Median sized and semi-aphaenopsian beetles, eyeless and depigmented; appendages rather long, antennae extending at (female) or over (male) elytral apices; dorsal surface glabrous though a few short hairs present on genae; fore part including mandibles nearly as long as elytra. Head rather elongated, much longer than wide, sub-tubiform; genea slightly and gradually narrowed posteriorly, frontal furrows uncompleted, effaced posteriorly, presence of two pairs of frontal setiferous pores; mandibles thin and elongated, feebly curved apically, right mandibular teeth bidentate; mentum and submentum fused, mental tooth simple, base of mentum distinctly concave, submentum 8- to 10-setose. Prothorax evidently wider than head, propleura distinctly convex and evidently visible from above; pronotum sub-quadrate, slightly wider than head, evidently longer than wide, presence of two pairs of latero-marginal setae, side margins slightly or strongly sinuate before hind angles which are more or less broadly lobed. Elytra sub-ovate, much wider than prothorax, shoulders rounded, prehumeral borders arcuate or nearly oblique, lateral margins ciliate in basal half; striae lacking though somewhat traceable; presence of two dorsal pores and the preapical pore on each elytron. Chaetotaxy: the 1^st pore in the humeral group of the marginal umbilicate series transversely and backwardly shifted, at level behind the 2^nd pore; the 5^th and 6^th pores in the middle group close to each other. Protibia smooth, without longitudinal sulcus; only the 1^st protarsomere modified in male. Abdominal ventrite VII bisetose in male, while quadrisetose in female. Male genitalia weakly sclerotized, very small, slightly curved ventrally in lateral view, with a quite large sagittal aileron; apical lobe broad in dorsal view; parameres moderately developed, each with 4 rather short apical setae.

Though Guiaphaenops is more or less similar to the genus Guizhaphaenops, the peculiar characteristics such as propleura of prothorax convex and visible from above and the 1^st pore of elytral marginal umbilicate series transversely and backwardly suggest that it has to be isolated from the latter genus (Uéno, 2006). Guiaphaenops is probably closer to Zhijinaphaenops Uéno & Ran, 2002 than to Guizhaphaenops in a strict sense because the above mentioned morphological features of Guiaphaenops are also shared by Zhijinaphaenops. However, Guiaphaenops is easily distinguished from the latter genus by its glabrous and smooth body (wholly pubescent in Zhijinaphaenops), roundly lobed hind angles (well-marked in Zhijinaphaenops), presence of anterior frontal pores on head and hind latero-marginal setae on pronotum (both absent in Zhijinaphaenops), and sub-ovate elytra (elongated ovate in Zhijinaphaenops).

China (Guangxi). Known only by two species from four limestone caves in Lingyun Xian (Fig. 1).

male, an anonymous cave near Yangli Cun, Jiayou Zhen, Lingyun Xian, Baise Shi, Guangxi, 24°28'39"N, 106°37'52"E, 643 m, VII-25-2012, Mingyi Tian, Weixin Liu, Feifei Sun & Haomin Yin leg., in South China Agricultural University, Guangzhou, China (SCAU).

Figure 1. 

Distribution of Guiaphaenops species. a, b, d G. lingyunensis Deuve c G. deuvei Tian, Feng & Wei, sp. n.

A larger species, latero-margins of pronotum strongly sinuate before hind angles which are distinctly lobed and reflexed (Fig. 3a); the 1^st pore of the humeral set of umbilicate pores at level before anterior dorsal pore, while the 7^th pore behind the level of the preapical pore (Fig. 4a); the median lobe of aedeagus a little slenderer, with apical lobe narrowly constricted towards apex in dorsal view (Fig. 5a, b).

Length: 7.0 mm, width: 2.0 mm. Fore body (including mandibles) shorter than elytra. Habitus as in Fig. 2.

Figure 2. 

Habitus of Guiaphaenops deuvei Tian, Feng & Wei, sp. n., holotype, male.

Yellowish brown, with pale appendages. Moderately shiny. Body smooth and glabrous, except genae, underside of head and prosternum each with several sparse setae, ventrites IV-VI with a few short setae between paramedian setae. Microsculptural engraved meshes finely transverse striated.

Head much longer than wide (HLm/HW = 2.45, HLl/HW = 1.75); genae fairly developed, slightly dilated laterally, slightly constricted posteriorly until the well-marked neck constriction; widest at about middle of head from labrum to base; frons and vertex convex, frontal furrows deep and well-marked, divergent at base and apex, ended a little behind the widest part; clypeus transverse, quadrisetose; labrum transverse, frontal margin more or less serrate, 6-setose; anterior and posterior frontal setiferous pores located at about middle of head from labrum to neck constriction and 1/3 from base to labrum respectively; ligula well developed, bisetose at apex; submentum 8-setose. Antennae long, the 1^st antennomere stouter than other, slightly shorter than the 2^nd which is slightly shorter than the 11^th; the 5^th and 6^th longest, each about twice as long as the 1^st, then gradually shortened towards the 10^th.

