Insects of Britain and Ireland: the families of Coleoptera

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L. Watson and M. J. Dallwitz


Including Catapochrotidae.

Fungus-feeders, Silken Fungus Beetles.

General appearance. 1.3–11 mm long. Body length/maximum body width 1.48–2.95. Elytral length/pronotal length 1.48–3.6. 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; not necked; somewhat waisted. Upper surfaces of body glabrous or subglabrous, or non-glabrous; not bristly; with neither scales nor scale-like setae.

Detailed morphology. Beetles without a rostrum; prognathous. Inclination of the head slight. Eyes strongly protuberant, or not strongly protuberant; bristly, or without bristles. The labrum at least partly visible in antero-dorsal view; labrum mostly moderately to heavily sclerotized. Mandibles with a well developed mola. The mandibular apices simple (some Caenoscelini), or bidentate or bilobed, or multidentate or multilobed. The incisor edges of the mandibles variously simple, or with a single tooth, or with two or more teeth. 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 short to about half the insect's head to tail length; (10–)11 segmented. Antennal scape swollen, or not swollen (?). Antennae clubbed. Antennal clubs 3 segmented (loosely); not comprising two small basal segments and a large terminal one. Antennal insertions visible from above, or hidden from above; not in fossae.

Cervical sclerites present (Cryptophaginae), or absent. Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.4–1.5. The pronotum with lateral keels (pronotal carinae), or without lateral keels (some Atomariini); keels when present, complete, or incomplete. Prothorax at its widest not markedly narrower than the adjoining part of the abdomen; having the front corners produced, or with serrated sides, or with neither produced front corners nor serrated sides. Prothorax without notopleural sutures. Hind corners of the thorax not extended rearwards into sharp points. Scutellum conspicuous (usually), or highly reduced (some Atomariinae); elevated above the mesoscutum in lateral view; anteriorly simple; posteriorly narrowly rounded or acute (some Atomariinae), or broadly rounded or obtusely angulate, or truncate. The prosternal process complete; slightly overlapping the mesoventrite to moderately or strongly overlapping the mesoventrite, or concealing most or all of the mesoventrite (in some Caenoscelini). Metaventrite without a transverse groove. The fore-leg coxae countersunk in ‘procoxal cavities’. The fore-leg coxal cavities open behind externally; broadly open, or narrowly open; quite widely separated; strongly transverse, or slightly transverse, or circular to longer than wide; with narrow lateral extensions, or without lateral extensions; internally open (mostly), or internally closed by a slender bar (some Cryptophaginae). 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; closed laterally. Hind-leg coxae variously contiguous or narrowly separated, or widely separated; not markedly extended laterally; not shaped posteriorly to receive the femur. Tarsal segmentation formula 5, 5, 5, or 5, 5, 4, or 4, 4, 4. The tarsi exhibiting bilobed segments; with a tiny penultimate segment hidden by distal lobing of the fourth and fused to the fifth, or without ‘hidden’ segments. 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 pseudotetramerous, or tetramerous; the penultimate segment not distinctly shorter than the antepenultimate one, or distinctly shorter than the antepenultimate one. The claws of the mid-leg tarsi paired, not appendaged. The claws of the mid-leg tarsi simple. Hind tarsi with as many segments as the mid-tarsi, or with one segment fewer than the mid-tarsi; 4-segmented (sometimes, in males), or 5-segmented.

Elytral length/maximum width across the elytra 1–2.1. Elytra covering most to all of the abdomen; exposing no more than part of the terminal tergite. Elytra apunctate, irregularly punctate, or each with fewer than 6 longitudinal lines of punctures or impressed striae. Scutellary striole absent. Elytra with epipleura. Elytral epipleura falling short of the elytral tips (limited to the basal half). Wings well developed, or absent or much reduced. Wings variously with an anal lobe, or without an anal lobe. Wings without a medial fleck. Abdominal sternites 5; all articulated and moveable. Abdominal segment 8 apparently without functional spiracles. The male external genitalia cucujiform.

