Ancient Bony Fish Forces Rethink of How Sharks Evolved – HeritageDaily

Sharks’ non-bony skeletons were thought to be the template before bony internal skeletons evolved, but a new fossil discovery suggests otherwise.
The discovery of a 410-million-year-old fish fossil with a bony skull suggests the lighter skeletons of sharks may have evolved from bony ancestors, rather than the other way around.
Sharks have skeletons made cartilage, which is around half the density of bone. Cartilaginous skeletons are known to evolve before bony ones, but it was thought that sha…

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