Cestradoretus melolonthoides ( Fairmaire, 1896 ) Frolov & Montreuil, 2019

Frolov, Andrey V. & Montreuil, Olivier, 2019, A review of the Madagascan species of the genus Cestradoretus Ohaus (Coleoptera: Scarabaeidae: Rutelinae: Adoretini), Zootaxa 4638 (2), pp. 296-300 : 299

Cestradoretus melolonthoides ( Fairmaire, 1896) , new combination ( Figs. 2 A–I)

Adoretus melolonthoides Fairmaire, 1896: 454 .

Trigonostomum melolonthoides: Ohaus, 1912: 412 .

Type material examined. Holotype ♀ ( Figs 2A, B ): “ Diego Suarez Bontemps / Muséum Paris Madagascar Collection Léon Fairmaire 1906 / ♀ / TYPE / Adoretus melolonthoides Madag. ” ( MNHN).

Additional material. 1♂: “Muséum Paris Madagascar Reg. de Sakarami [Sakaramy] Maurice de Rothshildt 1905” ( MNHN); 1♂: “ Ambodimadiro , Grande Terre ” ( MNHN) ; 1♀: “ Mt des Français , Madagascar ” ( MNHN) ; 2♂ and 3♀: “ Madagascar Nord , 37 km. N de Vohemar, foret de Analalava, 25 m, 10/ 18-XII-1968 P. Viette et P. Griveaud ” ( MNHN) ; 1♂: “ Madagascar Ile de Beraphia Cote Ouest 1934” ( MNHN) ; 19♂ and 4♀: “ Madagascar, Antsiranana Prov., Ankarana , Ambondromifehy, 5-6.XII.1996, Ivo Jenis leg. ” ( MNHG, MNHN, ZIN).

Differential diagnosis. Cestradoretus melolonthoides , new combination differs from C. tenuirostris in having para- meres less fused apically (separated about half length, narrow and spine-like apically) and having short spine dorsobasally ( Fig. 2C ), and darker color with elytra having striate pattern in most specimens ( Fig. 2D ). In addition, the sexual dimor- phism is more pronounced than in C. tenuirostris .

Male ( Fig. 2D ) differs from female in having longer antenna, narrower elytra, smaller tarsal claw being shorter, shorter and sinuate apical abdominal sternite ( Figs. 2H, G ), and clypeus being rounded (as opposed to being somewhat triangular apically in female, Figs. 2E, F ).

Variability. Color pattern of elytra varies from brown to dark brown with intermediate forms having more or less distinct longitudinal stripes ( Figs. 2A, D, F ).

Remarks. The species was described from a single female specimen and no more findings were recorded so far. It was originally described in the genus Adoretus Castelnau, 1840 . Ohaus (1912) moved it to the genus Trigonostonum, based on the short medial process on the apical margin of labrum. He failed to recognize that this process was broken in the type specimen and apparently he did not see any other specimens except for this type. In the large series available now we found all specimens having a long, acute process similar to that in C. tenuirostris .

Distribution. Northern and Eastern Madagascar: S.-P. Antsiarana, S.-P. Ambanja, S.-P. Vohemar ( Fig. 2I ).

Figures

FIGURES 2A–H. Cestradoretus melolonthoides (Fairmaire, 1896), new combination. A, B, holotype, female; C, D, H, male; E–G, female; A, D, F, habitus; B, labels; C, aedeagus in lateral and parameres in dorsal view; E, head in ventral view; G, H, abdomen in ventral view; I, locality map (white circle—C. tenuirostris, black circle—C. melolonthoides). Scale bar = 1.0 mm.