Bivalves and ammonoid from spain

[Entocarlos]

Hi all, first post in this forum! Happy to see it's pretty active.

 

In the coming days or weeks I'll be posting a few pictures of fossils from the area of Alto Tajo, near Molina de Aragón in the Guadalajara region, Spain.

 

These are fossils we have been collecting with my father since I was a kid, so I would be very happy to get them identified.

 

Today I share a first batch of a couple of very common bivalves and a small ammonoid. I'll be posting other larger ammonoids with better views of the sutures and the protrusion that runs along the outer edge in a few days or weeks.

 

Thank you!

[Rockwood]

I think these are actually brachiopods. I suspect the other one may be an ammonite. You should wait for more opinions though. 

[doushantuo]

Hiya, and welcome

Zigzag commissures and ornament style point heavily towards (rhynchonellid) brachiopod, as Rockwood already guessed

To show that this morphotype is not too uncommon:

 

Caracterización de Choffatirhynchia nov. gen. (Brachiopoda, Rhynchonellida) en el Toarciense (Jurásico) de la Cordillera Ibérica (España)
Autores: Fernando García Joral, Antonio Goy Goy
Boletín de la Real Sociedad Española de Historia Natural. Sección geológica, ISSN 0583-7510, Tomo 99, 1-4, 2004,

The coiled animal is an ammonite,a mollusc somewhat related to squid

82 (1).pdf

 

Edited November 30, 2024 by doushantuo

[Entocarlos]

Thank you! 

 

I was hoping to get an identification for the ammonite, although maybe it is too small or poorly fossilized. An idea of the geologic period would also be great. Any hopes for that?

 

Thanks again!

[doushantuo]

My guess is Toarcian

[Rockwood]

51 minutes ago, doushantuo said:

Zigzag commissures and ornamement style point heavily towards (rhynchonellid) brachiopod, as Rockwood already guessed

There are zigzagy oysters in Tezas. Caution seemed prudent. 

[Ludwigia]

40 minutes ago, Entocarlos said:

Thank you! 

 

I was hoping to get an identification for the ammonite, although maybe it is too small or poorly fossilized. An idea of the geologic period would also be great. Any hopes for that?

 

Thanks again!

 

Ammonites with this type of morphology and ornamention can be found in all 3 Jurassic stages, so the most one could say about it at this point is that it's probably from the Jurassic Period and unidentifiable until one could find out in exactly which sediments it was found. There is also a remote possibility that it's from the Triassic. Also, those "bivalves" are in my opinion all rhynchonellid brachiopods with the exception of one terebratulid in the middle.

[Entocarlos]

I believe the rock is limestone, but maybe this helps: see below a couple of pictures, one on-site with a large ammonite (about 20cm in diameter, but poorly fossilized - or at least I could not see any details) and some more fossils from the same area including (my guesses) several pieces of ammonites, more brachiopods, an upside-down coral, a gastropod, and a piece of Orthoceras. Sorry about the quality of those pictures! Additional identification for those is very welcome!

[Fossildude19]

23 minutes ago, Entocarlos said:

I believe the rock is limestone, but maybe this helps...

 

 

I think that Ludwigia was referring to the stratigraphy of the area, when he mentioned "which sediments it was found in".
To figure out the stratigraphy, you need to research the geology of the area they were found, and figure out what Geologic Formation you were hunting in.

People have already done the work of figuring out the geology of the area, you just need to research that yourself.

[Entocarlos]

1 hour ago, Fossildude19 said:

 

 

I think that Ludwigia was referring to the stratigraphy of the area, when he mentioned "which sediments it was found in".
To figure out the stratigraphy, you need to research the geology of the area they were found, and figure out what Geologic Formation you were hunting in.

People have already done the work of figuring out the geology of the area, you just need to research that yourself.

Thanks for the pointer! It seems to be between the Toarcian and the Bajocian then.

[Ludwigia]

1 hour ago, Entocarlos said:

Thanks for the pointer! It seems to be between the Toarcian and the Bajocian then.

Ok. That narrows it down a bit, but that's still a lot to cover. It might be a Harpoceras, but that's just guess work on my part.

[DPS Ammonite]

3 hours ago, Rockwood said:

There are zigzagy oysters in Tezas. Caution seemed prudent. 

These are all brachiopods since they have the  foraman openings for the pedicle.

 

https://www.alexstrekeisen.it/english/sedi/brachiopods.php

 

[Rockwood]

And I usually regret being overconfident. 

[DPS Ammonite]

8 minutes ago, Rockwood said:

And I usually regret being overconfident. 

The devil is in the details.

[Rockwood]

47 minutes ago, DPS Ammonite said:

The devil is in the details.

No. I saw the details. I knew what they were. The devil must have been in me.