Chenotrechus, Tian & Huang & Jia, 2023

Tian, Mingyi, Huang, Sunbin & Jia, Xinyang, 2023, A contribution to cavernicolous beetle diversity of South China Karst: eight new genera and fourteen new species (Coleoptera: Carabidae: Trechini), Zootaxa 5243 (1), pp. 1-66 : 15

Chenotrechus n. gen.

Type species: Chenotrechus parvulus n. sp. (Xiniuyan, Laibin , Guangxi)

Generic characteristics. Small-sized for cave trechines; body short and less elongate, fore body shorter than elytra; surface glabrous, but head with a few sparse setae on genae. Head elongated quadrate, sub-parallel-sided; neck short, constriction well-marked; presence of two pairs of supraorbital setiferous pores; frontal furrows well-marked but incomplete, sub-parallel-sided medially, slightly and moderately divergent forwardly and posteriorly respectively; frons slightly, and vertex strongly convex; clypeus quadrisetose, labrum widely emarginate at frontal margin; right mandibular tooth tridentate; mentum and submentum partially fused due to labial suture invisible medially; mentum bisetose, base largely concave; tooth short and blunt, unifid at apex; submentum with a row of 7 setae; 2 nd labial palp bisetose on inner margin; antennae thin and long, extending to apical margins of elytra. Prothorax moderately tumid, propleura visible from above; pronotum subquadrate, shorter than head excluding mandibles, lateral margins evidently bisinuate before hind angles; presence of two pairs of latero-marginal setae; disc moderately convex, base narrower than front. Elytra elongated ovate, apex much wider than base, widest at about apical 1/3; humeral angles completely rounded off; lateral margins ciliate throughout; disc strongly convex, striae obsolete and not traceable; apical striole absent; presence of two dorsal and a preapical pores; only 2 nd marginal umbilicate pore near marginal gutter; humeral set not aggregated, median set close to each other. Protarsomeres not modified in male; tibiae not sulcate longitudinally. Male genitalia weakly-sclerotized, short and moderately elongated, hardly arcuate medially; base quite large, with a rather small sagittal aileron which is almost translucent, apical lobe straight, broadly blunt at apex, longer than wide in dorsal view; parameres moderately developed, much shorter than the median lobe.

Remarks. Chenotrechus n. gen. is the first cave-adapted trechine lineage reported from central part of Guangxi Zhuang Autonomous Region. There is a wide geographical gap from other cave trechine beetles known in Guangxi, e.g., over 150 km from Du’an Karst, a kingdom of the genus Dongodytes Deuve, 1993 (where occur also Xuedytes Tian & Huang, 2017 , Libotrechus Uéno, 1998 and Uenotrechus Deuve & Tian, 1999 ) ( Tian et al. 2014, 2017, Lin & Tian 2014, Wei et al. 2017), and 180 km from the cave Chaotianyan in Pingle Karst, the locality of Oodinotrechus (Pingleotrechus) yinae Sun & Tian, 2015 ( Sun & Tian 2015). Chenotrechus is not related to any of the abovementioned genera. The characteristics combined, such as: fore body distinctly shorter than elytra, incomplete frontal furrows, small and short prothorax with tumid propleura, elytra widened posteriorly, nonaggregated humeral group of the marginal umbilicate pores which are distant from marginal gutter, vanished striae and apical striole, and protarsomeres not modified in male indicate for Chenotrechus a peculiar position among Chinese cave trechine fauna.

Etymology. “Chen” + “ Trechus ”. Dedicated to the late Prof. Shoujian Chen (SCAU), one of the pioneers of Carabidology in China.

Range. China (Guangxi) ( Figure 1k ).

Figures

FIGURE 1. Map indicating the locality caves of the new genera and species. a. Xianren Dong; b. Shisanya Dong; c. Da Dong, Tuoluo; d. Da Dong, Bali; e. Weixiao Tiankeng; f. Laba Dong; g. Gui Dong; h. Suolue Cave I; i. Xiannü Dong; j. Jiudu Cave I; k. Xiannü Dong; l. Yunxian Dong; m. Zhongguo Dong; n. Feixian Dong.