Fossil Jaw-Partial

[Katy2319]

Hi all! I was recently visiting with another naturalist, helping them to identify some of the donated rocks and fossils in their collection. There were a few that stumped us both, and unfortunately they couldn't tell me where any of the specimens were originally found, or the period anything was from with any certainty. I'll make separate posts for the different pieces. But here's part one to start with.

 

A partial jaw with large molars, certainly from a large herbivore. The other naturalist suggested perhaps from a moose, and I also found similarities in the shape to other cervids, so I think this is the right track, but I'm far from an expert, especially on teeth.

 

the jaw measures 8" long, and 3-4" wide. I didn't think to measure individual teeth, but each is over an inch wide.

 

 

[mkspsa]

I'm not an expert on vertebrates but these appear to be rhino teeth. I suspect someone else on the forum can provide a species, given the quality.

[Harry Pristis]

From appearance, I'd guess Subhyracodon.

[Katy2319]

Thank you so much! I honestly did consider a rhinoceros but wasn't confident enough to say it, so this is super cool! @Harry Pristis I'm wondering if you can point out any of the details that makes you think it's that particular species? I love any chance to learn from others.

[Harry Pristis]

Subhyracodon:

[fossilhunter21]

Yep. Definitely Subhyracodon. Possibly Subhyracodon occidentalis. I would say definitely from the White River Formation. Very cool fossil.  

 

Cheers and Shalom,

 

-Micah

Edited June 3, 2023 by fossilhunter21

[GarethGP]

100% subhyracodon, lovely specimen too. 

[fossillarry]

I believe that the maxilla fragment is from Trigonias osborni. I base this on my personal knowledge,  I have collected in the White River Group in Eastern Wyoming for over 40 year, and I have a fairly good collection of badlands rhinos.  In addition I checked the Prothro book on the evolution of North American rhinos and the W. B.. Scott book on White River perissodactyls and the illustrations and description confirm ( I believe) my ID.  Base on the color of the teeth and bone I believe the fossil is from the  Chadron Formation Late Eocene. The most common source of such fossils are the Big Badland of South Dakota or Sioux Co. Nebraska. Trigonias is somewhat larger than Subhyracodon and has a number of dental and skull differences that clearly differentiate the two genera. Subhyracodon does occur in the Late Chadronian but I do not think this specimen is that genus.