Mesonychids could not be studied by molecular biologists because they were extinct, and no skeletal features had been found to conclusively link the archaeocetes to ancient artiodactyls. Which ...

Mesonychids were part of an extinct group of mammals closely related to living hoofed mammals like horses, deer and cows. While mesonychids have been found in California and the Midwest, ...

But it occurred in groups that have either gone extinct, such as a group of hoofed carnivores called the mesonychids, or which now have few species, such as the sloths.