Hell Creek Mammal

[Peat Burns]

Sorry for the barrage of Hell Creek posts, I finally have time to go through some of my summer collections.

 

I am having a hard time with this mammal tooth (Hell Creek Formation, Late-Cretaceous, South Dakota).  The occlusal surface is heavily worn.  I was thinking perhaps Cimolodon? or Mesodma?  Any help / suggestions would be greatly appreciated.  Scale bar = 1 mm

 

[jpc]

This is an upper molar of neither Cimolodon nor Mesodma.  Those are both multituberculates.  In the Lance/ Hell Creek there are three groups of mammals...multituberculates, marsupials and  placentals.  This is one of the latter and, yes it is well worn.  IDing one group from the other is tough, but marsupials had  five little cusps on what is the right edge of your bottom shot,.  I think I see two of them posted in my copy of your photo.  Also, at 6 or 7 mm long it is very big so I am going to call it Alphadon, a big and common (relatively) genus in the Lance.  There are many species and I cannot guess which it is without my books. 

 

[Peat Burns]

3 hours ago, jpc said:

This is an upper molar of neither Cimolodon nor Mesodma.  Those are both multituberculates.  In the Lance/ Hell Creek there are three groups of mammals...multituberculates, marsupials and  placentals.  This is one of the latter and, yes it is well worn.  IDing one group from the other is tough, but marsupials had  five little cusps on what is the right edge of your bottom shot,.  I think I see two of them posted in my copy of your photo.  Also, at 6 or 7 mm long it is very big so I am going to call it Alphadon, a big and common (relatively) genus in the Lance.  There are many species and I cannot guess which it is without my books. 

 

 

Thank you, JPC.  Much appreciated.