Overview. Members of the Ceratocanthidae are distinguished from other scarabaeoids by the ability of the adult to form a nearly compact sphere. When disturbed, adults deflect the head, pronotum, and legs, thus forming a tight ball.

Description.Length 2.0-9.0 mm. Shape nearly spherical when head and pronotum deflexed. Color black, greenish black, or purplish, often with metallic luster. Head deflexed. Antennae 10-segmented with 3-segmented, opposable club (all segments tomentose); basal segment of antenna triangular and enlarged. Eyes partially divided by canthus, with eucone ommatidia. Clypeus lacking tubercle or horn. Labrum truncate, partially exposed beyond apex of clypeus. Mandibles partially exposed beyond apex of clypeus. Maxillae with 4-segmented palpi. Labium with 4-segmented palpi. Pronotum broad, compressed laterally. Elytra convex, surface highly polished and glabrous. Pygidium concealed by elytra. Scutellum exposed, triangular. Legs with anterior coxae conical, prominent; mesocoxae transverse; tibiae (especially meso- and metatibae) hortizontally flattened and broad (concealing sternites when contracted in spherical form), external surface striated; protibia with outer margin serrately toothed, apex with one spur; meso- and metatibia with 2 apical spurs; spurs mesad, adjacent (not separated by basal metatarsal segment); tarsi 5-5-5; claws equal in size, simple; empodium absent. Abdomen with 5 free sternites; 8 functional abdominal spiracles situated in pleural membrane (spiracles 1-7) and in tergite (spiracle 8). Wings well developed, M-Cu loop reduced or absent, with 1 apical detached vein. Male genitalia variable. References: Cooper 1983; Scholtz 1990.

Classification Status. The Ceratocanthidae is considered a family within the Scarabaeoidea or a subfamily of the family Scarabaeidae. In this volume, we follow Lawrence and Newton (1995) and consider the group a family. The group was previously referred to as the Acanthoceridae. The family name Ceratocanthidae has been erroneously attributed to Cartwright and Gordon (1971:275) and to Martínez (1968:14). However, White (1842:93) should be credited with the family name. White (1842) proposed the name Ceratocanthus as a replacement name for Acanthocerus MacLeay (1819), which is a hemipteran. White designated C. aeneus MacLeay as the type for the genus. Based on The Statement of Principle Coordination (Ride et al. 1985, International Rules of Nomenclature, Article 36), "A name established for a taxon at any rank in the family group is deemed to be simultaneously established with the same author and date for taxa based upon the same name-bearing type. . ." As such, the family should be correctly cited as Ceratocanthidae White 1842:93. Phylogenetic analyses postulate that the family Ceratocanthinae is most closely related to the family Hybosoridae (Scholtz et al. 1988; Howden and Gill 1988; Howden and Gill 2000). However, Cooper (1983) postulated that the Ceratocanthidae is most closely related to the Trogidae. Howden and Gill (2000) provide an excellent synopsis of the genera of New World ceratocanthids as well as keys to genera.

Distribution. The family is widely distributed in the tropics. No ceratocanthids are known from Europe, and only three are known from Australia. In North and South America, the group includes three tribes, sixteen genera and about 130 species (Paulian 1982; Howden and Gill 1988a; Howden and Gill 1988b; Howden and Gill 1995; Howden and Gill 2000).

New World Genera of Ceratocanthidae

Ceratocanthidae
Ceratocanthini Martínez, 1968
Anopsiostes Paulian, 1982
Astaenomoechus Martínez and Pereira, 1959
Aulisostes Howden and Gill, 2000
Ceratocanthoides Paulian, 1982
Ceratocanthopsis Paulian, 1982
Ceratocanthus White, 1842
Cloeotus Germar, 1843
Germarostes (Germarostes) Paulian, 1982
Germarostes (Haroldostes) Paulian, 1982
Glyptopterus Paulian, 1982
Martinezostes Paulian, 1982
Nesopalla Paulian and Howden, 1982
Scarabatermitini Nikolajev, 1999
Trachycrusus Howden and Gill 1995
Xenocanthus Howden and Gill 1982
Scarabaeinus Silvestri, 1939
Scarabatermes Howden, 1972
Ivieloini Howden and Gill, 2000
Ivieolus Howden and Gill 1988

Ecology. Adult ceratocanthids can be collected in a variety of habitats and using a variety of collecting methods. Adults have been collected on the bark and branches of dead trees and vines, on fungi, in the burrows of passalid beetles, in litter, in flight intercept traps, in carrion traps, and occasionally at lights. Adults have also been found in association with termites and ants. When disturbed, these beetles are able to deflex their head and pronotum, thus concealing the entire ventral side. When contracted in this manner, they resemble spherical seeds. This behavior probably allows them to evade potential predators. This trait occurs in a lesser degree in some Hybosoridae. Adults probably feed on fungi (Nel and Scholtz 1990) or on rotting wood (Ohaus 1909). Adults of one genus (Scarabaeinus) are termitophiles and possess an unusual, swollen abdomen with lateral, finger-like glands (Howden and Gill 2000). Larvae have been collected under bark (Ritcher 1966) and have been reared from the frass of passalid burrows (Woodruff 1973). Both adults and larvae of at least some species stridulate.

