Pterostichus minor (Gyllenhal, 1827)
This is a locally common species throughout Europe from Spain to Greece and Asia Minor, extending south to the middle of Italy but absent from North Africa, to the north it reaches the UK and far above the Arctic Circle in Fennoscandia and extends east into western Siberia. In the UK it is common and often abundant throughout England and Wales, and more local and scarce further north to Shetland, it is common across Northern Ireland but local and sporadic in the south. Adults occur year-round; they overwinter among leaf-litter and tussocks etc and are active over a long season from March until November, peaking in abundance during May and June although specimens may be found during the winter under debris or active during mild spells. Typical habitats are wetland margins, bogs and permanently damp grassland and woodland, often in shady situations on heavy soils with sparse vegetation, and invariably among other wetland carabids. Breeding occurs in the spring and larvae develop through the summer to produce adults from late summer until the autumn which will go on the overwinter. Both adults and larvae are predatory, feeding on mites and springtails as well as small insects and their early stages, and larvae inhabit much the same habitats as the adults. Overwintering quarters tend to be a short distance away from wetland margins and adults probably migrate by walking; wing development varies, apterous specimens are common, fully-winged individuals much less so and it is not known to what extent they fly. Adults may be samples by searching in likely habitats; they are common in pitfall traps and often appear among wetland litter and tussock samples through the winter.
6.8-7.9 mm. A rather nondescript small and dark carabid that can be identified in the field with a little experience; the double fovea and ridge at the pronotal base are distinctive. Body entirely black; moderately shiny but without a metallic lustre, legs dark brown, antennae black with several basal segments dark brown. Head with two setiferous punctures beside each eye, vertex and frons smooth, frontal furrows weakly impressed to about the anterior margins of the eyes. Mandibles robust and sharply-pointed, externally without punctures, palps pale red, with the terminal segment well-developed, antennae pubescent from the fourth segment. Pronotum transverse, about 5:4, broadest in front of the middle and sinuate before perpendicular posterior angles, strongly bordered laterally and strongly but sparsely punctured across the basal third, basal fovea doubled; the inner extending further forward and the outer delimited externally by a raised ridge. Elytra with rounded or very weakly toothed shoulders and evenly curved to a continuous apical margin, striae, including a short scutellary striole, well-impressed and weakly punctured, interstices weakly convex, the third usually with three setiferous punctures, epipleura crossed before the apex. Femora long and broad, all tibiae with a single spur at the inner apical angle, front tibiae very broad in front of a deep subapical notch. Claws smooth and only weakly toothed at the base. Basal pro-tarsomeres dilated in the male.
Pterostichus minor 1
Pterostichus minor 2