Longitarsus gracilis

Apparently one of the commoner species of Longitarsus.

This one keyed out to gracilis reasonably straightforwardly. My only hesitation was that the microsculpture on the pronotum wasn't as evident as the key suggested it should be.

female Longitarsus gracilis showing close-ups of pronotum, elytra tips and spermatheca, Wendling Beck Environment Project (Norfolk, UK), 30th October 2022

I took a while to satisfly myself that this next one was gracilis although it did key to this. Again I could barely make out the microsculpture on the pronotum (but the alternative here was agilis, and several things ruled that out). Comparing the aedeagus with the diagrams in Duff I wasn't convinced it was quite right for gracilis, and also the head and pronotum looked much darker than most photos of gracilis online, but after spending lots of time re-keying it and checking all the options where the aedeagus diagram looked closer I just kept ruling other options out and coming back to gracilis. Eventually I became convinced after checking Lech Borowiec's website where there are photos of many species' aedeagus including gracilis, and the ones for gracilis did indeed seem to be a good match for mine. The beetle was about 2.1mm long and had full wings.

male Longitarsus gracilis showing hind leg, elytra tips, pronotum and aedeagus (3 views), Wendling Beck Environment Project (Norfolk, UK), 12th March 2023

This one keyed fairly easily, once I realised I'd misread one of the couplets... A diagram would be useful to see what "normal" length hairs on the elytral tips should look like mind. Anyway, I think the aedeagus rules out longiseta. This one was at the same spot as the one above, a slightly different site to the one above that.

male Longitarsus gracilis showing pronotal microsculpture, elytral puncturing, elytral apical setae and aedeagus (flat and side view), Wendling Beck Environment Project (Norfolk, UK), 14th May 2023