Prothorax (Fig. 3a) shorter than head (PrL/HLm = 0.55, PrL/HLl = 0.77), widest at about 1/3 from base, longer than wide (PrL/PrW = 1.08), wider than head (PrW/HW = 1.25), slightly wider than pronotum (PrW/PnW = 1.11), much narrower than elytra (PrW/EW = 0.46). Pronotum (Fig. 3a) longer than wide (PnL/PnW = 1.20), and wider than head (PnW/HW = 1.13), base wider than front (PbW/PfW = 1.29); lateral sides and finely bordered throughout, base and front unbordered; lateral margin slightly expanded medially, widest at a little behind middle, strongly sinuate before hind angles which are broadly lobed, fore angle obtuse; latero-marginal setae at about 1/4 of pronotum from front and a little before hind angles respectively. Scutellum small.

Figure 3. 

Pronota of Guiaphaenops species. a G. deuvei Tian, Feng & Wei, sp. n. b G. lingyunensis Deuve.

Elytra (Fig. 4a) longer than head plus prothorax (EL/(HL+PrL) = 1.21), longer than wide (EL/EW = 1.71); widest at about middle, prehumeral borders evidently ciliate, and nearly oblique; disc moderately convex; striae present though superficial. Chaetotaxy: anterior and posterior dorsal pores at about 1/5 of elytra from base and middle of elytra, preapical pore at 1/6 of elytra from apex, much closer to suture than to apical margin; the 1^st pore of the humeral set of umbilicate pores located before anterior dorsal pore, while the 7^th pore behind the preapical.

Figure 4. 

Left elytra of Guiaphaenops species, chaetotaxy shown by white points. a G. deuvei Tian, Feng & Wei, sp. n. b G. lingyunensis Deuve.

Legs thin and rather long, the 1^st tarsomere as long as the 2^nd–4^th tarsomeres together in fore, but longer in middle and hind legs.

Male genitalia (Fig. 5a, b): Weakly sclerotized, small but stouter than in G. lingyunensis, apical lobe narrower at apical part.

Figure 5. 

Male genitalia of Guiaphaenops species, median lobe and parameres, lateral view (a, c) and apical lobe, dorsal view (b, d) (a, b G. deuvei Tian, Feng & Wei, sp. n. c, d G. lingyunensis Deuve).

Dedicated to Dr. Thierry Deuve of the National Museum of Natural History, Paris, a well-known carabidologist who has described many new ground beetles of China.

China (Guangxi) (Fig. 1c). Known only from the limestone cave near Yangli, Jiayou, Lingyun Xian. This cave opens at bottom of a hill near Yangli Cun on the right side of the road from Lingyun to Leye. It is short cave and the large part inside was dry. The single type specimen was collected in a small wet area. Other cave animals observed in this cave were millipedes, crickets and bats.

A smaller species, latero-margins of pronotum slightly sinuate before hind angles (Fig. 3b); elytra with prehumeral borders broadly arcuate, the 1^st pore of the humeral set of umbilicate pores at level behind anterior dorsal pore, while the 7^th pore before level of the preapical pore (Fig. 4b); the median lobe of aedeagus slenderer and more elongated than in G. deuvei sp. n., with apical lobe thinner in dorsal view (Fig. 5c, d).

1 male, X-14-2015, cave Mi Dong, Mawang Cun, Sicheng Zhen, Lingyun Xian, Baise, Guangxi, 24°24'20"N, 106°35'52"E, 410 m, XII-9-2015, Mingyi Tian & Jujian Chen leg., in SCAU; 1 female, ibid, VI-9-2015, Mingyi Tian, Weixin Liu, Xinhui Wang & Minruo Tang leg., in SCAU.

China (Guangxi). Known from three caves (Shen Dong, Mi Dong and a cave near Dazai Tun) in Lingyun Xian (Deuve 2002; Uéno 2006) (Fig. 1a, b, d).

Mi Dong is located at about one kilometre from Mawang Cun, in a valley below the main road from Lingyun to Leye. It opens above a path from the village to Sha Dong, a deeper and larger cave nearby. It is short, after 20 m from the entrance there is a large and complete dark room of 30–50 m in diameter. Majority part of this room was muddy or wet. The two beetle specimens were found quickly running on the wet ground. Other cave animals observed in Mi Dong were two species of millipedes and a bat.

Figure 6. 

The type locality cave of Guiaphaenops deuvei Tian, Feng & Wei, sp. n. a cave entrance b a millipede in cave.