Tianeotrechus trisetosus Tian & Tang

Tian, Mingyi, Huang, Sunbin, Wang, Xinhui & Tang, Mingruo, 2016, Contributions to the knowledge of subterranean trechine beetles in southern China's karsts: five new genera (Insecta, Coleoptera, Carabidae, Trechinae), ZooKeys 564, pp. 121-156 : 134-136

Taxon classification Animalia Coleoptera Carabidae

Tianeotrechus trisetosus Tian & Tang sp. n.

Holotype.

Male, Cave Bahao Dong, Gandong Village, Bala Xiang, Tian’e County, northern Guangxi, 24°55'57.10"N / 107°02'40.80"E, 686 m in altitude, VIII-7-2015, Mingruo Tang leg., in SCAU; paratypes: 4 males and 1 female, ibid., in SCAU.

Diagnosis.

A medium-sized trechine, with shiny and robust body, moderated appendages, convex pronotum and elytra, and elongated elytra which have round shoulders and reduced striae.

Description.

Length: 5.6-5.7 mm (mean 5.66), width: 1.6 mm. Habitus as in Fig. 9.

Body brownish red, with palps, antennae and tarsi pale; frons, vertex and underside of head, pronotum, inner part of elytra glabrous, propleura and prosternum glabrous; genae, lateral parts of elytra, meso- and metasterna, and visible ventrites clothed with short pubescence; legs densely pubescent, covered with longer setae; microsculptural engraved meshes moderately transverse on head, strongly striate on pronotum and elytra.

Head elongate, much longer than wide, HLm/HW = 1.78-1.80 (mean 1.79), HLl/HW = 1.29-1.34 (mean 1.32); frons and vertex moderately convex; frontal furrows fairly long but incomplete, nearly parallel-sided, albeit slightly divergent posteriad, ending near neck constriction; genae barely expanded laterally, both sides held almost parallel; anterior and posterior supra-orbital pores located in the middle of genae and near neck constriction, respectively, distance between anterior and posterior pores much less than that between anterior pores; clypeus 4-setose, labrum transverse, widely but shallowly emarginated at front margin, 6-setose; mandibles distinctly curved at apex; palps thin and moderately long, 3rd and 4th maxillary pal pomeres, and 3rd labial palpomere glabrous, 2nd labial palpomere 4-setose; penultimate palpomere evidently longer than apical one of labium, slightly longer in maxilla; suborbital pores on ventral side of genae, located closer to submentum than to base of head; antennae extending to about apical 3/4 of elytra, pubescent from 2nd in apical half; 1st antennomere stout and bearing several setae, slightly shorter than 2nd; 3rd 1.6 times longer than 2nd; 3rd, 4th and 5th subequal in length, then gradually shortened from 6th to 10th; 11th as long as 9th.

Prothorax expanded due to propleura, but concealed dorsally by pronotum, the latter being more strongly tumid laterally; pronotum longer than wide, PnL/PnW = 1.22-1.32 (mean 1.27); shorter than head with mandibles, PnL/HLm = 0.89-0.94 (mean 0.91); wider than head, PnW/HW = 1.24-1.32 (mean 1.28); base narrower than front, PbW/PfW = 0.885-0.894 (mean 0.889), both nearly straight and unbeaded; widest before middle, lateral margins of pronotum invisible from above; anterior lateromarginal pores present, located at about apical third; middle line fine; frontal impression faint, depressed medially, basal transverse sulcus well-marked; disc strongly convex. Scutellum small and short.

Elytra elongate ovate, much longer than wide, EL/EW = 1.72-1.75 (mean 1.74); as long as head (including mandibles) plus pronotum; much wider than pronotum, EW/PnW = 1.80-1.88 (mean 1.83); widest at about 3/7ths from base; prehumeral part short, humeral angles rounded; lateral sides smooth and well-beaded, ciliated throughout; disc strongly convex except for a small area near base just behind scutellum, the latter being somewhat depressed; striae more or less obliterated but traceable, intervals slightly convex; base not bordered; basal pores on either side of scutellum, close to basal margin; three dorsal pores present on 3rd stria, located at about 1/6th, 2/5ths, 2/3rds and 5/6ths of elytra from base, respectively; pre-apical pore lying at about 5/6ths of elytra, at site of junction of 2nd, 3rd and 4th striae, much closer to elytral suture than to apical margin; humeral group of marginal umbilicate pores not aggregated, 1st, 2nd and 3rd pores forming an equilateral triangle, 4th widely distant from other three, 2nd close to, 4th far from, marginal gutter; middle group located behind middle of elytra, close to each other, distant from marginal gutter; apical pore minute, placed near elytral apex.

Legs moderately long, tibiae not longitudinally furrowed, hind tibia as long as elytral width; protarsi short; 1st tarsomere shorter than, or subequal to, or longer than 2nd-4th tarsomeres combined in pro-, meso- and metatarsi, respectively; 4th tarsomere wider than long in fore leg, as long as wide in middle leg, and evidently longer than wide in hind leg. Ventrites IV-VII each with one pair of setae.

Male genitalia (Fig. 10A, B): The median lobe of aedeagus well-sclerotized, small and slender, moderately curved ventrally in middle part, pointed at apex in lateral view; in dorsal view, apical lobe roundly broad at apex, nearly parallel-sided; base widely opening, with a large and thick sagittal aileron; parameres broad, much shorter than median lobe.

Etymology.

To refer to the presence of three dorsal pores on elytron.

Distribution.

China (Guangxi) (Fig. 5d). Known so far from the limestone Cave Bahao Dong, southern Tian’e County (Fig. 11A).

The cave opens below a hill, surrounded by trees and bushes and is invisible from outside. The entrance is large, but the length remains unknown. It is deep and hardly accessible, accumulated by random ripraps; it takes the cavers about an hour to reach the underground river which runs through the deepest part of the cave. All of the type series were collected under stone in twilight and transition zones, thirty to fifty meters from the entrance. It is sympatric with Dongodytes giraffa Uéno, 2005 (Fig. 11B, C).