He continued, "We can look at white sharks today a little bit differently ecologically if we know that they come from a mako shark ancestor."
That ancestor is 2 million years older than previously suspected, based on recalibrated dating.
Ehret said,"That 2-million-year pushback is pretty significant because in the evolutionary history of white sharks, that puts this species in a more appropriate time category to be ancestral or kind of an intermediate form of white shark."
He made the connection between modern great whites and C. hubbelli by comparing the physical shapes of shark teeth to one another. While modern white sharks have serrations on their teeth for consuming marine mammals, mako sharks do not have serrations because they primarily feed on fish. Hubbell's white shark has coarse serrations indicative of a transition from broad-toothed mako sharks to modern white sharks.
So the relatives of great whites used to eat more fish, but then switched to a more red meat diet consisting of mammal flesh.
The Pisco Formation in Peru where the shark fossil was found also includes new whale, marine sloth and terrestrial vertebrate species. I look forward to hearing more about those finds in future.
This question also now remains: Did the great Carcharocles megalodon just die out, leaving behind no modern ancestors? For shark fans, hopefully not.