What do we call the idea that we can never know the first or last occurrence of an animal from the fossil record?

The idea that we can never know the first or last occurrence of an animal from the fossil record is often referred to as the "Fossil Record Limitation" or "Fossil Preservation Bias." This concept highlights the incomplete nature of the fossil record due to various factors such as the rarity of fossilization events, geological processes that may destroy fossils over time, and the difficulty in discovering fossils in certain environments. As a result, paleontologists can only make educated estimates about the existence of a species at any given time, rather than pinpoint definitive first or last occurrences. This limitation underscores the challenges faced in studying evolutionary history and understanding biodiversity through time.