Catopidius depressus (Murray, 1856)
POLYPHAGA Emery, 1886
STAPHYLINOIDEA Latreille, 1802
CHOLEVINAE Kirby, 1837
CHOLEVINI Kirby, 1837
Catopidius Jeannel, 1922
Beyond the UK this species is known from a few scattered localities across Northern Spain and Western France where it extends north to the English Channel, it is also very occasionally recorded further east but so far as is known it is not established beyond Western France. The other European member of the genus, C. murrayi (Wollaston, 1860), is endemic to the Madeira Islands. In the UK depressus is very local and rare; it occurs sporadically across the English Midlands and East Anglia and there are a few records from Northern Kent and London. The usual habitat open grassland and scrub, especially on light or sandy soils, but adults are occasionally associated with terrestrial sporocarps in other situations. In general the species is strongly associated with mammal burrows, especially rabbit burrows in sandy areas but also fox earths and badger sets, and while it is generally very local and rare very large populations sometimes form in the spring prior to dispersal. Adults have been recorded in all months from January to October and they peak in abundance during May and June which, typical of closely related species, is probably when reproduction begins. Beyond this very little is known of the biology, the overwintering stage is probably larval or pupal but it seems likely that at least some adults either pass the winter or eclose during mild winter spells. Adults may be sampled by placing carrion-baited pitfall traps on mammal runs or inside burrows, but they may also appear about nearby fungi or carrion or by sweeping turf in the spring.
4.2-5.0 mm. Broadly elongate and almost continuous in outline, broadest across the basal third of the elytra and smoothly narrowed to the apices. Entirely brown or with the forebody a little darker, dorsal surface microsculptured between fine punctures which are a little stronger on the elytra, entire surface with fine and quite dense recumbent pubescence. Head from above evenly convex, broadest across slightly convex eyes situated just in front of a curved basal margin. Antennae long and slender with segments 1-7 elongate, 8 transverse and 9 and 10 quadrate or very weakly transverse. Pronotum very distinctive; transverse broadest across perpendicular or slightly projecting posterior angles and narrowed to a curved apical margin, basal margin sinuate and slightly produced medially. Elytra evenly curved from angled shoulders to separately-rounded apical margins, finely and randomly punctured throughout and with a partial sutural stria behind the middle. Legs long and slender, posterior femora broader and longer than the others, front tibiae with a series of short spines around curved apices, middle and hind tibiae with strong spines along the external margin, truncate and with a stout apical spur. Tarsi 5-segmented, basal front tarsomeres expanded and all middle and hind tarsomeres long and slender in both sexes. The sexes are very similar but in males the ninth antennomere is quadrate while in females it is slightly transverse. Readily identified by the form of the antennae (not clubbed, eighth segment smaller than adjacent segments) and the pronotum.