This Friday I have something for you to identify that has been puzzling me for a while. It looks very distinctive, but I can’t narrow down what it is, so I’d really appreciate your thoughts.
Can you work out what this is?
As usual you can put your suggestions and thoughts below and I’ll do my best to reply. Feel free to ask questions, but at the moment I can only provide answers based on the physical object because I have no idea where it came from or when we got it. It’s a real puzzle!
Zygoma 
Intriguing… Open root reminds me of a pinniped–elephant seals have very similar hollow teeth, but the weird carnassial / melon slicing cusp has me befuddled. An extant Enaliarctos?
It’s quite short for an elephant seal tooth, but there are similarities… one to look into in more detail!
A colleague here reckons incisors of a R. un.c.rn.s, she says they fall out quite often. my first thought was Hyrax, but the scale bar proved me wrong.
It’s rather different in shape to a rhino incisor – they’re longer than they are wide, although perhaps a milk tooth (as suggested by Valters below) would have a somewhat different morphology.
i would agree – tooth. may be a milk tooth…
Hmmm. How about giant sloth molars?
Believe it or not, it’s too big!
When I suggested to ermineofthenorth I neglected to mention I meant the upper incisor. http://chestofbooks.com/animals/Manual-Of-Zoology/Ungulata-Order-VI-Ungulata-Continued.html Fig. 390, over half way down the page.
I have a vague recollection that not all of them have an upper incisor but there are some that definately do as I have seen them in the NHM collection. I guess you’d have to look at them next to each other to be sure as it’s hard to find pictures in the literature.
Aha – I see! I will check it against some reference material, but I think you may be on to something!
I will be very chuffed if I figured it out. All that digging about in collections may count something eh?
I agree that it is a deciduous tooth. Pinnipeds are open rooted, but I’ve never seen any that were broader than deep. I’m thinking it may not have even erupted yet-kind of hard to tell if there is any wear, but the top looks a little sharp. I will see if I can find any pup skulls to compare it to. At this point, I don’t even know which tooth it is.
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