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Showing results for tags 'ostracoderm'.
Found 14 results
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This looks similar to some jawless fish bone I’ve seen. Could this be some? Ordovician, Wisconsin, Dane county, Madison.
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Never seen this texture on a brachiopod or bryozoan before. Found in Wisconsin gravel.
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I’m legitimately lost as to what this could be. Devonian, Milwaukee formation. Fish tooth plate?
SilurianSalamander posted a topic in Fossil ID
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Hi guys! I found the attached Silurian and Devonian fish online and would appreciate your opinions on the specimens. The first is a Galeaspid, Polybranchiaspis, from Yunnan, China (43mm in size) and the second is an Osteostracan, Tremataspis schmidti, from the Rootsikula Formation, Island of Oesel, Estonia (28mm and 16mm headshields). They are dated to the Upper Silurian and Lower Devonian respectively. From some research it looks like the Tremataspis is genuine, however I’m not 100% on the Polybranchiaspis. Any input in terms of their authenticity would be greatly appreciated!
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This is another specimen I would like to share from my long-ago collected specimen box. It is my recollection that this was found while walking on exposed riverbed along the north shore of the St. Lawrence River somewhere near Quebec City. The rib-like grooves as seen on the top view are what caught my eye, but after picking up and examining it more closely, the cross-section really got my attention. This spoke "structural design" to me. Although we've certainly all seen unusually shaped rocks that didn't mean anything, this, along with the grooves on the top side, it made me think it wasn't a random rock. I'm guessing this is a fragment of an Ostracoderm, possibly Cephalaspis Lyelli(?). Any other thoughts on what this might be? Thanks in advance for your comments.
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From the album: Harding Sandstone
Armor plates with odontodes/tubercles. Magnification 40x + iPhone zoom. -
From the album: Harding Sandstone
Magnification 40x. -
From the album: Harding Sandstone
Magnified 40x. -
Here’s some fossils I’m working on from 18 mile creek in Hamburg,NY. They’re in pretty dense hard silica shale. Any ideas on identifying them?
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Here are some color pencil sketches of some Paleozoic agnathans I drew many years ago (maybe 6 or 7 years ago). Time is scarce, but seeing these again I somehow feel inclined to start sketching some new concepts again Polybranchiaspis yunannensis (Galeaspida) Early Devonian Qujing, Yunnan, China Haikouella lanceolata (Agnatha, Haikouellidae) Early Cambrian Chengjiang, Yunnan, China Stensiopelta pustulosa (Cephalaspida) Early Devonian Ternopil, Ukraine Pteraspis (Pteraspiformes) Early Devonian Ternopil, Ukraine
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From the album: Vertebrates
Tremataspis schmidti ROHON, 1892 Upper Silurian Island of Oesel Estonia Length 2,5cm / 1" -
Taxonomy according to GBIF.org Reconstruction by Patten, 1903, p. 237: Life reconstruction own work by Tamura By Nobu Tamura email:nobu.tamura@yahoo.com http://spinops.blogspot.com/ http://paleoexhibit.blogspot.com/ - Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=50279652 Identified by oilshale using Patten, 1902. References: Patten, William (1902) On the Structure and Classification of the Tremataspidæ. The American Naturalist Vol. 36, No. 425 (May, 1902), pp. 379-393. Patten, William (1903) On the Appendages of Tremataspis. The American Naturalist, Vol. 37, No. 436, pp. 223-242. Published by: The University of Chicago Press for The American Society of Naturalists. Denison, Robert H. (1947) The exoskeleton of Tremataspis. Am. J. Sci. 245: 337-365. Märss, T., Afanassieva, O. and Blom, H. (2014) Biodiversity of the Silurian osteostracans of the East Baltic. Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 105, pp 73-148. doi:10.1017/S1755691014000218 O'Shea, J., Keating, J. N. and Donoghue, P. (2019) The dermal skeleton of the jawless vertebrate Tremataspis mammillata (Osteostraci, stem-Gnathostomata). Journal of Morphology. 1–27. Bremer, O., Qu, Q., Sanchez, S., Märss, T., Fernandez, V., Blom, H. (2021) The emergence of a complex pore‐canal system in the dermal skeleton of Tremataspis (Osteostraci). Journal of Morphology 282, 8, 1141-1157. DOI:10.1002/jmor.21359
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References: George M. Robertson (1935): Oeselaspis, a new genus of ostracoderm. Am J Sci May 1, 1935 Series 5 Vol. 29:453-461 Qu, Q., Blom, H., Sanchez, S. and Ahlberg, P. (2015): Three-dimensional virtual histology of Silurian osteostracan scales revealed by synchrotron radiation microtomography. J. Morphol.2015 Aug;276(8):873-88. doi: 10.1002/jmor.20386. Epub 2015 Mar 21.
