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Triassic Ichthyosaur paddle bone I.D?


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I visted Aust Cliff on the River Severn, Gloucestershire UK back in Feburary and managed to find a large block of the 'Rhaetic Bone Bed' . Lots of bone fragments, fish teeth, even a shark fin spine! But my best finds are a paddle bone and large tooth. (Still got plenty more rock pieces to break open and search for more, so a long term project...)

 

However i would like to I.D this Ichthyosaur in particular. Does anyone know about the early ichthyosaurs from the late Triassic?

 

Age: 208 - 201mya (Late Triassic: Rhaetian) - Aust Cliff

 

Paddle bone - humerus?

 

IMG_0093JPG.thumb.jpg.788d54aef4a0c520cbb13fe697590bbb.jpgIMG_0095JPG.thumb.jpg.ac33ddd7496d35f6d39924484edfedbf.jpg

IMG_0097JPG.thumb.jpg.489e55525ea842d94bea75c5cf48362d.jpg

 

Tooth (broken off tip sadly):

 

IMG_0099JPG.thumb.jpg.c71c47e0960143db80666aa686f0cfc7.jpgIMG_0100JPG.thumb.jpg.464030c6c9cc6bf5b5d90ec843913310.jpg

 

 

 

 

 

Edited by Jay11
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Helpful if anyone can recognise if the tooth is in fact from an ichthyosaur or perhaps a plesiosaur? Not so sure now as I have seen similar teeth from the bone beds labelled as plesiosaur, and the early Leptonectes ichthyosaurs had smaller teeth?

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  • 4 months later...
pachy-pleuro-whatnot-odon
On 7/31/2020 at 10:14 PM, Jay11 said:

Helpful if anyone can recognise if the tooth is in fact from an ichthyosaur or perhaps a plesiosaur? Not so sure now as I have seen similar teeth from the bone beds labelled as plesiosaur, and the early Leptonectes ichthyosaurs had smaller teeth?

Sorry for arriving here so late, but may be I can help you along the way a bit. Plesiosaur and ichthyosaur teeth can indeed look very similar at times, especially when somewhat worn and in situations where no striations or plicidentine folds can be seen. In those cases the root can be very informative as to identifying plesiosaur from ichthyosaur, as plesiosaurian roots are smooth and rounded, much like that of a crocodile, whereas the roots of ichthyosaur teeth will exhibit folding and may have a rectangular cross-section in later species. Unfortunately, however, I'm not entirely sure the piece in the second photograph is a tooth, as the inside seems rather porous and vascularised, like a bone, rather than the dentine of a tooth or its root. May be you could take some more photographs of either end of the suspected tooth, so we can have a look at the internal structure of it?

As to the species, either of the tooth or the podial, Leptonectes sp. and Eurycleidus sp. are often mentioned for ichthyosaur and plesiosaur remains from Aust Cliff respectively. Beyond that, I typically refer to the below diagrams for a rough-grained quick overview of genera around during a specific age:

 

phylo_strat.gif.d286bffe5f8ba7d0a264c8e94a8bd800.gif

 

F1.large.jpg.95e5fecf451516dbe6c42f254cc70476.jpg

 

Phylogenetic-results-A-time-calibrated-strict-reduced-consensus-of-trees-derived-from_Q640.jpg.4c7d18f9c153f5fbacf71e3cd043e3ce.jpg

 

As can be made out from the above diagrams on ichthyosaurians, Leptonectes spp. is not the only species that may occur at Aust Cliff - at least from a spatiotemporal perspective - and the mentioned shastasaurids, Ichthyosaurus spp. and Temnodontosaurus spp. may all occur. In terms of plesiosaurians, the schematics are a bit more tricky to read, but seems mainly restricted to Pistosauria, Plesiosaurus spp. Thalassiodracon and a couple of early rhomealosaurids (including the mentioned Eurycleidus). Rhomealosaudis, however, to the best of my knowledge have clear clear striations on the labial (inner) side of the tooth, and none on the outer, much as is the case with the tooth in the below post:

 

 

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Hi

 

Thats a nice ichthyosaur humerus.
 

