Help With Oligocene Fossils

[mirbane]

Hi everyone. I am new to the forum and am hoping for some help identifying several oligocene/eocene vertebrate fossils. First is a small jaw section from the Brule or Chadron formation (from dry stream bed so not exactly sure) in northwest Nebraska. It looks like an oreodont to me but it seems too small. The second is a moderately large vertebra from the same location. Here I was thinking it looks like a titanothere vertebra but again it seems too small. Third is a scapula I think but from what I have not idea, also from the Nebraska location. Last is a tooth fragment from the Brule formation in South Dakota. I presume this is a partial canine of some sort but from what I'm not sure. Any input would be greatly appreciated. Thanks!

Edited August 14, 2014 by mirbane

[mirbane]

Second fossil

[mirbane]

Third fossil

[mirbane]

Last fossil

[jpevahouse]

The maxilla jaw section, oreodont. They varied in size. Vertebrae, hyracodon. Titanothere didn't live in the Oligiocene era, Eocene. Third picture, skull section, probably oreodont. Last picture, probably hyracodon tooth section.

Edited August 14, 2014 by jpevahouse

[snolly50]

Hello, great material. Regarding the teeth/jaw section, to me they indeed appear Oreodont. However, they do not have the typical appearance that I am used to seeing. That is, the cusps are not nearly as "pointy." Compare this picture with your last picture of the piece in buccal aspect. There is a pronounced visual difference. Under magnification can you tell if your teeth show signs of wear or being broken?

For fun run them under a short wave UV lamp and see if they fluoresce.

[mirbane]

Thank you both!

Jpevahouse, I can totally see that being a skull section now that you mention it. May I ask why you think hyracodon for the vertebra? Is this simple based on size or do they have a characteristic appearance? This was not found in situ and was from an area where both the chadron and brule formation were exposed so I think it could also be eocene. I found a large tooth section in the same area that I am nearly certain is titanothere, hence my thinking on the vertebra.

Snolly50, I definitely agree that it has a peculiar appearance. There are some signs of wear on the upper srufaces of the teeth, around the edges, but honestly it does not seem too dramatic. The enamel of the teeth still seems complete and unbroken. I have some other teeth that are very clearly oreodont and have the pointed appearance as shown in your picture and in others I have seen. Is leptomeryx a possibility? It looks very similar to this specimen on ebay (http://www.ebay.com/itm/Fossil-Deer-Jaw-With-Teeth-Leptomeryx-evansi-EA1219-Oligocene-USA-dinosaur-/161381566311?pt=AU_RocksFossilsMinerals&hash=item2593174767), although who knows how good their identification skills are.

Thanks again.

[snolly50]

Indeed, the link you provided does lead to a specimen that more closely resembles your piece. I have no "in hand" experience with Leptomeryx, so I am far from certain about any ID. The shape of the occlusal surface of your specimen does look "oreodonty," and that's the commonly found critter so the odds favor it. However, as I indicated, the cusps just don't look sharp or prominent enough. I would attempt more in hand comparison to Leptomeryx specimens or photos. I believe you may be on the right track. Good luck.

[jpevahouse]

Thank you both!

Jpevahouse, I can totally see that being a skull section now that you mention it. May I ask why you think hyracodon for the vertebra? Is this simple based on size or do they have a characteristic appearance? This was not found in situ and was from an area where both the chadron and brule formation were exposed so I think it could also be eocene. I found a large tooth section in the same area that I am nearly certain is titanothere, hence my thinking on the vertebra.

Snolly50, I definitely agree that it has a peculiar appearance. There are some signs of wear on the upper srufaces of the teeth, around the edges, but honestly it does not seem too dramatic. The enamel of the teeth still seems complete and unbroken. I have some other teeth that are very clearly oreodont and have the pointed appearance as shown in your picture and in others I have seen. Is leptomeryx a possibility? It looks very similar to this specimen on ebay (http://www.ebay.com/itm/Fossil-Deer-Jaw-With-Teeth-Leptomeryx-evansi-EA1219-Oligocene-USA-dinosaur-/161381566311?pt=AU_RocksFossilsMinerals&hash=item2593174767), although who knows how good their identification skills are.

Thanks again.

The hyracodon and subhyracodon were among largest of the Oligocene mammals. Hyracodon is a reasonable assumption for predominately Oligocene White River deposits. A titanothere vertebrae will measure between 3 and 5 inches diameter, a larger animal. Based on the size of the dime you use I would assume your speciment is about 2 inches.

Edited August 14, 2014 by jpevahouse

[jpc]

I do not have my refs with me here and now, but the maxilla may be a horse. Mesohippus.

[jpevahouse]

I have numerous examples of both oreodont and mesohippus maxilla. Without any doubt that is not from a mesohippus. Mesohippus molars have a very distinct S twist to the enamel ridges which makes them easy to ID.

See attached example.

Edited August 17, 2014 by jpevahouse

[tmaier]

I'm not a vertebrate guy, but here's an example of the "S" shape that is being described...

I got that photo from a video I took at Florida Museum of Natural History, about 15 years ago. My notes say it was labeled as "Ahippus", and not officially classified yet.

Here are more of that horse...

The Florida Museum of Natural History has a very good collection of horse fossils and here is part of their on line display of horse evolution...

https://www.flmnh.ufl.edu/fhc/Stratmap1.htm

And that concludes my feeble knowledge of fossil horses.

Edited August 17, 2014 by tmaier

[RichW9090]

The upper jaw section appears to be oreodont - fully selenodont.

[fossillarry]

It is the upper jaw section of the ''deer'' Leptomeryx.

[RichW9090]

Nope. Oreodont.

[Diceros]

I'm with Rich on the left maxilla frag. with P2-M3. The anterior premolars P2-3 are wrong for Leptomeryx evansi, and the teeth aren't high-crowned enough. I also agree it's too small for the typical badlands oreodont, Merycoidodon culbertsoni. I think it's the small oreodont Leptauchenia. Nice specimen (the others aren't).