Hello all! Any insight on this unidentified fossil, from Hell Creek Formation, in Harding County, South Dakota, would be deeply appreciated. The collector/seller is a deeply experienced and trusted seller, but they were not able to identify it. The specimen was found on the same ranch that often produces dromaeosaur, trike, and champsosaur partials.
Please see images.
[P.S., this is the 4th of 5 specimens that I'm posting for ID today; I deeply appreciate any insight that you can provide]. With gratitude, Ryan