Insects of Britain and Ireland: the families of Coleoptera

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L. Watson and M. J. Dallwitz


Family name listed by neither Kloet and Hincks nor Unwin.

Wounded-tree beetles.

General appearance. About 5 mm long. Body length/maximum body width 1.43–1.56. Elytral length/pronotal length 4–4.8. 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 oval; dorsally strongly convex; with the legs semi-contractile; not necked; not waisted; decidedly short-legged (retracting firmly into cavities in the ventral body surface, cf. Byrrhidae). Upper surfaces of body glabrous or subglabrous, or non-glabrous; not bristly; exhibiting scales or scale-like setae, or with neither scales nor scale-like setae.

Detailed morphology. Beetles not prognathous. Eyes not strongly protuberant; without bristles; finely facetted. The labrum at least partly visible in antero-dorsal view; labrum mostly moderately to heavily sclerotized. Mandibles with a well developed mola; with well developed prosthecae. The mandibular apices simple. The incisor edges of the mandibles simple, or with a single tooth. The maxillae with distinct galea and lacinia apically to the palp. The apical segment of the maxillary palps cylindrical to fusiform. The apical segment of the labial palps not expanded apically. Antennae very short to short; 11 segmented; clubbed (and with segment 3 unusually elongate). Antennal clubs 3 segmented (tomentose); preceded by a cupule. Antennal insertions hidden from above.

Cervical sclerites present. Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.31–0.35. The pronotum with lateral keels (pronotal carinae); keels complete. Prothorax at its widest markedly narrower than the adjoining part of the abdomen, or not markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Scutellum conspicuous; elevated above the mesoscutum in lateral view; anteriorly simple; posteriorly narrowly rounded or acute. The prosternal process complete; slightly overlapping the mesoventrite, or moderately or strongly overlapping the mesoventrite. Metaventrite without a transverse groove. The fore-leg coxae countersunk in ‘procoxal cavities’. The fore-leg coxal cavities open behind externally; broadly open; narrowly separated; strongly transverse; without lateral extensions; internally open. The mid-leg coxae countersunk in ‘mesocoxal cavities’; separated by less than the shortest diameter of the cavity, or more than the shortest diameter of the cavity. The mid-leg coxal cavities moderately to widely separated; not or scarcely oblique; open laterally. Hind-leg coxae contiguous or narrowly separated; not markedly extended laterally; moveable; posteriorly shaped to receive the retracted femur (with a sharp-edged declivity or hollow). 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 penultimate segment not distinctly shorter than the antepenultimate one. 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; 5-segmented.

Elytral length/maximum width across the elytra 1.14–1.28. Elytra covering most to all of the abdomen; exposing no more than part of the terminal tergite; hard; glossy. Elytra with six or more longitudinal lines of punctures, or apunctate, irregularly punctate, or each with fewer than 6 longitudinal lines of punctures or impressed striae; the lines per elytron when more than five, 11. Scutellary striole absent. Wings well developed. Wings with an anal lobe. Wings without a medial fleck. Abdominal sternites 5; all articulated and moveable. Abdominal segment 8 with apparently functional spiracles. The male external genitalia trilobate.

Adult habitat, ecology. Under bark (feeding on fermentation products?).

Larvae. Mature larvae small to medium-sized. The larvae elongate and more or less parallel-sided, or oblong to ovate. Body somewhat flattened. Vestiture restricted to fine hairs or setae. The larvae dorsally heavily pigmented or sclerotized; ventrally only very lightly pigmented. The antennae 3 segmented. Stemmata present; on either side of the larval head 5. The frontoclypeal suture between frons and clypeus distinct. The labrum and head capsule separated by a complete suture. Apices of the mandibles with a single lobe or tooth. The maxillary palps 3 segmented. The labium with a short ligula between the palps. Labial palps present and segmented; 2 segmented. Mesothoracic legs present and segmented; 5 segmented; with 1 moveable claw. Visible abdominal segments 9. Tergum 9 of the abdomen completely ventral. The abdomen having functional spiracles on anterior segments (these annular-biforous); with the spiracles on the eighth segment borne at the ends of spiracular tubes, or with anterior and 8th-segmental spiracles borne at the ends of a series of spiracular tubes. The abdominal apex without a respiratory chamber. Abdominal tergum 8 bearing a single median process with a pair of spiracles at its apex. The last abdominal segment without cerci.

Larvae in decaying plant material, in rotting wood, and under bark (associated with wounded trees); seemingly feeding on bacteria and slime fluxes associated with fermentation.

Classification. Suborder Polyphaga.

Representation in Britain and Ireland, and worldwide. Genera 2 (Nosodendron, Nosotetocus). 1 species in Britain (?); genera in Britain 1 (?); Nosodendron. E.g., the mainland-European Nosodendron fasciculare (Tufted Nosodendron), the probably adventive mainland-European species illustrated by Curtis.

Illustrations. • Nosodendron fasciculare (Tufted Nosodendron: B. Ent. 246. Probably adventive). • Nosodendron fasciculare (details, B. Ent. 246). • Nosodendron fasciculare: B. Ent. 246, legend+text. • Nosodendron fasciculare: B. Ent. 246, text cont..

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Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 2003 onwards. Insects of Britain and Ireland: the families of Coleoptera. Version: 16th May 2016.’.