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Showing results for tags 'aptychi'.
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Recent ammonite find and noticed the associated shelly fossil. Suspect most likely a pelecypod but has different crystal and growth pattern so wondering if it is possibly an aptychi? How can you tell the difference? Any input is much appreciated. Thanks.
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Hi everybody. I stumbled upon those photos on another forum and i wondered about what are they, and about how and "who" made those alignaments of aptychi. They've been found in Valanginian marls, Saynoceras verrucosum zone. Concerning what and how, the authors of that article Double alignments of ammonoid aptychi from the Lower Cretaceous of Southeast France proposed several hypothesis : a possible bottom current ; regurgitalites of an ammonoid eater ; stomachal residues ; cololites. But their best hypothesis is cylindrical coprolites that separated in two parts just after the animal defecated or being close to the sea bottom or in relation to the anatomy of the anus or the cloaca. As to who, the candidates could be teleost fishes, plesiosaurs, ichthyosaurs, marine turtles, crocodiles. I'm very curious about those alignments of aptychi and wondered if one of you has seen something similar to this or could have an idea about the animal that produced them ? Thank you for your participation. Cheers, Sophie.
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I have a few questions I’m unable to answer about ammonites. I’ve been doing some casual research, but it seems to lead to more confusion on this. I would really appreciate it if anyone could suggest more sites to look at as well. What kind of shell “decoration” is present on ammonites with ammonitic sutures? Was there any “normal” combination of shell and suture mark, or could their shells have any pattern of ridges, knobs, etc.? I’ve been hoping to find a sort of before and after polishing photo/sketch set, showing what shell went with what suture pattern, but have been unable to find anything. While trying to find the photo/sketch, I realized all photos of ammonitic sutures I’d found were of creatures that were involute, the outer whorls almost completely covering the inner. Is this just a coincidence, or were most/all ammonites with ammonitic sutures so involute? Also, did any/some/many/all ammonites with ammonitic sutures have an aptychus? I've been able to find all sorts of information on these features individually, but not on co-incidence, so to speak.