Wednesday, October 17, 2018

Dalgety bay quickie - The Call of Chthonid

Quickie update because I'm stoked about finding my second pseudoscorpion, common though it many be, and the smallest beetle I've ever ID'd (or am ever likely to?). The pseud was sieved out of woodland litter and just as I was thinking I'd finally added the one species I expected to find it turned out I may be looking at the possibility of recording TWO pseudoscorpions. IF I can find the other one that is...

The Rugilus came out of the woodchip pile and was about the only thing that did so far. There's an as-yet-undetermined Sepedophilus but I think that's the only other. (edit: Rugilus last recorded in the county pre-1900 and apparently few Scottish records)

Litter at the high tide of last week's storm dropped about 100 beetles in one tap, and I haven't even begun to get to the bottom of that though most were a black Aphodius. There's probably enough there for my expected 2-a-day until end of October. Two a day is about as fast as I can go on these I suspect. On a good day.

Having discovered two species of Ptiliidae I was happy to enjoy looking at them undetermined until I discovered that all the keys I needed were there in German but also in a very nice translation into English with pictures courtesy of Mike Hackston. 0.7mm of beetle is not a lot, and they were dwarfed under bark by the springtails they were beside (Neanura). The leaf-litter Atrotrichus was a whopper by comparison at 1.1mm and the heavyweight of its genus in Britain!

Common chthonid

Rugilus orbiculatus

Ptinella aptera

Spermotheca in situ - check the "trumpet" on the right had side

1351 diptera Polietes lardarius Muscidae
1352 * coleoptera Atrotrichis intermedia A feather-winged beetle
1353 * coleoptera Ptinella aptera A feather-winged beetle
1354 * pseudoscorpion Chthonius ischnocheles Common chthonid
1355 * coleoptera Rugilus orbiculatus A rove beetle


  1. Blimey, looking at Ptilids is brave. I'm afraid I avoid them. What sort of magnification is the final picture?

  2. Very small beetles I am happy to leave to people like you and Tim, but I would very much like to see a pseudoscorpion sometime. Good stuff.

  3. Great work, I'm impressed! I may have to take a sneaky day off work tomorrow (shush now....) and thrash the wrackline until it stops providing. Happily I bought pooter and pots whilst down south. Also, after today's efforts with the lawns, I'm now the proud owner of a rather huge pile of leaves which I've stashed in a quiet corner - could be productive in a few weeks time, hopefully.

  4. The Mike Hackston Ptiliidae keys are great and there's a fair bit of additional info online (kafer europas) - I'd struggle far more with a Bembidion to be honest. Final image is I think at x400 backlit on compound. At least I didn't have to dissect it.

  5. For what it's worth, Seth these beetles were all in matted grass deposits above the wrack line. Looking forward to next year where I will see zero sandhoppers.