A new investigation into a creature hailed as the world's first "four-legged snake" on its discovery has revealed it's actually just a lizard.
A study published in 2015 claimed a 120 million-year-old fossil discovered in Brazil, dubbed Tetrapodophis amplectus - Greek for "four-footed serpent" - was the first snake to have more than two limbs. Other early snake fossils only had two.
But scientists in the Canada said they doubted the findings from the start, so did their own study of the fossil, the University of Toronto said in a release this week.
"I was so upset about this kind of poor science making it into a top journal in the sciences," said biology professor Robert Reisz.
"Soon after the original publication, we secured access to the specimen by raising hell and then we were able to study it. And we basically went and did our detective work properly and we came up with a much more plausible alternative explanation that this is not a snake, but a little lizard.
For a start, its skull is more "lizard-like" than snake-like, lacking the ability to separate bones to swallow prey whole. Its teeth were also more like those of a lizard than a snake - the latter having curved incisors to stop live prey from escaping.
Another red flag for Dr Reisz was that the specimen studied was obtained illegally - Brazil has a ban on exporting fossils, but it was purchased by a private collector who made it available to researchers in the UK, who made the "grand claim" it was a legged snake.
"It was quite unethical. There are laws in place now to protect (these national treasures) and we should respect those and work within the system rather than be tempted by the attraction of an exciting fossil you get through unethical means."
Rather than being a snake evolving legs, it turns out the lizard was the complete opposite - a dolichosaur, de-evolving legs to survive better in the water.
"We want to find out, and get as close to, the truth as possible. Every time we find yet another interesting fossil, it gets us closer to that. We find out more about life before us."