Stenus picipes

I used Mike Hackston's keys to identify this beetle which was swept from some grass or a sedge in alder carr woodland close to the edge of a lake. It seems to key to picipes relatively straightforwardly. The only discrepancy was the size, which I measured at 3.5mm long, half a cm less than the minimum size given by Hackston. However, I measured the dried specimen and comparing it to the live photos it was clear that the abdominal segments had withdrawn into one another significantly reducing its overall length. I would have liked to have been able to double check by comparing its male genitalia to the diagram in Hackston's key, but on dissection it proved to be a female.

Stenus picipes showing antenna, hind tibia and tarsus, other hind tarsus and close ups of head + pronotum and basal abdominal segments, Wendling Beck Environment Project (Norfolk, UK), 26th May 2023