Stenothemus nigritibius Y. Yang et H. Liu, 2021

Ge, Shujuan, Yang, Xingke, Liu, Haoyu & Yang, Yuxia, 2021, Definitions of two species groups of Stenothemus Bourgeois (Coleoptera, Cantharidae), with descriptions of three new species from China, Zootaxa 5047 (2), pp. 139-152 : 141-142

publication ID	https://doi.org/ 10.11646/zootaxa.5047.2.3
publication LSID	lsid:zoobank.org:pub:0C398339-EF37-45C2-AA8C-3BDAF601E2AB
DOI	https://doi.org/10.5281/zenodo.5540646
persistent identifier	https://treatment.plazi.org/id/03F9A67D-FF9F-FFE8-FF0C-5EBBFD47492A
treatment provided by	Plazi
scientific name	Stenothemus nigritibius Y. Yang et H. Liu
status	sp. nov.

Treatment

Stenothemus nigritibius Y. Yang et H. Liu , sp. nov.

Figs 2A View FIGURE 2 , 3A‒C View FIGURE 3 , 4A‒B View FIGURE 4

Type material. Holotype ♂ ( IZAS, IOZ (E) 2003382), China, Xizang, Mêdog, Baibung, Gelin , 29.246º‒ 29.216º N, 95.174º‒ 95.170º E, 843‒1760 m, 30.VII. 2012, H.B. Liang leg. GoogleMaps Paratypes: 1♂, 4♀♀ ( MHBU, HBU (E) 410048‒ 410052), China, Xizang, Nyingchi, Mêdog, Lagong Chachang , 8.VIII.2016 , T.F. Qiu leg.; 1♀ ( MHBU, HBU (E) 410053); same locality and collector as the preceding one, 7.VIII.2016 ; 1♂ ( NHMB), NE India, Arunachal Pr., Hunli vicinity, 1500 ± 150 m, 28º19′N, 95 º57′E, Pacholatko leg. 4.‒5.VI.2007 GoogleMaps ; 2♀♀ ( NHMB), NE India, Arunachal Pr., Etalin vicinity, 800 ± 100 m, 28º35′N, 95 º52′E, L. Dembický leg. 1.‒3.VI.2007 GoogleMaps .

Description. Body length (both sexes): 8.7‒11.5 mm (8.7 mm in holotype); width: 2.0‒3.0 mm (2.0 mm in holotype).

Male ( Fig. 2A View FIGURE 2 ). Coloration. Body is yellow, head mostly pitch black on dorsum, with a narrow longitudinal dark reddish brown marking in the middle of vertex, antennae black, yellow at apex of each antennomere, pronotum mostly pitch black, dark reddish brown at anterior angles, scutellum and elytra pitch black, legs black, yellow at coxae, trochanters and basal two-thirds parts of femora. Body sparsely covered with short, semi-recumbent paleyellow pubescence.

Head. Surface densely punctate, each side with a smooth and rectangular impression behind antennal socket; eyes large, strongly protruding, head width across eyes nearly as wide as anterior margin of pronotum; terminal maxillary palpomeres long-triangular, widest at basal one-third; antennae filiform, extending to two-thirds length of elytra, antennomeres II 2.3 × as long as wide at apices, III 1.3 × longer than II, IV‒XI each with a small and smooth oval impression in the middle of inner edge, IV longest, XI longer than X, pointed at apex.

Pronotum 1.25 × as wide as long, anterior margin rounded, lateral margins sinuate and converging posteriorly, posterior margin bisinuate and narrowly bordered, anterior angles subrounded, posterior angles sharp and protruding, disc strongly convex on postero-lateral parts, surface densely punctate.

Elytra 2.9 × as long as humeral width, 4.6 × as long as pronotum, lateral margins moderately diverging posteriorly, surface densely punctate, longitudinal costae hardly visible.

Male genitalia ( Figs 3A‒C View FIGURE 3 ). Weakly swollen laterally at basal part in ventral view; basal piece 0.8 × as long as dorsal plates, with a moderately large, bifurcate conjoined middle nodule at base of ventral side; ventral processes of parameres slender, bent inwards at apical one-third part in ventral view, bent ventrally in lateral view; dorsal plates shorter than ventral processes, overlapping each other, abruptly narrowed in the middle, wide-triangularly protuberant at apical margins and largely emarginate at inner margins, each present with a longitudinal ridge along the whole length and extending from apex of the protuberance in dorsal view; laterophyses long and about two-thirds length of dorsal plates, tilting ventrally at an angle of 45° with dorsal plates, evenly narrowed apically in ventral view, conjoined at basal part and longitudinally divided at apical part, which compressed and slender, sharply hooked at apices in lateral view.

Female. Similar to male, but the body stouter than male, eyes smaller and less protruding, head width across eyes narrower than pronotum, antennae shorter and roughly extending to elytral mid-length, antennomeres IV‒XI without impressions; the lateral margins of elytra obviously diverging posteriorly, 2.7 × as long as humeral width.

Internal organ of reproductive system ( Fig. 4A View FIGURE 4 ). Vagina stout and abruptly narrowed apically and extended into a slender tube where diverticulum and spermathecal duct arising from; diverticulum extremely long, nearly as long as adult body length, evenly thinned apically, slender tube-shaped and spiral; spermathecal duct long and slender, 0.2 × as long as diverticulum; spermatheca slender tube-shaped and spiral, obviously thinner than spermathecal duct and nearly as long as diverticulum, with basal part extended into a short tube, at opening of accessory gland; accessory gland thin, 0.3 × as long as spermatheca.

Abdominal sternite VIII ( Fig. 4B View FIGURE 4 ). Sleekly narrowed posteriorly, latero-apical angles widely rounded, posterior margin deeply and rectangularly emarginate in the middle, behind the notch with a trapezoid and moderately sclerotized lobe.

Diagnosis. The new species resembles S. laterophysus Švihla, 2004 from N. Myanmar in the body coloration and the structure of male genitalia. The two species differ from each other in the following characters: legs of S. nigritibius are mostly black, and coxae, trochanters and basal part of femora are yellow, while in S. laterophysus ( Fig. 1A View FIGURE 1 ), legs are mostly yellow, and apical part of femora and basal part of tibiae are black. For male genitalia of S. nigritibius , ventral processes of parameres are longer than dorsal plates, the laterophyses are slender and evenly narrowed apically in ventral view, while in S. laterophysus , the ventral processes of parameres are nearly as long as dorsal plates, laterophyses are shout at basal part and abruptly narrowed apically in ventral view ( Švihla 2004: fig. 146).

Etymology. The specific name is derived from the Latin niger (black) and tibia (shinbone), referring to its uniformly black tibiae.

Distribution. China (Xizang); NE India.