Pterostichus aethiops (Panzer, 1796)
This generally rare and very local Western Palaearctic species is widespread but sporadic in Europe from south-eastern France to Austria, Romania and Serbia, and north to the UK, Latvia and southern Finland, it is absent from Denmark, Sweden and Norway but there are records from Northern European Russia and isolated records further east to the Caspian Sea. Throughout much of Europe it inhabits upland regions and it may be locally common in mountain regions, reaching up to the alpine zone. In the UK it is generally absent from Central and Southern England but locally common in the West Country, Western Wales and Northern England, it is very local across Southern and Central Scotland, including a few of the Western Isles, and there is a single record from Ireland (Waterford). The typical habitat is upland moorland, usually with plenty of dwarf shrub cover, damp woodland and shaded ravines etc where adults occur among moss or litter or under logs, stones and debris, or under bark and in soft decaying wood in logs and trunks. Adults are present year-round; they are active from March until September and peak in abundance during June (population peaks tend to occur earlier in Northern Europe), they are mostly nocturnal although specimens may occasionally be found active on the surface during warm weather, and so far as is known the species is short-winged. New generation adults appear in the spring and breeding occurs during spring and early summer, and while adults may live for several years, it appears that females breed only once and die off shortly after doing so. Both adults and larvae are predatory and larvae live among humid moss and litter etc., both stages have been recorded through the summer and winter and third instar larvae have been recorded during February. Adults may be sampled by pitfall trapping but they usually occur in small numbers.
11.5-13.5 mm. Entirely shiny black, discontinuous in outline and with a proportionally large forebody. Head with two setiferous punctures beside convex and protruding eyes, vertex smooth, frontoclypeal suture and frontal furrows usually only weakly impressed, mandibles sharp and strongly curved apically and without a setiferous puncture on the outer margin. Antennae densely pubescent from the fourth segment. Pronotum slightly transverse, broadest slightly in front of the middle and smoothly curved to rounded posterior angles, surface smooth and shiny, with shallow basal fovea not delimited by an external keel. Elytra broadest behind the middle and smoothly curved from rounded shoulders to a continuously curved apical margin, basal margin almost complete, striae, Including a short scutellary striole, deeply impressed, interstices convex, becoming more so towards the apex, the second with a puncture close to the basal margin and the third with three dorsal punctures, epipleura crossed before the apex. Legs long and robust, the front tibiae strongly widened beyond the antennal-cleaning notch, and all tibiae with paired apical spurs, the longest shorter than the first tarsomere. Terminal tarsomere with fine ventral setae, claws smooth. Males with dilated front tarsomeres and a transverse tooth on the penultimate abdominal sternite.