Chenotrechus parvulus, 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 : 15-20

publication ID	https://doi.org/ 10.11646/zootaxa.5243.1.1
DOI	https://doi.org/10.5281/zenodo.7642376
persistent identifier	https://treatment.plazi.org/id/039587AD-BF36-FFBA-FF7F-47D82336FB54
treatment provided by	Plazi
scientific name	Chenotrechus parvulus
status	sp. nov.

Treatment

Chenotrechus parvulus n. sp.

Figures 1k View FIGURE 1 , 8–11 View FIGURE 8 View FIGURE 9 View FIGURE 10 View FIGURE 11

Material. Holotype male, the cave Xiniuyan , Guhang , Luxin , Wuxuan , Laibin , Central Guangxi Zhuang Autonomous Region, Southern China, 109.55°E, 23.56°N, 115 m, 2021-I-15, leg. Mingyi Tian, Weixin Liu & Yi Zhao, in SCAU GoogleMaps ; Paratypes: 2 males, idem, in SCAU GoogleMaps .

Diagnosis. Small-sized aphaenopsian species, elytra longer than fore body, surface glabrous, eyeless and depigmented; propleura visible from above, elytra widened posteriorly, striae vanished.

Description. Length: 4.3–4.8 mm; width: 1.3–1.4 mm. Habitus as in Figure 8 View FIGURE 8 .

Body yellow to brown, but antennae, mouthparts, palps and tarsi pale; moderately shiny; head with a few sparse setae on genae, pronotum and elytra glabrous; ventrites covered with short pubescence; microsculptural engraved meshes moderately transverse on head and pronotum, irregular or vanished on elytra; fore body much shorter than elytra, (HLm+PL) / EL = 0.85–0.88.

Head elongate, much longer than wide, HLm/HW = 1.96–1.97, HLl/HW = 1.70–1.71; genae not evidently expanded medially, slightly narrower posteriorly, widest at about middle of head excluding mandibles; frons and vertex moderately convex; clypeus and labrum transverse, labrum 6-setose, median two smaller and shorter; anterior supraorbital setiferous pores located at about middle and the posterior ones in front of neck constriction; mandibles short and stout, feebly curved apically, right mandibular tooth tridentate though median one reduced; labial suture clear at sides, disappeared at middle, mentum tooth much shorter than lateral lobes; ligula thick and short, 8-setose at apex, inner two much longer than other; palps thin and elongate, all glabrous but bisetose on inner margin of 2 nd labial palpomere and with an additional seta on outer margin at subapex, penultimate palpomere 1.25 times longer than the apical one in labium, and as long as in maxillary; suborbital pores close to neck of head ( Figure 9A View FIGURE 9 ); antennae pubescent from pedicel; scape glabrous and stouter than other, as long as pedicel, the 3 rd – 6 th longest, 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 (2.46) / 4 th (2.46) / 5 th (2.46) / 6 th (2.46) / 7 th (2.27) / 8 th (2.00) / 9 th (1.91) / 10 th (1.82) / 11 th (2.27).

Prothorax slightly longer than wide, PrL/ PrW = 1.05–1.11; distinctly wider than pronotum, PrW/PnW = 1.20– 1.24; slightly wide than head, PrW/ HW = 1.04; widest at about middle. Pronotum much longer than wide, PnL/ PnW = 1.20–1.33; shorter than head, PnL/HLl = 0.75–0.80; slightly narrower than head, PnW/HW = 0.90; base narrower than front, PbW/PfW = 0.88–0.90; lateral margin feebly bordered throughout, widest at about apical 1/6 where antero-marginal seta located, strongly bi-sinuated and serrated near base, the posterior latero-marginal seta sited on the frontal serration, distant from hind angle; strongly and feebly contracted forwardly and backwardly respectively, nearly straight before hind angles; fore and posterior transverse impressions well marked, median line clear. Scutellum quite large.

Elytra ovate, longer than wide, EL/EW = 1.61–1.65; expanded posteriorly; much wider than pronotum, EW/ PnW = 2.04–2.12; lateral sides finely bordered throughout, marginal gutters well-marked; dorsal surface depressed medially near base; striae invisible, and neither of intervals. Chaetotaxy ( Figure 9B View FIGURE 9 ): basal pore present; dorsal and preapical pores large and well-marked, each with a large and long setae, anterior dorsal pore located at about basal 2/7, posterior one at the level of the middle marginal umbilicate set, preapical pore at about apical 1/7 of elytra, closer to suture than to apical margin; 1 st to 3 rd pores of the marginal umbilicate series equidistantly spaced sited, 4 th shifted posteriorly, 5 th and 6 th pores of the median set located behind middle; the anguloapical pore absent.

Legs thin and moderately slender for cave trechines, bearing setae or short pubescence; 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.

Ventrites smooth, IV–VI each with two pairs of paramedial setae, VII bisetose apically in male.

Male genitalia ( Figure 10 View FIGURE 10 ): The median lobe of aedeagus with a small copulatory piece in inner sac which is widely opened dorsally, paramere subequal sized, each with four long setae at apices. Genital ring broad, with a short handle.

Female: Unknown.

Etymology. Refers to the small size of this new species.

Distribution. China (Guangxi). Known only from a cave called Xiniuyan in Laibin Shi ( Figure 1k View FIGURE 1 ).

Xiniuyan is located at Guhang Village. It is 2750 m long, with several large chambers and there are some beautiful speleothems inside. Water pools exist in some parts of the main passage, making a suitable habitat for cave animals. Apart from the blind beetles, a millipede of Glyphiulus species and a scutiger were also observed in the cave ( Figure 11 View FIGURE 11 ).