fossil of a marine creature?

[ariburua]

It was found in a ravine in sedimentary rocks from the Upper Jurassic, in Spain. The rock surrounding the fossil is conglomerate, sandstone, siltstone, and clay. The fossil is approximately 2 centimeters long and has an irregular cylindrical shape. It is brown with some darker parts. One of the edges in its transversal section has shiny white spots as if it were crystal. The outer layer has a texture like veining along the cylinder.

 

It may be a fossil of a marine creature that lived during that time, such as a mollusk shell, a shark tooth, or a fish backbone? 

• Belemnites: These are fossils of prehistoric squid shells that have an irregular cylindrical shape and veined texture. They may also have mineral inclusions that give them white or iridescent shine. 
• Gryphaea: These are fossils of oyster shells from the genus Gryphaea, which also have an irregular cylindrical shape and may have a veined texture. They are often found in sedimentary rocks from the Upper Jurassic.
• Shark teeth: Shark teeth are common in sedimentary rocks from the Upper Jurassic and may have an irregular cylindrical shape. However, they are unlikely to have mineral inclusions that give them white shine.
• Fish spine: The spinal columns of some fish have an irregular cylindrical shape and may have a veined texture. They may also have mineral inclusions that give them white shine. But this is less common than the other fossils mentioned.

Thanks!

[Rockwood]

I think this looks more like a plant stem, maybe a fern ?

[ariburua]

Isn't the white, crystal-like shine on one of the edges of the cross-section more common in fossils of mineral or animal origin?

Edited February 18, 2023 by ariburua

[Rockwood]

10 minutes ago, ariburua said:

Isn't the white, crystal-like shine on one of the edges of the cross-section more common in fossils of mineral or animal origin?

Plant fossils can be as mineral as animal fossils. It's the organization in the texture that I'm thinking looks more like that seen in plant fossils. You should wait for other opinions though. 

[ariburua]

Thank you very much for your contributions Rockwood!