Paleontologists have long struggled to compare fossil biodiversity to the biodiversity we see around us. Yet such comparisons are crucial as we attempt to understand and divert an approaching wave of extinction. Here, we bridge the gap between modern and fossil biodiversity by modeling modern tetrapods as fossils, known only from remains preserved in sedimentary rocks. As the first global model of fossilization potential, this provides a profound and previously unavailable perspective. We find that geography strongly structures fossil diversity, producing deeply heterogeneous preservation rates in different tetrapod groups, and, for the globally threatened amphibians, massively underrepresenting extinction. Our results elucidate how physiological and ecological traits of animals influence our ability to recover the history of life.
We know the fossil record is incomplete, but just how much biodiversity does it miss? We produce the first geographically controlled estimate by comparing the geographic ranges of 34,266 modern tetrapods with a map of the world's sedimentary basins. By modeling which tetrapods live within sedimentary basins, we produce a first-order estimate of what might be found in the fossil record of the future. In this record, nearly 30% of tetrapod species have almost no chance of fossilizing, and more stringent criteria for fossilization exclude far more diversity. This geographically structured fossil record preserves disparate patterns of taxonomic and phylogenetic diversity in different tetrapod groups and underpreserves projected extinctions. For the globally threatened amphibians, the magnitude of the extinction of all endangered species would be underestimated by 66–98% in our future record. These results raise profound questions about the structure of the fossil record. Is it capable of recording major origination and extinction events on land? Have swaths of terrestrial diversity gone unrecorded based on geography alone? There are chapters of Earth history that paleontologists can never hope to know, but what is missing, and why?
