Insects of Britain and Ireland: the families of Coleoptera
Cryptic Slime-mould beetles.
General appearance. 2.1–2.4 mm long. Body length/maximum body width 1.37–2.45. Elytral length/pronotal length 2.25–3.3. 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. Beetles oval; not necked; not waisted; black or brown, with parts of antennae and legs red. Upper surfaces of body glabrous or subglabrous, or non-glabrous; 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. The mandibular apices simple, or bidentate or bilobed. 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 short; 10–11 segmented; clubbed. Antennal insertions visible from above; not in fossae.
Cervical sclerites present. Pronotal length/maximum pronotal width 0.42–0.85. The pronotum with lateral keels (pronotal carinae); keels complete. Prothorax without notopleural sutures. Scutellum conspicuous; elevated above the mesoscutum in lateral view, or not elevated; anteriorly simple; posteriorly broadly rounded or obtusely angulate. The prosternal process complete; slightly overlapping the mesoventrite to 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, or closed behind externally; broadly open to narrowly open, or narrowly closed; quite widely separated; slightly transverse, or circular to longer than wide; with narrow lateral extensions, or without lateral extensions; internally open, or internally closed by a slender bar. 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, or widely separated; not markedly extended laterally. Tarsal segmentation formula 4, 4, 4. 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 one segment fewer than the mid-tarsi; 4-segmented (in the British species).
Elytral length/maximum width across the elytra 1.02–1.85. Elytra covering most to all of the abdomen; exposing no more than part of the terminal tergite; striate (punctured in straight, parallel rows). 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, 10. Scutellary striole present. Wings well developed. Wings with an anal lobe. Wings with a medial fleck, or without a medial fleck; the medial fleck when present, not bisected by a vein. Abdominal sternites 5; all articulated and moveable. Abdominal segment 8 apparently without functional spiracles. The male external genitalia cucujiform.
Adult habitat, ecology. Associated with fungi (associated with Slime Moulds on trees); mycetophagous.
Larvae. Mature larvae minute (less than 3 mm long). The larvae elongate and more or less parallel-sided to oblong to ovate. Body somewhat flattened. Vestiture restricted to fine hairs or setae. The larvae dorsally heavily pigmented or sclerotized, or 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 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, or bilobed or bidentate. The maxillary palps 3 segmented. The labium without 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 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. Abdominal tergum 8 without amature. The last abdominal segment without cerci.
Larvae associated with fungi (or Slime Moulds); mycetophagous.
Classification. Suborder Polyphaga; Superfamily Cucujoidea.
Representation in Britain and Ireland, and worldwide. About 70 species worldwide; genera 9. 2 species in Britain (A. orbiculatus, S. dubius); genera in Britain 2; Aspidophorus, Sphindus.
General comments. Unwins tarsi 4,4,4 simple is contradicted by the 5,5,5 or 5,5,4 simple of Lawrence et al.
Illustrations. • Aspidiphorus orbiculatus (Orbicular Dermestes: B. Ent. 450). • Aspidiphorus orbiculatus (details, B. Ent. 450). • Aspidiphorus orbiculatus: B. Ent. 450, legend+text. • Aspidiphorus orbiculatus: B. Ent. 450, text cont.. • Biphyllus (from Joy). • Aspidiphorus orbiculatus (with Dermestidae, Byrrhidae etc.): Fowler 3, 97 (1889). • Fowler 3, 97 (1889): original legend.. • Sphindius dubius, with Cisidae etc.: Fowler 4, 119 (1890). • Fowler 4, 119 (1890): 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. Insects of Britain and Ireland: the families of Coleoptera. Version: 16th May 2016. delta-intkey.com’.