Ecotrechus ruruiae Tian & Huang & Jia 2023, n. sp

Ecotrechus ruruiae n. sp. Figures 1f, 15–16 Type material. Holotype female, the cave Laba Dong, Shaba, Ziyun Buyi & Miao Autonomous County, Guizhou Province, 25.84 N, 106.08 E, 1450 m in altitude, 2022-V-16, Rurui Ye leg., in SCAU; paratypes: 2 females, idem, in SCAU. Diagnosis. A medium-sized anophthalmic, eyeless and brown, somewhat like a Libotrechus species, but without supraorbital pores on head, latero-marginal setae on pronotum and dorsal and preapical pores on elytra. Description. Length: 6.3–6.6 mm; width: 2.4 mm. Habitus as in Figure 15A. Body brown, but mouthparts, palps and tarsi pale; surface glabrous and moderately shiny; ventrites covered with short pubescence; microsculptural engraved meshes more or less isodiametric on head, moderately or strongly transverse on pronotum and elytra; fore body much shorter than elytra, (HLm+PL) / EL = 0.93. Head elongate, much longer than wide, HLm/HW = 1.78–1.82, HLl/HW = 1.30–1.38; genae feebly expanded medially, widest at about middle of head excluding mandibles; clypeus transverse, 4-setose; labrum transverse, feebly bisinuate at frontal margin, 6-setose; mandibles fairly developed, feebly curved and slightly hooked at tips; mentum and submentum completely fused, ligula 6-setose at apex, inner two much longer than other; palps moderately elongate, glabrous except 2 nd labial palp bisetose on inner margin, with an additional seta on outer margin at subapex, about 1.2 times longer than 3 rd; 3 rd maxillary palp slightly longer than 4 th (1.1 times); suborbital pore absent; antennae pubescent from pedicel; scape glabrous, the 3 rd – 5 th longest; comparative length of each antennomere from the 1 st to 11 th in holotype as: 1 st (1.00) / 2 nd (1.32) / 3 rd (1.41) / 4 th (1.33) / 5 th (1.40) / 6 th (1.31) / 7 th (1.22) / 8 th (1.10) / 9 th (1.11) / 10 th (1.11) / 11 th (1.19). Pronotum discoid, slightly wider than long, or as long as wide (a paratype specimen), PnL/PnW = 0.96–1.00; slightly shorter than head, PnL/HLl = 0.96–0.98; much wider than head, PnW/HW = 1.42–1.50; base slightly narrower than front, PbW/PfW =0.85–0.91, both straight. Scutellum very small. Elytra ovate, much longer than fore body; longer than wide, EL/EW = 1.48–1.52; evidently contracted posteriorly; much wider than pronotum, EW/PnW = 2.04–2.12; lateral sides finely bordered throughout, marginal gutters well-marked; striae well-marked, punctures deep. Chaetotaxy (Figure 15B): basal pore present; dorsal and preapical pores absent; 1 st to 3 rd pores of the marginal umbilicate series equidistantly spaced, 4 th isolated; 5 th and 6 th pores of the median set located behind middle, very close to each other; the anguloapical pore present, closer to elytral margin than to suture. Legs moderately slender, bearing dense setae or short pubescence; procoxa asetose, middle and hind ones with two and three setae respectively; pro- and mesotrochanters unisetose, metatrochanter with several setae; the 1 st tarsomere much shorter than, as long as, and slightly longer than 2 nd –4 th tarsomeres together in fore, middle and hind legs, respectively. Prosternum glabrous, meso- and metasterna sparsely setose. Abdominal ventrites pubescent; IV–VI ventrites each with a pair of paramedial setae, VII ventrite quadrisetose in female. Male: Unknown. Etymology. In honour of Ms. Rurui Ye, an active caver of “Explore China ” team, who discovered and collected the type series. Distribution. China (Guizhou). Known only from a cave called Laba Dong in Ziyun County (Figures 1f). Laba Dong is a pothole of about 110 metres deep. It is located in a valley about 1.5 kilometres from Shaba Village. The beetles were found and collected in a platform about 90 metres deep from entrance. More beetle individuals were observed in the deepest part. Ecotrechus ruruiae n. sp. is co-occurring with Sinaphaenops bidraconis Uéno, 2002, an aphaenopsian cave beetle (Figure 16).