Genetic studies have led researchers to suggest that turtles are most closely related to the group that includes modern crocodiles. But studies of fossils have suggested instead that turtles are most closely related to other groups, such as the one that contains modern snakes. However, many of the fossil studies have relied on incomplete data sets. For a 2022 investigation, biologist Tiago R. Simões and colleagues examined more than 1,000 reptile fossils collected worldwide. From this large data set, they found clear agreement with the results of the genetic studies.