It's A Bear!

[Tethys]

I'm pretty sure that this is the lower left 1st molar of a Short Faced Bear, but an expert opinion would be appreciated. Thanks in advance!

[Tethys]

A close-up of the occlusal surface, and a pic of a piece of ice age mega-fauna antler found at the same site.

[JohnJ]

Tethys, neither of these are fossils.... The 'tooth' is just an interesting piece of a banded silicate rock (maybe chert). The other is just interestingly shaped rock. Your photos are greatly improved.

[Auspex]

I think it's way too tall for a bear molar, and the pattern in the material looks a lot more like agate or banded chert than enamel and dentin...

[Tethys]

Tethys, neither of these are fossils.... The 'tooth' is just an interesting piece of a banded silicate rock (maybe chert). The other is just interestingly shaped rock. Your photos are greatly improved.

Thanks John. They are both chert, and I am having fun photographing stuff with my new tripod and fancy phone. I don't wish to sound rude or ungrateful, but making human replacement teeth is how I made my living for over a decade. I recognize teeth after making a few hundred thousand of them. The banding is tooth wear down into the dentine, and the buccal and central lingual cusps are broken away. The banding is only on the occlusal surface, it does not extend through the entire rock as one would expect from banded chert.

[Tethys]

I think it's way too tall for a bear molar, and the pattern in the material looks a lot more like agate or banded chert than enamel and dentin...

Is there a metric for width to height ratios on bear teeth? At slightly under 3 inches tall it seems about the right size for a tooth that is 2 3/4 inches across the occlusal surface from mesial to distal, but the root portion has been polished by glaciers, and doesn't have much in the way of anatomical detail. (edited to add actual measurements rather than guesstimates)

Edited March 17, 2015 by Tethys

[Auspex]

...It seems about the right size for a tooth that is 4 inches across the occlusal surface from mesial to distal...

Where do you get the idea that a bear molar can measure 4"?

In any event, the crown will be much shorter than it is long.

[Tethys]

I edited my error to the actual measurements. Sorry for the confusion. It isn't 4 inches, it is 2 3/4. The crown is between 1/2 to 3/4 tall from cingulum to cusp tip.

[Harry Pristis]

Interesting . . . But, it's not a bear tooth.

[Uncle Siphuncle]

I have to agree with the others here. I'm not seeing a tooth. Breaking it down and examining things feature by feature, I'm not seeing any difference in sheen, shape, or other surface characteristics between "enamel" and "root", as one would expect in fossil teeth. Surface topography looks too irregular for a tooth, and the weathered and broken Pleistocene teeth I've seen, found, and handled, which number perhaps over 1000, tend to reveal predictable internal structure where broken, I think you've made an interesting find, but not one that's organic in nature.

[Auspex]

That is still way too big:

Giant Short Faced Bear (Arctodus simus) dentition:

vs:

[siteseer]

Your specimen has only the gross shape of a lower bear molar. I see why you think it's that but you should look at actual bear teeth or high quality casts and learn how they tend to wear. Then, look at your specimen again. I've seen lots of Ursus spelaeus (extinct European cave bear) molars in various states of wear. During the 90's, the late Father Floyd Jenkins of Loyola Marymount (Jesuit who taught biology there) was building a composite dentition and asked me to try to find teeth at mineral shows that would fit what he had. I'm not saying I'm an expert but that item does not look like a bear molar. I'll try to dig out an illustration of cave bear molars he gave me to use as a guide and provide a scan tomorrow (or maybe someone else has a similar figure handy as well).

Also, a glacier wouldn't just polish a tooth, it would grind it to powder with the root being less resistant to abrasion than the crown.

Thanks John. They are both chert, and I am having fun photographing stuff with my new tripod and fancy phone. I don't wish to sound rude or ungrateful, but making human replacement teeth is how I made my living for over a decade. I recognize teeth after making a few hundred thousand of them. The banding is tooth wear down into the dentine, and the buccal and central lingual cusps are broken away. The banding is only on the occlusal surface, it does not extend through the entire rock as one would expect from banded chert.

[Tethys]

Thanks so much for all the information everyone. I really appreciate it even if my tooth is not a tooth.

Auspex ~

That is still way too big:

Thanks especially to you for the picture. Unfortunately I can't make out the cusp tips and finer details of the molars The major central lingual cusp of a short faced bear molar is quite distinctive. I can only find good pics online of the European cave bear, and the smaller NA species that lived in Florida. Wouldn't bears that lived further north close to the edge of the glaciers be expected to have larger body size than bears in warmer areas like California and Florida?

siteseer ~ I'll try to dig out an illustration of cave bear molars he gave me to use as a guide and provide a scan tomorrow (or maybe someone else has a similar figure handy as well).

Also, a glacier wouldn't just polish a tooth, it would grind it to powder with the root being less resistant to abrasion than the crown.

I would appreciate a scan very much. Teeth are cool. Apparently in this area the glacier foundered on the Missouri Couteau, and then took thousands of years to melt. It left huge ice thrust masses of Cretaceous Fox hills formation. Petrified wood is abundant, up to and including whole tree trunks. The side of my rock visible in the previous photo is heavily wind polished in addition to having been run through a glacier. Here is a pic of the other side, which would be the lingual if it was a tooth. I also took a picture of the end of the piece that looks like antler, and a shot of a particularly fine piece of glacially polished banded chert from the same land.

[Uncle Siphuncle]

Tethys, thank you for providing a fine example of open minded reception to collective experience. An open mind is an open gate to learning. Too often, people become entrenched in prior conceptions, then leave the forum when opinions differ with these prior conceptions. Most of us here, regardless of background or experience level, have been enlightened more than once....part of the gig.

In closing, full examination of diagnostic features tends to lead to positive ID. Too often we look at the overall form factor and are too quick to stop there and assign ID. Gross attributes such as surface features/character, as well as more subtle features including wear pattern and histology should all line up and point to supportable ID.