A Dinosaur Cousin’s Crocodile Ankles Surprise Paleontologists

Apr 17, 2017

By NICHOLAS ST. FLEUR

Paleontologists excavating a basin in southern Tanzania have uncovered 245-million-year-old fossils belonging to one of the earliest relatives of dinosaurs. The carnivorous creature, which is not a direct ancestor to dinosaurs but more of a close cousin, is called Teleocrater rhadinus. The discovery, which was reported Wednesday in Nature, may help scientists fill in gaps in our understanding of how dinosaurs evolved as well as provide insight into what their earliest relatives looked like.

“For the first time we have a good idea of what the very first forms on the lineage leading to pterosaurs, dinosaurs and birds looked like,” Randall B. Irmis, a curator of paleontology at the Natural History Museum of Utah who was not involved in the study, said in an email about the study. “I think this will spark a lot of research into how and why pterosaurs and dinosaurs evolved into such different forms from their early relatives.”

The Teleocrater is an archosaur, a group that includes all birds, dinosaurs and the flying reptiles pterosaurs, as well as crocodiles and alligators. About 250 million years ago, at the beginning of the Triassic Period, the archosaurs broke into two main branches: the bird bunch, which includes dinosaurs, and the crocodile crew. Teleocrater is considered an early member of the bird-line archosaurs, appearing some 10 million to 15 million years before dinosaurs entered the lineage.

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One comment on “A Dinosaur Cousin’s Crocodile Ankles Surprise Paleontologists”

  • @OP – “For the first time we have a good idea of what the very first forms on the lineage leading to pterosaurs, dinosaurs and birds looked like,” Randall B. Irmis, a curator of paleontology at the Natural History Museum of Utah who was not involved in the study, said in an email about the study. “I think this will spark a lot of research into how and why pterosaurs and dinosaurs evolved into such different forms from their early relatives.”

    The evolution of those small adaptations, shows the enabling link to later specialist forms of Dinosaur.

    I see another important link to modern mammals appears to have been found in Scotland.

    http://www.bbc.co.uk/news/uk-scotland-highlands-islands-39791226

    Palaeontologists believe an animal that lived in what is now Skye 165 million years ago fed milk to its young.

    Milk teeth have been discovered in the fossil jaw of a juvenile Wareolestes rex, a species of mammal from the Middle Jurassic.

    Scientists suggest adult females secreted milk on to a bare patch of skin for their young to lap up.

    Nipples and suckling as seen in modern mammals had still to evolve when Wareolestes rex lived.

    The two centimetre-long jaw was found on Skye in 2015 and is one of the most complete fossils of the early mammal to be found outside of China.

    Single teeth of Wareolestes rex have previously been found in England.

    Palaeontologists from National Museums Scotland in Edinburgh and the University of Oxford have been examining the fossil from Skye.

    Using micro-CT scanning technology, they have identified milk teeth and, inside the jaw, adult teeth that had not erupted through the gums.

    The scientists said this showed that Wareolestes rex replaced its teeth once, like humans and other modern mammals.

    It had a set of milk teeth, followed by a set of adult teeth.

    This pattern of tooth replacement was an important step in the evolution of mammals and is linked to the production of milk to feed young, the scientists said.

    Living in a period when dinosaurs were the dominant animal, Wareolestes rex were a large mammal for the time, with adults growing to the size of a guinea pig.

    The method of Wareolestes rex delivery of milk to its young is similar to that of platypus.

    During the Middle Jurassic, Skye was covered in lagoons and filled with turtles, crocodiles, pterosaurs and dinosaurs.

    Mainland Scotland was an island surrounded by a semi-tropical sea filled with marine reptiles and ammonites.



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