A common skeptical argument put forward is that such and such a cryptid could not exist because either
(a) it is absent from the fossil record or
(b) the fossil record shows it became extinct 2
zillion years ago.
Neither of these arguments is conclusive. It is extremely difficult for an animal to become fossilized and this means that the proportion of animals that have done so is sparse when compared with the number of animals that have trodden on this planet. Thus animals completely unrepresented in the fossil record may once have frolicked about and animals that have not been found in the fossil record for millions of years may well have continued to exist until the present day.
Whether cryptids exist or not, the fossil record cannot be adduced in favor of their non-existence.