Paramecosoma melanocephalum (Herbst, 1793)

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POLYPHAGA Emery, 1886

CUCUJOIDEA Latreille, 1802

CRYPTOPHAGIDAE Kirby, 1826

CRYPTOPHAGINAE Kirby, 1826

CRYPTOPHAGINI Kirby, 1826

Paramecosoma Curtis, 1833

This widespread Palaearctic species is locally common from Europe to the far east of Russia, in Europe it occurs to middle mountain altitudes and extends from Spain through northern Italy to the Balkan Peninsula, north to the UK and reaching the Arctic Circle in Fennoscandia. It is widespread though very local throughout central and northern England and Wales, generally scarce in the south and there are isolated records from southern Scotland and the north of Ireland. Adults are present year-round; they overwinter among litter etc. and are active over a long season from February until late in the autumn, peaking in abundance during late spring and again in late summer. In the UK it is generally associated with decaying vegetation in marginal wetland habitats, often on the banks of streams and rivers, but in northern Europe it also occurs in permanently damp woodland and agricultural land. Adults spend much of their time among decaying vegetation but may sometimes be found among moss or under debris, especially in marshy areas or beside water flowing into lakes etc. Little is known of the biology but both adults and larvae are thought to feed on fungal spores and hyphae (though they are not associated with fruiting bodies) and it is likely that larvae develop through the spring and summer. Taking samples for extraction is the best way to find adults; they have often been found among decaying willow foliage and flood refuse and while they usually occur in small numbers they are sometimes locally abundant.

1.6-2.2 mm. Elongate and discontinuous in outline with the head relatively small and the pronotum narrower than the elytra, forebody dark grey to almost black, elytra brown, appendages pale brown, usually with the antennae darkened apically. Dorsal surface shiny and finely pubescent throughout. Head with large, convex and coarsely-faceted eyes, short and strongly-converging temples that are usually withdrawn into the thorax and so not visible, and rather long, converging cheeks. Surface finely punctured laterally behind the eyes, otherwise uneven and with a rather rough sculpture which obscures the punctures in places. Antennae long and slender, basal segment broad and slightly curved, 2-8 elongate, the second broader than the others, and 9-11 form a distinct club; the ninth gradually widened from the base, the tenth transverse and the terminal segment strongly asymmetric. Pronotum transverse, broadest in front of the middle and slightly sinuate before obtuse posterior angles, anterior angles obtuse and finely rounded, lateral margin uneven, appearing angulate or finely crenulate in places but without anterior calli, apical margin curved, basal margin weakly sinuate. Surface weakly convex, narrowly explanate and without sculpture, moderately strongly and densely but discretely punctured, the pubescence for the most part appearing to radiate transversely from the centreline. Scutellum short and widely transverse. Elytra evenly curved from rounded shoulders to an almost continuous apical margin, randomly punctured throughout, a little weaker and less dense than on the pronotum, without striae but with the sutural margins, which diverge towards the apex, finely raised. Elytral pubescence directed posteriorly; very fine and only slightly overlapping. Legs long and slender; the femora unarmed and only a little broader than the slender tibiae. Tarsi 5-segmented in females, 5-5-4 in males, basal segments narrow and weakly lobed below and the terminal segment long and only slightly curved. Claws smooth and not toothed at the base.

Paramecosoma melanocephalum 1

Paramecosoma melanocephalum 1

© Lech Borowiec

Paramecosoma melanocephalum 2

Paramecosoma melanocephalum 2

© Udo Schmidt