Shilinotrechus zhangfani, 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 : 54-57

Shilinotrechus zhangfani n. sp.

Figures 1a , 35−37

Material. Holotype male, cave Xianren Dong, Xi’er Township, Mile Shi , Honghe Hani &Yi Autonomous Prefecture, Yunnan Province, 103.20 E, 24.48 N, 1901 m above sea level, 2020-VIII-17, Mingyi Tian & Jingli Cheng leg., in SCAU.

Diagnosis. Small-sized and stout trechine species, eyeless and depigmented, body concolourous brown.

Description. Length: 4.9 mm; width: 1.8 mm. Habitus as in Figure 35 .

Body stout and strongly convex on dorsum; concolourous brown, but antennae, palps and tarsi slightly lighter; surface with fine and sparse pubescence; microsculpture engraved meshes irregularly isodiametric or polygonal on head, pronotum and elytra. For body much shorter than elytra, (HLm+PL) / EL = 0.71.

Head slightly longer than wide, HLm/HW = 1.67, HLl/HW = 1.22; widest at about middle excluding mandibles, frontal furrows widened, nearly parallel-sided; two pairs of supraorbital pores present; clypeus 4-setose; labrum distinctly emarginate, 6-setose; right mandibular tridentate; mentum and submentum separated; mentum bisetose, base bi-foveate, tooth thick and short, bluntly bifid at tip; submentum sharply spined medially, 6-setose; mouthparts palps very thin and elongated; apical one in maxillae widened at base, narrowed towards apex, reverse in penultimate one; apical one in labium similar to that in maxillae, while penultimate one gently narrowed towards base; the 2 nd labial palpomere bisetose on inner margin, with three additional setae near apical portion, the 3 rd maxillary palpomere with four short set ae on apical half, other palps smooth and glabrous; the 2 nd labial palpomere 1.2 times longer than 3 rd; the 3 rd maxillary palpomere as long as 4 th; suborbital pores present. Antennae filiform, extending to 1/3 of elytra from base; scape stout, with several setae, as long as pedicel; pedicel to 11 th antennomeres pubescent; the comparative length of each antennomere from the 1 st to 11 th in holotype as: 1 st (1,00) / 2 nd (1.00) / 3 rd (1.36) / 4 th (1.41) / 5 th (1.41) / 6 th (1.41) / 7 th (1.27) / 8 th (1.09) / 9 th (1.09) / 10 th (1.00) / 11 th (1.23).

Pronotum subtrapezoidal, wider than head, PW/HW = 1.33, clearly wider than long, PW/PL = 1.26; lateral margins finely bordered, widely and upwardly reflexed throughout, more so near base; hind angles obtuse, fore angles protruding; base much wider than front, PbW/PfW = 1.42; base shallowly bisinuate, slightly convex backwardly in median portion, front straight; two marginal setae present, the anterior located at about 1/6 from front, and a little after the front angles, the posterior at hind angle. Scutellum very small.

Elytra elongate, amygdaloidal, base more widened than apices; longer than wide, EL/EW = 1.53, much wider than pronotum, EW/PW = 1.72, more than two times longer than pronotum, EL/PL = 3.26, widest at about 1/4 from base; shoulders broadly protruding, lateral margins ciliate throughout; striae deep, the 8 th stria invisible; apical recurrent striole short; chaetotaxy ( Figure 36A ): basal pore present; two dorsal setiferous pores present along stria 3 before and behind middle of elytra respectively; the preapical dorsal pore present, located in the anastomosis of 3 rd and 4 th striae, closer to elytral suture; the humeral group of marginal umbilicate pores not aggregated, 1 st pore forwardly shifted; 1 st and 2 nd pores close to the marginal gutter; middle group (5 th and 6 th pores) locate before middle of elytra, not very close to each other; the anguloapical pore absent.

Legs slender, protibiae without longitudinal sulcus.the 1 st tarsomere much shorter than 2 nd –4 th tarsomeres together in fore leg, whereas as long as and longer than those in middle and hind legs respectively. The 1 st protarsomere enlarged and widened, not denticulate inwardly at apex in male.

Underside smooth and mostly glabrous in head and thorax; abdominal ventrites shortly and sparsely pubescent sparsely setose; IV−VI each with two paramedial setae; VII bisetose in male.

Male genitalia ( Figure 36B, C ): The median lobe of aedeagus very short and stout, moderately sclerotised, basal portion strongly bent ventrally; apical part nearly straight, parallel-sided until apex, which suddenly contracted and widely broad; in dorsal view, apical lobe gradually widened toward apex, which is broadly rounded, copulatory piece extending over apex; basal orifice small, with a small sagittal aileron; copulatory piece large and long, about 2/7 as long as the median lobe; parameres thin and elongated, slightly shorter than the median lobe, each bearing with three long setae at apex.

Female: Unknown.

Remarks. It is the fourth species of the Yunnan’s endemic genus Shilinotrechus Uéno, 2003 . It differs from other congeners by thinner body, shoulders of elytra strongly protruded, the 1 st marginal umbilicate pore evidently shifted forwardly, and in particular the strongly bent male genitalia ( Uéno 2003, Huang & Tian 2015, Huang et al. 2020b).

Etymology. This new species is named in honour of Mr. Fan Zhang (Institute of Geology, Yunnan University, Kunming), who is a leading caver in Yunnan Province.

Distribution. China (Yunnan).Known only from the limestone cave called Xianren Dong in Mile Shi ( Figure 1a ).

Xianren Dong is located on the left side of Road X016 about 7 kilometres from Xi’er Town. The length remains unknown, with a small entrance. Inside the cave, the humidity was rather high. Bats, two species of millipedes and growing mould were also observed inside the cave in addition to the unique trechine beetle, which was discovered under a stone in the inner most part of the main passage ( Figure 37 ).

Genus Guizhaphaenops Vigna Taglianti, 1997

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.

FIGURE 35. Habitus of Shilinotrechus zhangfani n. sp., male, holotype.

FIGURE 36. Shilinotrechus zhangfani n. sp. A. left elytron (white dots indicating the chaetotaxy); B. median lobe, lateral view; C. apical lobe, dorsal view.

FIGURE 37. Xianren Dong, the type locality of Shilinotrechus zhangfani n. sp. A. entrance; B. speleothems in cave; C. a running specimen of Shilinotrechus zhangfani n. sp.; D & E. millipedes of the genera Eutrichodesmus and Glyphiulus; F. mould growing in cave.