Stenothemus nigricolor Y. Yang & S. Ge, 2021

Ge, Shujuan, Yang, Xingke, Liu, Haoyu & Yang, Yuxia, 2021, Studies on the Stenothemus harmandi species-group (Coleoptera, Cantharidae), with descriptions of two new species from China, Biodiversity Data Journal 9, pp. 68659-68659 : 68659

Stenothemus nigricolor Y. Yang & S. Ge sp. n.

Materials

Type status: Holotype. Occurrence: recordedBy: Qiu Tengfei; individualCount: 1; sex: male; lifeStage: adult; Taxon : scientificName: Stenotemus nigricolor; Location : country: China; stateProvince: Xizang; locality: Nyingchi , Medog , Dagmo , 81 K ; Event : eventDate: 10.08.2016; Record Level : collectionCode: Insects ; ownerInstitutionCode: MHBU; basisOfRecord: Preserved Specimen Type status: Paratype. Occurrence: recordedBy: Qiu Tengfei; individualCount: 3; sex: males; lifeStage: adult; Taxon : scientificName: Stenotemus nigricolor; Location : country: China ; stateProvince: Xizang; locality: Nyingchi , Medog , Dagmo , 81 K ; Event : eventDate: 10.08.2016; Record Level : collectionCode: Insects ; ownerInstitutionCode: MHBU; basisOfRecord: Preserved Specimen Type status: Paratype. Occurrence: recordedBy: Qiu Tengfei; individualCount: 6; sex: females; lifeStage: adult; Taxon : scientificName: Stenotemus nigricolor; Location : country: China ; stateProvince: Xizang; locality: Nyingchi , Medog , Dagmo , 81 K ; Event : eventDate: 10.08.2016; Record Level : collectionCode: Insects ; ownerInstitutionCode: MHBU; basisOfRecord: Preserved Specimen

Description

Body length (both sexes): 5.1-6.5 mm (5.6 mm in holotype); width: 1.3-1.8 mm (1.3 mm in holotype).

Male (Fig. 1 d).

Body black, mouth-parts pale yellow, legs dark brown. Body densely covered with short, semi-recumbent pale pubescence.

Head. Surface densely punctate, each side with a smooth, rectangular impression behind antennal fossa; eyes small, strongly protruding, head across eyes 1.1 times wider than pronotum; terminal maxillary palpomeres elongate-triangular, widest at basal one-third; antennae filiform, extending to two-thirds length of elytra, antennomeres II 2.2 times as long as wide at apices, III 1.5 times longer than II, IV nearly as long as V, XI longer than X, pointed at apex.

Pronotum. 1.1 times wider than long, anterior margin arcuate, anterior angles rounded, lateral margins arcuate, posterior margin bisinuate and narrowly bordered, posterior angles sharp, protruding laterad, disc strongly convex on posterolateral parts, surface sparsely punctate.

Elytra. Nearly parallel-sided, 3.3 times as long as combined humeral width, 4.2 times as long as pronotum, surface densely punctate, longitudinal costae hardly visible.

Aedeagus (Fig. 3 ). Moderately swollen dorsally at base in lateral view, strongly reduced in diameter apically; basal piece nearly as long as dorsal plate of each paramere, with a large, bifurcate conjoined middle nodule at base of ventral side; ventral processes of parameres approaching each other in ventral view, long and thickened apically, bent ventrally at an angle of 30 degrees to median lobe in lateral view; dorsal plates shorter than ventral processes, abruptly narrowed apically (apical part about one-half as wide as basal part); laterophyses rounded at apices, exceeding into emargination between dorsal plates.

Female.

Body stouter than in male, eyes smaller, head across eyes nearly as long as pronotum, antennae shorter and approximately extending to quarter length of elytra; elytra 3.1 times as long as combined humeral width.

Internal organ of reproductive system (Fig. 4 b). Vagina stout, with median oviduct situated at ventro-apical part, vagina abruptly narrowed in apical part and extended into a short tube from where diverticulum and spermathecal duct are arising; diverticulum long, 0.3 times as long as adult body length, evenly thinned apically, slender tube-shaped and spiral; spermathecal duct 0.1 times as long as diverticulum; spermatheca slender tube-shaped and spiral, thinner than spermathecal duct and 0.9 times longer than diverticulum, with basal part extended into a short tube, at opening of accessory gland. Accessory gland thin in basal part and the remainder relatively thick, 0.5 times as long as spermatheca.

Abdominal sternite VIII (Fig. 6 c, d). Lateral margins narrowed posteriorly, latero-apical angles obtusely rounded, posterior margin shallowly emarginate, with a protuberance in the middle and arcuate on both sides, behind the notch with a membrane which is sclerotised.

Diagnosis

It resembles S. alexandrae Švihla, 2004 stat. n. (type locality: N. India) in the structure of aedeagus, but differs in the following characters: the body is black, pronotum is 1.1 times as wide as long, of which anterior margin is arcuate, the aedeagus has the ventral process of each paramere even in width in ventral view. In comparison, S. alexandrae has a dark brown body, pronotum is 1.4 times as wide as long, of which anterior margin is nearly straight and the ventral process of each paramere is widened apically ( Švihla 2004: figs. 142-144).

Etymology

The specific name is derived from the Latin niger (black) and color (colour), referring to its black body colouration.

Distribution

China (Xizang).

Figures

Figure 3. Aedeagus of S. nigricolor sp. n.: A. ventral view; B. dorsal view; C. lateral view; bp: basal piece; dp: dorsal plates; la: laterophyse; nd: nodule; vp: ventral processes of parameres; ag: accessory gland; Scale bar: 1.0 mm