Cybister cf. guerini Aubé, 1838

Jiang, Zhuo-Yin, Zhao, Shuang, Mai, Zu-Qi, Jia, Feng-Long & Hendrich, Lars, 2023, Review of the genus Cybister in China, with description of a new species from Guangdong (Coleoptera: Dytiscidae), Acta Entomologica Musei Nationalis Pragae 63 (1), pp. 75-102 : 80

Cybister cf. guerini Aubé, 1838

( Figs 4A–E ; 20A )

Cybister guerini Aubé, 1838:57 (orig.descr.); SHARP (1882): 741 ( China,

Manchuria); RḖGIMBART (1899): 342 (Guangdong); FENG (1932): 35

(Guangdong); ZENG (1989): 91 (Guangdong).

Material examined. CHINA: GUANGDONG: 76 spec., Guangzhou, 14.xi.1964, T.X.Peng got from market ( SYSU); 1J 1♀, Nanhai District, Xiqiaoshan Mt., 11.x.1973, S. T. Lu leg. ( SYSU); 1 J 2♀♀, Guangzhou ( SYSU). HAINAN: 1 J, Lingshui County, Diaoluoshan Mt., Xiaomei Village, 29.xii.1963, L. F. Huang leg. ( SYSU).

Diagnosis. TL 31–36 mm, elongate, oblong-oval ( Fig. 4A ). Head dark green, clypeus yellow. Pronotum and elytra dark green to black, with distinct yellow margins laterally; apex of yellow margin on elytra hooked. Ventral surface black; abdominal ventrites III–V with a yellow spot on each side ( Fig. 4B ). Dorsal surface dimorphic: smooth sometimes with inconspicuous small granules in male, in female with isolated short, irregular striae on pronotum, and with dense longitudinal striae of various lengths on elytra except at its apex. Prosternal process lanceolate, with distinct lateral bead, surface flat, apex pointed; lateral parts of metaventrite tongue-shaped, slender, not reaching lateral margins; metacoxal lines distinct, well impressed, nearly parallel medially, divergent anteriorly, along metacoxal lines with a row of punctures. Forelegs reddish-brown, midlegs and hindlegs reddish-brown to black; protarsomeres 1–3 of male broadly expanded into a palette, with four rows of adhesive setae on their ventral side; metatarsal claws single in both sexes. Median lobe of aedeagus ʻCʼ- shaped in lateral view, moderately curved ( Fig. 4C ); slightly narrow near apex in ventral view, apex furcate, with a notch medially, lateral margins of apex sinuate ( Fig. 4D ). Parameres moderately broad, strap-like apically ( Fig. 4E ).

Comments to classification. As already mentioned in HENDRICH & BRANCUCCI (2013), it will be necessary to study the type material of C. guerini and C. limbatus carefully before identifying freshly collected material. In many collections, historical specimens of the same species can be found under the two different names.

Habitat. The knowledge of habitat of Cybister guerini is very poor, all specimens examined here were collected in 1960s and 70s without habitat information. Some specimens from Guangzhou were obtained from a market.

Distribution. China (Guangdong, Hainan, Hong Kong, “Manchuria”) ( Fig. 20A ), India, Indonesia, Laos, Thailand, Vietnam (RḖGIMBART 1899; ZIMMERMANN 1920; FENG 1932, 1933b; GSCHWENDTNER 1938; VAZIRANI 1969; ZENG 1989; NILSSON 1995, NILSSON & HÁJEK 2022b). The record of C. guerini from Northeast China by SHARP (1882) is outside the distribution area of this Oriental species and needs to be confirmed. First record from Hainan.

Figures

Fig. 4. Cybister guerini Aubé, 1838 (J, Guangzhou, Guangdong).A – habitus in dorsal view; B – habitus in ventral view; C – median lobe of aedeagus in lateral view; D – median lobe of aedeagus in ventral view; E – paramere. Scale bars: 5.0 mm (A, B), 1.0 mm (C–E).

Fig. 20. Map of distribution of Cybister in China.