Cybister cf. limbatus ( Fabricius, 1775 ), 1882

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 : 85

Cybister cf. limbatus ( Fabricius, 1775)

( Figs 8A–E ; 18F ; 21A)

Dytiscus limbatus Fabricius, 1775: 230 (orig. descr.).

Dytiscus aciculatus Herbst, 1784: 123 (orig. descr.), synonymy by SCHÖNHERR (1808: 10).

Cybister limbatus: SHARP (1882: 739) (Manchuria) ; ZIMMERMANN (1919: 77) (Taiwan); KANO (1931: 176) (Taiwan); MORI & KITAYAMA (1993: 144) (Taiwan).

Material examined. CHINA: GUANGDONG: 1 ♀, Canton, Honam

Island, P’an-yu District. 25.vii.1934, William E. Hoffmann leg. ( SYSU);

1 J, Lung-tau Shan,Yiu vill., above Taokokwan, 600 m, 7.vi.1947, PM,

Gressitt & Lam ( SYSU); 13 JJ 3 ♀♀, Guangzhou, 14.xi.1964, T. X.

Peng got from market ( SYSU). GUANGXI: 1 J, Nanning, 19.vi.1977,

Z. H. Huang leg. ( SYSU). HAINAN: 1 J, Sanya, 28.xii.1963, T. X. Peng leg. ( SYSU); 1 J, Jianfengling Mt., 1.xi.1983, P. L. Chen leg. ( SYSU);

1 ♀, Limushan Mt., 28.v.1984, G. R. Lin leg. ( SYSU). YUNNAN: 1 ♀,

Longling County, 1060 m, 24.vi.1956, B. S. Zhou leg. ( SYSU).

Diagnosis. TL 33–39 mm, elongate, oblong-oval ( Fig. 8A ). 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 reddish-brown spot on each side ( Fig. 8B ). Dorsal surface dimorphic: smooth sometimes with inconspicuous small granules in male, in female with isolated short, irregular striae on pronotum and dense longitudinal striae of various length 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; both sexes with a single metatarsal claw. Median lobe of aedeagus ʻCʼ- shaped in lateral view, moderately curved ( Fig. 8C ); gradually narrowed from base to near apex in ventral view, apex furcate, with a deep obtuse-angled notch medially, lateral margins of apex concave ( Fig. 8D ). Parameres moderately broad, strap-like apically ( Fig. 8E ).

Comments to classification. As mentioned under C. guerini , it will be necessary to study the type material of C. limbatus and C. guerini to clarify the status of both taxa. Specimens of the same morphospecies can be found under the two different names in many historical collections ( HENDRICH & BRANCUCCI 2013).

Habitat. This species inhabits deep ponds and abandoned paddy fields with aquatic plants ( MORI & KITAYAMA 1993, HENDRICH & BRANCUCCI 2013); specimens from Danxiashan Mt. (Guangdong) were found in a temporary pond in a valley ( Fig. 18F ). In Thailand, the adults prey on larvae and pupae of Aedes aegypti (Linnaeus, 1762) and Culex quinquefasciatus Say, 1823 ( YUKALAND 2005). The species is sold as food in Thailand ( CHEN et al. 1998) and Laos ( HENDRICH & BRANCUCCI 2013).

Distribution. China (Guangdong, Guangxi, Hainan, Taiwan, Xizang, Yunnan, “Manchuria”) ( Fig. 21A), Afghanistan, India, Japan, Laos, Myanmar, Nepal, Pakistan, Philippines, Thailand, Vietnam (RḖGIMBART 1899; ZIMMERMANN 1920; FENG 1932, 1933b; GSCHWENDTNER 1938; VAZIRANI 1969; ZAITZEV 1972; MORI & KITAYAMA 1993; NILSSON 1995; GHOSH & NILSSON 2012; HENDRICH & BRANCUCCI 2013; NILSSON & HÁJEK 2022b). The record of C. limbatus from Northeast China by SHARP (1882) is outside the distribution area of this Oriental species and needs to be confirmed. First records from Guangdong, Guangxi and Hainan.

Figures

Fig. 8. Cybister limbatus (Fabricius, 1775) (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. 18. Habitats of Cybister in China. A–C – lake, Shanxi (C. chinensis); D–E – lowland marsh, Shenzhen, Guangdong (C. rugosus, C. tripunctatus lateralis and C. sugillatus); F – temporary pond in a valley, Danxiashan Mt., Guangdong (C. tripunctatus lateralis and C. limbatus); G – natural pond, Lankeshan Mt., Zhejiang (C. rugosus and C. brevis); H – terraced fields pools, Lvchun County, Yunnan (C. convexus and C. sugillatus).