I've killed like 12 or more of these things tonight in 4hrs that I've been playing so far, along with greater skeletons, I'm lvl 12, dinged to 13 btw, only seen one ulna, one tibia two skulls, and two ribcages. Mostly dropping off the greater skeletons except for the ulna. Gonna stay all night till I get my second humerus bone...
Btw I didn't stay in one place, I started off at the camp site near lavastorm, then ran to the wizard spiers, then ran around near the ec zoneline using sense the dead locating greater skeletons then finally at the monolith right now...