Cyclocephala robusta LeConte, 1863

Ratcliffe, Brett C. & Hoffman, Richard L., 2011, Cyclocephala nigricollisBurmeister (Coleoptera: Scarabaeidae: Dynastinae: Cyclocephalini). What is It? and Where is It?, The Coleopterists Bulletin 65 (2), pp. 135-138 : 136-138

Cyclocephala robusta LeConte, 1863 ( Figs. 1–5 )

Cyclocephala nigricollis Burmeister 1847: 54 (nomen dubium).

Cyclocephala robusta LeConte 1863: 79 (original combination).

Ochrosidia subvittata Brown 1930: 5 (synonym).

Description. Length 10.0– 12.2 mm; width 5.1– 6.8 mm. Color of males castaneous on head, elytra, and pygidium; pronotum, legs, and venter testaceous; some males on pronotum with castaneous clouding either side of testaceous midline; many specimens from Hinds Co., Mississippi totally black; females rufotestaceous to castaneous. Head: Frons completely, densely rugopunctate; punctures small, setigerous on frons in males, punctures slightly larger, less setose in females; setae long, reddish brown. Clypeus with apex broadly, semicircularly rounded, weakly reflexed in males; apex parabolic in females, noticeably thickened. Interocular width equals 2.0–3.5 transverse eye diameters in males, 6.0–6.5 transverse eye diameters in females. Antenna 10-segmented, club in males longer than segments 1–7, club in females subequal in length to segments 2–7. Pronotum: Surface in males densely punctate, punctures large, setigerous; setae long, reddish brown; surface in females with punctures moderate in density and size, glabrous. Base with slender marginal bead. Elytra: Surface in males densely punctate; punctures moderately large to large, setigerous; setae long, reddish brown. Surface in females similar but glabrous. Epipleuron (ventral view) of females simple, imperceptibly thickened at level of abdominal sternite 1. Pygidium: Surface in males shagreened, with sparse, small to moderately sized punctures, setose in pristine specimens; setae long, reddish brown, often abraded. Females with surface moderately to densely punctate; punctures glabrous, mostly moderately large, glabrous. In lateral view, surface in males strongly convex, females with surface nearly flat to weakly convex. Legs: Protibia tridentate, teeth subequally spaced. Protarsus in males enlarged: tarsomere 5 large, curved, flattened on venter with longitudinal row of setae; median claw large, curved, apex entire. Protarsus in female simple. Metatarsus in male distinctly longer than metatibia, subequal in length in female. Metatibia at apex with spurs long, acute in males, short and phylliform in females. Venter: Prosternal process extremely short, rounded, nearly obsolete. Parameres: As in Figs. 3–4 .

Diagnosis. While most species of Cyclocephala have some differences between the sexes, C. robusta

3) Caudal view; 4) Lateral view.

is remarkably different between males and females in ways not normally seen. Typical secondary sexual characteristics are, of course, present, such as differing lengths of the antennal clubs and metatarsi, size of the protarsus, form of the epipleuron, and convexity of the pygidium. But the body color, shape of the clypeus, size of the eyes, interocular distance, and metatibial spurs in C. robusta are all totally different. If the males and females had not been collected together, one would think they represent different species.

Cyclocephala robusta is differentiated from other Cyclocephala species in the United States by a combination of characters: presence of a basal bead on the pronotum; antenna with ten segments and with a club longer than the shaft in males; males with larger claw on the protarsus entire; the near absence of a prosternal process; phylliform metatibial spurs of the females; simple epipleuron in the females; and form of the parameres ( Figs. 3–4 ).

Distribution. Cyclocephala robusta is known from Arkansas, Louisiana, Mississippi, Oklahoma, Texas, South Carolina, North Carolina, and Virginia ( Fig. 5 ). The Carolinas/ Virginia population is extremely disjunct, and specimens are rarely encountered. It is difficult to explain this broad separation between eastern and southern populations, but our careful examination of specimens from both areas satisfies us that they are the same species.

problems. We are grateful to two anonymous reviewers for their comments to improve the manuscript. This project was supported by an NSF/ BS&I grant (DEB 0716899) to B. C. Ratcliffe and R. D. Cave.

Harpootlian (2001) referred to Kirk’ s (1970) listing of “ C. nigricollis ” in South Carolina but discounted its occurrence there and so did not include it in his scarab beetles of South Carolina. Brimley (1938) reported C. nigricollis from Morganton, North Carolina, but his specimen, now in the insect museum at North Carolina State University, is referable to C. lurida .

Biology. Adults are attracted to lights, but otherwise nothing is known of the life history of C. robusta .

Figures

Figs. 1–2. Habitus of Cyclocephala robusta. 1) Male; 2) Female.

Figs. 3–4. Parameres of Cyclocephala robusta.

Fig. 5. Distribution map for Cyclocephala robusta.