Cercyon (Cercyon) kubani, Ryndevich & Jia & Fikáček, 2017

Ryndevich, Sergey K., Jia, Fenglong & Fikáček, Martin, 2017, A review of the Asian species of the Cercyon unipunctatus group (Coleoptera: Hydrophilidae: Sphaeridiinae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 57 (2), pp. 535-576 : 547-549

Cercyon (Cercyon) kubani sp. nov.

( Figs 5 , 13 )

Type locality. China, Yunnan, Weibaushan Mts., 2800-3000 m, 25º12N 100º24E.

Type material. HOLOTYPE: ♂ ( NHMB):‘ Yunnan, 2800-3000 m, 25º12N 100º24E, Weibaushan, mts. , 29-30/6.92, Vít Kubáň leg.’ PARATYPES: CHINA: YUNNAN: 13 spec. ( NHMB, NMPC, CSR, SYSU): same data as holotype; 2 spec. ( NHMB): same label data but 2600–3000 m, D. Král leg.; 1 spec. ( CSR): E slope of Daxueshan , W of Niutoushan, 24º07’31’’N 99º40’21’’E to 24º07’15’’N 99º39’12’’E, 2940–3375 m, 3.vi.2010, I. Belousov & I. Kabak leg.

Diagnosis. Head black; pronotum pale brown to yellowish with central dark spot which may extend more or less laterally; elytra brown to yellowish, in some specimens with darker coloration along suture and in humeral area; epipleuron yellowish brown; maxillary palpi yellowish, last palpomere darker; elytra and pronotum with very sparse short pale hairs; elytral intervals flat, very slightly convex in apical part; mesoventral plate very narrowly elongate, ca. 9.0–10.0× as long as wide; fifth abdominal ventrite not emarginate apically; paramere wide subapically, strongly narrowing in apical half; median lobe strongly widening at midlength, strongly narrowing apically; apex of sternite 9 with six short subapical setae, base slightly rounded.

Description. Form and color. Body elongate oval ( Figs 5A–B ), length 2.4–2.7 mm, width 1.5–1.7 mm. Head black with very small brownish preocular spots. Pronotum pale brown to yellowish, with dark central spot which may extend more less laterally but still leaving large lateral part of pronotum pale. Scutellum yellowish to brown. Elytra brown to yellowish brown, whole elytral disc may be slightly darker, or sutural interval and humeral area may bear vague dark areas; epipleuron brownish yellow. Antennae yellowish to yellowish brown except for darker club. Maxillary palpomeres yellowish to brownish yellow, last palpomere darker. Ventral surface dark brown to black, mesoventral plate and metaventral pentagon yellowish brown to brown, posterior margins of abdominal ventrites yellowish brown or brownish. Legs yellowish brown.

Head. Clypeus with densely arranged, moderately coarse punctures, interstices without microsculpture. Anterior margin of clypeus with narrow bead. Frontoclypeal suture undetectable. Frons without microsculpture on interstices. Eyes small, somewhat protruding, interocular distance ca. 6.0× the width of one eye in dorsal view. Mentum glabrous, ca. 1.6× as wide as long, densely and coarsely punctate. Antennae with 9 antennomeres, scapus ca. 1.3× as long as antennomeres 2–5 combined, club compact. Maxillary palpomere 2 strongly swollen, palpomere 4 almost symmetrical, equal to palpomere 3 in length.

Thorax. Elytra and pronotum with very sparse short pale hairs. Pronotum ca. 2.2–2.3× as wide as long. Pronotal punctation similar to that on head. Lateral margins of pronotum with narrow bead overlapping anterior and posterior corners, anterior and central part of posterior margin of pronotum without bead. Prosternum with strong longitudinal carina medially; antennal groove distinct, moderately large, rounded laterally. Mesoventral plate very narrowly elongate, ca. 9.0–10.0× as long as wide, widest in medial part ( Fig. 5G ). Metaventrite with raised, glabrous, sparsely punctate median pentagonal area; femoral lines absent. Elytra with ten punctate striae, striae 1–9 impressed and reaching base, stria 10 very short; elytral intervals flat, very slightly convex in apically part; ground punctures on intervals very fine. Humeral bulge indistinct. Epipleuron flat, horizontal. Femora with sparse and shallow punctures ventrally, with distinct tibial groove. Tarsi with densely arranged whitish setae ventrally, first metatarsomere about as long as metatarsomeres 2–3 combined.

Abdomen. Abdomen with five ventrites, first ventrite distinctly longer than other ventrites, ca. 2× as long as second ventrite, bearing distinct median longitudinal carina; fifth ventrite not emarginate apically.

Male genitalia ( Figs 5C–E ). Phallobase shorter than parameres, asymmetrical basally. Paramere rather wide basally, strongly narrowed in apical half; apex membranous, obliquely cut-off, its mesal edge with setae subapically. Median lobe swelling at midlength, weakly narrowing towards base with short ароdemes, strongly narrowing towards widely triangular apex; apex obtusely pointed; gonopore rather large, situated subapically. Median projection of sternite 9 bearing six short subapical setae, base slightly rounded, median portion shorter than lateral struts.

Variation. The species varies in the dorsal coloration of the pronotum and elytra ( Figs 5A–B ). The genitalia of all specimens are identical irrespective of the coloration.

Etymology. The species is named after Vít Kubáň ( Czech Republic) who collected the type material.

Biology. Almost all type specimens were collected at light in forest (V. Kubáň, pers. comm.).

Distribution. The species is known from two localities in the mountains of SW Yunnan, in altitudes 2800–3400 m a.s.l.

Figures

Fig. 5. Cercyon kubani sp. nov.A–B dorsal and lateral habitus of paratypes from China: Yunnan: Weibaoshan; C–E – male genitalia of the holotype (C – tegmen; D – median lobe; E – sternite 9). F–I – ventral morphology (F – meso- and metaventrite; G – detail of mesoventral plate; H – prosternum and antennal groove; I – mentum).

Fig. 13. Known distribution of the species of C. unipunctatus species group in Asia.