''Tesakoviaspis concentrica'' is an extinct species of primitive jawless fish from the
Middle Ordovician
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya.
The ...
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References
Ordovician jawless fish
Pteraspidomorphi genera
Middle Ordovician animals
{{Pteraspidomorphi-stub