Insects of Britain and Ireland: the families of Coleoptera

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L. Watson and M. J. Dallwitz


Latridiidae, Corticariidae; ~ Endomychidae.

Minute Brown Scavenger Beetles.

General appearance. 1–3 mm long. Body length/maximum body width 1.45–2.6. Elytral length/pronotal length 2.2–4.9. Base of prothorax not or scarcely narrower than the combined elytral bases, or distinctly 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 elongate-oval to elongate; conspicuously necked; conspicuously waisted. Upper surfaces of body glabrous or subglabrous, or non-glabrous; exhibiting stiff, erect, dark bristles, or not bristly; with neither scales nor scale-like setae.

Detailed morphology. Eyes strongly protuberant, or not strongly protuberant; without bristles. 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, or bidentate or bilobed, or multidentate or multilobed (some Latridiinae). The incisor edges of the mandibles with a single tooth (some Corticariinae), or with two or more teeth. The maxillae with distinct galea and lacinia apically to the palp (some Corticariinae), or with a single apical structure additional to the palp. The apical segment of the maxillary palps cylindrical to fusiform (Corticariinae), or aciculate (Latridiinae). The apical segment of the labial palps not expanded apically. Antennae short; 10–11 segmented. Antennal scape not swollen. Antennae clubbed (sometimes weakly). Antennal clubs 2 segmented, or 3 segmented. Antennal insertions visible from above, or hidden from above.

Cervical sclerites absent. Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.45–1.3. The pronotum with lateral keels (pronotal carinae), or without lateral keels (some Corticariinae); keels when present, complete, or incomplete. Prothorax at its widest markedly narrower than the adjoining part of the abdomen (often sculptured). Prothorax without notopleural sutures. Scutellum conspicuous to absent; when applicable, elevated above the mesoscutum in lateral view, or not elevated; anteriorly simple; posteriorly broadly rounded or obtusely angulate, or truncate. The prosternal process complete; slightly overlapping the mesoventrite. Metaventrite without a transverse groove. The fore-leg coxae countersunk in ‘procoxal cavities’. The fore-leg coxal cavities closed behind externally; broadly closed; narrowly separated; circular to longer than wide; without lateral extensions; internally closed by a slender bar (some Corticariinae), or broadly closed internally. 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 (some Latridiinae). The mid-leg coxal cavities narrowly separated, or moderately to widely separated; not or scarcely oblique; closed laterally. Hind-leg coxae contiguous or narrowly separated, or widely separated; not markedly extended laterally; not shaped posteriorly to receive the femur. Tarsal segmentation formula 3, 3, 3. The tarsi without bilobed segments; without ‘hidden’ segments. Front tarsi with as many segments as the mid-tarsi; 3-segmented. Mid-leg tarsi 3-segmented; trimerous; 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, or one-toothed or bifid. Hind tarsi with as many segments as the mid-tarsi; 3-segmented.

Elytral length/maximum width across the elytra 1–2.2. Elytra covering most to all of the abdomen; exposing no more than part of the terminal tergite; rough (or wrinkled), or smooth; non-glabrous, or glabrous. 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, 6–7, or 8, or 12 or more. Scutellary striole absent. Wings well developed, or absent or much reduced; fringed with long hairs on the hind margin. Wings with an anal lobe, or without an anal lobe. Wings with a medial fleck; the medial fleck not bisected by a vein. Abdominal sternites 5, or 6; all articulated and moveable. Abdominal segment 8 apparently without functional spiracles. The male external genitalia cucujiform.

Adult habitat, ecology. Not predacious; in decaying plant material, in rotting wood, under bark, associated with fungi, and on shed fur or feathers (i.e., in diverse habitats, including damp plaster in houses and nests of insects); mycetophagous (feeding on moulds and mycetozoa, fungal spores and hyphae of larger fungi).

Larvae. Mature larvae minute (less than 3 mm long). The larvae elongate and more or less parallel-sided. Body circular in cross-section to somewhat flattened. Vestiture restricted to fine hairs or setae, or not restricted to fine hairs or setae. The larvae dorsally only very lightly pigmented or sclerotized; ventrally only very lightly pigmented. The antennae 3 segmented. Stemmata present; on either side of the larval head 1–5, or 6. The frontoclypeal suture between frons and clypeus indistinct or absent. The labrum and head capsule separated by a complete suture. Apices of the mandibles with a single lobe or tooth to multilobed or multidentate. The maxillary palps 3 segmented. The labium without ligula between the palps, or with a short ligula between the palps. Labial palps present and segmented; 1 segmented, or 2 segmented. Mesothoracic legs present and segmented; 5 segmented; with 1 moveable claw. Visible abdominal segments 10. Tergum 9 of the abdomen entirely dorsal. The abdomen having functional spiracles on anterior segments (these annular); without spiracular tubes. The abdominal apex without a respiratory chamber. The last abdominal segment without cerci.

Larvae in decaying plant material, in rotting wood, under bark, associated with fungi, and in shed fur or feathers (cf. the adults); seemingly mainly mycetophagous (feeding on moulds and mycetozoa, and on larger fungi and spores).

Classification. Suborder Polyphaga; Superfamily Cucujoidea.

Representation in Britain and Ireland, and worldwide. At least 1050 species worldwide; genera about 30. 61 species in Britain; genera in Britain 13; Adistemia, Aridius, Cartodere, Corticaria, Corticarina, Cortinicara, Dienerella, Enicmus, Holoparamecus, Lathridius, Lithostignus, Melanophthalma, Stephostethus, Thes. E.g., Dienerella elongata (Elongated Latridius); Holoparamecus singularis.

General comments. Tiny beetles, with elytra often coarsely punctured or ribbed.

Illustrations. • Dienerella elongata (Curtis) (Elongated Latridius: B. Ent. 311). • Dienerella elongata (details, B. Ent. 311). • Dienerella elongata: B. Ent. 311, legend+text. • Dienerella elongata: B. Ent. 311, text cont.. • Aridius, Cartodere, Corticaria, Corticarina, Enicmus, Lathridius and Melanophthalma, with Cucujidae: Fowler 3, 92 (1889). • Fowler 3, 92 (1889): original legend.. • Lathridius lardarius (with Rhizophagidae, Trogossitidae, Merophysiidae, etc.): Fowler 3, 91 (1889). • Fowler 3, 91 (1889): original legend.. • Corticaria (3 spp.), Melanophthalma distinguenda and Thes bergrothi, with unrelated taxa: Fowler Suppl. 13, 1913. • Fowler Suppl. 13, 1913: original legend..

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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.’.