Ckacus youcha, Tian & Huang, 2021

Tian, Mingyi & Huang, Sunbin, 2021, Discovery of a new cavernicolous trechine genus and species from a deep pit in Anlong, southwestern Guizhou Province (Coleoptera: Carabidae: Trechinae), Zootaxa 4985 (2), pp. 194-202 : 196-201

publication ID	https://doi.org/10.11646/zootaxa.4985.2.3
publication LSID	lsid:zoobank.org:pub:46CAA718-9DFE-4C79-8878-32BB5CA9A4D7
DOI	https://doi.org/10.5281/zenodo.4943356
persistent identifier	https://treatment.plazi.org/id/03F7A821-D954-3527-FF67-F95F8AD264E0
treatment provided by	Plazi
scientific name	Ckacus youcha
status	sp. nov.

Treatment

Ckacus youcha View in CoL n. sp.

(Chinese name: 油ë喀Ḇù步ffl)

( Figs. 2–5 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 )

Type material. Holotype male, Luoshui Dong cave, Xianheping, Anlong Xian (County), Qianxinan Miao & Buyi Zizhizhou (Autonomous Prefecture), southwest Guizhou, 105°35’31.42’’E, 24°59’16.11’’N, 1163 m, 2020-XII-06, leg. Huanghe Zhou (“You Cha”), in SCAU. GoogleMaps

Diagnosis. A medium-sized semi-aphaenopsian trechine species, wholly pubescent, with moderately elongated body and thin appendages.

Description. Length: 7.0 mm, width: 2.0 mm. Habitus as in Fig. 2 View FIGURE 2 .

Body yellowish-brown, but palps and tarsi yellow; wholly covered with long setae, moderately shining, underside of head with a few setae, thorax glabrous ventrally but prosternum with several setae, abdominal ventrites shortly and densely pubescent. Macrosculpture: transversely meshed on head, densely and transversely striate on pronotum and elytra.

Head much longer than wide, HLm/HW = 2.1, HLl/HW = 1.6; widest at about middle of head excluding mandibles, neck constriction well-marked; frons and vertex moderately convex; frontal furrows shallow and short, ended at about middle of head; anterior and posterior supraorbital pores located at middle and basal 1/4 of head respectively; clypeus 6-setose; labrum transverse, frontal margin straight, 6-setose; mentum bisetose on either side of tooth base, tooth moderately long, unified at tip; ligula thick and short, 8-setose at apex, inner two much longer than other; palps thin and elongate, all glabrous but bisetose on inner margin of 2 nd labial palpomere and two additional setae at outer margin medially and subapically, penultimate palpomere longer than the apical one in labium and maxillaries (cf. 1.2 times); suborbital pores intermedially sited; antennae slender, 1 st antennomere with several cilia then densely pubescent from the 2 nd antennomere, 1 st stouter than others, as long as 2 nd, 3 rd the longest, relative length of each antennomere as follows: the 1 st (1.0), 2 nd (1.0), 3 rd (1.9), 4 th (1.8), 5 th (1.7), 6 th (1.7), 7 th (1.5), 8 th (1.5), 9 th (1.3, 10 th (1.1) and 11 th (1.5).

Propleura invisible from above. Pronotum slightly longer than wide, PnL /PnW = 1.1, shorter than head excluding mandibles, PL/HLl = 0.8; lateral margins finely bordered throughout; widest at about 1/3 from front, gently contracted forwards and backwards, contracted and nearly straight near hind angles which are acute; fore angles slightly protruded, nearly acutangular; base faintly bisinuate, front nearly straight, both unbordered, front slightly wider than base, PfW/PbW = 1.2; anterior and posterior latero-marginal setae at 5/6 from base and just before hind angles respectively; disc moderately convex, mid-line distinct. Scutellum small and narrow.

Elytra slightly longer than fore body including mandibles, much longer than wide, EL/EW = 1.7, twice as wide as pronotum; base unbordered, lateral margins finely ciliate throughout, nearly obliquely truncate at humeral portions, humeral angles broad, widest a little behind middle of elytra; disc strongly convex; basal pore present at sides of scutellum, anterior and posterior dorsal pores on the 3 rd stria at basal 1/4 and middle of elytra respectively, preapical pore at exactly the anastomotic point between the 2 nd and 3 rd striae, closer to elytral suture than to apical margin; locations of umbilicate marginal pores as in Fig. 3A View FIGURE 3 .

Legs densely pubescent; 1 st and 2 nd protarsomeres slightly widened in male, shortly and bluntly denticulate at inner apex; 1 st tarsomere much shorter than 2 nd –4 th combined in fore legs, whereas as long as in middle and hind legs; tibiae without longitudinal sulci.

Each abdominal ventrites V-VI bisetose paramedially, VII bisetose in male.

Male genitalia ( Fig. 3B, C View FIGURE 3 ): The median lobe of aedeagus medium-sized, quite elongate, gently arcuate towards apex which is sharp; basal opening quite small, with a large and almost rounded sagittal aileron; inner sac armed with a long copulatory piece, which is about 1/4 as long as aedeagus; in dorsal view, apical lobe thin, much longer than wide, broadly rounded at apex; parameres well-developed, but much shorter than median lobe, each paramere with four long setae at apex.

Etymology. Dedicated to “You Cha”, a nickname of Ms. Huanghe Zhou, an active member of Guilin Cave Exploration Team, Guilin.

Distribution. China ( Guizhou). Known only from the limestone cave Luoshui Dong, sympatric with Satotrechus rieae Uéno, 2006 .

Luoshui Dong is located within Xianheping Forest Park. This vertical pothole is 515 m deep, one of the deepest caves in China ( Figs. 4 View FIGURE 4 , 5A, B View FIGURE 5 ). There is a lot of debris in the muddy terrace of about 400 m below the entrance. The specimens sampled, as well as many other Trechini, observed wandering on the ground and walls between - 330 m to - 450 m ( Fig. 4 View FIGURE 4 ). Apart from beetle species, other animals living inside the cave were cricket Tachycines (Gymnaeta) sp., millipedes of the genera Glyphiulus and Paracortina , harvestmen, bats, frog Oreolalax rhodostigmatus Hu & Fei, 1979 and crab Diyutamon cereum Huang et al., 2017 ( Fig. 5 View FIGURE 5 C-E).