Thanatophilus rugosus (Linnaeus, 1758)
This widespread species is locally abundant throughout the Palaearctic region from Portugal to the far east of Russia, China and Japan; in Europe it occurs from lowlands to the upper tree line in mountain regions and extends north to the UK and far above the Arctic Circle in Scandinavia, it is present throughout Asia Minor and on many of the Mediterranean islands but absent from North Africa and the Atlantic islands. In the UK it occurs throughout the mainland and is present on most of the islands north to Shetland although it seems to be very local and scarce in the West Country, and in Ireland it is known from only a few coastal sites in the north. Adults are active over a long season from late winter or early spring and are thought to overwinter in the soil, they are probably most frequently recorded in open situations such as grassland and agricultural land but they are strongly attracted to carrion and so may be found in a wide range of habitats including woodland, scrub and even parkland and domestic gardens. In general they are attracted to carrion in the later stages of decay, when it is infested with diptera larvae and producing gas, but they may arrive earlier or later and begin feeding; in Europe they have also been recorded among compost and, rarely, under dung. Breeding occurs over a very long season from early spring and is probably opportunistic according to the availability of larval host material. They have been observed feeding directly upon and mating on or about carrion from March until July, when they begin to die off, but they are probably univoltine with new-generation adults becoming sexually mature after overwintering. Females bury batches of up to 20 eggs in a chamber a few centimetres below the carrion and then moves on to find more sites. Larvae eclose synchronously after four or five days and remain in the egg chamber for about twelve hours before leaving and working their way up through the soil to the host material. Larval development is generally very rapid although this may depend on the quality of the host material e.g. in Europe they have been found on large bones and here they may take longer; on carrion it lasts between 10 and 12 days, the larva passes through three instars of which the final instar feeds only briefly before burrowing a few cm into the soil to form a pupal chamber. The pupal stage lasts about five days and adults leave the chamber shortly after eclosing. Adults are very active and will scatter or fly off rapidly if disturbed, sampling usually involves moving carrion and grabbing the beetles before they can escape but placing pitfall traps around a sample can be productive (as well as destructive), adults are often common at fish-baited carrion traps and they sometimes occur in flight-interception traps.
Thanatophilus rugosus 1
Thanatophilus rugosus 2
Thanatophilus rugosus 3
8.0-12.0 mm. Broadly-oval and rather parallel-sided, entirely dull black or dark grey, the dorsal surface with fine yellowish pubescence; this is often sparse or patchy on the pronotum and elytra, especially in older specimens, but is usually obvious on the head, pronotal margins and scutellum. Head finely punctured between convex eyes and short temples that converge strongly to a short neck, clypeus widely transverse and smoothly curved anteriorly, all maxillary palpomeres long and narrow. Antennae with a distinct four-segmented club; segment 7 much shorter than 8-10, and segments 2 and 4 much shorter than segment 2. Pronotum transverse, broadest in the basal half and narrowed to rounded posterior angles and slightly projecting anterior angles, posterior margin sinuate and widely produced medially, surface uneven and widely explanate and finely and densely punctured throughout. Scutellum large and triangular, sinuate laterally and acute apically, surface finely punctured, as the pronotum. Elytra weakly broadened towards a continuously-rounded apical margin, widely explanate, each with three longitudinal ridges which almost reach the basal and apical margins, interstices finely punctured throughout and each with several shiny raised transverse ridges. Legs long and robust, tibiae with dense short spines and long paired apical spurs, tarsi 5-segmented and simple; the basal segments of the front tarsi dilated in the male, claws smooth and not toothed at the base.