Adult habitat, ecology. In decaying plant material, in rotting wood, in dried plant material, associated with fungi, and on shed fur or feathers; consuming decaying plant material and mycetophagous (generally feeding on fungal material, whatever the habitat; commonly in houses, on moulds associated with damp plaster).

Larvae. Mature larvae minute (less than 3 mm long), or small to medium-sized. The larvae elongate and more or less parallel-sided. Body circular in cross-section, or somewhat flattened. Vestiture restricted to fine hairs or setae. The larvae dorsally heavily pigmented or sclerotized, or dorsally only very lightly pigmented or sclerotized (Cryptogasterus only); ventrally only very lightly pigmented. The antennae 3 segmented. Stemmata present, or absent; on either side of the larval head when present, 1–2, or 5. The frontoclypeal suture between frons and clypeus indistinct or absent. The labrum and head capsule separated by a complete suture, or partly fused, with an incomplete suture. Apices of the mandibles bilobed or bidentate. The maxillary palps 3 segmented. The labium with a short ligula between the palps (mostly), or with a ligula at least as long as the palps (Cryptogasterus). 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, or extending to the underside. The abdomen having functional spiracles on anterior segments (these annular or annular-biforous); without spiracular tubes. The abdominal apex without a respiratory chamber. Abdominal tergum 8 without amature. The last abdominal segment with cerci (mostly), or without cerci (some Atomariinae).

Larvae in decaying plant material, or in rotting wood, or in dried plant material, or under bark, or associated with fungi, or in shed fur or feathers, or associated with flowers (some Telmatophilus species being found in flowers of aquatic monocots); mostly mycetophagous (feeding on fungal material, whatever the habitat; commonly in houses, on moulds associated with damp plaster).

The larvae subcylindrical, whitish, with ocelli and 3-segmented antennae, the abdomen 10 segmented with the tenth constituting a proleg.

Classification. Suborder Polyphaga; Superfamily Cucujoidea.

Representation in Britain and Ireland, and worldwide. About 800 species worldwide. 110 species in Britain; genera in Britain 10; Antherophagus, Atomaria, Coenoscelis, Cryptophagus, Ephistemus, Henoticus, Micrambe, Ootypus, Paramecosoma, Telmatophilus. E.g., Antherophagus pallens (Punctured Antherophagus); Cryptophagus populi (Dark Cryptophagus Fungus-feeder); Paramecosoma melanocephalum.

General comments. Beetles very small, pubescent.

Illustrations. • Antherophagus pallens (Punctured Antherophagus: B. Ent. 546). • Antherophagus pallens: B. Ent. 546, legend+text. • Antherophagus pallens: B. Ent. 546, text cont.. • Cryptophagus populi (Dark Fungus-feeder: B. Ent. 160). • Cryptophagus populi (details, B. Ent. 160). • Cryptophagus populi: B. Ent. 160, legend+text. • Cryptophagus populi: B. Ent. 160, text cont.. • Paramecosoma melanocephalum: B. Ent. 606. • Paramecosoma melanocephalum: B. Ent. 606, legend+text. • Paramecosoma melanocephalum: B. Ent. 606, text cont.. • Antherophagus, Cryptophagus (8 spp.), Micrambe, Paramecosoma, Telmatophilus: Fowler 3, 94 (1889). • Fowler 3, 94 (1889): original legend.. • Atomaria (8spp.), Caenoscelis, Ephistemus (with Mycetophagidae and Scaphiidae): Fowler 3, 95 (1889). • Fowler 3, 95 (1889): original legend.. • Henoticus serratus, Micrambe abietis and M. bimaculatus, with Dryopidae, etc.: Fowler 6, 14 (1913). • Fowler 6, 14 (1913): original legend.. • Telmatophilus sparganii, with Cucujidae, Silvanidae etc.: Fowler 3, 93 (1889). • Fowler 3, 93 (1889): original legend.. • Paramecosoma melanocephalum (Janson 134).

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. Insects of Britain and Ireland: the families of Coleoptera. Version: 16th May 2016.’.