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[Old Board Archive] Vampyroteuthis Question (and ammonites)

Steve O'Shea

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Phil said:
I would love to start up a discussion on this bizarre Cambrian predator but as the thing was probably an arthropod and most certainly not a cephalopod I can't really do it here.

Go for it Phil!!! I'm sure that the live animal had an extensive velum-like membrane that is actually responsible for secreting the ammonite shell, and it is this beast that actually scurried along inside that last chamber :wink: Either that or it was parasitic on ammonites .... I'm sure there's a link there somewhere, and I'm sure it's not that tenuous.

Then I can start up a thread about boats, nets and how to catch squid, and trucks to tow them with that have loud macho horns and big V8 engines :biggrin2:

....just call it an early mid-life (or ?end of .... as we know it) crisis.....
O
 

Phil

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Steve, I think the only way of bringing Anomalocaris into a discussion about ammonites would be to look at interrelationships of the ancestors of the mollusca (mostly conjecture) and primitive arthropods. Seriously heavy territory there! I've tried reading a bit about that before but it just made my head bleed. :bonk: Much easier to watch 'Wheel of Fortune' instead.

As I didn’t clearly explain what was in the last picture I posted of fossil and recent cephalopods from my collection, I’d thought I’d post it again with a key.

The variety of cephalopod forms is quite astounding!

1. Cleoniceras besairei Lower Cretaceous Madagascar (half polished to show the sutures) 100mya.
2. Nautilus sp. Lower Cretaceous Madagascar
3 Desmonceras latidorsatum Lower Cretaceous Madagascar
4. Nautilus pompilius, Recent
5. Anahoplites splendens Lower Cretaceous, Folkestone Kent, UK
6 Spirula spirula, Ramshorn squid, Australia, Recent..
7. Belemnite sp? Cretaceous, Kent. (Don’t know precise details. No excuse, really).
8. Dichotomosphinctes sp. Jurassic, Madagascar
9. Hermitetragonites sp. Lower Cretaceous Madagascar
10. Anahoplites planus Lower Cretaceous, Folkestone Kent, UK
11. Euhoplites sp. Lower Cretaceous, Folkestone Kent, UK (very clear spine bases on this one)
12. Belemnites various sp. Lower Cretaceous, Folkestone Kent, UK
 

Phil

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I thought I would post a picture of a few more of my collection of ammonites and bits and pieces. If anyone is wondering what ‘Lappets’ are on the ammonite, they are clearly visible on the large ammonite.

Apologies that some of the specimens are a bit dark, unfortunately it’s the nature of the rock they are preserved in. Can’t be helped!

This time I’ve labelled them up if anyone is interested.

1. Pectinacrites sp? Upper Jurassic Kimmeridge, Dorset, UK
2. Promicroceras sp? Jurassic, (180mya) Charmouth, Dorset, UK
3.Otoites sauzei Jurassic, Argentina (spherical ammonite)
4. Hoplites sp? Lower Cretaceous, Folkestone, UK
5. Hysteroceras orbignyi. Lower Cretaceous, Folkestone, UK
6. Absolutely no idea. Given this one as a kid. Surrounded by crystals it’s quite beautiful though! :goofysca:
7. Anahoplites planus? Lower Cretaceous, Folkestone, UK
8. Euhoplites sp? Lower Cretaceous, Folkestone, UK
9. Dichotomosphintes sp. Jurassic, Msadagascar. Male microconch with lappets.
10.Anahoplites sp. Lower Cretaceous, Folkestone, UK
11. Belemnites, various species. Lower Cretaceous, Folkestone, UK
12. Hamites sp. Fragments only, these bizarre ammonites grew in a ‘G’ shape.

Hope you like them.
 

Steve O'Shea

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Stunning stuff Phil! Is the Dichotomosphintes specimen the one you've just bought? Very nice!

Here's a couple of tough questions (watch that head of yours :wink: ):

Any idea if the aptychus in any of these microconch males differs in any way from that of the female? (This should really be preceded by the question - is an aptychus known for any genera/species that possess lappets?)

You mentioned a few posts back that not all microconchs possessed lappets. Within any presently recognised genus are there species with and without lappets (as in is the presence of lappets used at all to define genera?)?

Finally, are the lappets present only on mature specimens, or is a precursor apparent from the juvenile/submature stages?
Cheers
O
 

Phil

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Kevin.......HELP!

