I took pictures of this skeleton a few years ago in a zoology class but I can't figure out which animal is it. I hope you can help!
(The skeleton belongs to a Croatian university so it's probably an animal from this region.)
I agree Andreja, this could be either a rodent or rabbit/Hare species but there are many features which point away from it being a rat. In particular look at the cheek teeth. I will see waht I can dig up.
You are quite right, lemming tails are too short. Rats, Mice, Dormice, Squirrel all have teeth with cusps (like our teeth), this skull has teeth in the lower jaw which are more like Vole, Rabbit, Hare, but again as you have pointed out the long tail excludes these groups. Coypu and Beaver teeth are different again and the zygomatic arches are much more developed than on this skull so I don't think it is either of these. There is a chance that is not a native species so we could be looking at a world list to chose from.