being a lazy git, I'm posting an IM conversation I had with Hallucigenia with some minor edits to protect the guilty and eliminate pointless blather: Monty: http://www.tonmo.com/community/index.php?threads/8491/#post-8490 Hallucigenia:so actually, one of the things we were discussing at the GSA (http://www.geosociety.org/meetings/2007/index.htm ) "friends of the cephalopods" meetings was "why don't ammonites ever show up in soft-body preservation?" Monty:yeah, I've occasionally wondered if we don't know what to look for, or something. Hallucigenia:i can't imagine that's the problem. Hallucigenia:i'm wondering whether the shell creates a mechanical problem, that's all. Monty:then it seems weird that nautiloids and ammonoids don't, but belemnites and coleoids do, albeit rarely. (or are belemnites coleoids?) Hallucigenia:belemnite soft body? Monty:with belemnites, at least there is the internal shell and hooks to give "hints" Monty:yeah, there's a few, I think. Hallucigenia:hey, found it Hallucigenia:there's a pyritized one apparently Monty:url? Monty:I don't see the pic I was thinking of in Phil's article... Hallucigenia:yeah, it's on tonmo but the pic is missing Monty:oh, from the "great image disaster" I expect. (that was before my time, but was really unfortunate) Monty:I guess they are coleoids. Hallucigenia:yes, they are Hallucigenia:pyritized guts, it says Monty:my recollection is that it looked similar to the fossil squid I started this chat with, but the hooks on the arms were very obvious. Hallucigenia:hm. alright. what did the shell look like? (i.e. squashed flat, well preserved?) Monty:I think it was somewhat well preserved... maybe it was in a fossil book rather than online... BRB... I found one pic in Monks' Ammonites book... Monty: http://www.dkimages.com/discover/previews/893/20155582.JPG Monty:once I knew to search for belemnoteuthis Hallucigenia:ok, so it looks crushed Hallucigenia:but it's otherwise damn nice Monty:I remember one that had better hooks, but less soft tissue somewhere, too. Monty: http://www.tonmo.com/science/graeme/graeme-fig10.png Monty:It would be nice to see a non-sucky version of this picture, too: http://upload.wikimedia.org/wikipedia/commons/thumb/8/86/Belemnit.jpg/250px-Belemnit.jpg Hallucigenia:...! Hallucigenia:yeah, was wondering what the second one was too Monty:well, we can ask Graeme where he got the image... Hallucigenia:the third, i suppose, then Hallucigenia:the second is very pretty Hallucigenia:is it a belemnite? Monty:the one on TONMO? I think so... just a sec. Monty:fig. 10: Acanthoteuthis from Solenhofen, Germany, currently residing in the collection of U. S. National Museum of Natural History. Of particular recognition is the clear detail of the animal's body, including the hooks clearly radiating off the arms! Monty:from http://www.tonmo.com/science/public/gcwalla.php Hallucigenia:the shell isn't at all preserved in that picture! Hallucigenia:it looks like a flat silhouette Monty:yup Monty: http://mollus.oxfordjournals.org/cgi/content/citation/3/1/57 claims to have the buccal membrane... does Caltech get that journal? Hallucigenia:no Monty:nuts. Hallucigenia:pretty much. Hallucigenia:well, it's still an interesting idea. Monty: http://piclib.nhm.ac.uk/piclib/www/image.php?search=acanthoteuthis&getprev=95986 Monty:fairly similar to the other ones... Hallucigenia:also broken up Hallucigenia:i might e-mail someone about this Monty:ok Monty:but this just makes the question even more curious... why all these coleoida and no recognizable shelled species? Hallucigenia:right Hallucigenia:i don't know...this is why i need to e-mail a Real Paleontologist (tm) Monty:As I was hearing about the gastropod evo-devo ( at a talk I went to today) I wanted to compare spirula's shell evo-devo to nautilus. But I don't think spirula's been kept alive long enough to breed, let alone tag embryos with florescent proteins on HOX markers or whatever. Monty:so, I distracted you from telling me what the GSA folks actually had to say on the "why aren't there preserved ammonite soft bodies?" subject, I think... Hallucigenia:oh, they didn't have any idea Monty:it just seems inconsistent that there are a number of belemnites and the occasional pteroctopus or vampyromporph, but no shelled ones. Hallucigenia:well, that's what makes me think the shell might be the problem. Monty:that seems consistent with the observations... I guess I don't know enough about the various fossilization processes to say much intelligent about it. I suppose most of the Burgess shale critters that show lots of soft tissue preservation don't have shells... Hallucigenia:yeah, that's the problem. i'm not sure i do either. Hallucigenia:i'll send you a copy of what i'm writing to (fossil expert name redacted for privacy) though. Monty:thanks... Monty:asking on TONMO probably wouldn't hurt either... Kevin and Phil and others know astounding amounts for people who don't do it for a living... Monty:I know Neale Monks is a co-author on one of the TONMO articles, but I've never seen him post... Monty:regarding the original "squid" I can't see the part where the shell would be enough to know if it could be a belemnite rather than a teuthid. *** end IM log *** So, I'm hoping this will open the door to other random discussion, and it at least collects a bunch of fossil belemnite pics in one place.