fossil soft body parts and belemnites and related

[monty]

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

Hallucigeniayritized 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.

Hallucigeniaretty 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.

 

[Architeuthoceras]

Sordes's ceph fossils from Tubingen, Germany has some pics of tentacles and hooks

and a few links in this thread


The one just posted on the other thread is one of these?* Palaeoctopus from Lebanon.


some pics on this thread A Fossil Squid from Germany

Unfortunately alot of the pics of Trachyteuthis* from Lebanon disappeared in the great photo extinction like this thread.

and this thread

and dont forget Phils great fossil octopus article


*I may be confused as to the ID Palaeoctopus or Trachyteuthis probably both are present in lebanon.

This just in: Fuchs, D., Engeser, T., and Keupp, H. 2007. Gladius shape variation in coleoid cephalopod Trachyteuthis from the Upper
Jurassic Nusplingen and Solnhofen Plattenkalks. Acta Palaeontologica Polonica 52 (3): 575–589.

 

[Architeuthoceras]

Ooops forgot this thread.

The Hollingsworth soft body ammonite -- picture!

Not at all conclusive.

Beaks? (aptychi etc.) radula, gut contents? have all been found associated with ammonoid shells. Perhaps the soft body gets a better chance for decay because of the cavity in the shell post burial. If jellyfish can fossilize, or at least leave a trace, you would think shelled cephalopod soft parts would be more common. Maybe ammonoids were just softer than jellyfish.

 

[monty]

Thanks, Kevin.

In re-reading Phil's article on fossil octos, I was struck by the urge to point out that it's mentioned there that

All these differing forms of coleoid had another very important feature in common; they all had ten arms. Each group took this in a separate direction; the belemnites, which probably represent the most 'primitive' condition, had ten equal arms covered in hooks.

This is part of why I found the detailed analysis of Nautilus so interesting ( http://www.tonmo.com/community/index.php?threads/8045/ ) -- It describes the origins of Nautilus' tentacles to be from 5 pairs of buds early in the embryonic development. That suggests to me that the 10-armed form could easily be basal to the whole cephalopod lineage.

As long as I'm asking for fossil lore, what's the story on fossil cephs and chirality? Do the asymmetric coils consistently go dextral or sinistral (I just learned these two-dollar-words yesterday, so I better use them today before I forget them!) within a species? Does there appear to be a preferred handedness for any subgroups? In modern gastropods, there are some species that are locked to one or the other, and some that show both, but I'm wondering how that extends to fossil cephs (since that's one question, unlike the others in this thread, that's really easy to answer from just the shells!)

 

[Architeuthoceras]

There are very few cephalopod shells that are torticonic, most are planispiral so there is no "handedness" to them. There was a time when they were exogastric or endogastric, meaning they coiled down from the top of the head or up from the top of the head (is this upperhandedness?). Some heteromorphs like turrilites were torticones and others like didymoceras were torticonic to start and then changed to scaphitoid coiling but I havent checked if they were dextral or sinistral. I am quite sure that nipponites didnt even know which way was up let alone left or right.

 

[monty]

There are very few cephalopod shells that are torticonic, most are planispiral so there is no "handedness" to them. There was a time when they were exogastric or endogastric, meaning they coiled down from the top of the head or up from the top of the head (is this upperhandedness?). Some heteromorphs like turrilites were torticones and others like didymoceras were torticonic to start and then changed to scaphitoid coiling but I havent checked if they were dextral or sinistral. I am quite sure that nipponites didnt even know which way was up let alone left or right.

I remember the exogastric/endogastric distinction comes up with respect to spirula's shell being different from typical ammonites, but I'm just looking for any left-right deviations from perfect bilateral symmetry.

 

[Architeuthoceras]

If we could find fossils with internal organs preserved and correlate with living shelled (and non shelled) forms (all molluscs?) to see which side the organs were on, and if they are on the same side in all, all the time, I guess we could infer dextral or sinistral in a planispiral shell.

 

[Steve O'Shea]

Here's a new paper on belemnite hooks, related to modern squid hooks. Unfortunately you cannot access the article (other than abstract), but if you have access it might be worth a read to you.

http://www.informaworld.com/smpp/content~content=a931475978~frm=abslink

 

[Hajar]

Interesting.

I found this statement in the Klug et al, paper about a belemnite from the Nusplingen lithographic limestone: "As Hibolithes semisulcatus is known to possess one pair of mega-onychites, the absence of those in the present specimen provides evidence of sexual dimorphism in Hibolithes semisulcatus. This phenomenon was previously presumed for all belemnites, but it is known only from Passaloteuthis with certainty since the rostrum of the latter is unambiguously associated with an arm crown that occasionally includes one pair of mega-onychites."

 

[DWhatley]

I wonder if the enlarged suckers sometimes found on male octopuses is an artifact from the mega-onychites (the reason for the enlarged suckers is unknown, not always present even in the same species and varies in count and on which and how many arms).

 

[Hajar]

I don't know about octopods, but this seems to mean that my Phragmoteuthis is a girl.

 

[DWhatley]

so the enlarged pair of mega-onychites is found on females (not clear which sex has them in your quote)?

 

[Hajar]

True! They didn't specify, but I'd been looking at rom the Löwentor-Museum in Stuttgart, posted by Sordes together with his accompanying information. The mega-onychites are inferred to have belonged to the males. My Phragmoteuthis doesn't show them.

 

[Architeuthoceras]

Does your Phragmoteuthis have a guard?

 

[DWhatley]

Thanks for the clarification and putting me back on the same page by explaining that your determination of female was the absence of the enlargements. It would be curious if the enlarged suckers on some males octopuses have no purpose today and are just throw backs but there must have been some reason for the dimorphistic trait.