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Pterostichus vernalis (Panzer, 1795)







ADEPHAGA Clairville, 1806

CARABIDAE Latreille, 1802



Pterostichus Bonelli, 1810

Argutor Dejean, 1821

Widespread and locally common across the entire Palaearctic region including North Africa and the Near East, this species was first recorded in North America in 1997 from Vermont and is now becoming widely established in northern Vermont and southern Quebec. In Europe it is generally common throughout except for southern parts of the Iberian Peninsula, the Balkans and the far north of Fennoscandia, it also is known from many of the Mediterranean islands and is common on the Azores. The species is generally common and often abundant throughout England and Wales, including all the islands, and rather more sporadic and local across Ireland, it is common across south west Scotland and there are scattered records north to Inverness. Adults occur year-round, they overwinter among litter at the base of trees and shrubs or in tussocks, often in permanently damp situations, and are active from early in the year until late autumn or early winter, peaking in numbers during May and June. They are usually associated with well-vegetated and shaded wetland or marginal situations where they may be abundant among sedges or moss, but the species is eurytopic and often occurs on arable borders, heathland, grassland and disturbed sites such as road verges, parks and gardens. They are generally nocturnal but adults are sometimes active in hot weather, especially on wet marginal soils or in marshes, and they occasionally fly although both macropterous and brachypterous forms are common. Breeding occurs in the spring and larvae develop through the summer to produce adults later in the year, and so far as is known only adults overwinter and the species is univoltine. Adults are easily found by searching among litter and matted vegetation, they occur in pitfall traps and among flood refuse and usually appear in numbers but other small carabids are usually present and so they will need to be examined carefully in the field.

Pterostichus vernalis 1

Pterostichus vernalis 1

Pterostichus vernalis 2

Pterostichus vernalis 2

Pterostichus vernalis 3

Pterostichus vernalis 3

6.0-7.5 mm. A very typical and rather nondescript carabid; parallel-sided and discontinuous in outline, entirely shiny black with dark brown appendages. Head with two setiferous punctures beside prominent eyes and very weakly developed frontal furrows, vertex and frons smoothly convex and extremely finely punctured, antennae dark with the basal segment at least in part pale, densely pubescent from the fourth segment. Penultimate labial palpomere with two external setae. Pronotum transverse, broadest about the middle and evenly curved laterally to denticulate posterior angles and obtuse anterior angles, surface punctured across the base and with elongate and well-impressed inner basal fovea, outer fovea at most only barely suggested. Elytra glabrous, with well impressed striae but lacking a scutellary striole, interstices flat or only slightly impressed, the third with three punctures, epipleura crossed before the apex. Legs dark brown, usually with paler tarsi. Front tibiae strongly widened in front of the antennae-cleaning notch. Tarsi finely furrowed dorsally. Males with basal front tarsomeres dilated.

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