for National Geographic News
A 25-million-year-old fossilized skeleton of a kangaroo is shedding new light on the evolution of the iconic Australian animal, scientists say.
The nearly complete specimen reveals a creature that once plucked fruit from Australian rain forests and bounded on all fours like a modern-day possum.
Ben Kear of La Trobe University in Melbourne analyzed the remains of Nambaroo gillespieae, which were discovered in northwestern Queensland in the 1990s.
"This specimen is the oldest—and certainly the most complete—of any yet discovered," Kear said.
"Prior to this, all we knew of Nambaroo were isolated teeth. The door has been thrown open. We can actually see for the first time what the great-great-great granddaddy of kangaroos looked like."
The size of a small dog, Nambaroo had fangs, probably for display, and mostly ate soft food such as fruit and fungi, Kear said.
The ancient 'roo gathered its food with powerful forearms that, along with flexible back feet and opposable big toes, may have allowed it to climb.
On the ground, the kangaroo's forearms gave it a loping, quadrupedal gait—a far cry from the hopping two-legged travel of present-day kangaroos, Kear said.
The skeleton's extraordinary detail offers rare insights into the ancient animal, he added.
"We can see traces of blood vessels. We can see muscle attachments as scarring left on the bones," Kear said. "Believe it or not, we've even got brain casts out of these things—the preservation is that good."
Australia's Ancient Animals
By studying such details, Kear and his team were able to establish that Nambaroo and other members of its group, known as called balbarids, were an early offshoot of kangaroos with no living descendants.
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