Anaspida
| Anaspida Fossil range: early Silurian - Late Devonian | ||||||||
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 Jamoytius kerwoodi | ||||||||
| Scientific classification | ||||||||
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- For turtles, see Anapsida.
The Anaspida ("Without Shields") are stem gnathostomes, and are classically regarded as the ancestors of lampreys. Anaspids were small marine agnathans that lacked scales and paired fins. They first appeared sometime during the early Silurian, and flourished until the Late Devonian Extinction Event, during the late Devonian, where most species, save for lampreys, went extinct due to the environmental upheaval during that time. The gills opened as a row of holes along either side of the animal that typically numbered anywhere from from 6-15 pairs.
Source: adapted by the editor from Wikipedia, the free encyclopedia; from the article "Anaspida". Image Credit.
