British Theropod Bone?

[FF7_Yuffie]

1 hour ago, Omnomosaurus said:

 

It actually does look to be the same fossil. This site isn't where I saw it for sale, so it must've changed hands (and received a big price increase in the process).

 

 

Thanks for checking and providing an update here! 

 

Hopefully anyone thinking of buying it as a theropod bone does a little research and finds this thread first.

 

No worries. This is what Oxford said when I emailed them

 

"it looks more like a piece of plesiosaur limb girdle from the photo, either a coracoid, ischium or pubis."

 

 

[pachy-pleuro-whatnot-odon]

On 6/12/2019 at 9:15 PM, paulgdls said:

Plesiosaur pubis?

 

On 6/13/2019 at 11:59 AM, paulgdls said:

All I can say is that dinosaur material from the Kimmeridge and Oxford Clay formations is incredibly rare and theropod material even more so. 99.9% of bone is from marine reptiles but sometimes sold as dinosaur. Differentiating between the massive dorsal vertebral centra of pliosaurs and sauropods can be almost impossible and is often the subject of controversy.

I'm with Paul on this one, on both counts. Since the pertinent Kimmeridge and Oxford Clay formations are primarily marine in composition, it's very rare to find dinosaurian material there. Let alone remains of a terrestrial predator, seeing the natural balance between predator and prey is always skewed towards there being more prey (this is why the Kem Kem is such a notable exception). I would therefore say, as many have already done, that this is plesiosaur material (sensu lato).

 

However, since plesiosaurian plesiosaur appears to be rarer at Abingdon than pliosaurian plesiosaur, I would even say that rather than being plesiosaurian (sensu stricto), this piece is much more likely to derive from a pliosaur. As to what part it is  - again I agree with Paul: part of a pliosaur pubis. Below is an image of the Liopleurodon ferox skeleton on display at palaeontological collections of the MUT Tübingen, where I've circled (kind off) the piece of bone matching that illustrated by the OP.

 

The pubis of the Peloneustes philarchus skeleton at the Senckenberg Museum in Frankfurt (illustrated below) shows a similar notch, though much more anteriorly than in the above example.

 

In contrast, the pubis of plesiosaurian plesiosaurs is much smaller - as can be seen below in the Plesiosaurus dolichodeirus from the Naturalis Biodiversity Center or the Cryptoclidus sp. from the Natural History Museum Stuttgart. And as the constriction of the bone leading up to the notch cuts much deeper, the incline seen on the OP's piece would have been much sharper, would it have been plesiosaurian plesiosaur.

 

And though the incline could be argued to match something akin to that of the pubis of the Meyerasaurus (Thaumatosaurus) victor from the palaeontological collections of the University of Zürich below (cast, original from Holzmaden) if the bone is rotated (thus with the notch marking the end of the constriction in the bone), it would seem likely that the bone at that part would, in that case, have been thicker. It may also be worth pointing out that Meyerasaurus is classified as a rhomaleosaurid plesiosaur, which may be considered an early pliosaurian branch of plesiosaur.

[pachy-pleuro-whatnot-odon]

While I realise this is an old one that's probably lost its relevance quite a while ago, I recently had opportunity to review my above response, and have changed my opinion. I've got some other photographs of the piece, and for sake of educational purposes for anybody facing a similar question in the future, I'll share my updated opinion here. For me, clue to the identification of this piece are the thickened rounded edge immediately adjacent a very robust looking articulation surface, which, moreover, has a bend in it, suggestive of the articulation of two bones rather than one.

 

 

 

As you can see in the circled area of the Peloneustes philarchus specimen at the Naturmuseum Senckenberg in Frankfurt below, a similarly bent articulation face is located laterialy to the anterior portion of the coracoid, providing a contact surface for the humerus and scapula to articulate with. I therefore posit that this specimen is an anterior part of a pliosaur coracoid, although I shouldn't think it's diagnostic as to genus or species.