Amara tibialis

Although there are lots of records of this species in Norfolk these records are concentrated in the Brecks, the far western heaths and the coast, with a few also in the Norwich area. In north-central Norfolk it appears to be very thin on the ground, so I checked and double-checked my first very carefully.

This beetle came to light in my garden. It was just 4.5mm long and hardly over 2.0mm wide, so at the bottom end of the size range for tibialis which is the smallest of all the Amara species in the UK. The elytra were barely metallic at all, but it seems this doesn't disqualify it from being tibialis although it sounds like the species is normally more metallic than this one was. The abbreviated scutellar striae were practically absent, their path marked by two (on one side) or three (on the other side) small punctures.

Amara tibialis showing dimensions and close-ups of abbreviated scutellar striae and pronotum base, North Elmham (Norfolk, UK), 9th July 2021

This one was in a pitfall trap in an ex-arable field that's being restored to lowland meadow. The same spot has produced a range of species of insects (including several moths and a bug) that are more typically associated with the Brecks. I wasn't entirely convinced that the basal puncture on the right hand scutellar stria wasn't a scutellary pore but keying it as having scutellary pores led to a dead-end. The small size (c. 4.4mm) and pair of deep laterobasal fovae on each side of the pronotum seems quite conclusive. The abbreviated scutellar striae were a little more distinct than on the one above but still quite poorly-marked compared to many other Amara.

Amara tibialis showing pronotum base and scutellar striae (both sides), Wendling Beck Environment Project (Norfolk, UK), 4th-5th April 2025