A Mysterious Ammonite.

[Phil]

So there was I last night down the pub, as usual, listening to some terrible jazz, when this chap says to me: “Phil, I know you are interested in fossils. I’ve got a really large one in my shed. Do you want to see it?” Rather nervously accepting his offer, I went to his house at two in the morning, carried on drinking copious amounts of his lethal home-brewed cider and he gave me this enormous ammonite!

I got stopped by the police on the way home who asked me what on earth I was doing at half past four in the morning staggering around and carrying something gigantic and suspicious in a bag. I explained to the officer, in a half-cut sort of way, that it was a limestone ammonite of immense proportions. The officer looked somewhat perplexed and drove on, obviously thinking I was some sort of nutter.

Anyway, I have absolutely no idea what the species of ammonite actually is, and I would gratefully like to hear any suggestions. Unfortunately the person who gave it to me did not know either and did not know where it was found. All I can say is that it is preserved as limestone, came from the UK, has complex suture marks and has no keel. It is 13 inches across. I suspect it may be Jurassic, due to the lack of ornamentation, but I’m not exactly sure.

 

[tonmo]

Wow! Nice catch. See, good things *do* happen when you drink heavily.

Why do I get the feeling that your friend is going to wake up this morning and say, "ugh, my head... hey! Where the hell is my ammonite???"

 

[Architeuthoceras]

Great fossil Phil!

Sorry I can't help you with an I.D., It does look like it came from the Jurassic or Early Cretaceous.

I used to come home with pretty things like that after a good night on the town, well maybe they were a little softer, I can't remember.

 

[WhiteKiboko]

are you sure he gave it to you? i know a few times in the past ive gone klepto in the wee hours.... but not to worry, if you were subjected to horrible jazz all night, you can plead temporary insanity.... also, its good to see that a bottle of beer is still a well recognized unit of measurement... (as long as theyre the 12oz/355ml kind and not those little 6-7oz ones)

congrats on the interesting find...

 

[Melissa]

Your story is almost as good as the ammonite! You make me think I should hit the bars more often.

Melissa

 

[Fujisawas Sake]

"oooooooh,

A Guiness goes well
with an ammonite shell
At any time o' night

I'll wager some quid
and a big local squid
It's not a be-le-mite

O' fossil, old fossil
those secrets you keep
of muscle scars
and tissue deep
Obsession of ours,
Goodbye to sleep

A Guiness goes well
With an ammonite shell
At any time o' night..."

Okay, this doesn't answer the question, and its not QUITE a pub song, but since the topic seems to be drinking and thinking... of squid... :P

Sushi and Sake,

John

 

[Phil]

Thanks John, that was great! I'll copy that and show my ammonite donating aquaintance next timer I'm out. I think he will love it!

I think you should throw in a 'Heave-to, me hearties' and make it a sea shanty!

 

[Phil]

I think I've got it.

If anyone out there knows any better, then please shout!

I believe that this is an example of Lytoceras aaleniarum based upon a photo on page 42 of Neale Monks & Philip Palmers book. The form and the suture lines look, as far as I can tell, identical.

If I am right then this was a big and bulky Jurassic ammonite that was probably a bottom feeder. As it was so bulky and unstreamlined it would have been a poor swimmer. What is quite interesting about this fossil is that the sutures are really quite complex up until the final three or four body chambers when they rapidly become very simple, just a slight curve on the final (preserved) body chamber. This can be seen in the photo if you look closely.

I would imagine that this would imply the animal had reached a specific stage of development in its life, probably sexual maturity, and we may be looking at the whole and intact animal rather than a fragment.

 

[Architeuthoceras]

Phil,
It looks to me like the last half whorl or so has been weathered, and so the more complex part of the sutures are missing. The sutures on ammonitic ammonoids are complex but as you move toward the center of the septa they become alot more simple, almost smooth in the center of the whorl. Usually as an ammonite reaches maturity it begins to slow it's growth so the sutures would become approximated (closer together). I cannot tell if the sutures on your specimen are closer because of the weathering. another indication of maturity would be a change in ornamentation or shape of the aperture, but I cannot see any ornamentation and the last whorl or body chamber is missing, this would add another 3/4 or more whorls to the conch. The complete conch would have been alot bigger.

Just the opinion of an amateur ammonitologist.

 

[Phil]

Thanks Kevin.

I've gone back and had another look at it and I think you are absolutely right. I may have jumped the gun a bit in my post above (Still learning, you know!).

The lack of complexity on the final couple of sutures does indeed seem to be an artifact of weathering and the sutures do not become more compacted towards the (missing) aperture. It's a pity the centre is quite worn and the rear of the fossil, which you can't see in the photo, is much more eroded.

I still think it was a lucky find!

Thanks a million.

 

[Fujisawas Sake]

Phil,

Maybe I should compose "squid songs" to spin a much more positive image of our teuthoid buddies...

Okay, maybe not...

BUT... It was a lucky find, and I'm happy for you. Is there any way you can find out more? Any schools nearby with an "ammonitologist"?

Sushi and Sake,

John

 

[Architeuthoceras]

It is a great find Phil, and after looking thru Monks & Palmer it looks like your ID is on the money.

 

[Fujisawas Sake]

Phil (or anyone),

The last question I asked in my topic "Malacology: H.G. Wells Style" was about freshwater cephs, or the lack thereof. Is there any evidence that ammonites were exclusively marine? And is there any evidence that any cephs may have tried to make it to the freshwater? Any ideas on why we don't have freshwater cephs? I mean, I can guess the physiological reasons, but not the evolutionary ones....

Sushi and Sake (And other food for thought)

John

 

[Phil]

As far as I know there is absolutely no evidence for freshwater ammonites. Very few molluscs at all seem to have made the transition to freshwater, and those are bivalves and gastropods.

I've had a search on this and can find no evidence, but if I can find anything to the contrary I will, of course, let you know.

Pity really, who wouldn't like a pet ceph in their village pond?

 

[Fujisawas Sake]

Phil,

My wife thinks it has to do with niches occupied by vertebrate predators. That might be true as well....