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Monday, March 11, 2019

Getting ahead of myself

Last September, I had a day out with some fellow beetlers at a Cambridge Fen site. We did a mixture of direct searching, either by sieving or poking around in relatively fresh cow dung. Given the dry summer we had had there was very little damp ground left but we still managed a good haul of species, many of which were new to me.

Basically lots of staphs. Species like this Lathrobium elongatum. This was a dark individual that lacked the reddish elytra, but as it was a male, a dissection clinched it as the aedeagus is diagnostic. This species likes damper places from fens through to the wetter bits of woodland and is very similar to the more regularly encountered L. brunnipes.




There were plenty of Stenus species too. Easily identified by the big eyes there are 74 spp on the UK list. This one has short tarsi, raised margins to the abdomen and a very bi-lobed 4th tarsal segment which tells you it's in the subgenus Metastenus. This narrows it down to 13 species. The body shape, but particularly the entirely yellow legs IDs this as Stenus flavipes - and the tackle confirms it. A very common species and one of the most frequently encountered Stenus species at least in my neck of the woods.



Another staph, this time a Lesteva species. It keys to sicula but I'm not entirely sure so one to get checked at some point.


I was finishing IDing the last couple of beetles this weekend just gone. I came across this one that looked like an Oxytelus and I assumed O. laqueatus which is one of the common staphs in dung. This one had been taken in cow dung. But the eyes were massive and take up almost the entire side of the head. Went to the key and it came out as a female O. piceus. But this is supposed to be a really rare beetle. Common a couple of hundred years ago but one of the dung fauna that has taken a hit in modern times.

I got very excited and thought I'd turned up an amazing record. But no. Not quite.

Long story, short. If I'd bothered to check the compiled checklist from that day that everyone had put together, I'd have seen that three O. piceus had been found in dung by other people. 

Still a rare beetle, but possibly not quite as rare as previously thought.



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