Ammonoid ID

[RicBiol]

Dear forum members, I have just joined the forum and need your help for ammonoid identification. Although I´m an aquatic biologist of extant animals, my knowlege is very limited regarding fossil creatures.  I´ve just acquired two ammonoid display specimens through the family of a deceased Japanese-Brazilian regarded merchant of ornamental stones. These pieces belonged to his private collection and didn´t receive a data tag because the informations were in his mind.  His family only recalls those ammonoids to have been brought from Japan many years ago, but most likely have originated elsewhere. In this message I´m attaching pictures of the first ammonoid up to the allowed 3.95 MB volume, but may provide more specific pictures if desirable. I will be delighted to have any information on this animal.

Thanking for your kindness,

Best regards

Ricardo

 

[JamieLynn]

I am certainly no expert, but this looks more nautiloid to me. What I have observed is that nautiloids tend to have that larger "curled into themselves' look than ammonoids. Fatter, not flatter. 

[FossilDAWG]

The suture lines mark these specimens as being goniatites; goniatitic sutures are more complex than the simple suture lines of nautiloids, but they are less complex than the suture lines of ammonites which have numerous saddles and lobes.  Goniatites can be considered to be ammonoids in the sense that they are "pre-ammonites", i.e. they occurred earlier than the true ammonites.  Your specimens are typical of those that originate in Morocco and can be found for sale in rock shops around the world.  Because they have been ground smooth and polished, surface ornament and details of the suture lines have been removed, and unfortunately these features are needed for a precise ID.  Perhaps someone who is more familiar with Moroccan goniatites can offer a suggestion as to a more precise ID based on the species that are known to occur there.

 

Don

[Ludwigia]

Don hit the ball on the mark: Polished Goniatite. Probably Moroccan.

[Mark Kmiecik]

And most polished specimens have had the features that would make identification possible removed by the polishing.

[RicBiol]

Thank you very much JamieLynn, FossilDAWG, Ludwigia and Mark Kmiecik for the precise and ultrafast identification of the Morrocan polished Goniatite !!!

 

The other piece I´ve got from the same source is illustrated here. And thanks to your advice, I found this to be a commercial display composed of a Goniatite plus three Orthoceras specimens glued onto a slab, with such fossils also being from Morocco. Thus, bith pieces came from the same original source. Thanks again !

 

Kind regards,

Ricardo