British insects: the families of Coleoptera
British insects: the families of Coleoptera | |
Including Calyptomeridae.
Fringe-winged beetles.
General appearance. 0.8–1.8 mm long. Body length/maximum body width 1.1–1.55. Elytral length/pronotal length 0.85–3.6. 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 broadly oval; dorsally somewhat convex to dorsally strongly convex; not necked; not waisted. Upper surfaces of body glabrous or subglabrous, or non-glabrous; not bristly; with neither scales nor scale-like setae. Beetles rolling into a ball when alarmed (sometimes), or not conglobulating.
Detailed morphology. Inclination of the head slight. Eyes strongly protuberant, or not strongly protuberant; without bristles; coarsely facetted. Antennae short; 8–10 segmented; clubbed. Antennal clubs 2 segmented. Antennal insertions visible from above, or hidden from above. Pronotal length/maximum pronotal width 0.3–0.5. Prothorax without notopleural sutures. The scutellum elevated. Metaventrite without a transverse groove. Hind coxae posteriorly shaped to receive the retracted femur (transversely excavated). Tarsal segmentation formula 5, 5, 5. The tarsi without bilobed segments; without ‘hidden’ segments. Front tarsi with as many segments as the mid-tarsi; 4-segmented. Mid-leg tarsi 4-segmented (usually, cf. Imms (1957), Britton 1970, Lawrence et al. 1999); tetramerous (sometimes trimerous in non-British species). The claws of the mid-leg tarsi not appendaged. The claws of the mid-leg tarsi simple. Hind tarsi with as many segments as the mid-tarsi; 4-segmented. Elytral length/maximum width across the elytra 0.85–1.2. Elytra exposing no more than part of the terminal tergite. Scutellary striole absent. Elytra non-glabrous (sparsely setose). Wings well developed; fringed with long hairs on the hind margin, or not fringed. Exposed abdominal sternites 5–6; all articulated and movable. Abdominal segment 8 with apparently functional spiracles, or apparently without functional spiracles.
Adult habitat, ecology. Not predacious (?); in decaying plant material.
Larvae. Larvae not predacious (?); mycetophagous (?).
Classification. Suborder Polyphaga; Infraorder Elateriformia; Superfamily Eucinetoidea.
Worldwide and British representation. About 50 species worldwide; genera 5. 9 species in Britain; genera in Britain 2; Calyptomerus, Clambus.
General comments. Very small, oval beetles, commonly conglobulating when alarmed. Unwin gives tarsi as 5,5,5, seemingly in error: the other sources give 4,4,4, with Lawrence et al. also allowing 3,3,3.
Illustrations. • Calyptomerus, Clambus (from Joy). • Calyptomerus dubius and Clambus pubescens (with Leptinidae and Leiodidae): Fowler 3, 71 (1889). • Fowler 3, 71 (1889): original legend.. • Clambus punctulus: Fowler 6, 13 (1913).
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’.
