Stenothemus minutissimus (Pic, 1933) Yang & Yang & Liu, 2021

Yang, Yuxia, Ge, Shujuan, Yang, Xingke & Liu, Haoyu, 2021, Taxonomic revision of the species of Stenothemus from Southwest China (Coleoptera, Cantharidae), with the descriptions of five new species, European Journal of Taxonomy 757 (1), pp. 1-36 : 15-17

Stenothemus minutissimus (Pic, 1933) comb. nov.

Figs 5B , 6D‒F , 7A , 8C

Cantharis minutissima Pic, 1933b: 117 .

Kandyosilis minutissima – Wittmer 1954: 76.

Micropodabrus minutissimus – Kazantsev & Brancucci 2007: 257.

Material examined

Holotype

CHINA • ♂; [h] “Chine // Kansu”, “Ongles // simples”, “ Cantharis // minutissima // n. sp.”, [p] “HOLOTYPE”, [h-p] “genre? // det. W.Wittmer”, “ Stenothemus // minutissimus (Pic) // det. Y. X. Yang, 2009”; MNHN.

Additional material

CHINA ‒ Sichuan • 1 ♀; Maerkang-Daoping ; 3230 m a.s.l.; 8 Jul. 1961; G.F. Li leg.; IZAS • 2 ♂♂; same collection data as for preceding; 22 Jul. 1961; G.F. Li leg.; IZAS • 13 ♂♂, 11 ♀♀; Sigu’niang Shan, Changpinggou ; 3300‒3400 m a.s.l.; 31 Jul. 2004; H.J. Xue leg.; IZAS .

Redescription

Body length (both sexes): 5.0‒ 6.3 mm; width: 1.0‒ 1.4 mm.

Male ( Fig. 5B )

COLORATION. Body black, mouthparts and pronotum yellow, pronotum with an irregularly darkened marking on central disc, elytra brown. Body sparsely covered with short, semi-recumbent yellow pubescence.

HEAD. Subquadrate, surface densely and finely punctate, each side with a smooth and rectangular impression behind antennal socket; eyes moderately protruding, head width across eyes 1.4 times as wide as pronotum; terminal maxillary palpomeres long-triangular, widest in middle; antennae filiform, extending to ⅔ length of elytra, antennomeres II about 1.8 times as long as wide at apices, III about 1.6

times as long as II, IV‒XI each with a small and smooth longitudinal impression in middle of outer edge, VII longest, XI slightly longer than X, pointed at apex.

PRONOTUM. Subquadrate, about 1.1 times as long as wide, anterior margin nearly straight, anterior angles obtuse, widely truncate, lateral margins narrowed posteriorly, and slightly sinuate, posterior margin slightly sinuate, posterior angles obtuse, slightly protruding, disc distinctly convex on posterolateral parts, surface finely and densely punctate.

ELYTRA. Nearly parallel-sided, about 3.6 times as long as humeral width, 4.6 times longer than pronotum, surface finely and densely punctate, present with hardly visible longitudinal costae.

AEDEAGUS ( Fig. 6D‒F ). Strongly swollen laterally at basal part, apically reduced in diameter; basal piece slightly shorter than dorsal plate of each paramere, with a moderately large, bifurcate conjoined middle nodule at base of ventral side; ventral processes of parameres nearly parallel to each other, short and distinctly thickened apically; dorsal plates of parameres conjoined, with a rounded emargination in the middle of the apical margin, distinctly longer than the ventral process, apex rounded, with a pair of protuberances on inner surface; apical part of laterophyses depressed and separated from each other, apex acute, not reaching middle emargination between dorsal plates.

Female

Similar to male, but body stouter, eyes small, less protruding, head width across eyes 1.2 times as wide as pronotum, antennae shorter and extending to elytral mid-length, IV‒XI without impressions; elytra about 3.0 times as long as humeral width.

ABDOMINAL STERNITE VIII ( Fig. 7A ). Moderately narrowed posteriorly, lateroapical angles obtusely triangular and protruding, posterior margin shallowly and triangularly emarginate in middle and slightly sinuate on both sides; behind the notch with a membrane, which is sclerotized and triangularly bilobed at apex.

INTERNAL ORGAN OF REPRODUCTIVE SYSTEM ( Fig. 8C ). Vagina stout, with median oviduct situated at ventroapical part, vagina abruptly narrowed in apical part and extended into a short duct which diverticulum and spermathecal duct are arising from; diverticulum relatively short, about 0.41 times adult body length, evenly thinned apically, slender tube-shaped and spiral; spermathecal duct slightly long but much shorter than diverticulum; spermatheca slender tube-shaped and spiral, obviously thinner than spermathecal duct and slightly longer than diverticulum, with basal part extended into a short tube, at opening of accessory gland. Accessory gland thin and slightly shorter than spermatheca.

Distribution

China (Gansu, Sichuan). New record for Sichuan Province.

Remarks

Having examined the type, and some additional specimens available, we redescribe this little-known species. Based on the structure of the aedeagus and all simple claws, it should be placed in Stenothemus .

Figures

Fig. 5. Habitus, dorsalview.A. Stenothemus jindraiŠvihla, 2004, holotype, ♂ (NMPC).B. S. minutissimus (Pic, 1933) comb. nov., holotype, ♂ (MNHN). C. S. tryznai Švihla, 2004, holotype, ♂ (NMPC). D. S. singularicollis (Pic, 1933) comb. nov., holotype, ♀ (NHMH). E. S. melleus Švihla, 2005 syn. nov., holotype, ♂ (= S. singularicollis) (NMPC). Scale bars = 1.0 mm.

Fig. 6. Aedeagus (A, D, G = ventral view; B, E, H = dorsal view; C, F, I = lateral view).A‒C. Stenothemus grahami Wittmer, 1974 (MHBU, Henan). D‒F. S. minutissimus (Pic, 1933) comb. nov. (IZAS, Sichuan). G‒I. S. gracilis Y. Yang & X. Yang sp. nov. (MHBU HBU(E) 410022). Scale bars = 0.5 mm.

Fig. 7. Abdominal sternite VIII of female, ventral view. A. Stenothemus minutissimus (Pic, 1933) comb. nov. (IZAS, Sichuan). B. S. tryznai Švihla, 2004 (IZAS, Sichuan). C. S. singularicollis (Pic, 1933) comb. nov. (MHBU, Shaanxi). D. S. gracilis Y. Yang & X. Yang sp. nov., paratype (IZAS IOZ(E) 225787). E. S. flavicollis Y. Yang & S. Ge sp. nov., paratype (MHBU HBU(E) 410039). F. S. laticornis Y. Yang & H. Liu sp. nov., paratype (MHBU HBU(E) 410047). Scale bars = 1.0 mm.

Fig. 8. Female reproductive system, ventral view. A. Stenothemus grahami Wittmer, 1974 (IZAS, Gansu). B. S. jindrai Švihla, 2004 (IZAS, Sichuan). C. S. minutissimus (Pic, 1933) comb. nov. (IZAS, Sichuan). D. S. tryznai Švihla, 2004 (IZAS, Sichuan). Abbreviations: see Material and methods. Scale bars = 0.5 mm.