Shell size: how turtles evolved over the last 200 million years Diversity of turtle body size studied

Homopus areolatus - one of the smallest recent turtle species. With a shell length of about 100 millimeters, the land-dwelling areolate flat-shelled turtle (Homopus areolatus) is one of today's smallest turtle species. The record at the other end of the scale is held by the leatherback turtle (Dermochelys coriacea), which is common in tropical and subtropical seas and can reach up to two meters in length. Among fossil turtles, the range of body sizes is even more pronounced," says Dr. Gabriel Ferreira of the Senckenberg Centre for Human Evolution and Palaeoenvironment at the University of Tübingen, and continues: "We were interested in how this diversity of carapace sizes evolved over the last 200 million years and which factors played the decisive role in this." To this end, the research team, led by first author Bruna Farina of the Swiss University of Fribourg, compiled the most comprehensive collection of data on turtle body sizes to date: For a total of 795 turtle species, the researchers recorded information on carapace lengths, preferred habitats and the temporal occurrence of the species in the history of the earth. Previous studies that focused on size evolution often ignored fossil species. Our results also incorporate data from 536 extinct turtle species - which is essential if you want to understand the evolutionary history and physical adaptations of the shell bearers," Ferreira adds. The new study shows that today's global climate does not appear to have a major impact on the body size of the recent turtles studied.