British insects: the families of Coleoptera
British insects: the families of Coleoptera | |
Including Syncalyptidae.
General appearance. 1.2–10 mm long. Body length/maximum body width 1.25–1.8. Elytral length/pronotal length 1.9–3.9. 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, or distinctly narrower than greatest elytral width. Beetles short, stout, oval; dorsally strongly convex; having ventral body cavities into which the legs fold to conform with the general body surface; not necked; not waisted; decidedly short-legged (retracting the legs firmly into cavities in the ventral body surface when alarmed); dull black, or bright metallic green. Upper surfaces of body glabrous or subglabrous, or non-glabrous; not bristly, or exhibiting stiff, erect, dark bristles; exhibiting scales or scale-like setae, or with neither scales nor scale-like setae.
Detailed morphology. Beetles prognathous, or not prognathous. Inclination of the head slight. Eyes strongly protuberant, or not strongly protuberant; without bristles; finely facetted. Antennae very short to short; (10–)11 segmented; gradually expanding towards the apex. Antennal insertions visible from above, or hidden from above; not in fossae. Mandibular prosthecae well developed to absent. Pronotal length/maximum pronotal width 0.38–0.65. Prothorax without notopleural sutures. The scutellum elevated. Metaventrite with a transverse groove, or without a transverse groove. Hind coxae posteriorly shaped to receive the retracted femur (with a sharp-edged declivity or hollow). Tarsal segmentation formula 5, 5, 5, or 4, 4, 4. The tarsi without bilobed segments; with a tiny penultimate segment hidden by distal lobing of the fourth and fused to the fifth, or without ‘hidden’ segments (third segment lobed beneath, fourth small, fifth long, the terminal segment not as long as the other four together). Front tarsi with as many segments as the mid-tarsi; 4-segmented, or 5-segmented. Mid-leg tarsi 4-segmented, or 5-segmented; pentamerous, or tetramerous. 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; 4-segmented, or 5-segmented. Elytral length/maximum width across the elytra 0.9–1.43. Elytra exposing no more than part of the terminal tergite. Scutellary striole absent. Wings well developed, or absent or much reduced. Exposed abdominal sternites 5; comprising both fused and movable components; immovably joined 2, or 3. Abdominal segment 8 apparently without functional spiracles.
Larvae. Larvae under stones, in moss, in grass roots, etc.
Classification. Suborder Polyphaga; Infraorder Elateriformia; Superfamily Byrrhoidea.
Worldwide and British representation. About 280 species worldwide. 12 species in Britain; genera in Britain 6; Byrrhys, Cytilus, Morychus, Porcinolus, Simplocaria, Syncalypta. E.g., Byrrhus pilula ssp. dennii (Denny's Byrrhus); Simplocaria semistriata (Half-channelled Byrrhus).
General comments. Retracting the appendages tightly when alarmed.
Illustrations. • Byrrhus pilula ssp. dennii (Denny's Byrrhus: B. Ent. 135). • Byrrhus pilula ssp. dennii (details, B. Ent. 135). • Byrrhus pilula: B. Ent. 135, legend+text. • Byrrhus pilula: B. Ent. 135, text cont.. • Simplocaria semistriata (Half-channelled Byrrhus: B. Ent. 335). • Simplocaria semistriata (detail, dissections: B. Ent. 335). • Simplocaria semistriata (legend+text: B. Ent. 335). • Simplocaria semistriata (text, cont.: B. Ent. 335). • Byrrhus, Cytilus, Morychus, Syncalypta and Simplocaria (with Dermestidae etc.): Fowler 3, 97 (1889). • Fowler 3, 97 (1889): 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’.
