Cercyon analis

I used Duff to key this and it turned out to be relatively straightforward (compared to some previous challenges I've had with this genus). The way the mesosternum slots into the metasternum seems to be unique to analis among the genus. The beetle was 1.95mm long.

Cercyon analis showing mesosternum, Wendling Beck Environment Project (Norfolk, UK), 6th September 2023

This one was also straightforward enough, at least wtih the notch in the metasternum holding the apex of the mesosternum. I'm not so sure about the shape of the apex of the elytra though. I caught this with a Cercyon marinus and I struggled to see the difference in the shape of the elytral apices. Side by side I could see a subtle difference, but it seems to be to be a stretch to describe analis as "acuminate" and marinus (etc.) as "rounded" at the apex, as Duff's key states. This beetle was 2.0mm long.

Cercyon analis showing mesosternum and elytra comparison with Cercyon marinus (marinus above, analis below), Wendling Beck Environment Project (Norfolk, UK), 6th September 2023