How to classify the Phalanges of Spinosaurus and Carcharodontosaurus?

[Cris Tang]

According to the owner/ seller, he showed his fossils from somewhere.

And he marked them as the Phalanges of Spinosaurus and the Phalanges of Carcharodontosaurus.

My question is, how do he classify them?

For me, they are totally same.

Would you share the knowledge about this part to me, please?

Thank you.

 

The pictures are following, 

 

Phalanges of Spinosaurus 

 

Phalanges of Carcharodontosaurus

[Troodon]

You should ask the seller how he arrived at these assignments I would love to know, maybe he has information no one else has.   Identification of isolated phalanges is very difficult since they can be very similar and little to nothing is published.  All we have are some illustration/photos of some associated with Spinosaurids and a lot less with Carcharodontosaurus. 

 

I will also make this more complex in that it's impossible to differentiate between the Spinosaurids (Spinosaurus and Sigilmassasaurus) and Carcharodontosaurids ( Sauroniops and Carcharodontosaurus). 

 

With Spinosaurids we have this illustration from Ibrahim et al

 

Sereno replica display of a Spinosaurus

 

Ibrahim et al included this photo of Digit IV phalanges l in his Tail paper on Spinosaurus