Clyster scaurus Prell, 1911

Pathomwattananurak, W., Jeenthong, T. & Tasen, W., 2019, To the knowledge of the subfamily Dynastinae (Coleoptera: Scarabaeidae) from Thailand, Far Eastern Entomologist 393, pp. 1-10 : 2-4

Clyster scaurus Prell, 1911

Figs 1–5

Clyster scaurus Prell, 1911: 208 . Type locality: Cochinchine [ VIETNAM], Saigon [Ho

Chi Minh] (MfN).

Clyster scaurus: Endrodi, 1974: 320 , fig. 1.

MATERIAL. Thailand: Trat Province, Ko Kud district, Ban Khlong Chao, 19.IV

2009, 1♂ (THNHM-I-10052, THNHM), T. Jeenthong leg.; Trat Province, Muang district , Laemglad, Lan Sai beach, 29.V 2016 , 1♀ (THNHM-I-10010, THNHM), T .

Jeenthong leg.

genitalia, dorsal view; 4 – male genitalia, ventral view; 5 – male genitalia, lateral view.

DIAGNOSIS. Adult male ( Figs 1–2 ). BL 26 mm, BW 12 mm. Body entirely dark brown; anterior face of pronotum punctate, while posterior face smooth and shiny; elytra finely punctate. This species is most closely related to Clyster itys

(Olivier, 1789), a Sundaland species ( Figs 6–10 ), but can be separated from the latter by the following characteristics: 1) anterior face of pronotum flat and steep anteriorly, its posterior margin laterally with two small acute denticles, and ridge connecting the denticles sinuate (with two large truncate denticles, and ridge connecting the denticles with a distinct denticle in the latter), 2) area around lateral denticles shallowly depressed (distinctly deeply depressed in the latter, see figs 6–7). Male genitalia ( Figs 3–5 ). In dorsal view, paramere relatively long, broader anteriorly and gradually narrowed medially then suddenly broaden apically; apex of paramere with strongly convex lateral margin but almost straight inner margin ( Fig. 3 ). In lateral view, paramere strongly curved down, its apex relatively sharp ( Fig. 15 ) (see male genitalia of the closely related species C. itys , Figs 8–10 , for comparison).

DISTRIBUTION. Vietnam (Prell, 1911; Endrodi, 1974) and Thailand (new record).

REMARKS. To date, C. scaurus has been known only from the type locality

(Ho Chi Minh, Vietnam). We record this species in Thailand for the first time.

dorsal view; 9 – male genitalia, ventral view; 10 – male genitalia, lateral view.

Figures

Figs 1–5. Clyster scaurus: 1 – male, lateral view; 2 – male, dorsal view; 3 – male

Figs 6–10. Clyster itys: 6 – male, lateral view; 7 – male, dorsal view; 8 – male genitalia,

Figs. 11 – 15. Dichodontus crassus: 11– male, lateral view; 12 – male, dorsal view; 13–