Larvae. Form scarabaeoiform (C-shaped, cylindrical). Color creamy-white or yellow (except at caudal end which may be darkened by accumulated feces). Cranium heavily sclerotized, yellow-brown to dark brown. Antennae 4-segmented. Frontoclypeal suture distinct. Labrum with apical margin serrate, palpi 1-2 segmented. Epipharynx with dextral, beak-like process. Maxilla with galea and lacinia separate; maxillary stridulatory area with a row of conical teeth; maxillary palp 4-segmented. Abdominal segments 1-6 with 3 annuli, each with one or more transverse rows of short setae. Spiracles cribriform. Venter of last abdominal segment with transverse palidia of spatulate setae. Legs 4-segmented, well developed, with stridulatory apparatus on all legs or on meso- and metathoracic legs, each with a well-developed claw. References: Ritcher 1966; Scholtz 1990.

References Cited

CARTWRIGHT, O. L. and R. D. GORDON. 1971. Coleoptera: Scarabaeidae. Insects of Micronesia 17: 257-296.

COOPER, J. B. 1983. A review of the Nearctic genera of the family Scarabaeidae (exclusive of the subfamilies Scarabaeinae and Geotrupinae) (Coleoptera), with an evaluation of computer generated keys. Doctoral Thesis, Department of Biology, Carleton University, Ottawa, Ontario, Canada. 1,121 pp.

HOWDEN, H. F. and B. D. GILL. 2000. Tribes of New World Ceratocanthinae, with keys to genera and descriptions of new species (Coleoptera: Scarabaeidae). Sociobiology 35(2B): 281-329.

HOWDEN, H. F. and B. D. GILL. 1988a. Xenocanthus, a new genus of inquiline Scarabaeidae from southeastern Venezuela (Coleoptera). Canadian Journal of Zoology 66: 2071-2076.

HOWDEN, H. F. and B. D. GILL. 1988b. A fourth genus of unusually modified Ceratocanthinae (Coleoptera: Scarabaeidae) from South America. Canadian Journal of Zoology 66: 2077-2079.

HOWDEN, H. F. and B. D. GILL. 1995. Trachycrusus, a new genus of Ceratocanthinae (Coleoptera: Scarabaeidae) with two new species from Peru. The Canadian Entomologist 127: 587-593.

LAWRENCE, J. F. and A. F. NEWTON, JR. 1995. Families and subfamilies of Coleoptera (with selected genera, notes, and references and data on family-group names), pp. 779-1006. In J. Pakaluk and S. A. Slipinski (eds.), Biology, Phylogeny, and Classification of Coleoptera. Papers Celebrating the 80th Birthday of Roy A. Crowson. Muzeum i Instytut Zoologii PAN, Warszawa, Poland.

MacLEAY, W. S. 1819. Horae Entomologicae: or Essays on the Annulose Animals, Volume 1: 1-524. London.

MARTÍNEZ, A. 1968. Insectos nuevos o poco conocidos XIII. Ceratocanthini nom. nov. para Acanthocerini (Coleoptera, Scarabaeidae, Troginae). Revista de la Sociedad Entomológica Argentina 30: 9-16.

NEL, A. and C. H. SCHOLTZ. 1990. Comparative morphology of the mouthparts of adult Scarabaeoidea (Coleoptera). Entomology Memoires of the Republic of South Africa Department of Agricultural Development 80: 1-84.

OHAUS, F. 1909. Beitrage zur Kenntnis unserer einheimschen Rosskafer. Deutsche Entomologische Zeitschrift 109: 105-111.

PAULIAN, R. 1982. Révision des Cératocanthides (Coleoptera Scarabaeoidea) d'Amérique du Sud. Mémoires du Muséum National d'Histoire Naturelle, Série A, Zoologie 124: 1-110.

RIDE, W. D. L., C. W. SABROSKY, G. BERNARDI, and R. V. MELVILLE (eds.). 1985. International Code of Zoological Nomenclature, third edition. University of California Press, Berkeley. 338 pp.

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

SCHOLTZ, C.H. 1990. Phylogenetic trends in the Scarabaeoidea (Coleoptera). Journal of Natural History 24: 1027-1066.

SCHOLTZ, C.H., D. D'HOTMAN, A.V. EVANS, and A. NEL. 1988. Phylogeny and systematics of the Ochodaeidae (Insecta: Coleoptera: Scarabaeidae). Journal of the Entomological Society of South Africa 51: 207-240.

WHITE, A. 1842. XIII. Description of some hemipterous insects of the section Heteroptera. Transaction of the Entomological Society of London 3: 84-94.

WOODRUFF, R. E. 1973. Arthropods of Florida and Neighboring Land Areas. Volume 8. The Scarab Beetles of Florida (Coleoptera: Scarabaeidae). Part 1. The Laparosticti (Subfamilies: Scarabaeinae, Aphodiinae, Hybosorinae, Ochodaeinae, Geotrupinae, Acanthocerinae). Florida Department of Agriculture and Consumer Services, Contribution No. 260 Bureau of Entomology, Gainesville, Florida. 220 pp.