?Abelisaurid bones

[Anomotodon]

I decided to sort through some of the Kem Kem bones I got at the Tucson show, and I think I found several Abelisaurid bones. Please let me know if I got it right  

 

(Ifezouane formation, Late Cretaceous, Cenomanian)

 

Here is what I think is a distal tibia 

 

 

Here are some Abelisaurid tibias: A - Quilmesaurus, G - Rajasaurus, I - Pycnonemosaurus

 

 

 

@LordTrilobite @Troodon

[Anomotodon]

And here is what I think is an Abelisaurid right radius

 

lateral

 

 

Medial 

 

 

Distal

 

Proximal

 

 

Here is a Majungasaurus radius for comparison, ulna is much more symmetrical. I think it works, assuming Kem Kem abelisaurid was more basal and smaller, however distal end still looks odd

 

[LordTrilobite]

The first bone does seem to resemble some type of distal end of a tibia. But I wouldn't say for sure. I'd label it as a probable tibia from a theropod. I have a similar but smaller bone that I also think is tibia, but I haven't put any name on it. Theropod tibias can be pretty similar. And we know very little of the Abelisaurids in the Kem Kem beds.

 

The second bone is very interesting. Actually I think it resembles the ulna of Majungasaurus more than the radius. Though still different it seems to have some of the same features. But I don't think it's clear enough to say anything conclusive. Carnotaurus doesn't seem to be a match at all. And so far from what I've seen kinda seems to point to a more derived Abelisaurid. Scientists have mostly compared the few scraps to Rugops from Niger, which does look fairly based on what's found so far.

 

Majungasaurus radius

 

Majungasaurus ulna

 

Majungasaurus shoulder girdle

 

Carnotaurus arm

 

[Anomotodon]

35 minutes ago, LordTrilobite said:

The first bone does seem to resemble some type of distal end of a tibia. But I wouldn't say for sure. I'd label it as a probable tibia from a theropod. I have a similar but smaller bone that I also think is tibia, but I haven't put any name on it. Theropod tibias can be pretty similar. And we know very little of the Abelisaurids in the Kem Kem beds.

 

The second bone is very interesting. Actually I think it resembles the ulna of Majungasaurus more than the radius. Though still different it seems to have some of the same features. But I don't think it's clear enough to say anything conclusive. Carnotaurus doesn't seem to be a match at all. And so far from what I've seen kinda seems to point to a more derived Abelisaurid. Scientists have mostly compared the few scraps to Rugops from Niger, which does look fairly based on what's found so far.

 

Majungasaurus radius

 

Majungasaurus ulna

 

Majungasaurus shoulder girdle

 

Carnotaurus arm

 

 

Thanks! I thought it's a radius because of how proximal surface is more angled relative to distal surface. Anyways, the distal surface looks much smaller and less convex than in Majungasaurus ulna and radius. I wonder if it could be a derived trait, since smaller surface implies less mobility, like in Carnotaurus and unlike Majungasaurus which is considered more basal. Although Carnotaurus had a much larger proximal surface...

 

I wish someone would describe these Moroccan Abelisaurids...

[Troodon]

I agree the first bone should be identified as indeterminate.  Here is the distal ends of Spinosaurid tibia and considering how dense the broken end looks a case could be made for it being a juvie of one.  However like LT said so little is known or published on Abelisaurids indeterminate is the right call.

 

 

I love your other bone, here us a photo of arm bones of Majungasaurus. Agree with LT that there is more of a resemblance with the ulna.   Unfortunately the problem with describing post crainal bones is finding associated elements and thats a tall task in the KK but it would be nice to see it happen.  I hope that we at least get the maxilla ( UCPC 10) described as Rugops