Fossils are the preserved remains or traces of ancient life, offering scientists a glimpse into the history of plants, animals, and ecosystems long gone. However, the fossil record is not complete—only a small fraction of all organisms that have ever lived become fossils, and many of these are never discovered due to geological and environmental factors. As a result, our understanding of life in the past varies greatly across different time periods and parts of the world. Some regions have been extensively studied, while others remain poorly explored. Because fossil hunting is both costly and time-consuming, it’s crucial to focus research efforts on areas where new discoveries are most likely. A team of researchers, including Thomas A. Neubauer from the Bavarian State Collections of Natural History (SNSB) and Mathias Harzhauser from the Natural History Museum in Vienna, has developed a method to help scientists identify these promising locations. By analyzing the global distribution of fossils from shallow-water marine environments over the past 540 million years, they created a map highlighting regions where fossil data is currently missing. Their study used the Paleobiology Database (PBDB), a major public resource containing extensive fossil records, and combined it with geological data from the Macrostat database to identify gaps in the fossil record. The findings reveal that the Mesozoic Era (252 to 66 million years ago) and the Paleozoic Era (539 to 252 million years ago) are already well-researched, with little expectation of major new discoveries from these periods. In contrast, the Cenozoic Era (starting 66 million years ago), which includes the age of mammals and recent evolutionary developments, has the most incomplete fossil record. Despite the wealth of existing evidence, the researchers believe that many more fossils—especially from shallow-water marine deposits—could still be found in this era. The researchers identified specific regions around the world where previously unknown species might be discovered, as well as areas where the necessary geological layers are exposed and accessible. Neubauer noted that the vast portions of the Earth that remain unexplored offer exciting opportunities for new findings. However, since expanding the fossil record is a slow and difficult process, their work provides a valuable guide for researchers to direct their efforts more effectively. The study has been published in the journal Science Advances.