Are you sure it’s a tooth? It looks like a piece of bone although it’s hard to tell with the Aust material unless it’s in your hands.

 

All the best

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pachy-pleuro-whatnot-odon
1 hour ago, Welsh Wizard said:

Hi

 

Thats a nice ichthyosaur humerus.
 

Are you sure it’s a tooth? It looks like a piece of bone although it’s hard to tell with the Aust material unless it’s in your hands.

 

All the best

What he said! I haven't seen such a nice ichthyosaur humerus come out of Aust yet - in fact, any yet - so to see this is really nice...!

 

And, as indicated, I'd need some photographs from the inside of the tooth (i.e. both areas in which it was broken) to be able to confirm it is indeed a tooth we're dealing with an not bone...

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Large ichthyosaur femur and probable broken jaw bit from large ichthyosaur from Aust.

 

9ED83877-AA5A-49F8-92CD-BCDE84E2A766.thumb.jpeg.875697e496d7528e9166f0eb8940996d.jpeg

 

44EB40F2-48AB-455F-A08C-3E19032A7572.thumb.jpeg.8c33a29242b3ef1ee05c9a19928a8912.jpeg

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pachy-pleuro-whatnot-odon

Very nice pieces! Really like the podial. And it's indeed quite a sizeable one too! Very nice finds! Would love to add something like that to the Triassic part of my collection at some point!

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pachy-pleuro-whatnot-odon

For sake of comparison, here's what the inside of a tooth from Aust Cliff should look like.

 

20201213_120616_resize_66.jpg.ed2be93f3e7a965be2ba19bf76bac74c.jpg20201213_120656_resize_12.jpg.2a910f59daa56375911547f808062744.jpg20201213_120827_resize_47.jpg.1155dc531b253213a0929bb549b546bf.jpg20201213_120737_resize_42.jpg.f2154069db8c11f18dc2cd1d8f7888c5.jpg20201213_120543_resize_65.jpg.8040c167d159d7e707a429cc391458f1.jpg

 

The tooth itself is unidentified, by the way, as I originally acquired it as plesiosaur, but it has at least one carina - which rules out plesiosaur, except for certain Cretaceous polycotylids. It can't be marine crocodile either - even if the presence of carinae might suggest this - since, as far as I'm aware, these hadn't evolved yet (though I don't know what kind of teeth the champsosaurid Pachystropheus rhaeticus had, I doubt whether they'd have been this big). As fish teeth are conical, this kind of only leaves ichthyosaur as an option. But these too don't usually have carina. The only genus I know of that does have carina, is Temnodontosaurus, and within that genus it's possibly only even T. platyodon that has carina on an otherwise smooth surface. Does this mean the tooth is from a temnodontosaurid ichthyosaur? Please let me know if you might have any idea (@Welsh Wizard, @Pterygotus)...

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Antonio Musolino

 

very beautiful, i found the same teeth in the bajocian layer in switzerland 15 years ago!

regards

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pachy-pleuro-whatnot-odon
5 hours ago, Antonio Musolino said:

 

very beautiful, i found the same teeth in the bajocian layer in switzerland 15 years ago!

regards

First of all, welcome to the forum from the Alsace in France!

 

Seeing as the big time difference I doubt it would concern the same species, and with your dating I'd probably classify my tooth as a thalattosuchian, probably metriorhynchid, tooth. How did you classify yours?

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7 hours ago, pachy-pleuro-whatnot-odon said:

For sake of comparison, here's what the inside of a tooth from Aust Cliff should look like.