Steve, I'm terribly sorry but I've completely failed here. None of my books are specialised enough to answer your questions and I can't seem to find any answers on the net.

However, what I can say with a fair degree of certainty is that lappets were a feature of the mature microconch only and are not present in juvenile specimens.

(Another personal theory) Looking at some photographs of fossils it seems that the lappets are suddenly grown at the aperture of the microconch. There does not seem to be a progession of smaller less well developed lappets in the immediate preceding body chambers. I suppose this might imply that the onset of sexual maturity is very sudden in the ammonite, if the purpose of the lappets were for display. I have no idea how long an ammonite lived for but body chambers in the nautilus are secreted, I think, about once every thirty days. If the ammonite grew at a similar rate then I suppose it would become sexually active in a month.

Interestingly, I found another intriguing nugget regarding the possible coleoid form to the ammonite. Apparantly ammonite radula have been studied that reveal they had seven teeth in a transverse row as have many modern dibranchiate cephalopods unlike the nautilus which has nine. The upper jaw is also supposed to resemble that of modern octopuses. Another reference mentioned ammonoid ink sacs. I'll see if I can find some info on that!

I think I only deserve 2/10 for my homework!

Phil
 

Architeuthoceras

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Phil, youre right AFAIK, lappets only appear as mature modifications on the shells. Scaphites have small dorsal lappets on both the mature micro and macro conchs (just to throw a wrench in the cogs) but most lateral lappets of any size are only found on microconchs. There are other forms of mature modifications to the aperture that are alot more common such as constriction, becoming scaphitoid, enlargement or change of sculpture, coiling eccentrically, etc.
Aptychi were described as seperate genera in the treatise of invertebrate paleontology (1957) but I dont think any genera of ammonoid has been defined by the aptychus. Not very many ammonoids have been found with the aptychus in situ . Only a few have been found with the radula in situ, but I think enough have been found and studied that they are pretty sure that all ammonoids had the seven radular teeth..

Hope this helps, none of my pet rocks seem to have any good answers.
:nautilus:
 

Steve O'Shea

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Took me a while (I am slow), but I figure AFAIK stands for 'as far as I know'. Do you guys just invent this alphabet soup as you go along?

Got a little distracted today when packing up the office .... started reading some obscure literature that I didn't even know I had ... happened upon a pile of ammonite papers I'd acquired years ago and completely lost track of several hours. Had a friend down this weekend ... a Recent shell collector, and he commented on a few stunning ammonites Phil had sent me (thanks again Phil). Years ago he did a trade with someone in South Africa and they sent him ~ 50 ammonite specimens in exchange for something Recent. He's not even unpacked them ... and is giving them to me :biggrin2: :biggrin2: :biggrin2: So my ammonite collection is growing quite rapidly.

When we move north in a few weeks for the new job I'll track down a few of the sites where the New Zealand specimens occur (as the new boss is a fossil guru, and another collegue up there an ammonite fanatic) and I'll be able to collect for you chaps and return your favours.

I was wondering today ... as one does when they should be doing other things ... whether there was an equivalent site to Tonmo dedicated to fossil cephs. Tony's site (Tonmo) is pretty unique as far as I know ... how could we spread the word for fossil collectors to log on ... and perhaps have more detailed discussion on these beasts for the likes of you two (and for the likes of me to follow from an inquisitive point of view)? I really know nothing about them ... that comes as no surprise to you two .... and it seems a crying shame that there's not more active discussion/banter online from others more versed in this really quite fascinating group.
Cheers
O
 

Phil

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Steve, you have been given 50 + ammonites. I'm soooooo jealous! Thankyou for the offer. Fantastic!

Please post some pictures of the best of them here so that we can make theories up about them.

(Found a Permian Goniatite with lappets for sale for £25 the other day. Shall I buy it? That's 12 pints of beer I will have to do without. What do you reckon?)
 

Steve O'Shea

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25 pounds would buy you ~ 25 jugs of beer down this neck of the woods .... that's a lot of beer Phil!

Yesterday was my last official day at work (I am officially unemployed for 2 weeks!!! :biggrin2: :biggrin2: :biggrin2: :biggrin2: ) - now just personal things at home to tidy up, a relocation to Auckland, and investment in a couple of pick axes, dynamite and a lot of glue :lol: and I'll be knee-deep in fossils.

Sorry I've been so quiet of late - will be able to post more often soon.
Cheers
O
 

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