Daniel Field, Smithsonian Predoctoral Fellow, Division of Birds, Tyler Lyson, Smithsonian Peter Buck Postdoctoral Fellow, Division of Amphibians & Reptiles, and four co-authors, have just published a research study on the evolutionary history of reptiles clarifying the phylogenetic position of turtles. They propose that turtles are most closely related to archosaurs, the ruling reptiles.
The study in the journal Evolution & Development argues that turtles share a more recent common ancestor with birds and crocodiles than with lizards and snakes. Small RNA molecules, called microRNAs, were surveyed across the vertebrate tree of life, with several unique microRNAs found to be shared exclusively between turtles and archosaurs (birds + crocodilians). Contrary to previously published research, no support was recovered for a turtle-lepidosaur (lizards, snakes, tuatara) clade.
The paper can be accessed here: http://onlinelibrary.wiley.com/doi/10.1111/ede.12081/abstract
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