Clypeus expanded, covering mouthparts. Mandibles lamelliform, mostly membranous, with only outer margin hardened. Antennae with 8 or 9 segments, club with 3. Middle coxae widely separated. Posterior tibiae nearly always with single apical spur; if two spurs present (i.e., Melanocanthon), spurs mesad, adjacent (not separated by basal metatarsal segment). Elytra exposing pygidium, 6 visible, fused abdominal sternites. Anterior tarsi sometimes absent either in female or in both sexes.

This subfamily was divided by Cambefort (1991) into 12 tribes, ten of which are represented in the New World and two of which are limited to the Old World (Gymnopleurini and Scarabaeini). Members of this subfamily are commonly called dung beetles. Although many species feed on mammalian dung, others specialize to varying degrees upon the dung of other vertebrates and invertebrates, as well as on carrion, mushrooms, rotting fruit, and other decomposing plant material. The World fauna includes slightly over 5,000 described species in 234 genera, with close to 1,800 of these species belonging to the genus Onthophagus. Biology: Halffter and Matthews 1966, Halffter and Edmonds 1982, Hanski and Cambefort 1991. Keys to larvae: Ritcher 1966; Edmonds and Halffter 1978.

New World Tribes

Body size small to large (length 2-25 mm), shape round or oval. Head and pronotum lacking horns or carinae. Antenna with 9 segments. Middle and posterior tibiae slender, curved, only slightly expanded apically. Sexual dimorphism minimal.

The New World has 340 species in 27 genera, which equates to a third of the World fauna. Adults of most species are ball-rollers, and they shape carrion or dung into balls that are rolled away and buried at a distance from the food source. Key to genera: Halffter and Martínez 1977. Biology: Gordon and Cartwright 1974; Halffter and Halffter 1989.

Characteristics: Body 8-20 mm in length, elongate, robust, convex, generally black in color. Head or pronotum often with horns or tubercles, especially in males. Elytra with 9 discal striae. Scutellum hidden. Antenna with 9 segments. Middle and posterior tibia strongly expanded apically.

The Coprini is a relatively small tribe with ten genera and slightly under 400 species worldwide. Copris is the only representative of the tribe in the New World.

Characteristics: Body small and compact or large and robust (length 4-30 mm). Elytra with 7 or 8 discal striae. Scutellum hidden. Antenna with 9 segments. Middle and posterior tibia strongly expanded apically.

The Dichotomini is a diverse tribe with approximately 30 genera and 750 species worldwide. The New World has a large proportion of this diversity with close to 600 species in 23 genera.

Characteristics: Body 7-14 mm in length, elongate, usually flattened. Pronotum without basal pits near midline. Scutellum visible. Antenna with 8 segments.

Most of the 14 genera and 165 species in the tribe are found in Africa and Asia although Anoplodrepanus is restricted to the West Indies (Simonis 1981). Key to adults: Janssens 1953. Biogeography: Zunino 1982.

Characteristics: Body 10-20 mm in length, oblong, robust. Pronotum with pit on each side of midline near base. Scutellum small but visible. Elytron with prominent lateral carina. Antenna with 9 segments. Anterior tarsi lacking in both sexes. Middle and posterior tibiae strongly expanded at apex.

The Onitini is an Old World group with 18 genera and about 200 species.

Characteristics: Body 2-12 mm in length, oval, convex. Head and/or pronotum often with horns or carinae. Scutellum hidden. Elytra with 7 discal striae. Third segment of labial palpus small or inconspicuous. Antenna with 9 segments. Tarsi and tarsal claws present on all legs. Middle and posterior tibiae broadly expanded at apex.

Sexual dimorphism is usually well developed in Onthophagus species. Males typically have large horns on the head and/or pronotum (females with only carinae or rudimentary horns) or males have elongated foretibiae with a long setal brush at the apex. The world fauna includes over 2,200 species in 34 genera.

Characteristics: Body length 12-25 mm, robust, often with metallic coloration. Antenna with 9 segments, basal segment of club cup-shaped, enclosing distal 2 segments. Tarsal claws absent. Anterior tarsi lacking in males, present or absent in females.

