sjaak Posted November 13, 2020 Share Posted November 13, 2020 Hello, I found this bone in the marine deposits of the Boulonnais, France. Upper Jurassic. I assumed it is a part of the jaw (snout) of a toothless ophthalmosaurus, which are abundant there (mainly vertebrae). However, this week I read the article about a toothless pterosaur jaw from the UK and saw some resemblance. https://www.bbc.com/news/uk-england-cambridgeshire-54891483 I added the pictures of the bone, the pterosaur and an ophthalmosaurus for comparison. I am curious about your thoughts. Regards, Niels Link to comment Share on other sites More sharing options...
BadlandTraveller Posted November 13, 2020 Share Posted November 13, 2020 Looks Pterosaur to me but I am far from an expert. That said great find! Nice work. 1 Link to comment Share on other sites More sharing options...
Troodon Posted November 13, 2020 Share Posted November 13, 2020 Do you have any photos of the broken end ? Want to see cross-section and wall thickness. My initial reaction is that its not 1 Link to comment Share on other sites More sharing options...
pachy-pleuro-whatnot-odon Posted November 13, 2020 Share Posted November 13, 2020 As Troodon suggests, it's quite difficult to say whether this is a piece of ichthyosaur rostrum or pterosaur beak, especially as it's hard to get a good impression of its three-dimensional look, and it's unclear whether some features diagnostic of ichthyosaur are just not present, or still hidden by matrix. For comparison, I attached some photographs of Ophthalmosaurus sp. ichthyosaurs, with a focus on different angles of the jaw. Both specimens come from Peterborough in the UK (Oxfordian stage Jurassic), with the first being housed in the palaeontological collections of Tübingen University and the second in the Senckenberg Natural History Museum in Frankfurt. You'll notice these two specimens have one feature of their jaw in common (which they share with the phylogenetically related brachpterygiine and platepterygiine ichthyosaurs): a groove that runs directly along the margin of the mouth. This trait differs from earlier species, which have sensory pitting instead. Seeing how gracile your find is and that there's no visible groove (rather what seems to be pitting), I'm inclined to share BadlandTraveller's opinion in this being a pterosaur jaw - even if I haven't seen or held any myself yet for comparison. However, the latter point may be easy to resolve, as the news article itself proposes the British pterosaur would've looked much like Aranqa saharica, the north-African azhdarchid pterosaur. If we presume their jaws to be similar (which doesn't seem too far fetched, seeing as the British species is currently only know from a jaw), there should be plenty of reference material out there, including on this forum: I hope this helps... 3 'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett Link to comment Share on other sites More sharing options...
pachy-pleuro-whatnot-odon Posted November 13, 2020 Share Posted November 13, 2020 Quite a spectacular find, by the easy, Niels! Pterosaur remains are rare in general, but if this turns out to have been a toothless pterosaur...! As far as I'm aware these only became common in the Cretaceous! 2 'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett Link to comment Share on other sites More sharing options...
sjaak Posted November 14, 2020 Author Share Posted November 14, 2020 Thank you all for your replies and especially Alexander for all the useful information and pictures! As requested by Troodon I added some pictures of the bone structure at both ends. The bone structure is quite normal for bones of this area. Its not hollow or something like that. So that would plead against pterosaur? I also added a video on Google Drive, hope it works: https://drive.google.com/file/d/1oXMuNjUPhO23YnVHQswq4oamdw5Q6JZ9/view?usp=sharing 1 Link to comment Share on other sites More sharing options...
Troodon Posted November 14, 2020 Share Posted November 14, 2020 Thanks for the photos, Agree not pterosaur. Their bones would not be as robust as this one, but thin walled and gracile. Still a nice find enjoy... 2 Link to comment Share on other sites More sharing options...
sjaak Posted November 14, 2020 Author Share Posted November 14, 2020 Pity, but thanks ! Link to comment Share on other sites More sharing options...
pachy-pleuro-whatnot-odon Posted November 14, 2020 Share Posted November 14, 2020 Based especially on the video I've now started to doubt the pterosaur interpretation, mainly for the reasons that the pitting I observed does not appear to be located on the bone surface/the cortex - thus is likely to be damage to the bone instead - and that the carination in the bone doesn't mean it's shape is triangular, as I originally thought. Also, though I believe only pterosaur long bones are truly hollow inside, this bone looks way too massive, pachyostic even, to be pterosaur. So, I agree with Troodon on this... 2 'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett Link to comment Share on other sites More sharing options...
sjaak Posted November 14, 2020 Author Share Posted November 14, 2020 Yes, so then I get back to my original assumption that this is the snout an ichtyosaurus/ toothless ophthalmosaurus. Although, it’s a bit strange that the proximal end is very thin. Link to comment Share on other sites More sharing options...
pachy-pleuro-whatnot-odon Posted November 14, 2020 Share Posted November 14, 2020 The mandibles of ichthyosaurs, just like those of other animals, are relatively thin bone constructs, which, in part, already explains why the bone is so thin. In addition, the lower jaw, just like the rest of the skull, is made up of various comprising bones. While viewing the video, it very much seemed to me the bone is incomplete on the side sticking out of the matrix. It's very well possible that your jaw section is so thin because it lacks some if the bones that it would normally be made up off. All the same, it remains an awesome find! 1 'There's nothing like millions of years of really frustrating trial and error to give a species moral fibre and, in some cases, backbone' -- Terry Pratchett Link to comment Share on other sites More sharing options...
Pemphix Posted November 15, 2020 Share Posted November 15, 2020 21 hours ago, pachy-pleuro-whatnot-odon said: All the same, it remains an awesome find! Exact, and especially for this formation and region... Link to comment Share on other sites More sharing options...
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