 

20201213_120616_resize_66.jpg.ed2be93f3e7a965be2ba19bf76bac74c.jpg20201213_120656_resize_12.jpg.2a910f59daa56375911547f808062744.jpg20201213_120827_resize_47.jpg.1155dc531b253213a0929bb549b546bf.jpg20201213_120737_resize_42.jpg.f2154069db8c11f18dc2cd1d8f7888c5.jpg20201213_120543_resize_65.jpg.8040c167d159d7e707a429cc391458f1.jpg

 

The tooth itself is unidentified, by the way, as I originally acquired it as plesiosaur, but it has at least one carina - which rules out plesiosaur, except for certain Cretaceous polycotylids. It can't be marine crocodile either - even if the presence of carinae might suggest this - since, as far as I'm aware, these hadn't evolved yet (though I don't know what kind of teeth the champsosaurid Pachystropheus rhaeticus had, I doubt whether they'd have been this big). As fish teeth are conical, this kind of only leaves ichthyosaur as an option. But these too don't usually have carina. The only genus I know of that does have carina, is Temnodontosaurus, and within that genus it's possibly only even T. platyodon that has carina on an otherwise smooth surface. Does this mean the tooth is from a temnodontosaurid ichthyosaur? Please let me know if you might have any idea (@Welsh Wizard, @Pterygotus)...


Hi

 

hard to tell really. It looks like a fish tooth but from what you say, it’s probably the broken end of a large ichthyosaur tooth.

 

the plesiosaur teeth are quite variable but tend to be flattened in cross section rather than round. Here are a few for comparison:

 

D2A073F3-2C8E-441D-8272-FC59693200B1.thumb.jpeg.cddf5c4ce044d1e3f503e71a582cc4a5.jpeg

 

95B6F5E7-9577-4062-9B94-66D2A9F3E686.thumb.jpeg.488af475b8d4189a38cd0fa76f89c008.jpeg

 

8E72202E-F314-4DD9-8CBC-5AFC17B11E3A.thumb.jpeg.055e02bf8fdc8903149a679a3c433036.jpeg

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pachy-pleuro-whatnot-odon

Those are some really nice specimens - especially the one in the middle, with the partial root! Wouldn't mind adding one like that to my collection at all! :cool07:

 

But, yeah, I've got two plesiosaur teeth from Aust Cliff in my collection, and one from Lavernock, and this particular tooth doesn't match (mine do have a rounded cross-section though, might be a different species). But since some more derived species of plesiosaur do have carinae, and there didn't seem to be any other obvious choices for what the tooth could be, I didn't quite know what to make of it. However, predatory fish to occasionally have carinae too, that's true. So probably you're right. Seems a much more likely explanation than this being a Temnodontosaurus sp. tooth, as, pending counter-evidence, I think those teeth would be quite rare from the Triassic... All the same, quite a sizeable fish, in that case - but a fish it'll be :)

 

Would it be Severnichthys then?

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pachy-pleuro-whatnot-odon
33 minutes ago, pachy-pleuro-whatnot-odon said:

Would it be Severnichthys then?

To answer my own question, I've been scouring around on Google and TFF a bit and found plenty of low-quality photographs, which kind of convince me that, indeed, this tooth belongs to Severnichthys accuminatus. Though it lacks the striations at the base of the crown,not all teeth seem to have them going equally high up - and my specimen is far from smooth in that area anyway (kind of what you might expect from "rolled" ridges). Size, thickness, curvature and carinae all match. Plus, these teeth are not uncommon at Aust. Don't know why I didn't consider that before, though...

 

c13f084a3ae1efab78bc0c9e61ffb409.jpg.13c73b4e4e0af3ca051ea98a113692ac.jpgimage.png.379314ac4663ed3a11a911e007f10d7d.png11.jpg.fc331a8bec3cdde51688d192ef7bd10c.jpgimage.png.3b731bcb2af3f0269006cf6ed1966bbd.png

5fd689d0caef9_severnichthys-accuminatus-3-152-1-p.thumb.jpg.76791cb2adf2e9c3e181eaa885f493d8.jpg

bGUfwpE.thumb.jpg.a8a5cfc63dd84af72e290f7fffa04785.jpg

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