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Showing results for tags 'marine reptile bone'.
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To pass some time I've been recently researching early Paleocene life and I keep coming back to researching (in my view) the two strangest and controversial Late Cretaceous-Early Paleocene Formations I know of. These are the Hornerstown Formation dating 66.5-65.5 Million Years ago in what is now New Jersey, U.S. And the Takatika Grit Formation dating 66.5-60.0 Million Years ago in what is now the Chatham Islands, New Zealand. https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=0b3baee9ab1afc7973337f5047495b723fcfa4f2 https://www.researchgate.net/publication/315461615_The_age_of_the_Takatika_Grit_Chatham_Islands_New_Zealand https://www.sciencedirect.com/science/article/abs/pii/S0195667109000184?via%3Dihub I've read many reports about these formations and the pretty controversial stuff that's been found in both these areas (Paleocene ammonites and reports of archaic marine reptiles like Paleocene Mosasaurs). I'm really not 100% sure what to make of this as I've heard conflicting hypotheses on whether these more archaic marine reptile fossils were reworked from older formations while others say it's not too too likely? https://www.cambridge.org/core/journals/journal-of-paleontology/article/abs/maastrichtian-ammonites-from-the-hornerstown-formation-in-new-jersey/4F051D07668B7B893EEFECF0506E2F1B https://bioone.org/journals/acta-palaeontologica-polonica/volume-57/issue-4/app.2011.0068/Short-Term-Survival-of-Ammonites-in-New-Jersey-After-the/10.4202/app.2011.0068.full For most of these "controversial" specimens, I would say reworking is likely while some I'll admit I'm not sure? For the Mosasaurs, it's clear that the astroid impact 66 Million Years ago caused their total extinction, but I'm still not 100% convinced that none emerged from the event alive (at least barely) and swam the seas in the very first days of the Danian Paleocene but not too long after. Unlike the mostly terrestrial Non-Avian Dinosaurs, which could only hide in so many places and it's very unlike more than a tiny amount of individuals (not enough to support a population) made it into the Paleocene, the Oceans have slightly more areas to hide and more even for endothermic air breathing animals like Mosasaurs (though as an endotherm, food does become a major issue especially when the ocean food chain nearly collapsed completely). What I'm wondering is how valid are at least "some" of these supposed archaic marine reptile and ammonite fossils from the earliest Paleocene sections of the Hornerstown Formation and the Takatika Grit? Also, of all the Maastrichtian Mosasaurs known so far, which ones would have been the mostly likely to have (at least briefly) survived the Cretaceous-Paleocene Extinction Event of 66 Million Years ago (would it have been generalist feeders, ones that specialized in deep sea hunting, ones with cosmopolitan distributions, ones small by mosasaur standards but still around the same size of the few confirmed large reptiles that survived the event like the 8 meter (26 feet) in length Thoracosaurus, or ones with all these traits and advantages)?
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- hornerstown formation
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- marine reptile bone
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Interesting piece found in the junction bed Jurassic layers in Somerset. Bone like texture. Possibly ichthyosaur?? Any help much appreciated. Found amongst Jurassic ammonites layers.
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From the album: Post Oak Creek
This bone is almost identical to mosasaur bones found in the NSR, despite being from a different formation a few million years older.-
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The quarry Kromer near Holzmaden did open two weeks ago (it was closed during winter). So last Saturday I was there the first time this year and I have to say that I am kinda satisfied with my finds! I found several marine reptile teeth, some mainly incomplete bones and a fish with much potential. In this topic I want to show how I prep/prepped a plate on which originally two Ichthyosaur verts were visible. The verts are all about 4 cm big. Here is a picture of the unprepped plate: (I have the other parts...) The prep work is very difficult because the stone is extremely hard. So I have to use my air pen to remove the stone directly above the verts and then I remove the remaining thin layer with my sandblaster with about 6 bar which is probably too much for the bones but otherwise I wouldnt do any progress ... This is the current situation: Until now I prepped about 4 hours and now you see that there are even more vertebrae on the plate At least 3 and a half.... And here is the one which wasnt visible at first. I damaged it a bit but I think its not too bad. Hopefully the stone is a bit softer around this one: I think I have to work many hours on it so wish me luck @LiamL
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Last Sunday I was able to find a piece with some jaw bones and teeth of an Ichthyosaur in the quarry Kromer near Holzmaden. I was very pleased with that find because the situation in the quarry is not the best. There is only a kinda small pile of stones where you are allowed to search (and where you can find marine reptile fossils, in the other regions of the quarry its very unlikely to find a bone or a teeth of a marine reptile). And this pile consists at the moment only out of very small rocks because they were laying until the beginning of the year there. So many collectors already searched there. And it's very likely that they don't get new material in this summer... Here is a bad picture of the quarry: And here are some pictures of the jaw bone with the teeth: The prep work took about 5 hours. It's a pity that I lost that missing part in the quarry. I searched about 1 hour for it but couldn't find it. But at that time I didn't know that its a jaw bone (no teeth were visible). Now about 65 small Ichthyosaur teeth are visible. They are from a very small Ichthyosaur, maybe even from a juvenile!
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From the album: Holzmaden
A 3.5 cm long Ichthyosaur vertebra from the Posidonia shale from the quarry Kromer near Holzmaden. Another picture:- 2 comments
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From the album: Holzmaden
A tiny 10 cm long Ichthyosaur rib from the lower Jurassic of the quarry Kromer near Holzmaden. At first you could only see the cross section. The prep work took about 2 hours (I was slow ) One more picture:-
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