubercles. Eyes fully developed, large and prominent, each composed of approximately 55 facets. Gular area slightly depressed; with thin median longitudinal carina. Antenna long and slender, unmodified, length 1.22–1.24 mm; antennomeres 9–11 forming distinct club. Pronotum ( Fig. 4B ) as long as wide, length along midline and maximum width 0.56–0.59 mm; lateral sides spinose, each with one large spine and few smaller denticles; with broad median longitudinal impression followed by short median carina at base, with pair of sinuate lateral sulci and pair of discal carinae, with three discal spines on each carina. Elytra transverse, length along suture 0.78–0.80 mm, maximum width 0.87–0.89 mm, with truncate base and straight posterior margin; discal stria approximately half length of elytra; sutural stria complete. Metathoracic wings fully developed. Legs elongate; mesotrochanter with long spine at ventral margin, mesotibia ( Fig. 4D ) with small protuberance at apex; metatrochanter ( Fig. 4E ) with long, apically curved projection ventrally. Abdomen relatively short in dorsal view, length along midline 0.74–0.78 mm, maximum width 0.83–0.86 mm; tergite 1 (IV) with basal sulcus interrupted by short discal carinae, with oblique inner and complete outer marginal carinae; sternite 2 (IV) along middle as long as sternites 3–5 (V–VII) combined. Aedeagus ( Fig. 4F, G ) 0.38 mm long, triangular, basal capsule strongly constricted, with large foramen, ventral lobe broad, dorsal lobe strongly curved downwards and pointed at apex; parameres fused to form ventral lamina.

Female. External morphology similar to that of male, except head lacking modifications, antennae slightly shorter, eyes smaller, and legs simple. Each eye composed of about 58 facets. Measurements (as for male): body length 2.48–2.63 mm, length/width of head 0.47–0.52/ 0.50–0.55 mm, pronotum 0.52–0.57/ 0.53–0.57 mm, elytra 0.75–0.77/ 0.87–0.89 mm, abdomen 0.74–0.77/ 0.82–0.85 mm. Tergite 5 (VIII) ( Fig. 4H ) and sternite 6 (VIII) ( Fig. 4I ) each transverse; genital complex ( Fig. 4J ) strongly transverse, lateral lobes short, width 0.33 mm.

Comparative notes. A total of 16 Chinese species of this genus have been described ( Li et al. 2019), with a majority of them (13 spp.) restricted to cave environments in southern and southwestern areas of the country (Yin et al. 2015; Yin & Zhou 2018). The male of Tribasodites tubericeps sp. nov. is highly distinctive in the strongly modified vertex (cephalic modification lacking in the three free-living Chinese species), and the median lobe of the aedeagus has a greatly constricted basal capsule. The new species can be further separated from T. semipunctatus (Raffray) of Taiwan by the more elongate antennomeres and larger lateral spines of the pronotum; from T. spinacaritus Yin, Li & Zhao of Zhejiang ( Zhao et al. 2010a) by the unmodified antennal clubs of the male and much shorter apical spine of the mesotibia; and from T. tianmuensis Yin, Zhao & Li of Zhejiang ( Zhao et al. 2010b) by the relatively thicker mesotibiae, and much larger elytra in relation to the size of the head and pronotum.

Distribution. Southern China: Yunnan.

Etymology. The new specific epithet refers to the modification of the male head.

Figures

FIGURE 4. Tribasodites tubericeps sp. nov. (A–G. Male. H–J. Female). A. Habitus. B. Head and pronotum. C. Head, in dorsolateral view. D. Mesotibia. E. Metatrochanter. F–G. Aedeagus, lateral (F) and ventral (G). H. Tergite 5 (VIII). I. Sternite 6 (VIII). J. Genital complex. Scale bars: 0.5 mm in A; 0.2 mm in B, C; 0.1 mm in D–J.