This tribe is restricted to the New World with most of the 9 genera and 150 species found in the Neotropics. Many of the species exhibit strong sexual dimorphism with the males often possessing long horns on the head and/or pronotum. Zunino (1985) considered the Phanaeini to be a subtribe of the Onitini. Key to genera: Edmonds 1972, 1994.

Characteristics: Body length 6-10 mm, oval, compressed laterally with sides of pronotum and metasternum vertical. Color reddish brown to gray, surface matte, with setae on dorsum. Scutellum hidden. Antenna with 8 segments. Middle coxae very widely separated, forming lateral margin of body. Middle and posterior tibiae elongate, curved, barely enlarged at apex.

This tribe includes three genera of ball-rolling dung beetles. Most of the 60 species in the tribe are found in Africa and Asia, with only a few representatives in Europe and the New World.

References Cited
CAMBEFORT, Y. 1991. From saprophagy to coprophagy. In Hanski, I. and Y. Cambefort (eds.), Dung Beetle Ecology, pages 22-35. Princeton University Press, Princeton, NJ. 481 pp.

EDMONDS, W. D. 1972.
Comparative skeletal morphology, systematics and evolution of the Phanaeine dung beetles (Coleoptera: Scarabaeidae). University of Kansas Science Bulletin 49: 731-874.

EDMONDS, W. D. 1994. Revision of Phanaeus Macleay, a New World genus of Scarabaeine dung beetles (Coleoptera: Scarabaeidae, Scarabaeinae). Natural History Museum of Los Angeles County Contributions in Science 443: 1-105.

EDMONDS, W. D. and G. HALFFTER. 1978. Taxonomic review of immature dung beetles of the subfamily Scarabaeinae (Coleoptera: Scarabaeidae). Systematic Entomology 3: 307-331.

GORDON, R. D. and O. L. CARTWRIGHT. 1974.
Survey of food preferences of some North American Canthonini (Coleoptera: Scarabaeidae). Entomological News 85: 181-185.

HALFFTER, G. and W. D. EDMONDS. 1982. The Nesting Behavior of Dung Beetles (Scarabaeinae). An Ecological and Evolutive Approach. Instituto de Ecología, México, D.F. 176 pp.

HALFFTER, G. and V. HALFFTER. 1989. Behavioral evolution of the non-rolling roller beetles (Coleoptera: Scarabaeidae; Scarabaeinae). Acta Zoologica Mexicana (N.S.) 32: 1-53.

Revision monographica de los Canthonina americanos, IV parte. Clave para generos y subgeneros. Folia Entomologica Mexicana 38: 29-107.

HALFFTER, G. and E. G. MATTHEWS. 1966. The natural history of dung beetles of the subfamily Scarabaeinae (Coleoptera: Scarabaeidae). Folia Entomologica Mexicana 12-14: 1-312.

HANSKI, I. and Y. CAMBEFORT (eds.). 1991. Dung Beetle Ecology. Princeton University Press, Princeton, NJ. 481 pp.

JANSSENS, A. 1953.
Oniticellini (Coleoptera Lamellicornia). In Exploration du Parc National de l'Upemba, Mission G.F. De Witte. Institut des Parcs Nationaux du Congo Belge. Fascicle 11: 1-118.

RITCHER, P. O. 1966. White Grubs and Their Allies. A Study of North American Scarabaeoid Larvae. Oregon State University Press, Corvallis, OR. 219 pp.

SIMONIS, A. 1981. Anoplodrepanus, nuovo genere di Oniticellini (Coleoptera, Scarabaeidae). Bollettino del Museo di Zoologia dell'Universiti di Torino 7: 87-94.

ZUNINO, M. 1982. Aspectos taxonomicos y biogeográficos del poblamiento americano de Oniticellini (Coleoptera, Scarabaeidae). Acta del VIII Congreso Latinoamericano de Zoología, Mérida, Venezuela 2: 1083-1089.

ZUNINO, M. 1985. Las relaciones taxonomicas de los Phanaeina (Coleoptera, Scarabaeinae) y sus implicaciones biogeographicas. Folia Entomologica Mexicana 64: 101-115.