'Proto-mammal' fossil shows evolutionary path to modern creatures

Aug. 7, 2013 at 4:36 PM

CHICAGO, Aug. 7 (UPI) -- A newly discovered fossil of a "proto-mammal" is yielding clues to the evolution of the world's earliest mammals, University of Chicago biologists report.

The fossil of an ancient mammalian relative, Megaconus mammaliaformis, reveals the evolutionary adaptations of a 165-million-year-old proto-mammal, providing evidence traits such as hair and fur originated well before the rise of the first true mammals, the researchers said.

"We finally have a glimpse of what may be the ancestral condition of all mammals, by looking at what is preserved in Megaconus," Zhe-Xi Luo, a professor of biology and anatomy, said. "It allows us to piece together poorly understood details of the critical transition of modern mammals from pre-mammalian ancestors."

Discovered in Inner Mongolia, China, Megaconus is one of the best-preserved fossils of the mammaliaform groups, long-extinct relatives to modern mammals that shared the Earth with feathered dinosaurs in the Jurassic era nearly 100 million years before Tyrannosaurus Rex roamed Earth.

The fossil shows a clear halo of guard hairs and underfur residue, making Megaconus -- a terrestrial animal about the size of a large ground squirrel -- only the second known pre-mammalian fossil with fur, the researchers said.

"We cannot say that Megaconus is our direct ancestor, but it certainly looks like a great-great-grand uncle 165 million years removed," Luo said. "These features are evidence of what our mammalian ancestor looked like during the Triassic-Jurassic transition."

Related UPI Stories
Latest Headlines
Trending News
Seattle sea otter learns how to use an inhaler
Catholic conservatives wary of Pope's climate change message
Apple signals delivery of electric car by 2019, report says
Self-impregnated snake in Missouri has another 'virgin birth'
Ancient Roman village found in Germany