Controversial ‘four-legged snake’ may be ancient lizard instead
Controversial ‘four-legged snake’ may be ancient lizard instead
By Carolyn Gramling Nov. 1, 2016 , 2:30 PM
SALT LAKE CITY—It is a tiny, fragile thing: a squashed skull barely a centimeter in length; a sinuous curving body about two fingers long; four delicate limbs with grasping hands. In a major paper last year, researchers called this rare fossil from more than 100 million years ago the first known four-legged snake. But at a meeting of the Society of Vertebrate Paleontology (SVP) here last week, another team suggested that it’s a marine lizard instead. Even as scientists debate the identity of this controversial specimen, the only one of its kind, it appears to be inaccessible for further study. And paleontologists are mad as hell.
“It’s horrifying,” says Jacques Gauthier, a paleontologist at Yale University. As far as he’s concerned, if the fossil can’t be studied, it doesn’t exist. “For me, the take-home message is that I don’t want to mention the name Tetrapodophis ever again.”
A year ago, researchers led by David Martill of the University of Portsmouth in the United Kingdom reported in Science that the fossil, which they named Tetrapodophis amplectus (for four-footed snake), was a missing link in the snake evolutionary tree. Researchers knew snakes had evolved from four-limbed reptiles, but few transitional forms had been discovered, and researchers continue to wrangle over whether the first lizards to lose their limbs and become snakes were terrestrial burrowers or aquatic swimmers.
Martill and colleagues reported that the fossil, which they described as a specimen in a German museum, originated from a Brazilian outcrop of the Crato Formation, a 108-million-year-old limestone layer rich in both marine and terrestrial species. They identified snakelike features in the fossil, including a long body consisting of more than 150 vertebrae, a relatively short tail of 112 vertebrae, hooked teeth, and scales on its belly. Those features, they say, support the hypothesis that snakes evolved from burrowing ancestors.
More:
http://www.sciencemag.org/news/2016/11/controversial-four-legged-snake-may-be-ancient-lizard-instead
