Tonkinaphaenops yinquanicus Huang & Tian, 2019

Huang, Sunbin, Tú, Výõng Tân, Phú, Ph ạm Văn, Tian, Mingyi & Faille, Arnaud, 2019, Contributions to the knowledge of the genus Tonkinaphaenops Deuve, 2013 from China and Vietnam (Coleoptera: Carabidae: Trechinae), Zootaxa 4701 (1), pp. 35-53 : 37-42

Tonkinaphaenops yinquanicus Huang & Tian , sp. nov.

( Figs. 1 , 3–5 , 14B, C )

Holotype. ♂; China: Guangxi: Jingxi: Longbang: Nianlong : cave Yinquan Dong ; 22°53’30.40’’N 106°20’19.60’’E, 698 m; coll. Sunbin Huang, Dianmei Wang, Mengzhen Chen, Ruiqi Han; 31 January 2018; SCAU . Paratypes. 2 ♂♂ and 4 ♀♀; same data as holotype .

Description. Length: 5.6–6.2 mm (from apical margin of labrum to elytral apex), 6.0– 6.7 mm (including mandibles); width: 2.0– 2.3 mm. Habitus as in Fig. 3 .

Similar to T. marinae . Fore body long and narrow, hind body elongated obovate, strongly convex on dorsum; concolourously light brown or reddish-brown, but antennae, palps and tarsi slightly lighter at the apical parts; pronotum glabrous on its dorsal surface, sparsely pubescent on the head and densely pubescent on elytra.

Head elongate, subparallel-sided; frontal furrows variable in length, effaced near neck constriction in most individuals, clypeus quadrisetose, secondary setae seen in only one individual; right mandible retinacular tooth with 2 (6 ex.) or 3 (1 ex.) cusps. Head slightly longer than wide, widest at about the middle, HLm/HW = 1.5–1.9 (mean 1.8), HLl/HW = 1.1–1.3 (mean 1.2); eyes absent, two pairs of supraorbital pores present; labrum reverse trapezoidal, 6-setose; mentum and submentum fused; mentum bisetose, mental tooth small, subtriangular at apex; submentum 6- setose; ligula broadened at tip, multi-setose; labial palpomere 2 bisetose on inner margin, with two additional setae on outer side at subapical and apical portions; maxillary palpomere glabrous; antennae filiform, extending to middle of elytra; scape with several setae; the 2 nd– 11 th antennomeres pubescent; 2 nd antennomere slightly longer than scape; the 5 th antennomere the longest, a little longer than the 4 th.

Pronotum nearly barrel-shaped; slightly wider than head, PW/HW = 1.0–1.3 (mean 1.2), longer than wide, PW/ PL = 0.7–0.8 (mean 0.8), width of base subequal to front, PbW/PfW = 0.9–1.0 (mean 1.0); front angles obtuse and blunt; disc convex, smooth, the median line distinct but fine and superficial, meeting and passing slightly through the apical transverse impression and basal transverse impression, not reaching the margins of both front and base; hind angles thick and blunt; lateral margins bordered throughout, although reduced in the middle part and slightly sinuate before hind angles; two marginal setae present, anterior located at the level of one fifths from the front and the posterior a little before hind angle; basal foveae well-marked, deep and oblique.

Elytra amygdaloid and strongly convex in dorsum, with humeral part rounder than in T. marinae ; longer than wide, EL/EW = 1.5–1.7 (mean 1.6), widest at about 1/3 from base, about twice as wide as pronotum, EW/PW = 1.9–2.1 (mean 2.0), more than two times longer than pronotum, EL/PL = 2.3–2.6 (mean 2.5); striae shallow, rendered by alignments of strong foveae, faded in the apical 1/3 of the elytron; chaetotaxy as in Fig. 14B, C : basal pore present at the beginning of the 2 nd stria; the 3 rd stria with dorsal setiferous pores variable in number and position; preapical pore located at the apical anastomosis of the 2 nd and 3 rd striae; 2 apical pores present, the posterior one is much smaller; the 1 st pore of the humeral group of marginal umbilicate series moved to the location of the 7 th stria and a little before the 2 nd pore, distance between the 3 rd and 4 th pores is as long as or a little longer than that between the 2 nd and 3 rd; two pores of the middle group at about 3/5 of elytra from base.

Legs slightly elongated, protibiae smooth, the first two tarsomeres slightly widened and not distinctly denticulate.

Abdominal ventrites pubescent. Two paramedian setae present in ventrites IV, V and VI; ventrite VII quadrisetose both in male and female.

Male genitalia ( Fig. 4 ) similar to T. marinae though the apical part of median lobe obviously more dilated; basal orifice large; sagittal aileron fine, moderately sclerotized; apical part of median lobe wide and dilated; in dorsal view, apical orifice large with a broad apical lobe; parameres thin and elongated, each bearing 2 or 3 apical setae.

Etymology. “yinquan” means underground river in Chinese. The name is an adjective referring to the type locality of this species.

Remarks. Tonkinaphaenops yinquanicus is the second known species of the genus, which was previously found in northern Vietnam. It is closely similar to the type species T. marinae , but can be clearly identified by the following two main points: (1) the 1 st humeral pore of marginal umbilicate series normally located, before the 2 nd pore in T. yinquanicus but behind the 2 nd pore in T. marinae ; (2) from the ventral view, the apical lobe of aedeagus broader and enlarged in T. yinquanicus , but narrower and smaller in T. marinae .

Distribution. Guangxi (Jingxi), China.

Known so far only from a limestone cave called Yinquan Dong, at Nianlong Cun, Longbang Zhen ( Fig. 1 ). The cave is near the border between China and Vietnam and is about 15.6 km in straight distance from the cave “TH 20” near the lake Thang Hen, the type locality of T. marinae . Yinquan Dong is located at the foot of a small hill ( Fig. 5A ), with two passages in different layers. The upper layer is about 2 km long, and there is an underground river in the lower layer. The trechine beetles were found on a wet and muddy place in the lower layer ( Fig. 5B ), which is at the upper side of the river and not far away from the entrance.

Figures

FIGURE 1. Distribution map of Tonkinaphaenops Deuve, 2013

FIGURE 3. Tonkinaphaenops yinquanicus sp. nov., habitus of holotype, male.

FIGURE 4. Male genitalia of Tonkinaphaenops yinquanicus sp. nov. (A. median lobe and parameres, lateral view; B. apical lobe, dorsal view).

FIGURE 5. Cave Yinquan Dong, type locality of Tonkinaphaenops yinquanicus sp. nov. (A. entrance; B. a running individual of Tonkinaphaenops yinquanicus).

FIGURE 14. Chaetotaxal pattern of Tonkinaphaenops (A. Tonkinaphaenops marinae Deuve, 2013, holotype, male from cave TH20; B, C. Tonkinaphaenops yinquanicus sp. nov.: B. male from Yinquan Dong, C. female from Yinquan Dong; D. Tonkinaphaenops impunctatus sp. nov., male from Hang Rắn cave; E. Tonkinaphaenops jingxicus sp. nov., female from Nianluo Dong; F. Tonkinaphaenops anthonyi sp. nov., male from Hang Dõi cave).