Help With Lance Formation Skull Bone

[RCFossils]

I had an opportunity to do some digging in a channel deposit in Eastern Wyoming.

The deposit is in the Lance Formation (Late Cretaceous) on private property.

I dug out an unusual skull bone that I am having trouble identifying.

The bone is quite thin and appears to be relatively complete. It measures approximately 5 1/2” in length.

it has an unusual triangular shaped furrow on one side and is quite smooth on the other.

My best guess is the upper portion of a theropod maxilla.

I am hopeful that someone more familiar with skull bones might have an answer.

 

 

[jpc]

my guess is that this is one of the many small sheets of bone found on the underside of a ceratopsian frill.  We prepped a Torosaurus skull recently and the fornt end has numerous sheets of bone that were found broken off and in the matrix nearby. 

 

It could still be something else, but that is my semi-educated guess based on photos and my experience.  I don't think a theropod maxilla would have this many thin flanges of bone.   

[RCFossils]

Thanks JPC,

I was comparing it to this structure here (see picture).

not an exact match but same general shape.

It is rounded on one end which is what was leading me to believe it was preserving a portion of the small opening next to the maxillary fenestra.

 

 

[jpc]

Some thing like this that is partial and quite three dimensional can be tough to ID without side by side comparisons.  We have a ton of unidentified but interesting pieces in the museum.  

 

 

[rfarrar]

My first guess would be that this is an incomplete Triceratops pterygoid...

[jpc]

1 minute ago, rfarrar said:

My first guess would be that this is an incomplete Triceratops pterygoid...

rfarrar has seen a lot of this sort of material.   I would put money on his ID.  Maybe not all my money, but his hunch might better than mine. 

 

Hello rfarrar.    

[RCFossils]

Thanks for taking a look.

i will do a little research on Triceratops pterygoid bones and try to match it up.

[jpc]

I was inspired... had a look at our Torosaurus pterygoids and Yes, that is a great match.

Ceratopsian pterygoid it is.  Good call, rfarrar.