Ichthyosaurus Stenopterygius?

[charlie3425]

This is supposed to be a Stenopterygius vertebra from Holzmaden, Germany. But is it?

Could be a fish vert? (Xiphactinus audax?)

 

 

[Top Trilo]

I haven't seen many ichytosaur verts but this looks fishy to me. (ichytosaur first, xiphactinus second)

[charlie3425]

7 hours ago, Top Trilo said:

I haven't seen many ichytosaur verts but this looks fishy to me. (ichytosaur first, xiphactinus second)

Yeah, I think someone was fishing in my wallet... nice vertebra though. But not what I orderded it for...

 

[pachy-pleuro-whatnot-odon]

Yeah, I know this one and have always thought there was something fishy about it (pun intended)

 

But to answer your question: no, this is not what an ichthyosaur vertebra is supposed to look like, nor is this conservation consistent with that found at Holzmaden. I thus have no idea where this vertebra might be from and consequently what fish it could've belonged to.

 

There are a couple of features on this vertebra that give it away as not being ichthyosaurian:

1. The neural arch is never directly attached to an ichthyosaurian vertebra, except maybe the very earliest of species.
2. The sides of an ichthyosaurian vertebra are smooth, not ribbed as this one is.
3. Ichthyosaurian vertebrae aren't waisted along their axial length, as this one is.
4. Ribs are not attached to vertebrae in ichthyosaurs.
5. The bevelling or layering of the concavity in the centrum isn't encountered in ichthyosaurs.

 

Points two and three from the above list are actually indicators of this vertebra being a fish vertebra, as is the fact that the vertebra is amphicoelous, a condition found in both fish and ichthyosaurs (and to lesser extend in the amphiplatian to platycoelous plesiosaurs) for the reason it "decouples" the vertebrae from one another and thus gives the spinal chord much more lateral freedom, needed for different modes of swimming.

 

Below are just a couple of examples of ichthyosaurian vertebrae for comparison:

 

Brachypterygius extremus anterior dorsal vertebra, dredged off of Weymouth

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Anterior caudal vertebra from an unidentified early ichthyosaurian species (Rhaetian or Hettangian) from Newark

 

 

 

 

 

 

 

 

 

 

 

 

 

Cf. Platypterygius sp. tail vertebra from l'Aube

 

 

 

 

 

 

 

 

 

 

 

 

Eurhynosaurus longirostris anterior caudal vertebra from Whitby

 

 

 

 

 

 

Stenopterygius sp. posterior tail vertebrae from Holzmaden

Edited April 10, 2021 by pachy-pleuro-whatnot-odon

[jpc]

pachy-etc. is spot on.  

[Carl]

I agree with the others: Definitely not an ichthyosaur and the preservation is wrong for Holzmaden. It is a vertebra from a very large, bony fish.

Edited April 11, 2021 by Carl

[charlie3425]

13 hours ago, pachy-pleuro-whatnot-odon said:

Yeah, I know this one and have always thought there was something fishy about it (pun intended)

 

But to answer your question: no, this is not what an ichthyosaur vertebra is supposed to look like, nor is this conservation consistent with that found at Holzmaden. I thus have no idea where this vertebra might be from and consequently what fish it could've belonged to.

 

There are a couple of features on this vertebra that give it away as not being ichthyosaurian:

1. The neural arch is never directly attached to an ichthyosaurian vertebra, except maybe the very earliest of species.
2. The sides of an ichthyosaurian vertebra are smooth, not ribbed as this one is.
3. Ichthyosaurian vertebrae aren't waisted along their axial length, as this one is.
4. Ribs are not attached to vertebrae in ichthyosaurs.
5. The bevelling or layering of the concavity in the centrum isn't encountered in ichthyosaurs.

 

Points two and three from the above list are actually indicators of this vertebra being a fish vertebra, as is the fact that the vertebra is amphicoelous, a condition found in both fish and ichthyosaurs (and to lesser extend in the amphiplatian to platycoelous plesiosaurs) for the reason it "decouples" the vertebrae from one another and thus gives the spinal chord much more lateral freedom, needed for different modes of swimming.

 

Below are just a couple of examples of ichthyosaurian vertebrae for comparison:

 

Brachypterygius extremus anterior dorsal vertebra, dredged off of Weymouth

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Anterior caudal vertebra from an unidentified early ichthyosaurian species (Rhaetian or Hettangian) from Newark

 

 

 

 

 

 

 

 

 

 

 

 

 

Cf. Platypterygius sp. tail vertebra from l'Aube

 

 

 

 

 

 

 

 

 

 

 

 

Eurhynosaurus longirostris anterior caudal vertebra from Whitby

 

 

 

 

 

 

Stenopterygius sp. posterior tail vertebrae from Holzmaden

Thank you very much. I've learned a lot today. The seller agreed on a partial refund. It is a nice vert though. Wish I knew wich (big) fish it was from. Next time I will know better anyway!