Jeannette Daniel | Sunday, November 29, 2015

"How snakes lost their legs has always been a mystery to scientists",
Dr. Hongyu Yi says in press release form the University of Edinburgh.

"With a snout-tail length exceeding 1.8 m, Dinilysia patagonica is the
largest known burrowing snake, living or extinct", the paleontologists
said.

The study used CT scans to analyze the inner ear of the Dinilysia
patagonica, a species of reptile that is closely linked to modern
snakes. The snake's inner ears are used as vital tools for balance and
movement but in the case of this fossil, they also served another
goal.

Snakes lost their legs to be able to more effectively hunt and live in
burrows - Scottish and American scientists have concluded after
studying a 90-million-year old fossilized snake skull - and not to
adapt to living in the sea, as many experts had previously suggested.

The braincase and inner ear of Dinilysia patagonica. Left braincase of
D. patagonica showing the right otic region in lateral view. Right
X-ray CT model of the fossil with the inner ear highlighted in blue.
Scale bars- 5 mm. Image credit Hongyu Yi

X-ray images of snake and lizard skulls suggest that modern snakes'
ancestors burrowed rather than swam, scientists report November 27 in
Science Advances.


A new study carried out by researchers from the American Museum of
Natural History and the University of Edinburgh claims to have solved
a long-term puzzle related to evolution of snakes.

The braincase and inner ear of Dinilysia patagonica. Scale bars, 5 mm.
And although, sadly, numerous bones found were quite damaged, the team
did manage to spot an inner ear formation still intact. When they
sought this structure in modern snakes that lived above ground or
operated primarily in marine environments, it was notably absent. This adaptation likely helps burrowers detect prey and predators and was
not found in modern snakes that live in water or on the Earth's
surface.

"This discovery would not have been possible a decade ago-CT scanning
has revolutionized how we can study ancient animals", said Norell in a statement.

He added: "We hope similar studies can shed light on the evolution of
more species, including lizards, crocodiles and turtles".

"A burrowing life-style predated modern snakes, but it remained as the
main, if not exclusive, habit for basal lineages among crown snakes",
Dr Yi and Dr Norell said.


http://observerleader.com/2015/11/reptile-fossil-explains-how-snakes-lost-their-legs/

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