New Members Krebalt Posted February 26, 2023 New Members Share Posted February 26, 2023 (edited) Hi! I'm a new user who's really into marine reptile bones, by which I mean mosasaurs and plesiosaurs from the Late Cretaceous strata found where I live. I've recently found a small yet satisfying piece that seems to be a hollow bone of a pterosaur/bird. The age of the strata is Late Campanian/Early Mastrichtian and the rock itself is an erratic piece of an "opoka" - a siliceous limestone typically found in Poland and Germany. The bedrock from which it originates lies very likely underneath the Quarternary cover in what is now the Gdańsk Bay (SE Baltic Sea region). It's hollow inside and when viewed with a 60x magnification LAGs and Haversian Canals are visible. Is it likely to be a bone of some tetrapod, say pterosaur/bird? Or might it come from a fish? (that is, if fish actually posses hollow bones, which I might be not aware of yet). Any answers will be very much appreciated. Excuse me for any writing mistakes, which I might make, I'm not any native English speaker. If any more photos are needed I'll send them right away. Cheers, Simon Edited February 26, 2023 by Krebalt spelling Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted February 26, 2023 Share Posted February 26, 2023 Hi, Simon, and a very warm welcome to TFF from Morocco. Yes, it does look like something organic in limestone, but I don't think there's enough of it left to say what it could have been. Pterosaur or bird is a real stretch 1 Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
Jared C Posted February 27, 2023 Share Posted February 27, 2023 this is interesting, bone is possible but we need to see if there are any porous areas - that would imply bone. 2 “Not only is the universe stranger than we think, it is stranger than we can think” -Werner Heisenberg Link to comment Share on other sites More sharing options...
pachy-pleuro-whatnot-odon Posted February 27, 2023 Share Posted February 27, 2023 I agree, this does look like bone. However, there are various reasons why this bone could appear to be hollow, such as the cancellous bits having eroded away, leaving just the bone cortex - although I'm not sure how realistic of a scenario that is. From personal experience hunting on the Isle of Wight, I have found hollow pieces of bone that were, however, very difficult to identify. Part of this is that shark-fin spines may appear similar in cross-section. All the same, I did also find a complete piece of bone that was also obviously hollow and, as such, was identified as pterosaur by local experts. Whether that could be the case here, I wouldn't dare say, as there's not a lot to go on. My hunch, however, is that this is pterosaur bone, seeing as the bone texture isn't as dense as you'd expect from a shark-fin spine, and marine reptile bones aren't hollow. That means the most likely candidates here would either be either pterosaur or bird, or terrestrial creature that got washed out to see. Maybe @msantix has any opinion about this piece? '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...
New Members Krebalt Posted February 27, 2023 Author New Members Share Posted February 27, 2023 Thanks very much for your answers. I think I may try to take some microphotographs in a few hours when home. When it comes to the idea with isolated cortex it seems to me the piece is to curved for that to be possible, still it's just my guess. Link to comment Share on other sites More sharing options...
New Members Krebalt Posted March 1, 2023 Author New Members Share Posted March 1, 2023 (edited) Since the bone is very thin and its surface is pretty rough it was almost impossible to take any nice microphotographs. The one below shows the bone's flaky nature. What can be observed, I think, are LAGs, but I am not 100% sure, anyways it's definitely flaky and it's got some cracks and displacements in the other segments. At the bone's end canals are observable (I think it's the Haversian System) but the surface was simply too rough to get a good focus with a 60× magnification. Edited March 1, 2023 by Krebalt Link to comment Share on other sites More sharing options...
pachy-pleuro-whatnot-odon Posted March 1, 2023 Share Posted March 1, 2023 3 hours ago, Krebalt said: Since the bone is very thin and its surface is pretty rough it was almost impossible to take any nice microphotographs. The one below shows the bone's flaky nature. What can be observed, I think, are LAGs, but I am not 100% sure, anyways it's definitely flaky and it's got some cracks and displacements in the other segments. At the bone's end canals are observable (I think it's the Haversian System) but the surface was simply too rough to get a good focus with a 60× magnification. Thanks for the photograph! I'm not too versed in histology myself - let alone pterosaur histology - but I'd expect that for LAGs (Lines of Arrested Growth) to show up, you'd need a clean cut surface, much as you'd do when creating a thin section or doing analysis of ceramic texture on archaeological pottery. I, unfortunately, also wouldn't quite know who might be more familiar with this material on the forum, as the subject matter is quite specific... I'll tag @Praefectus and @ThePhysicist on the off chance that they have experience with bone histology or would know other members that do, but otherwise I think I'll just tag along for the ride and see who shows up with an answer to this little riddle '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...
mamlambo Posted March 1, 2023 Share Posted March 1, 2023 I'm not familiar with pterosaur bone structure at all, but the close-up does remind me of the shiny flake structure I've seen in fossil fish bones I've found. 2 Link to comment Share on other sites More sharing options...
Praefectus Posted March 2, 2023 Share Posted March 2, 2023 5 hours ago, pachy-pleuro-whatnot-odon said: I'll tag @Praefectus and @ThePhysicist on the off chance that they have experience with bone histology or would know other members that do Thanks for the tag but I'm not experienced enough with histology to say. 1 Link to comment Share on other sites More sharing options...
ThePhysicist Posted March 3, 2023 Share Posted March 3, 2023 Hello, I'm also not an expert. I however can say that to properly see LAGs, you really need to thin section as @pachy-pleuro-whatnot-odon suggested. I cannot see any with the picture provided. I'm also having trouble seeing haversian systems, but that may be because we're not looking at the "grain" straight-on. I don't know of anything that would suggest this is pterosaur/bird. My best guess is fish, given the "flakiness" you mentioned. 1 Forever a student of Nature Link to comment Share on other sites More sharing options...
New Members Krebalt Posted June 9, 2023 Author New Members Share Posted June 9, 2023 Hi! After making a small cross-section the bone turned out to be a fin spine of some stingray, possibly, with its structure simply too porous (around>40% of the section) to be of any kind of a pterosaur or a bird. Also, some grooves extending outwards showed up in the section, making it even more likely to be a stingray fin spine. Therefore, I consider the question answered and the topic closed Anyways, I'm still hoping to find a real ptero bone, so if there should be any possible ptero-finds I'll post them immediately. Thanks for all of your answers Cheers, Krebalt 1 Link to comment Share on other sites More sharing options...
pachy-pleuro-whatnot-odon Posted June 11, 2023 Share Posted June 11, 2023 Thanks for the update! Interesting conclusion '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...
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