Ophonus ardosiacus

Quite a scarce beetle in Norfolk apparently.

I had a slight wobble keying this to genus when using Hackston's key when it comes to assessing the hairs on the head, because for the choice that leads to Ophonus (and Scybalicus) it says that the hairs tend to lie on the surface. On this beetle the hairs were very clearly erect and not lying on the surface at all, but they were covering pretty much the whole head which they shouldn't for the alternative (Harpalus). Duff's key doesn't require the hairs to be erect, but just to make quite sure I hadn't gone wrong I also ran it through the Harpalus key and quickly reached a dead-end.

Unlike e.g. Harpalus rufipes, the hairs on the elytra were quite hard to see being dark, but they covered the whole elytra. In life the beetle had strong green reflections on the elytra - under the microscope they look bluer. The length of the beetle was about 11.5mm.

Ophonus ardosiacus showing hairs on head and base of pronotum & elytra, Wendling Beck Environment Project (Norfolk, UK), 9th August 2023

This one came to light at a different site within the same project area a couple of nights later. Like the last, the hairs on the head were erect so using Hackston to key it ran into problems, but once past that it was straightforward enough. It was about 11.25mm long.

Ophonus ardosiacus, Wendling Beck Environment Project (Norfolk, UK), 11th August 2023