Description: A moderately large (10-15mm) black ground beetle. Predatory. In 1988 it was realised that two species were included under this name, P. nigrita and P.rhaeticus, the two being separable only on structure of the genitalia. The present (nominate) species is widespread in lowland marshes and water margins.

NI account: P. nigrita s.s. is widespread and common in the lowlands at least in the northern counties. Status elsewhere uncertain due to confusion with P. rhaeticus. In the map some southern records may refer to P. rhaeticus.

Ecology: A moderately hygrophilous species characteristic of wet riparian habitats in the lowlands, but also in hedgerows on heavy agricultural soils. Rarely recorded from oligotrophic peatlands or in exposed places on high ground.

Distribution: A species recorded from the whole of Europe and Siberia to the Pacific Ocean, but probably conflated with its recent segregates, P. rhaeticus and P. mukdenensis Breit, in large parts of its range. True P. nigrita appears to be Eurosiberian Wide-temperate (64).

Similar Species: Pterostichus rhaeticus: slightly smaller; aedeagus (male) characteristic (Fig. 99); 8th abdominal sternite (female) characteristic (Fig. 100) P. anthracinus; pronotum not denticulate; apices of elytra in female with sutural teeth P. minor/gracilis: pronotum not denticulate.

Key Identification Features:

• Medium species, black
• Hind angles of pronotum sharp, denticulate
• Pronotum with two basal foveae
• Last abdominal sternite of male with a small tubercle
• Apices of elytra in female without teeth
• Aedeagus (male) characteristic (Fig 99); 8th abdominal sternite (female) characteristic (Fig. 100)

Distribution Map from NBN: Pterostichus nigrita at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Pterostichus nigrita at iNaturalist World Species Observations database.

GBIF data for Pterostichus nigrita | Classification: Insecta, Coleoptera, Carabidae, Pterostichus

Thumbnails for genus Pterostichus