Lunedi, 23 Aprile, 2018

New reptile species from 212 million years ago identified

Vivaron haydeni New Discovery: This Ancient Reptile Species is Related to Crocodiles
Irmina Pasquarelli | 10 Settembre, 2016, 12:06

A new species of extinct reptile said to be distant cousins with crocodiles has been identified by an undergraduate student working in a lab at Virginia Tech. Some of the fossils remained sealed in protective plaster jackets until 2014 when they were transported to Blacksburg for study. When Lessner heard of the opportunity and the chance to work with Nesbitt and Michelle Stocker, also a newly arriving paleontologist in the college, Lessner jumped at the chance.

The new species is named and described in a paper published this week in the journal PeerJ. "I began looking at Vivaron pretty soon after".

The new reptile gets its name from John Hayden, a hiker who first discovered the Hayden Quarry in northern New Mexico in 2002 and from the mythical 30-foot rattlesnake spirit called the Vivaron which, so goes the legend, lived under the Orphan Mesa at Ghost Ranch.

Ultimately, however, her work with the professor led to the identification of just the sixth species of rauisuchid ever discovered, and only the sixth found in what is now the southwestern USA but was at one time the western part of the supercontinent Pangea. Vivaron likely measured 12 to 18 feet long, walked on four legs and was a meat eater, according to the study authors.

Vivaron was a carnivorous archosaur - a large set of animals that includes crocodilians and dinosaurs, as mammals includes humans and dogs. Multiple fossils were found in New Mexico including jaw bones, pieces of skull and hip bones.

"These were some of the biggest predators at the time, all dinosaurs were much smaller", said Sterling Nesbitt, a co-leader of the excavation, referring to the Triassic Period - the period between 251 and 199 million years ago. Fully grown Vivaron haydeni would measure between 12 and 18 feet in length. Researchers say that the fossils put Vivaron as a relative of Teratosaurus suevicus, another rauisuchid from the same period which so far has only been unearthed on the other side of the planet in Germany. There is hope for researchers though given that the area where it was found is a hot spot for paleontologists. Other parts of Vivaron may still be there. "Initially, I cleaned fossils in the lab and worked on a project reconstructing soft tissue structures using computed tomographic, or CT, scans on the computer", says Lessner, now a senior majoring in biological sciences at Virginia Tech.

"When you look at anything so long, so close, you realize extra details and patterns you would not otherwise notice", she added.

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