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Yezoteuthis: a new giant squid fossil from Japan

Phil

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This fossil giant squid has just been published (10/01/06). Here's a quick summary, my words. (Thanks to Monty for providing the original article)


Potentially the largest fossil coleoid to be discovered to date was published in January 2006 by Kazaushiga Tanabe, Yoshinori Hikida and Yasuhiro Iba. It consisted of one half of an enormous set of jaws discovered in Late Cretaceous Campanian (83-71 mya) sediments at Wakkaweenbetsu Creek, Nakagawa Town, Hokkaido, Japan. The fossil was composed of a black phosphatic material and was contained inside a calcareous nodule. Included with the specimen were numerous bivalves and specimens of the heteromorphic ammonite Polyptychoceras. The fossil came from the Upper Yezo Group of mudstones, ‘Yezo’ being an old name for Hokkaido. The fossil is an upper jaw that measures 97mm in length and is 22.5mm wide at its maximum point. It has a very sharply pointed rostrum that is angled acutely, and both the inner and outer lamellae are present.

In order to determine the systematic relationship of the specimen, the authors performed a cladistic analysis based on 5 morphological characteristics of the jaw in comparison with 22 other extant coleoids and Nautilus. As a result of this and from a physical comparison of the shape of the rostrum and wings, the authors determined that the specimen is closest to the sub-order Oegopsina. The authors then attempted to estimate a total size for the animal, by examining the ratio of the maximum length of the upper jaw (LUJ) to total mantle length (ML) in eight extant coleoid species. Applying these derived ratios to the fossil jaw and plotting it along with these other specimens, it was concluded that the Mantle Length was probably akin to Architeuthis. The jaw is similar to Architeuthis not only in overall size, but in shape, and structure. It differs in that the crest margin is more convex in shape and has more prominent growth lines on the inner lamella.

The authors conclude that this specimen represents a large new species, Yezoteuthis giganteus, that would have been present in Late Cretaceous Northwest Pacific along with many small ammonoid and nautiloid shelled cephalopods. The jaw is currently housed at the Nakagawa Museum of Natural History.

TANABE, K., HIKIDA, Y., and IBA, Y., Two coleoid jaws from the Upper Cretaceous of Hokkaido, Japan. Journal of Paleontology 80 (1) 138-145, 2006.
 

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Phil, very cool-- more big a$$ cephs.

Once again you rock. :band:

And I know whereof I speak as I rock for a living (such as it is, I don't even get peanuts - just the bare shells).

My question to you is are there any giant octos or cuttles out there in the fossil record? I have this image of a minivan sized cuttle stalking its prey.
 

Phil

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bigGdelta said:
Once again you rock.
That's the nature of fossils....geddit? (Groan).

bigGdelta said:
My question to you is are there any giant octos or cuttles out there in the fossil record? I have this image of a minivan sized cuttle stalking its prey.
I'd love to see that too!

No giant prehistoric octos or cuttlefish I'm afraid. Mind you, the fossil record of octopuses is so appalling it's hard to preclude any reasonable possibility. Only three forms are known, the largest being the Cretaceous Palaeoctopus, and that was only five or six inches long at most. I'm certain the same is true of cuttlefish, but they probably have a much more recent ancestry, possibly post-Cretaceous.

The other cephalopod groups all showed evidence of giganticism. I once listed out the largest examples in this old thread, so please forgive a link instead of copying it all out again:

http://www.tonmo.com/community/index.php?threads/4944/&highlight=megateuthis

Cheers!
 

OB

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Hmmmm..... Maybe Polyptychoceras might throw some light on the question of "largest eyes in the animal kingdom ever", as dealt with in another thread, to which I'm too lazy to hyperlink right now :wink:
 
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Phil said:
By your command.

The official TONMO Cephalopod Measurement Routemaster returns once more just for you, Capn.

Thanks Phil, nice to see the TONMO CMR survived both the cull in London and the recent fire in the depot.

That's a pretty big ceph though.
 

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