A bizarre new vegetarian dinosaur has recently been discovered in Chile that was closely related to notorious carnivore Tyrannosaurus rex.
Palaeontologists are referring to Chilesaurus diegosuarezi as a 'platypus' dinosaur because of its extremely bizarre combination of characters that include a proportionally small skull and feet more akin to primitive long-neck dinosaurs.
Chilesaurus diegosuarezi was nested within the theropod group of dinosaurs, the dinosaurian group that gathers the famous meat eaters Velociraptor, Carnotaurus and Tyrannosaurus, and from which birds today evolved. The presence of herbivorous theropods was up until now only known in close relatives of birds, but Chilesaurus showed that a meat-free diet was acquired much earlier than thought.
Chilesaurus diegosuarezi has been named after the country where it was collected, as well as honouring Diego Suarez, the seven year old boy who discovered the bones. He discovered the fossil remains of this creature at the Toqui Formation in Aysen, south of Chilean Patagonia, in rocks deposited at the end of the Jurassic Period, approximately 145 million years ago.
Other features present in very different groups of dinosaurs Chilesaurus adopted were robust forelimbs similar to Jurassic theropods such as Allosaurus, although its hands were provided with two blunt fingers, unlike the sharp claws of fellow theropod Velociraptor.
Chilesaurus' pelvic girdle resembled that of the ornithischian dinosaurs, whereas it was actually classified in the other basic dinosaur division - Saurischia.
The different parts of the body of Chilesaurus were adapted to a particular diet and way of life, which was similar to other groups of dinosaurs. As a result of these similar habits, different regions of the body of Chilesaurus evolved resembling those present in other, unrelated groups of dinosaurs, which is a phenomenon called evolutionary convergence.
Chilesaurus represented one of the most extreme cases of mosaic convergent evolution recorded in the history of life. For example, the teeth of Chilesaurus are very similar to those of primitive long-neck dinosaurs because they were selected over millions of years as a result of a similar diet between these two lineages of dinosaurs.
