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Hi all, This is a follow-on from the first post in my ‘Adventures in Thin Sectioning’ thread where I showed this fossil from the Aust bone bed. I wanted to have it scanned so that I have a record of both halves before I try to make histological sections of the ‘offcut’. Luckily, my department has a micro X-ray CT scanner (Nikon XT H 225ST) and when there was a gap in demand I was able to book time for a couple hours of scanning. I got three separate scans done, the two pieces of the Aust block done together and then two articulating fragments from the Woodhill Bay Fish Bed at Portishead which are full of upper Devonian placoderm and sarcopterygian fragments. Florists foam is used to hold the pieces in place during scanning as it is easy to press the rocks into and low enough density as to not interfere with the scan. The scan for the Aust block took a little over an hour, and after reconstruction the vertebra is differentiable. The scan isn’t brilliant due to the abundance of pyrite in the stone which scatters the X-rays but it should hopefully be good enough to segment out the bone by hand and make a 3D model, so mission accomplished! The scans for the Portishead material were much shorter exploratory scans (>30 minutes) but turned out better due to the lower density sandstone matrix and lack of pyrite. Both pieces are full of fragments of scale and bits of bone but the larger of the two has a couple particularly interesting features. A large ?spine which I haven’t yet identified: A fragment of jaw with three teeth, likely belonging to the Sarcopterygian Holoptychius: Using a free program called Drishti I’ve been able to quickly reconstruct the Portishead scans in 3D and while the differentiation between bone and matrix isn’t fantastic it is good enough to get an idea of the spatial arrangement of the fragments. I intend to spend some time learning to segment out the fragments individually in Dragonfly (another free program for working with slice data) but am currently struggling with a few bugs so that will have to come later. The two fragments as rendered volumes in rough alignment: A rough rendering of the locations of the bone/scale fragments in both blocks. I believe the majority of the scales are Holoptychius as it is the most abundant taxa in this deposit: Close up on the area with the fragment of jaw, the three teeth are clearly visible as well as the stumps of two others: Thanks for looking, let me know if you have any questions.

A while back I found a concretion containing some rather large teeth. The area was a mid-Miocene coastal deposit here on the South Island of New Zealand. These were my largest teeth yet so I was rather excited, tempered a bit by the fact that it was in a very, veeery hard concretion. I got in contact with Dr Joseph Bevitt at ANSTO where they had a nuclear reactor and are able to do neutron scanning. The instrument is called the Dingo: https://www.ansto.gov.au/our-facilities/australian-centre-for-neutron-scattering/neutron-scattering-instruments/dingo Neutron scanning is needed as it would be able to penetrate this rock where x-rays would have a harder time giving an image with enough contrast. From their website: After getting a temporary export permit from Heritage NZ, I sent the concretion over to ANSTO where it was scanned and then had to sit in a special vault for the radioactivity level to get back to a safe level. The result of the scan was a very cool video (link further below) as well as a stack of TIFF images which can be used to reconstruct a 3D model of the teeth inside the rock! Crazy!! One of the frames from the neutron scanning result: I tried to create the 3D model myself but didn't have the necessary skills, and this is where Andrew Cuff stepped in. He spent hours creating the 3D model which he sent to me. I then loaded the 3D model of the teeth into Blender and combined it with a 3D model (made with a RevoPoint 3D scanner) of the tooth concretion. The result is that you can see exactly where the teeth are INSIDE the concretion!! This is going to make prepping it so much easier. Also, check out Andrew's fossil hunting and prep videos: https://www.youtube.com/@dinoskool/videos Below is an image but have a look at the second video I linked below to see it in 3D, the 2D image doesn't do it justice Here is the video of my finding the concretion, getting it scanned and the resulting video clip: https://youtu.be/BllRDIIsPbw A video of the 3D model fitted into the concretion digitally showing the position of the teeth: https://youtu.be/SIfSAO39I3M

What’s Next for the 1.2 Million Prehistoric Fossils Now at Smithsonian Digitization will soon allow researchers around the globe to access the latest specimens in the National Fossil Collection Abigail Eisenstadt, Smithsonian Magazine, October 19th, 2021 The National Fossil Collection More fossil articles in Smithsonian Magazine Yours, Paul H.