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; 11 segmented; 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. Tarsal segmentation formula 5, 5, 5. The tarsi without bilobed segments; without ‘hidden’ segments. Front tarsi with as many segments as the mid-tarsi; 5-segmented. Mid-leg tarsi 5-segmented; pentamerous. The claws of the mid-leg tarsi not appendaged. The claws of the mid-leg tarsi simple; with an empodium between them (this with no more than two setae). Hind tarsi with as many segments as the mid-tarsi; 5-segmented. 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. Exposed abdominal sternites 6–7; all articulated and movable. Abdominal segment 8 with apparently functional spiracles.
Adult habitat, ecology. Not predacious; coprophagous; associated with dung, or in decaying plant material.
Larvae. Larvae not predacious; coprophagous, or consuming decaying plant material; in dung, or in decaying plant material. The larvae stridulating by rubbing the mid- and hind-legs, the latter being atrophied.
Classification. Suborder Polyphaga; Infraorder Scarabaeiformia; Superfamily Scarabaeoidea.
Worldwide and British representation. About 600 species worldwide; genera about 30. 8 species in Britain; genera in Britain 3; Geotrupes, Odontaeus, Typhaeus. E.g., Odontaeus armiger (Many-horned Scarab); Geotrupes vernalis (Smooth Dor, or Clock-beetle).
General comments. Head and/or pronotum often conspicuously horned; the legs very powerful and heavily armed, stridulating by rubbing a file on the hind coxae over an abdominal ridge..
Illustrations. • Odontaeus armiger (Many-horned Scarab: B. Ent. 259). • Odontaeus armiger (details, B. Ent. 259). • Odontaeus armiger: B. Ent. 259, legend+text. • Odontaeus armiger: B. Ent. 259, text cont.. • Geotrupes vernalis (Smooth Dor Beetle): B. Ent. 266. • Geotrupes vernalis: B. Ent. 266, legend+text. • Geotrupes vernalis: B. Ent. 266, text cont.. • Geotrupes stercorarius, G. sylvaticus (= stercorarius), G. vernalis, Odontaeus armiger (with Scarabaeidae and Trogidae): Fowler 4, 102 (1890). • Fowler 5, 102 (1890): original legend..
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: 2nd January 2012. http://delta-intkey.com’.
