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.
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.
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).
World Genera of 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.
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