Aleochara ruficornis

This was in a pitfall trap (in propylene glycol, so no live photos). I embarked on the ID prior to the publication of Duff's volume for this family so used Hackston's keys (and possibly Lott & Anderson to get it to subfamily). As is so often the case with this subfamily I struggled to key it to Aleocharinae and wasted a fair bit of time attempting to get somewhere in one or two other subfamilies (it actually seemed to key remarkably well to something entirely different that looks superficially similar but having some niggling doubts I checked a high resolution photo of that species and there were a number of small but significant differences). Eventually I realised and using Hackston's Aleocharinae keys it seemed to key to Ocalea picata. I might have been happy with that except for the spermatheca. The German website Käfer Europas showed the spermatheca of that species to be less simple with a coiled section at the tip. I was pretty sure I hadn't just broken this off as the unsclerotised duct was still present beyond it. But the German site doesn't show any other species of Ocalea with a similar spermatheca, and I couldn't find any way of keying it to anything else satisfactorily. I tried re-keying it taking alternative routes at any couplet that wasn't totally clear, but usually ended up with genera that had quite different habitus. I figured I must either be missing something or it must be Ocalea with abnormal/damaged spermatheca. So I posted it here as Ocalea picata but with a query and a request for feedback from more experienced coleopterists.

Now Duff has been published I've had another look at this record and I have to conclude that it cannot be Ocalea. Looking through the spermatheca diagrams in Duff the closest matches appear to be either in the genus Amarochara (which I don't think has been recorded in Norfolk) or Aleochara. Of the Aleochara none of the common species match the spermatheca but ruficornis looks like a very good match. This species is apparently unusual among the genus as being more tawny than most, and that does seem to match my insect. The colour isn't perfectly clear from my photos as it was wet but it is clear that the pronotum and elytra are tawny and I think the abdomen is to a lesser extent too. In particular the pronotum appears to be paler than the elytra and that seems to be unsual among Aleochara. I also note that the pronotum shape matches ruficornis but not some of the other Aleochara.

Hackston notes the similarity between genus Ocalea and the tribe Aleocharini and notes that Ocalea "has long erect bristles on the sides of the pronotum and lacks the tiny fifth segment on the maxillary palps". I didn't notice the latter, but it is so small maybe I just didn't use high enough magnification? I think it was more the presence of fairly long erect bristles/setae on the sides of the pronotum that persuaded me it must be Ocalea, but now looking at Udo Schmidt's high quality photo of Aleochara ruficornis that also seems to have reasonably long bristles/setae on the pronotum sides. Unfortunately the beetle was in such a bad state after I'd examined it I don't appear to have retained it, so I can't double check the presence of that tiny fifth segment on the maxillary palps or any other character that isn't visible in my photos. I think I can see transverse impressions at the base of the basal abdominal segments which are shown by ruficornis.

On balance, given the spermatheca and the habitus and what detail I can make out from the photos I now think it's Aleochara ruficornis. But that seems to be a relatively scarce species in Norfolk so I welcome feedback from others in case I'm (still) missing something.

apparent Aleochara ruficornis showing foreparts, pronotum, bristles on side of pronotum and elytral shoulder, elytra (two views), palps, hind tarsus and spermatheca, Wendling Beck Environment Project (Norfolk, UK), 29th to 31st March 2024