British insects: the families of Coleoptera
British insects: the families of Coleoptera | |
~Anobiidae-Ptininae.
Spider-beetles.
General appearance. 2–5.5 mm long. Body length/maximum body width 1.45–4.63. Elytral length/pronotal length 1.65–3.2. 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 oval to elongate; not necked; conspicuously waisted; conspicuously long-legged; brown to black. 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, or exhibiting scales or scale-like setae.
Detailed morphology. Eyes not strongly protuberant; without bristles. Antennae short to long, but not exceeding the insect’s head to tail length; 8–9 segmented, or 11 segmented. Antennal scape not swollen. Antennae filiform. Antennal insertions visible from above. Mandibular prosthecae absent. Prothorax shorter than wide. Pronotal length/maximum pronotal width 0.6–1.42. Prothorax at its widest not markedly narrower than the adjoining part of the abdomen. Prothorax without notopleural sutures. Metaventrite without a transverse groove. Hind coxae not shaped posteriorly to receive the femur. 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 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, or with one segment fewer than the mid-tarsi; 5-segmented (rarely 4?). Elytral length/maximum width across the elytra 1.03–2.63. Elytra covering most to all of the abdomen; exposing no more than part of the terminal tergite. Scutellary striole present, or absent. Wings well developed, or absent or much reduced. Exposed abdominal sternites 5; comprising both fused and movable components; immovably joined 3. Abdominal segment 8 with apparently functional spiracles, or apparently without functional spiracles.
Adult habitat, ecology. Not predacious; in decaying plant material, in rotting wood, in dried plant material, on shed fur or feathers, and in stored plant products (mainly in dry plant or animal material).
Larvae. Larvae not predacious; necrophagous, feeding on dried animal remains, consuming decaying plant material, and eating dried plant material or stored plant products; in decaying plant material, in rotting wood, in dried plant material, in shed fur or feathers, and in stored plant products (mainly in dry plant or animal material; not borers). The larvae C-shaped, white, setose, hypognathous with small, 2-segmented antennae, the 10 segmented abdomen sometimes with the last two reduced.
Classification. Suborder Polyphaga; Infraorder Bostrichiformia; Superfamily Bostrichoidea.
Worldwide and British representation. About 500 species worldwide; genera 11. 21 species in Britain; genera in Britain 7; Gibbium, Mezium, Ptinus, etc. E.g., Gibbium psylloides (Northern Ptinus); Mezium affine (Shining Ptinus); Ptinus sexpunctatus.
General comments. The antennal insertions close together, separated by less than the length of the scape; the hind coxae without any obvious transverse cavity for reception of the femur..
Illustrations. • Gibbium psylloides (Northern Ptinus: B. Ent. 342). • Gibbium psylloides (details, B. Ent. 342). • Gibbium psylloides: B. Ent. 342, legend+text. • Gibbium psylloides: B. Ent. 342, text cont.. • Mezium affine (Shining Ptinus: B. Ent. 232). • Mezium affine: B. Ent. 232, legend+text. • Mezium affine: B. Ent. 232, text cont.. • Ptinus sexpunctatus: B. Ent. 646. • Ptinus sexpunctatus: B. Ent. 646, legend+text. • Ptinus sexpunctatus: B. Ent. 646, text cont.. • Ptinus (4 spp.), with Cleridae, Drilus and Lymexilidae: Fowler 4, 116 (1890). • Fowler 4, 116 (1890): original legend.. • Gibbium, Ptinus fur, Mezium, Niptus and Tipnus (with Anobiidae): Fowler 4, 117 (1890). • Fowler 4, 117 (1890): original legend.. • Ptinus (3 spp.) and Trigonogenius globulus, with unrelated taxa: Fowler Suppl. 15, 1913. • Fowler Suppl. 15, 1913: original legend.. • Ptinus sexpunctatus (Janson 166).
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’.
