Pterostichus cristatus (Dufour, 1820)
A rather local species of Western and Central Europe, extending from Northern Spain to Italy (including Sicily), Austria and Germany, and north to the Netherlands and the UK, which represents the northern limit of the distribution. In Spain it is represented by ssp. cantaber (Chaudoir, 1868), and at least 10 subspecies have been listed from France, ssp. parumpunctatus Germar, 1824 is widespread and extends to the UK. Here it is locally common across Northern England but otherwise very local and rare in Central England, Wales and Southern Scotland; the southernmost record is a single specimen found on the northern edge of Dartmoor in 2016, see HERE. Adults occur year-round; they are active from March until October and they peak in abundance during late summer. Typical habitats are humid deciduous woodland and shaded grassland, often in upland valleys and on hillsides, and specimens sometimes occur in disturbed sites such as parks and gardens. They are flightless and mostly nocturnal, spending the day under stones or matted vegetation etc. and both adults and larvae are generalist terrestrial predators. Breeding occurs in spring and summer; larvae from early breeding produce adults in late summer or autumn while later developing larvae overwinter to produce adults in spring and early summer (Cole et al, 2002). Adults may be found under debris, especially in damp situations, at any time and they often appear in numbers in pitfall traps along with other carabids.
14-17 mm. Large and flattened, shiny black but for the tips of the antennae and palps which are red, elytra strongly iridescent in both sexes. Head smooth, with two setiferous punctures beside convex and protruding eyes, frontal furrows variable but usually long and rather weakly impressed, mandibles long, sharp and without external setae. Antennae long and slender, densely pubescent from the third segment and with the first and third segments about equal in length. Pronotum slightly transverse, broadest in front of the middle and strongly narrowed and sinuate to perpendicular posterior angles, lateral margins strongly bordered, inner basal fovea long, deep and angled outwards, outer fovea obsolete and not delimited by an external ridge. Elytra elongate, rather narrow and smoothly curved from rounded shoulders to a weak subapical constriction, striae, including a short scutellary striole, deep and not, or scarcely punctured, interstices convex, the third with 3 or 4 setiferous punctures, epipleura not crossed (this last feature unique among our members of the genus). Legs long and relatively slender, front tibiae strongly widened beyond the internal notch and with a single apical spur. Terminal segment of all tarsi with ventral rows of setae. Claws smooth. Males with dilated front tarsi and a ridge on the last abdominal sternite.