Dongodytes (s. str.) troglodytes, Tian, Mingyi, Yin, Haomin & Huang, Sunbin, 2014

Tian, Mingyi, Yin, Haomin & Huang, Sunbin, 2014, Du'an Karst of Guangxi: a kingdom of the cavernicolous genus Dongodytes Deuve (Coleoptera, Carabidae, Trechinae), ZooKeys 454, pp. 69-107 : 75-78

Taxon classification Animalia Coleoptera Carabidae

Dongodytes (s. str.) troglodytes sp. n. Figs 1c, 9, 19, 30, 37-38, 50-52, 73f

Description.

Length: 7.0-7.5 mm (mean 7.3 mm); width: 1.9-2.4 mm (mean 2.1 mm). Habitus as in Fig. 9.

Colour: Light yellowish brown, palps pale.

Macrosculpture: Surface smooth, polish and strongly shiny; head including underside surface and prothorax sparsely covered with rather long and erected setae except the tumid propleura, elytra glabrous; prosternum with a row of 6-8 setae on each side; legs and abdominal ventrites pubescent.

Microsculpture: Engraved meshes faint, densely and strongly transverse on head and pronotum, without clear meshes on elytra.

Head (Fig. 19) nearly reverse triangular shaped, much longer than wide, HL/HW=3.1-3.7 (mean 3.4); slightly less elongate than in Dongodytes elongatus sp. n., but more slender than in Dongodytes baxian ; head excluding mandibles slightly longer than pronotum, with mandibles much longer than pronotum (1.9-2.0 times, mean 1.9); gradually narrowed posteriad, forming a collar-like neck, neck constriction distinct, about half as wide as head; two pairs of supraorbital setae present, at about 1/3 and 2/3 from apex respectively; setae of anterior pores long and distinct, of posterior pores short and indistinct, only slightly longer than other erected setae nearby; frontal furrows short, deeply impressed and narrow; clypeus transverse, sexsetose; labrum similar in Dongodytes baxian , but less emarginated apically; palps thin and very elongate, 3rd maxillary palpomere as long as 4th; 2nd labial palpomere distinctly longer than 3rd, and bisetose on inner margin; mentum and submentum not fused, labial suture distinct; mentum bisetose basally, mental tooth simple, blunt apically, a pair of basal pits small but distinct; submentum octosetose but 12-setose in one female paratype, and 14-setose in one male paratype; antennae filiform, wholly pubescent, extending over elytral apex, as long as in Dongodytes baxian ; 1st antennomere as long as 2nd, 10th, and 11th, respectively, 3rd longest, about twice as long as 2nd, then gradually shortened towards apex.

Prothorax short though much longer than wide and narrow, slightly wider than head, propleura strongly tumid, PW/PTW=0.8, front narrower than base, PAW/PBW=0.7-0.8 (mean 0.8); pronotum narrower than head, PW/HW=0.8-1.0 (mean 0.9); lateral borders of pronotum invisible from above at 1/6 of apical parts (but visible in a male paratype); hind angles nearly rectangular, but obtuse (Fig. 30), posterior latero-marginal setae present, with location as in Dongodytes (s. str.) baxian .

Elytra very elongate, much longer than wide, EL/EW=1.8-2.0 (mean 2.0); slightly longer than head (excluding mandibles) plus prothorax, twice as wide as prothorax, EW/PTW=2.0-2.2 (mean 2.1); base thin (Fig. 30); humeral parts slightly and widely sinuate, apex round; widest at about 3/5 from base; disc strongly convex; striae shallow and vague though 2nd and 3rd traceable; 3rd stria with three dorsal pores at about 1/3, 1/2 and 5/6 from base, respectively; chaetotaxal pattern of marginal umbilicate pores similar in Dongodytes baxian .

Male genitalia (Figs 37-38): Median lobe of aedeagus short and rather slender, ventral margin strongly arcuate, not sinuate before apex, bisinuate dorsally; apical part short and blunt, basal part very wide and long, basal orifice very large; sagittal aileron very small; inner sac armed with a broad and long copulatory piece which covered with scale structures on surface, about 1/3 as long as the median lobe; in dorsal, apical lobe very broad, and more rounded at apex than other species; parameres wide and rather long, each of right and left parameres with two long setae at apex.

Remarks.

Dongodytes troglodytes sp. n. is similar to Dongodytes baxian . It differs from the latter by the following characters: head more elongate, narrower, gently and gradually constricted towards neck constriction (stouter and quickly constricted before neck constriction in Dongodytes baxian ); hind angles of pronotum blunt (sharp in Dongodytes baxian ); head and pronotum covered with denser setae (sparser in Dongodytes baxian ); elytra narrower, but more convex (broader but rather flat in Dongodytes baxian ); and marginal borders at humeral parts slightly sinuate (nearly straight in Dongodytes baxian ).

Etymology.

Referring to its cave-adapted morphological characters.

Materials examined.

Holotype: male, Guangxi: Du’an: Longfu: Shangme: cave Shuiyuan Dong, 24° 11.335N, 107° 49.865E, 509 m, 2013-VI-28, leg. Mingyi Tian, Wei Lin, Weixin Liu, Haomin Yin & Sunbin Huang, in SCAU; Paratypes: 9 males, 22 females, ibid; 11 females, 2013-V-2, leg. Mingyi Tian, Weixin Liu, Feifei Sun & Haomin Yin, in SCAU, MNHN, IOZ and ZUBM, respectively.

Distribution.

Guangxi ( Du’an) (Fig. 73f). Known only from the type locality, a cave called Shuiyuan Dong in Longfu (Figs 1c and 73f).

Shuiyuan Dong (Figs 50-52) is composed of two layers. The lower layer is an underground river which provides water source for the local people and it is impossible to entre. The upper part is a short passage, one to one and half metres high, two to four metres wide, and about 15 m long. All of the specimens of Dongodytes troglodytes sp. n. were collected in the upper part of the cave. Apart from Dongodytes , another anophthalmic trechine, belonging to the genus Libotrechus Ueno, 1998 , was also collected in the cave ( Lin and Tian 2014). Other cave animals found in Shuiyuan Dong are crickets, millipedes, isopods, moths, spiders, mosquitoes, snails, bats and cave fishes.