The popular observation that "extraordinary claims require extraordinary evidence" has been referred to as the "Sagan standard", as Carl Sagan popularized it as much as anyone.
https://en.wikipedia.org/wiki/Sagan_standard
It's a bit misleading, since extraordinary claims simply require evidence sufficient to prove those claims. The evidence need not be extraordinary, and labeling a claim itself as extraordinary is a subjective excercise to some degree:
"The aphorism has been criticized both for its apparent support of "orthodoxy" by raising the evidential standard for claims which are outside current social consensus, and for introducing subjectivity and ambiguity in determining what merits an "extraordinary claim".
David Deming writes: "science does not contemplate two types of evidence. The misuse of ECREE ["extraordinary claims require extraordinary evidence"] to suppress innovation and maintain orthodoxy should be avoided as it must inevitably retard the scientific goal of establishing reliable knowledge."
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Extraordinary claims do not require extraordinary evidence. They simply require evidence that is sufficient to demonstrate the claim is correct.
Further, what is extraordinary in the eyes of consensus scientific opinion at one time, is not always seen as such at a later time. In our own lifetime, the "Clovis First" paradigm of American prehistory has finally fallen by the wayside, but that paradigm ruled American prehistory for generations. Claims of pre-Clovis prehistoric sites could lead to being ostracized. Best have tenure before one rocks the orthodox vessel. The evidence for pre-Clovis dates for the Monte Verde, Chile site was solid right from the start. But those dates were rejected, not because the claim lacked "extraordinary" evidence, but because it went against the orthodoxy of the time. In other words, the rejection of the claims was itself unscientific. Thomas Kuhn's seminal work, The Structure of Scientific Revolutions, explained how science can advance grudgingly, so to speak. The old guard protects its cherished paradigms, and, as has been said, sometimes "science advances one funeral at a time."
https://www.goodreads.com/book/show/61539.The_Structure_of_Scientific_Revolutions