The research team (Eugenia Naro-Maciel and colleagues, Marine Biodiversity Scientists at the Center for Biodiversity and Conservation at the American Museum of Natural History) tested the evolutionary relationships of all species of marine turtles. The results formed a well-supported phylogenetic tree that tells the story of sea turtle evolution and is reported in the journal Molecular Phylogenetics and Evolution. The evolution of a specialised diet appears to have occurred three times, independently,â says Naro-Maciel. âMany sea turtles are carnivorous generalists. However, hawksbills tend to have a diet of grassâthey eat toxic spongesâwhile the leatherback consumes jellyfish and the green, graze mainly on algae or sea grass.â Determining the evolutionary relationships among sea turtles as well as the species identity of different populations of this highly migratory group of animals has implications for conservation. All sea turtles are included on the IUCNâs Red List of Threatened Species, some of them as critically endangered.