Ruteloryctes Arrow, 1908

Moore, Matthew R., Cave, Ronald D. & Branham, Marc A., 2018, Synopsis of the cyclocephaline scarab beetles (Coleoptera, Scarabaeidae, Dynastinae), ZooKeys 745, pp. 1-99 : 59-60

Ruteloryctes Arrow, 1908

Types species.

Ruteloryctes tristis Arrow, 1908: 336, by monotypy.

Valid taxa.

Two species.

The two species of Ruteloryctes are distributed in the Guinea-Congo lowland rainforests of West and Central Africa. Ruteloryctes specimens have been collected in Angola, Benin, Cameroon, Chad, Côte d’Ivoire, Democratic Republic of the Congo, Guinea, Guinea-Bissau, Nigeria, Senegal, Sierra Leone, and The Gambia ( Burgeon 1947, Paulian 1954, Endrődi 1960, 1966, 1985a, Krell et al. 2003, Hirthe and Porembski 2003, Ervik and Knudsen 2003) (Fig. 62). Ruteloryctes morio is a pollinator of nocturnally blooming Nymphaea lotus L., and this floral association has been reported from Côte d’Ivoire, Senegal, and Nigeria ( Fabricius 1798, Krell et al. 2003, Hirthe and Porembski 2003, Ervik and Knudsen 2003). The immature stages of Ruteloryctes are undescribed.

Ruteloryctes species can be recognized by the following combination of characters: 1) dorsal coloration black to dark brown; 2) body convex, not strongly anteroposteriorly compressed or dorsoventrally flattened; 3) clypeal apex truncate or rounded in dorsal view; 4) frontoclypeal suture incomplete medially; 5) males with anterolateral margin of the mandibles lacking weak tooth; 6) mandibular molar area with rows of circular micropunctures; 7) apex of mentum weakly emarginated at middle; 8) galea of maxilla on inner surface with 3 fused basal teeth, a free median tooth, and 2 fused apical teeth (3-1-2 arrangement); 9) pronotum with broadly incomplete beaded basal margin; 10) males and females with 3 protibial teeth on lateral margin, basal tooth not greatly reduced, slightly removed from apical 2 teeth, and oriented laterally; 11) protibial spur straight to weakly deflexed; 12) males with inner protarsal claw enlarged and narrowly cleft at apex; 13) mesocoxae not widely separated, nearly touching; 14) meso- and metatibiae with distal, transverse carinae; 15) metacoxae with lateral edge perpendicular to ventral surface; 16) anterior edge of hindwing distal to apical hinge lacking setae and with produced, membranous border; 17) vein RA with single row of pegs proximal to apical hinge.

The original description of Ruteloryctes compared the genus to New World Dyscinetus species, and it was hypothesized to have "strayed across the Atlantic" ( Arrow 1908). Endrődi (1966) thought that Ruteloryctes was one of the most “primitive” cyclocephaline genera. The 3-1-2 arrangement of the teeth on the maxillary galea in Ruteloryctes is most similar to Arriguttia , Augoderia , and many Cyclocephala species. The membranous border of the hindwing present in Ruteloryctes is also shared with Arriguttia , Acrobolbia , Ancognatha , Aspidolea , and Cyclocephala . However, the single row of pegs present on the hindwing RA vein in Ruteloryctes is present in Ancognatha , Surutu , Harposceles , Stenocrates , Dyscinetus , Erioscelis , and Chalepides .