Graciliblemus gui, 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 : 61-64

Graciliblemus gui n. sp.

Figures 1m , 41–42

Material. Holotype male, Gui Dong (Ghost Cave), Pilin , Zhaoxing , Liping , Guizhou, 2020-VI- 22, 305 m, Mingyi Tian leg., in SCAU; paratype: 1 female, idem, in SCAU.

Diagnosis. Very small and slender trechine beetle, wholly pubescent, anophthalmic, depigmented, fore body much shorter than elytra.

Description. Length: 3.1–3.8 mm; width: 0.9–1.0 mm. Habitus as in Figure 41A .

Head with antennae brown, pronotum and elytra yellow, mouthparts, palps and tarsi pale; head slightly shiny, pronotum and elytra dim. Microsculptural engraved meshes indistinct. Head and pronotum smooth, whole elytral covered with coarse and irregular punctures.

Head stout though longer than wide excluding mandibles, HLl/HW = 1.0–1.04, HLm/HW = 1.42–1.44, frons rather flat, vertex convex, with longer pubescence; genae broadly expanded, with shorter pubescence; frontal furrows entire, nearly parallel-sided but strongly divergent posteriorly; both anterior and posterior supraorbital pores closely located, the anterior at about middle excluding mandibles, the posterior just before neck constriction which is well marked; clypeus transverse, 4-setose, labrum transverse, frontal margin distinctly bisinuate, making median part bluntly protruding, 6-setose; mandibles rather short, strongly curved apically; right mandibular tooth bidentate; labial suture invisible; mentum bisetose, tooth thin and simple, base largely concaved; submentum 6- setose, with setae very long; 2 nd labial and 3 rd maxillary palps strongly tumid, 3 rd labial and 4 th maxillary palps thin; 2 nd labial palp bisetose, with an additional seta near apex on outer margin; penultimate palp slightly longer than the apical ones in both labium and maxillae; antennae filiform, short and stout, extending at about basal 2/3 of elytra; scape stouter and smooth, with several long setae, slightly longer than pedicel which is the shortest; the 11 th the longest; pubescent from pedicel to 11 th antennomere; the comparative length of each antennomere from the 1 st to 11 th in holotype as: 1 st (1.16) / 2 nd (1.00) / 3 rd (1.20) / 4 th (1.34) / 5 th (1.32) / 6 th (1.28) / 7 th (1.24) / 8 th (1.04) / 9 th (1.16) / 10 th (1.08) / 11 th (1.52).

Propleura invisible from above; pronotum subcordate, slightly transverse, PnL/PnW = 0.88–0.91, wider than head, PnW/HW = 1.32–1.39, slightly longer than head excluding mandibles, HLl/PnL = 1.02–1.10, HLm/PnL = 1.36–1.44; widest a little before middle, lateral margins finely bordered, strongly sinuate before hind angles which are acute, fore angles broadly obtuse, slightly protruded forwardly; two pairs of latero-marginal setae present, the anterior located at before middle, the posterior a little before hind angle; base almost straight in most part, but shortly oblique forwardly near hind angle on both sides; front nearly straight; median line fine and well-defined; posterior transversal impression faint. Scutellum moderately sized.

Elytra oblongus, elongate and slender, moderately convex; much longer than head plus pronotum,EL/(HLm+PnL) = 1.28–1.35; much longer than wide, EL/EW = 1.86–1.93, wider than pronotum, EW/PnW = 1.40–1.44; base unbordered, shoulders rounded, without humeral angle; lateral margins gently expanded, widest at about middle of elytra, sub-serrate and ciliate throughout; disc coarsely and irregularly punctate, striae rather deep, intervals slightly convex; apical striole present in the continuation of stria 6; chaetotaxy ( Figure 41B ): basal pore present; both dorsal pores located along 5 th stria, at about basal 1/5 and a little behind the middle of elytra, respectively, preapical pore located at apical fusion of 2 nd and 3 rd striae, much closer to suture than to apical margin of elytra; marginal umbilicate series with 1 st, 2 nd and anguloapical pore close to the marginal gutter; humeral group equidistantly spaced, while both 5 th and 6 th pores widely separated.

Legs covered with dense and short hairs; tibiae without longitudinal sulcus; the 1 st tarsomere shorter than 2 nd- 4 th combined in fore leg, while as long as 2 nd- 4 th combined in middle and hind legs. In male, the 1 st and 2 nd protarsomeres feebly more widened, both distinctly denticulate inwardly at apex.

Abdominal ventrites pubescent, ventrites IV–VI each with a pair of paramedial setae; VII bisetose in male, while quadrisetose in female.

Male genitalia ( Figure 41C, D ): Weakly sclerotized, very small but elongate, evidently arcuate medially, base large, with a small sagittal aileron; apical dorsal membranous open fairly wide, inner sac without distinct copulatory piece, apical lobe evenly narrowed, blunt at apex in lateral view; in dorsal view, apical lobe wide, gradually narrowed toward the broad apex; both parameres fairly developed, slightly curved, right one with 4, while the left with 3 long setae at apex respectively.

Remarks. This is the second species of the genus Graciliblemus , differing from the type species G. lipingensis Deuve & Tian, 2016 by its larger body size, pronotum with lateral margins strongly sinuate before hind angles, and elytra more elongate ( Deuve & Tian 2016).

Etymology. “Gui” means ghost in Chinese. It refers to the type locality, Gui Dong Cave.

Distribution. China (Guizhou). Known only from the limestone cave Gui Dong in southern Liping County, Qiandongnan Miao & Dong Autonomous Prefecture, eastern Guizhou Province ( Figure 1m ).

Gui Dong is near Pilin Village, and opens just along a road. There is a monument near the entrance. It is a short cave, about 30 metres long, connecting to an underground creek in the inner most part. As it was muddy and wet, moulds and mushrooms were growing inside. Apart from the trechine beetles, cave crickets also occur in Gui Dong ( Figure 42 ).

Additional generic characteristics of Graciliblemus Deuve & Tian, 2016 . Ventrite VII bisetose in male, while quadrisetose in female; the 1 st and 2 nd protarsomeres modified in male.

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 41. Graciliblemus gui n. sp. A. Habitus of male, holotype; B. left elytron (white dots indicating the chaetotaxy); C. median lobe, lateral view; D. apical lobe, dorsal view.

FIGURE 42. Gui Dong, the type locality of Graciliblemus gui n. sp. A. entrance; B. main passage; C. two individuals of G. gui n. sp.; D & F. mould and mushroom growing in cave; E. a cricket of the genus Tachycines.