Parastasia bimaculata ( Guérin-Méneville, 1843 )

Hongsuwong, Thitipong, Sanguansub, Sunisa & Jaitrong, Weeyawat, 2022, A new species and a new synonym in the scarab genus Parastasia Westwood, 1841 (Coleoptera: Scarabaeidae: Rutelinae), with a key to species from Thailand, Zootaxa 5205 (6), pp. 547-562 : 556

Parastasia bimaculata ( Guérin-Méneville, 1843)

( Figs. 40–50 )

Barymorpha bimaculata Guérin-Méneville, 1843: 41 , plate XI, fig. 2. Type locality: Pulo Pinang, Malay Peninsula (type depository not known).

Parastasia bimaculata ( Guérin-Méneville, 1843) : Burmeister 1844: 376; Westwood 1845: 99; Snellen van Vollenhoven 1864: 150; Ohaus 1898: 21; Ohaus 1900: 232, fig. 1; Arrow 1917: 42; Ohaus 1918: 33; Ohaus 1926: 111; Ohaus 1932: 130, Ohaus 1934: 101; Ohaus 1935: 5; Machatschke 1972: 40; Kuijten 1992: 35, figs. 25–29.

Cyclocephala bimaculata Montrouzier, 1855: 23 . Type locality: unknown; Reiche in Montrouzier 1860: 271 [junior synonymy].

Material examined. Southern Thailand: 1 female (THNHM-I-09984, THNHM), Ranong province, Kay Hotel , 9.II.1967, N. Kobayashi leg. ; 1 female (THNHM-I-09985, THNHM), Nakhon Si Thammarat province, Krungching waterfall, tropical rain forest, 21.I.2007, N. Pinkhaw [= N. Pinkaew] leg .; 1 male (THNHM-I-09986, THNHM), Nakhon Si Thammarat province, Sichon district, Khao Nan national park, Yod Nam waterfall, 21.II.2008, T. Jeenthong leg. ; 1 male and 1 female ( CTH), Nakhon Si Thammarat province, Promkiri district, Phrom Lok subdistrict, 12.III.2021, larva and pupa collected from the rotten log, 31.III.2021 – 14.IV.2021, emerged, C. Phothaworn leg.

Diagnosis (based on Thai specimens). Male: Dorsal surface of body mostly orange to reddish brown; posterior portion of pronotum with a pair of round darkish spots; ground color of elytra reddish brown, with irregular yellowish bands; anterior margin of elytra with dark markings medially. Head rather small with convex eye, ratio of IOD and HW 0.65. Lateral margins of pronotum rimmed, while posterior margin convex without rim. Elytra with 11 rows of round punctures, each row with distinct shallow longitudinal impression. Pygidium widely oval, 0.48 as long as width; anterior and lateral portions of pygidium densely reticulate, remaining parts smooth and shiny. All tarsal claws simply, acuminate, sickle-shaped, internal claws clearly smaller than external claws. Male genitalia: Extremely asymmetric (see Figs. 48–50 ) with parameres fused together; in dorsal view, external margin of parameres swollen; surface variously pitted. Female: Similar to the male in body size, sculpturing, and coloration with the following exceptions: body color slightly darker than male; pygidium subtriangular and convex; posterior portion of pygidium foveate; abdominal ventrites, especially ventrites 4–6 narrow.

Measurements. Male: TL 13.64–14.52 mm; BH 6.76–7.18 mm; EL 8.35–9.06 mm; EW 8.98–9.31 mm; PL 5.19–5.30 mm; PW 7.84–7.97 mm; HW 3.27–3.41 mm; IOD 2.04–2.10 mm; ED 1.42–1.44 mm. Female: TL 13.11–14.47 mm; BH 6.6–6.85 mm; EL 8.35–8.71 mm; EW 9.04–9.38 mm; PL 5.06–5.40 mm; PW 7.59–7.99 mm; HW 3.09–3.12 mm; IOD 2.02–2.04 mm; ED 1.32–1.33 mm.

Differential diagnosis. The species can be easily distinguished from the other Thai species as follows: 1) posterior portion of pronotum with a pair of round darkish spots; 2) unclear dimorphism between both sexes; 3) all claws simple, sickle-shaped in both male and female; 4) parameres extremely asymmetric.

Distribution. Thailand (Ranong and Nakhon Si Thammarat provinces, new records), India (Andaman Islands and Nicobar Islands); Myanmar (Rangoon) ( Ohaus 1898; Arrow 1917); Malaysia (Malay peninsula and Borneo) ( Guérin-Méneville 1843; Snellen van Vollenhoven 1864), Singapore ( Ohaus 1898), Indonesia (Sumatra and Java) ( Kuijten 1992), and Philippines ( Kuijten 1992).

Remarks. Kato et al. (2000) mentioned that P. bimaculata was associated with the flowers of Homalomena propinqua (= currently H. humilis ) ( Araceae ) in Borneo. In Thailand, we have never observed P. bimaculata visiting flowers of H. humilis .

Figures

FIGURES 40–50. Parastasia bimaculata (Guérin-Méneville, 1843), non-type specimens. 40–42, 46, male (CTH); 43–45, 47, female (CTH); 48–50, aedeagus of male; 40, 43, 48, dorsal view; 41, 44, 49, ventral view; 42, 45, 50, lateral view; 46–47, caudal view.