This is a Plesiosaur paddle right?

[talon22]

Hi,

 

Saw this for sale, was thinking of purchasing it, but wanted to confirm if this is indeed Plesiosaur. it is quite large for a partial paddle at 14 inches in length and from the Goulmima region in Morocco. Thanks.

 

[Troodon]

Here is an illustration from a Mosasaur and they are described from Goulmima region

[talon22]

Thanks. So do you believe this is more likely to be from a Mosasaur? i know Tethysaurus is described from the same region.   

[Aurelius]

I'm not an expert, but I believe that the specimens of tethysaurus are usually quite poorly preserved and distorted, this looks to me as though it's from a different bed.

[jdp]

Looks plesiosaur to me.

[talon22]

I want to purchase it if it is indeed plesiosaur. Are there any specific features that help differentiate between plesiosaur and mosasaur ulnas? Does the largish size of the paddle make it more likely to be plesiosaur since the mosasaurs from the Turonian were relatively small and basal? Or maybe i am wrong in that assessment.

[jdp]

The large bone is a humerus, not an ulna. The crescent shape of the smaller bones (radius and ulna) with space between them shows clearly that those are not carpals.

[jdp]

e.g.

 

[talon22]

Oh ok thanks, i was going by the mosasaur picture and thought it was an ulna (larger bone) with two carpals. My mistake.

[talon22]

2 hours ago, jdp said:

Looks plesiosaur to me.

Are you confident about the id?, if you don't mind me asking.

[jdp]

Confident enough but I am not giving an appraisal of value.

[pachy-pleuro-whatnot-odon]

Definitely part of a plesiosaur paddle, almost certainly polycotylid, as these are found in the same beds. Compare to the below two paddles, and the Manemergus anguirostris skeleton.