David in Japan Posted July 6, 2021 Share Posted July 6, 2021 Dear TFF friends, It's been a while since I visited our fossil lovers community. I hope you're all doing well. Few months ago, I went to my favorite late cretaceous spot in Japan. Himenoura formation is a marine formation from the late Cretaceous (Santonian) where ammonites, bivalves, shark teeth, and crustaceans can be found. Last time I went there, I found the following fossil. In is quite small, and at first glance I thought it was some kind of bone fragment or small tooth's enamel negative but after observing it under microscope, I was able to see that it was multiple fragments (some still inside the matrix) of a quite thin "kind of bone" with this kind of hexagonal pattern on the outside (cf photo) and vertical columns in cross section (wasn't able to take picture, will post pictures as soon as I can). I may have an idea of what it could be (possible shark cartilage?) but I would like to hear your opinion about that fossil. Thanks by advance, David 1 ~~~~~~~~~~~~〇~~~~~~~~~~~~~ Warmest greetings from Kumamoto、 Japan Link to comment Share on other sites More sharing options...
Bobby Rico Posted July 9, 2021 Share Posted July 9, 2021 Maybe @Fossildude19 Tim can help 1 Link to comment Share on other sites More sharing options...
Rockwood Posted July 10, 2021 Share Posted July 10, 2021 On 7/6/2021 at 1:47 AM, David in Japan said: possible shark cartilage? I'll see your possible and raise a probable, just for the first round. @Carl May know. 1 Link to comment Share on other sites More sharing options...
BobWill Posted July 10, 2021 Share Posted July 10, 2021 I can't rule out cartilage based on what I have found but a picture showing the whole specimen with good focus might confirm that. 1 Link to comment Share on other sites More sharing options...
Carl Posted July 12, 2021 Share Posted July 12, 2021 On 7/9/2021 at 8:39 PM, Rockwood said: I'll see your possible and raise a probable, just for the first round. @Carl May know. It does not have the regular geometry of shark cartilage. 1 Link to comment Share on other sites More sharing options...
Rockwood Posted July 13, 2021 Share Posted July 13, 2021 5 hours ago, Carl said: It does not have the regular geometry of shark cartilage. Aw ! Man ! You just cost me a possible, and a probable. Link to comment Share on other sites More sharing options...
Carl Posted July 13, 2021 Share Posted July 13, 2021 10 hours ago, Rockwood said: Aw ! Man ! You just cost me a possible, and a probable. Sorry, Rocky! Link to comment Share on other sites More sharing options...
Rockwood Posted July 13, 2021 Share Posted July 13, 2021 36 minutes ago, Carl said: Sorry, Rocky! 'salright. You didn't think I really valued them anyway. Did you ? Link to comment Share on other sites More sharing options...
David in Japan Posted July 16, 2021 Author Share Posted July 16, 2021 Sorry for making you wait like that. I took some additional photos. Help it can help even though i could not take it with the best material. Smartphone microscope combo is not the best. On 7/13/2021 at 5:02 AM, Carl said: It does not have the regular geometry of shark cartilage. I agree with you, the geometry is not regular. The fossil is quite small with lots of fragments still in the matrix. Biggest fragment emerging from the matrix. Focus on the biggest fragment. The geometry of the pattern is not as regular as in shark cartilage. Could it be because of the taphonomy? Fossil cross section composed of columns. ~~~~~~~~~~~~〇~~~~~~~~~~~~~ Warmest greetings from Kumamoto、 Japan Link to comment Share on other sites More sharing options...
ThePhysicist Posted July 16, 2021 Share Posted July 16, 2021 I vote not cartilage. Here's some modern shark cartilage (digitally modified to enhance prism outlines): It's remarkably similar to shark cartilage from the Permian: 1 1 "Argumentation cannot suffice for the discovery of new work, since the subtlety of Nature is greater many times than the subtlety of argument." - Carl Sagan "I was born not knowing and have had only a little time to change that here and there." - Richard Feynman Collections: Hell Creek Microsite | Hell Creek/Lance | Dinosaurs | Sharks | Squamates | Post Oak Creek | North Sulphur River | Lee Creek | Aguja | Permian | Devonian | Triassic | Harding Sandstone Instagram: @thephysicist_tff Link to comment Share on other sites More sharing options...
Mahnmut Posted July 17, 2021 Share Posted July 17, 2021 hi, I do not know much about sharks, but there is some structure on the lower end of the second pic in the second set of pics ("biggest fragment emerging"that may be helpful? Best Regards, J Try to learn something about everything and everything about something Thomas Henry Huxley Link to comment Share on other sites More sharing options...
David in Japan Posted July 18, 2021 Author Share Posted July 18, 2021 19 hours ago, Mahnmut said: hi, I do not know much about sharks, but there is some structure on the lower end of the second pic in the second set of pics ("biggest fragment emerging"that may be helpful? Best Regards, J This structure is not a fossil, it is poly ethylene glycol. It looks a lot like candle wax. I melt poly ethyl glycol and put the fossil inside it. When poly ethylene glycol harden, it helps a lot during preparation to absorb vibration from the air scriber and to avoid the fossil to break. Once one side is done, I melt once again the poly ethylene glycol, turn the fossil and proceed to the other side preparation. 1 ~~~~~~~~~~~~〇~~~~~~~~~~~~~ Warmest greetings from Kumamoto、 Japan Link to comment Share on other sites More sharing options...
Rockwood Posted July 18, 2021 Share Posted July 18, 2021 Good woodworking procedure as well. 1 Link to comment Share on other sites More sharing options...
Mahnmut Posted July 18, 2021 Share Posted July 18, 2021 8 hours ago, David in Japan said: This structure is not a fossil, it is poly ethylene glycol. It looks a lot like candle wax. I melt poly ethyl glycol and put the fossil inside it. When poly ethylene glycol harden, it helps a lot during preparation to absorb vibration from the air scriber and to avoid the fossil to break. Once one side is done, I melt once again the poly ethylene glycol, turn the fossil and proceed to the other side preparation. Ok, that lowers said structures diagnostic value ;) Looked a bit like denticles. Cheers, J 1 Try to learn something about everything and everything about something Thomas Henry Huxley Link to comment Share on other sites More sharing options...
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