Carpelimus rivularis (?)

These came to light in a meadow. I keyed them to either Carpelimus rivularis or the much scarcer Carpelimus similis, however telling these two apart from Carpelimus erichsoni and Carpelimus bilineatus depends on the extent of the larger punctures at the sides of the pronotum, and these are pretty hard to see. I have previously caught Carpelimus erichsoni in the same spot and although I think I have excluded that on the pronotum puncturing, I am not 100% certain.

Using Lott, the two pairs of species can only be fully identified to species with reference to the male genitalia, so I set about dissecting these in the hope that one was a male. Unfortunately both proved to be female, and it was only after dissecting them that I discoverd that the new Duff volume provides a difference in female genitalia - not the spermatheca which I had extracted and photographed, but the "ring sclerite", a structure I hadn't heard of. I still had the abdomens, but unfortunately I was not able to find the ring sclerite for either of them. Perhaps if I had known to look out for it before dissecting them I would have been able to locate it?

In conclusion I think they are probably Carpelimus rivularis but I cannot exclude the possibility that they are the scarcer similis, or possibly erichsoni or bilineatus.

female probable Carpelimus rivularis showing head (2 views), palps, antenna, pronotum from side, pronotum from above (2 views), pronotum with elytra, tergites and spermatheca, Wendling Beck Project (Norfolk, UK), 21st May 2026

second female probable Carpelimus rivularis showing head and pronotum, tergites and spermatheca, Wendling Beck Project (Norfolk, UK), 21st May 2026