British Insects: the Families of Coleoptera
British Insects: the Families of Coleoptera |
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~Scarabaeidae.
Dor-, Dung-, Clock-beetles.
General appearance. 11–26 mm long. Body length/maximum body width 1.17–1.57. Elytral length/pronotal length 1.4–2.35. Base of prothorax not or scarcely narrower than the combined elytral bases. Greatest prothoracic width not narrower or only slightly narrower than the greatest elytral width. Beetles stoutly oval to elongate-oval; dorsally strongly convex; not necked; conspicuously waisted; generally dark reddish brown or black. Upper surfaces of body glabrous or subglabrous; not bristly; with neither scales nor scale-like setae.
Detailed morphology. Beetles prognathous. Inclination of the head slight. Eyes not strongly protuberant; without bristles; finely facetted. Antennae very short to short; strongly asymmetric; conspicuously elbowed, or not elbowed; 10–11 segmented; without a much-elongated scape; clubbed. Antennal clubs lamellate (circular, biconvex); preceded by a cupule, or without a cupule. Antennal insertions hidden from above; not in fossae.
Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.36–0.58. Prothorax at its widest not markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Metaventrite without a transverse groove. The tarsi without bilobed segments; without ‘hidden’ segments. Mid-leg tarsi 5-segmented; pentamerous. Claws of the mid-leg tarsi not appendaged. Front tarsi with as many segments as the mid-tarsi; 5-segmented. Hind tarsi with as many segments as the mid-tarsi; 5-segmented. Tarsal claws simple; with an empodium between them (this with no more than two setae). Elytral length/maximum width across the elytra 0.75–1.1. Elytra exposing no more than part of the terminal tergite; glossy; iridescent (commonly), or not iridescent. Scutellary striole absent. Elytra glabrous. Wings well developed, or absent or much reduced.
Visible abdominal sternites 6–7; immovably joined 0. Abdominal segment 8 with apparently functional spiracles.
Habitat, ecology. Not predacious; coprophagous; associated with dung, or in decaying plant material.
General comments. Head and/or pronotum often conspicuously horned; stridulating by rubbing a file on the hind coxae over an abdominal ridge; the legs powerful and heavily armed.
Larvae. Larvae not predacious; coprophagous, or consuming decaying plant material; in dung, or in decaying plant material.
Classification. Suborder Polyphaga; Superfamily Scarabaeoidea.
British representation. Genera 3; 8 species. E.g., Odontaeus armiger (Many-horned Scarab); Geotrupes vernalis (Smooth Dor, or Clock-beetle).
Illustrations. • Odontaeus armiger (Many-horned Scarab: B. Ent. 259). • Odontaeus armiger (details, B. Ent. 259). • Odontaeus armiger: B. Ent. 259, legend+text. • Geotrupes vernalis (Smooth Dor Beetle: B. Ent. 266).
To view the illustrations with detailed captions, go to the interactive key. This also offers full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, and distributions of character states within any set of taxa.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. British insects: the families of Coleoptera. Version: 9th June 2008. http://delta-intkey.com’.
