Original: The entire class of Conodonts, or at least what was left of them at the time, are postulated to have been wiped out by the Triassicâ "Jurassic extinction event, which occurred roughly 200 million years ago.
Simplified: The entire class of Conodonts, or at least what was left of them at the time, were wiped out by the Triassicâ "Jurassic extinction event, which occurred roughly 200 million years ago.