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Showing results for tags 'rounded cross section of teeth'.
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ichthyostegalian fragments in Lithuanian erratics, help to confirm
D.N.FossilmanLithuania posted a topic in Fossil ID
Dear Guys, Merry Christmas to everybody! <3 I recently collected many fragmentary remains probably from ichthyostegalians in shallow marine, and fluvial rocks that belong to Devonian judging by onychodont, lungfish and placoderm like Bothriolepis finds. The identification of thick scales as placoderms is not reliable in my opinion because placoderm armors are much bigger in area and sometimes the surface texture contains wavy ornamentaion or web of protuberant points what is not very common in primitive fishes. The scales are rhombic in shape but they are thicker than in more primitive tetrapodomorphs and similar to scutes. The jaw fragment is found in Late Famennian sandy dolomite together with huge spiriferid brachiopod and shows very interesting rough texture. The elpistostegalians with similar texture of bones went extinct in Early Frasnianso ichthyostegalian (even ichthyostegid) is much more reliable version. In the cross section this bone is angle shaped so it probably covered hind end of jaw as plate of external surface. The other fossil is ilium of ichthyostegalian, it is found in red Frasnian dolomite and shows typical upper part and wide lower joint with pit of contour in the mid part of bottom. I saw very similar shape in Ventastega that is found in Latvia. And the last part is teeth- rounded cross section is visible everywhere, they are curved and sharp. If they would belong to onychodonts they would have the long cavity inside but this is not visible in that finds. They have vertical grooves in the surface as tusks and show labyrinthine type. Please help to confirm these remains or suggest contacts of stem tetrapod specialist. Any help will be very appreciated! The first find I show is gnathal plate of ichthyostegid (?), it is 1,5 cm length.- 5 replies
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- external jaw plate
- frasnian and famennian
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