A question about ammonites

[Misha]

Hello everyone,

Some time ago I was talking about a gastropod fossil with an individual online who thought that it was an ammonite, 

During this conversation one thing was brought up that I have wondered about for a long time but have not actually been able to answer, and that is what exactly do we consider an ammonite?

I have always thought that ammonites are the cephalopods with an external shell containing complex sutures which occur throughout the Mesozoic, but people have pointed out that certain sites talk about ammonites going back to the Devonian. I have always thought that those were ammonoids but not necessarily ammonites, I don't know how I decided that this was the case and now I realize that this might be wrong.

Does anyone know if those Paleozoic ammonoids are actually considered ammonites? What exactly is an ammonite and when do they appear?

I would be very interested to hear what you guys have to say, any input is appreciated.

Thank you!

Edited April 9, 2021 by Misha

[Fossildude19]

Wikipedia has a fairly good writeup on Ammonoidea. 

 

I've always believed/understood that Ammonites were strictly Mesozoic, but it looks like that may not be entirely accurate. 

[Misha]

11 minutes ago, Fossildude19 said:

Wikipedia has a fairly good writeup on Ammonoidea. 

 

I've always believed/understood that Ammonites were strictly Mesozoic, but it looks like that may not be entirely accurate. 

I've looked through that, and I believe they also have a list of ammonite genera which features Devonian organisms.

 

My assumption about ammonites was the same.

[Notidanodon]

 Ammonoids were around in the Devonian I think, but they were goniatites I think, ammonites to my knowledge only existed in the Jurassic and cretaceous

[LabRatKing]

1 hour ago, will stevenson said:

 Ammonoids were around in the Devonian I think, but they were goniatites I think, ammonites to my knowledge only existed in the Jurassic and cretaceous

And Triassic see also Cowboy Pass Utah.

[Notidanodon]

7 minutes ago, LabRatKing said:

And Triassic see also Cowboy Pass Utah.

True!  In the late Triassic there are a few

[Ludwigia]

The word ammonite is actually an ambiguous, rather than a scientific term, which is why it can get confusing. All of the orders under the subclass Ammonoidea: Ammonitida, Ceratitida, Goniatitida, etc. have been called "ammonites" at some point, but in the end, it's actually just a layman's term.

[Misha]

@Ludwigia

That's very interesting, thank you for the information!

I think I was thinking of ammonitida as being what we consider ammonites and the rest as ammonoids which is why I experienced that confusion.

Edited April 13, 2021 by Misha