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Showing results for tags 'astraspis'.
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Back in May or so I got my hands on some micromatrix from the Harding Sandstone, CO, USA. This formation dates back to the Ordovician: ~450-475 mya. It's chock full of some really cool and important fossils. It has some of the earliest vertebrate material, and some of the earliest steps in the evolution of teeth! I hope this is an informative and fun look into an important period in life's history. If you feel I have mischaracterized something or have left out pertinent information, please do speak up! I do also plan to post more pictures as I sort through material. If there's something specific you would like a better view of, let me know. So without further ado, let's dive in! All the matrix I have came in this small vial (not all of it is in the vial - this is just what I still have to go through). It's been heavily concentrated. What you're seeing is a mix of shells, some sandstone bits, and vertebrate remains. The majority of the vertebrate material is from ostracoderms - armored fish whose skin was made of bone. They had no jaws, teeth, or fins. They look to me like a cross between an armadillo and a potato. Most of the fossils are of their skin-armor which was studded with "tubercles:" little bumps and ridges. These are important and we'll talk about them later. Also in the mix are scales from potentially the earliest sharks. It seems there is still debate on this, as they could also belong to another class of fish named the thelodonts. There are also the well-preserved "teeth" of conodonts. Conodonts were jawless, bug-eyed, hagfish-like animals.
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From the album: Harding Sandstone
These star-like tubercles give Astraspis its name. Magnification 40x + iPhone zoom.-
- astraspis
- fish armor
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From the album: Harding Sandstone
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- astraspis
- harding sandstone
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(and 2 more)
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From the album: Harding Sandstone
Armor plates with odontodes/tubercles. Magnification 40x + iPhone zoom.-
- astraspis
- fish armor
-
(and 3 more)
Tagged with: