Anisodactylus binotatus

I turned to Hackston's keys first to identify this and came unstuck where it is claimed that on Anisodactylus, "First segment of hind-tarsi as long as the second and third segments combined." That wasn't the case (it was distinctly shorter) but by this time I was pretty sure it actually was Anisodactylus, so checked Duff. I assume both keys are picking up on the longer first tarsomere on Anisodactylus compared to Harpalus, but in this case I think Duff describes it more accurately. Instead of focusing on the relative lengths of the segments Duff compares the length of the tibial spur (relatively short) compared to the first tarsal segment. Using that measure it keys to Anisodactylus perfectly. Unfortunately there must have been some moisture in the pot as the specimen went badly mouldy, but by clearing the mould away from the vertex I could see the pair of reddish spots that had not been visible in my photos of the live insect.

Anisodactylus binotatus and showing hind tarsus and centre of vertex (with mould around the edges), Cranwich Camp (Norfolk, UK), 21st March 2025