Common Dumble Dor Geotrupes spiniger

I didn't find this particularly easy to identify, though I think that probably came down to inexperience with the family rather than it being truly difficult. I used a combination of Duff, Hackston and the John Walters PDF and in the end I was happy that everything checked out for spiniger. I used Duff first: the hind tibial keels were easy enough to see if you hold the tibia at the right angle, although as my specimen was covered in dust I had to clean it a bit first. The mandibles were more sinuate, or bumpy, than shown in the diagram in Duff for spiniger (so clearly much more so than stercorarius which at this point was the only alternative remaining). I was also slightly confused by the statement that male spiniger had a ventral tooth on the hind femora whereas female didn't - this appeared to have two teeth! I wasn't quite sure if the distribution of hairs on the sternites was right either - the centre line was bare but fairly narrowly, whereas I thought Duff was perhaps implying they should be restricted to the sides.

All this made me wonder if I'd gone wrong, so I turned to Hackston. With Hackston I got a bit confused about what it was saying about the middle of the pronotum for Anoplotrupes stercorosus, possibly because I was trying to compare it to photos identified as that species which may in fact have been something else. However it did help clear up the mystery with the femoral teeth as it says that for spiniger (only I think) has a femoral tooth that is longer than the coxal spur - in looking for the coxal spur I realised that what I thought was a second tooth on the femur actually came off the lateral extension of the coxa. Ultimately Hackston appeared to confirm spiniger, but I still felt slightly uncomfortable about the ID and had a look to see if John Walters had a PDF guide to this family.

I found the Walters guide really helpful and put my mind at rest about the ID. Among other things he illustrates the extent of the glabrous line down the centre of the sternites and this pretty well matched my specimen.

male Common Dumble Dor Geotrupes spiniger showing hind tibia keels, mandibles, apical sternites, side of pronotum, elytral sculturing and femoral & coxal teeth, North Elmham (Norfolk, UK), 20th July 2022

That probably wasn't my first Geotrupes caught in my garden moth trap, but when I caught this one I didn't have any decent references to enable a full ID. I didn't retain the specimen and the photos aren't quite clear enough (not helped by the beetle being covered in moth scales) for me to be certain of the ID. However I suspect it was most likely another spiniger.

possible Common Dumble Dor Geotrupes spiniger, North Elmham (Norfolk, UK), 24th July 2016

Here's another one that came to light before I was very interested in beetles. I think it's either Geotrupes spiniger or Geotrupes stercorarius but I'm 50-50 as to which. Most useful characters aren't visible, although the puncturing on the side of the pronotum might be enough for someone more experienced with these than me?

Dor Beetle sp. Geotrupes spiniger or Geotrupes stercorarius, Buxton Heath (Norfolk, UK), 13th August 2011

This one from the French Pyrenees looks like it's probably Geotrupes too, but I've no idea what species are even possible at this location - it could be something that's not in any of references that deal only with British species.

Dor Beetle sp., probably Geotrupes sp., Gavarnie (Hautes-Pyrénées, France), 24th June 2009