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rdawkins

Need Help With Id Of Madagascan Ammonites

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rdawkins

Hi all!,

My first post :) ive recently discovered the joy of collecting fossills and am kicking myself for leaving it for so late. Purchased my first fossills recently and need your help with identifying species please.

First one:

post-0-0-75268700-1347735144_thumb.jpgpost-0-0-17150900-1347735150_thumb.jpg

Second one:

post-0-0-87059800-1347735171_thumb.jpgpost-0-0-37866400-1347735175_thumb.jpg

From my very modest knowledge on fossils, i think they maybe cleoniceras.. ? I would love to get more details on species and region and period if possible. All that was in the Seller's description was cut and polished madasgan ammonite.

Thanks so much!

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Kosmoceras

I think it is Cleoniceras cleon, from Mahajunga, Madagascar and they are Cretaceous in age.

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rdawkins

Thanks for your reply Kosmoceras.

Edited by rdawkins

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FossilDAWG

I think it is Cleoniceras cleon, from Mahajunga, Madagascar and they are Cretaceous in age.

Just out of curiosity, what specific features do you see that distinguish a Cleoniceras cleon from other possible Cleoniceras species (C. besairea, etc), or other ammonites from around the world? When I post a possible ID, I always try to say what specific features led me to that ID; otherwise, there is no opportunity for people to learn anything about how to recognize and distinguish between species. In this case, to me one ammonite cross section looks very much like another, and the range of characters available to examine is very limited. I need to be able to see the exterior, any ribs, nodes, bullae, or other shell ornamentation, the size and shape of the umbilicus, the whorl shape, and ideally the suture line. Information about the age and a general locality is immensely useful to sort out possible homeomorphs. A cross section provides none of that information, especially in the case of a specimen with limited age or locality data.

This forum would be more useful (i.e. educational) if people would make a habit of explaining the reasoning that led them to their IDs.

Don

Edited by FossilDAWG

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Kosmoceras

Just out of curiosity, what specific features do you see that distinguish a Cleoniceras cleon from other possible Cleoniceras species (C. besairea, etc), or other ammonites from around the world?

Don

I wrote "I think" for a reason. Most ammonites from Madagascar are Cleoniceras cleon, so it is likely to be that, but it could be wrong. If I am sure on something, I would not write "I think", I would say "it is". I am sure however on the locality details. On most ammonites from Madagascar, a lot of damage is done to the specimens, so to be able to determine for sure can be next to impossible.

In the pictures you can see how worn down and polished they are, the one in picture two is easier to identify because it is not all polished down.

post-4683-0-37238300-1347799192_thumb.jpg post-4683-0-89265000-1347799198_thumb.jpg

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rdawkins

i guess i should've stated how big they were, both of them are around 6cm wide and about 4 cm high... im very new to this, so after you said cleoniceras, i read up on them and compared them to others of the same species and it helped

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Scylla

I thought objects, people, fossils,etc fron Madagascar were referred to by the adjective "malagasy"? As in the malagasy dinosaur Majungasaurus was found in Madagascar. Welcome to the forum and I love those geodised cephalopods, show us more of what you have!

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FossilDAWG

I wrote "I think" for a reason. Most ammonites from Madagascar are Cleoniceras cleon, so it is likely to be that, but it could be wrong.

That's what I also believe. I was curious if you had anything more specific to go on.
If I am sure on something, I would not write "I think", I would say "it is".
I think you're being too subtle for an internet forum with this. I think I can comfortably assure you that very few readers would interpret any difference between "I think" and an unstated "It is". That's part of the reason why I almost always state my reasoning, so readers can judge for themselves whether or not I have good reason for giving a specific ID. Only someone who knows you personally, and is familiar with your habits of speech, would say "Aha! He didn't say "it is" so he must not be very sure". In fact, every ID given on these forums is at the very best an "I think", as 1) it is the opinion of one person, and 2) photographs (which is what we have to work with on this forum) can never convey all the subtle detail, from every possible angle of view, that a specimen in the hand can offer.
In the pictures you can see how worn down and polished they are, the one in picture two is easier to identify because it is not all polished down.

Agreed, which is why I said one needs to see those features to offer a reasonably confident ID.

Don

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rdawkins

I thought objects, people, fossils,etc fron Madagascar were referred to by the adjective "malagasy"? As in the malagasy dinosaur Majungasaurus was found in Madagascar. Welcome to the forum and I love those geodised cephalopods, show us more of what you have!

Yes, you're right... it should be malagasy! As a matter of fact, these are the very first fossils ive purchased :) Now, im hooked, will definitely get more... Im a software developer and i collected vintage computers as well as ancient roman and greek coins but ive lately become very interested in ammonites :)

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