fossils

A broken bone sheds a light on evolutionary transition to land

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Nick
Garland

Founder and Editor
Animals emerged from the water and clamored onto land more than 300 million years ago, but paleontologists are looking for even more details about the transition. A healed broken bone that later fossilized is offering some new and unexpected clues.

A new fossil from Australia pushes back the origin of tetrapods, or four-limbed animals, more than two million years.


The creature, Ossinodus, lived during the Devonian Period 333 million years ago in what would have been temperate forests.


Researchers analyzed only one Ossinodus radius bone from the front leg but this was a special and rare bone. The scientists used CT imaging to examine the structure of the bone to discover that it contained a partially healed fracture. But how did it become fractured?


Because the force of the trauma to the bone was upward of 11 times the animal’s body weight, the researchers find it highly unlikely that a water-dwelling animal could sustain a force that high. Generally, water cushions the blow of any object. This animal must have fallen from a height of almost three feet, possibly from a rock. Based on the nature of the fracture, researchers ruled out an attack from a predator.


Ossinodus now takes the title of oldest known tetrapod from the previous owners, its relatives from Scotland. But the search for the first true tetrapod continues.

Image Credit: Zach Coker

5c3e0c5dff4b84c2d89b8da7be5adf3e

Nick
Garland

Founder and Editor


http://sulc.us/hmrfr
http://www.eartharchives.org/articles/a-broken-bone-is-newest-clue-in-evolutionary-transition-to-land/