Life reconstruction of the new species Teleocrater rhadinus, a close relative of dinosaurs. (Image by Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” (Buenos Aires, Argentina), artwork by Gabriel Lio.)

Certain physical traits previously thought to be unique to dinosaurs evolved much earlier, a new study suggests. Fossil analysis of a newly described species, named Teleocrater rhadinus, places this carnivorous animal in a new spot on the evolutionary tree, directly after the split between birds and crocodilians. Teleocrater marks the first of an entirely new clade of reptiles, Aphanosauria, which possesses both transitional physical bird-crocodylian characteristics, such as a crocodilian-like ankle joint, and classic dinosaur features in limb proportion and body size.


Sterling J. Nesbitt, Richard J. Butler, Martín D. Ezcurra, Paul M. Barrett, Michelle R. Stocker, Kenneth D. Angielczyk, Roger M. H. Smith, Christian A. Sidor, Grzegorz Niedźwiedzki, Andrey G. Sennikov & Alan J. Charig

Corresponding author:

Sterling Nesbitt, Virginia Tech, Blacksburg, Virginia, United States, Email:

Original paper published in Nature on April 12, 2017.