Hell Creek Mammal Tooth still in jaw

[Ozzie123]

My youngest brother found this on his first microsite hunt.  I could not believe it.  I have not found many mammal teeth and am unsure as to what this belonged to. I also added some pictures of another tooth found in the area that I am having a hard time placing an ID on. Any help is appreciated! Hell Creek formation, Dawson County, MT.

[siteseer]

Cretaceous mammals are truly their own category as they are completely alien to many who collect Cenozoic mammals, the vast majority of which range from Oligocene-Recent in age.  You should compare that to images of Cimolestes lower molars and see what you think.  There's never a Cretaceous mammal expert around when you need one.  I had a friend, Father Floyd Jenkins of Loyola Marymount University, who could do it but he passed away years ago. 

[ThePhysicist]

I can't be of very much help, but @jpc probably can be.

 

The first one looks like a lower metatherian multituberculate, the second looks like a very large mammal maybe something like Didelphodon.

[Nimravis]

Beautiful tooth.

[Troodon]

Check out F, G & H might fit, a

Revision to  Pediomylid in 2007 now Protolambda florencae (Davis 2007)

 

Hunter et al 2002

 

Yes given the size the canine tooth is most likely  Didelphodon

 

[jpc]

Excellent find, but gee whiz...don't you just hate it when a noobie comes out with you and finds something that makes you jealous.

 

"There's never a Cretaceous mammal expert around when you need one."

I may not be an expert, but troodon and I are the closest things we have here.   : )

Troodon's suggestion is pretty spot on.

 

Indeed, these things are not common at all.  I am with my family in Pennsylvania this week, away from my books, so this a an educated guess.  It is indeed a lower molar, but not at all a multituberculate.  There are not many options for Lancian large mammals and I am going to say look into Didelphodon vorax.  D. vorax is a marsupial.  The big difference between marsupial and 'regular mammals' (=placentals) as seen in the lower molar is that two of the little cusps on the lowest portion of the tooth on marsupials are very close to each other.  There are three little cusps there and in placentals, those three cusps are more or less equidistant.  I cannot tell from these pix what the condition of these cusps is, hence my guess based on size.  There are no known placentals this big in the Lance/Hell Creek.  

 

Can I say it again... great find.  In my many years of collecting in the Lance with may extra volunteers, we have only found three Didelphodon dentaries.