Thanatophilus dispar (Herbst, 1793)

A widespread Palaearctic species extending east through Russia to Central Asia, Siberia and China; it occurs sporadically in Central and Northern Europe but is absent from the Iberian Peninsula and much of the Mediterranean region although it is present in Northern Italy. Through most of the European range it is very local and rare, becoming locally common only in the Baltic region where it extends to the far north of Norway and Sweden. In the UK, where it is classed as critically endangered, it was formerly known from a few scattered sites in Central and Northern England and the Scottish Highlands, but following a recent decline it is now restricted to a few sites in the Outer Hebrides and Northern and Western Ireland. The typical habitat is wetland margins with patchy vegetation, often beside larger ponds and lakes on light sandy, gravelly or limestone substrates, in northern Europe also on beaches, salt marshes and maritime grassland. The species develops in carrion, often dead fish washed up onto the shore, but also on mammal and bird carcasses, otherwise the adults, which are mostly nocturnal, occur under stones or matted vegetation etc. Adults are active between March and October and peak in abundance during June; it is also likely they overwinter as they have been recorded from moss and leaf-litter during January and February on the continent. Despite being very local and rare, adults may be locally abundant, they may be found by general searching but they are mostly nocturnal the use of fish-baited pitfall traps is usually the best way to sample the species.

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​7-12 mm. Elongate and discontinuous in outline, matt black or occasionally with reddish elytra, dorsal surface with both dark and yellowish pubescence, appendages black or with the basal antennal segment sometimes a little lighter. Head weakly convex, uneven and finely punctured between convex eyes that follow the outline, temples short and strongly converging to a short neck, clypeal margin smoothly rounded. Antennae 11-segmented; segments 1-7 more or less equal in width, 8 wider and strongly transverse, and 9-11 larger, forming a distinct club. Pronotum transverse, broadest behind the middle and narrowed to widely-rounded posterior angles and obtuse and slightly projecting anterior angles, apical margin curved, basal margin strongly bisinuate, surface finely and rather densely punctured and with broad and shallow depressions throughout. Scutellum large and triangular, with angled lateral margins and an acutely-pointed apex, surface densely punctured pubescence pale medially and across the base, otherwise dark. Elytra almost parallel-sided from rounded (not toothed) shoulders to a continuous apical margin, each with three almost complete longitudinal keels and transverse callus which raises the second keel above the others in the apical third, surface less densely and a little more strongly punctured than the pronotum. Legs long and robust, front tibiae weakly curved and with small apical spurs, middle and hind tibiae straight and with longer apical spurs. Tarsi with five simple segments, male front tarsi dilated.