What is the Ammonite with the greatest number of whorls? Which one has the least?

[MeargleSchmeargl]

After looking at different pictures of ammonites for a hot minute this burning question hit me. I know that some ammonites have a greater number of whorls from keel to umbilicus than others, but which ammonites have the most/least number of whorls in their shells from keel to umbilicus? I haven't yet found any satisfying answer in my own searches and I know this is gonna be one of those questions that keeps me up at night.

[Lone Hunter]

I consider this one whorl and I would think it's the least,  I believe there are a number of them with just one.

[Ludwigia]

2 hours ago, Lone Hunter said:

I consider this one whorl and I would think it's the least,  I believe there are a number of them with just one.

 You would need to also count the inner whorls of that ammonite which are still covered with matrix and you'll see that there are still a good number of them. There are absolutely no ammonites which have only one whorl. A whorl is one rotation as indicated in the photo below.

 

[Ludwigia]

3 hours ago, MeargleSchmeargl said:

After looking at different pictures of ammonites for a hot minute this burning question hit me. I know that some ammonites have a greater number of whorls from keel to umbilicus than others, but which ammonites have the most/least number of whorls in their shells from keel to umbilicus? I haven't yet found any satisfying answer in my own searches and I know this is gonna be one of those questions that keeps me up at night.

 

This is a question which is very difficult, if not impossible to answer. There are a number of factors to consider other than the outward appearance. First of all, one can only count the whorls on complete specimens. A large portion of ammonites which are found are not complete, so they must be discounted. Also the number of whorls on a mature specimen of a particular species is greater than that on its juvenile counterpart. The form can also be deceptive. Evolute ammonites with a wide whorl often appear to have less of them than involute ones with a serpentine form, but that is because the preceding whorls on the former are hidden under the visible ones. One also needs to count the inner whorls right down to the protoconch.

I wouldn't even want to start to guess an answer to your question since it would take an awful lot of research and counting to get close to a satisfying result, as you may have already noticed by your searches. I suppose I could at least say that microconches have less whorls than macroconches. But maybe there's someone in the scientific world who has already researched your question, so don't give up searching. But try to sleep at night nevertheless

[FranzBernhard]

4 hours ago, MeargleSchmeargl said:

least number of whorls

Any straight shelled, aberrant ammonite?
Franz Bernhard

[Ludwigia]

6 hours ago, FranzBernhard said:

Any straight shelled, aberrant ammonite?
Franz Bernhard

You do have a point there Franz. A lot of heteromorph ammonites have few whorls and I believe that Baculites has only at most 2 whorls at the end of its straight shell.

[opalbug]

What about the whorl of a Nautilus

 

 

Edited May 24, 2022 by opalbug