Acanthodii

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Acanthodii

[ə‚kan′thō·dē‚ī]
(paleontology)
A class of extinct fusiform fishes, the first jaw-bearing vertebrates in the fossil record.
References in periodicals archive ?
Graptolite biozones are usually the most trusted ones, but we will also analyse the behaviour of biozones based on conodonts and chitinozoans, and also on less 'authoritative' groups of fossils such as ostracodes and 'microvertebrates' (mostly thelodont and acanthodian microremains).
Don and Eldon collected skull roofs of haplolepidid fishes and a fin-spine of a small acanthodian fish (Gyracanthus) that Don later described in detail (Baird 1962a, 1978a).
But armed with new data on what the earliest sharks and bony fishes looked like, Coates and colleagues re-examined fossils of Acanthodes bronni, the best-preserved acanthodian species.
In addition, acanthodian fish scales and a portion of a fin spine, and numerous actinopterygian and sarcopterygian fish scales and tips of actinopterygian teeth from the MNSC were identified by Kenaga and Sellepack (1995).
These substages correspond to the acanthodian zones established by Valiukevicius [5].
Also interesting are the results of a close study of the acanthodian scales within the excrement.
Another peculiarity highlighted by the data at hand is the sudden appearance of several acanthodian taxa in the Nar Formation on Gotland.
According to a report in National Geographic News, the specimen is of a 415-million-year-old Ptomacanthus, which is only the second known example of a braincase from an Acanthodian, a long-extinct group of fossil fish.
On the other hand, the acanthodian species Diplacanthus gravis is only known to occur in the Arukula Regional Stage (Mark-Kurik 2000; Valiukevicius 2000).