Two papers published today shed light on our early evolution, though "early" is a relative term. The first describes what could've been the first species of mammal, a tiny beast that quivered in the shadows of the dinosaurs 195 million years ago. The second reports on a shift in eating habits of early modern humans compared to Neanderthals about 25,000 years ago.
A team of U.S. and Chinese researchers has identified a new species of primitive mammal, uncovered from Early Jurassic rocks in the Lower Lufeng formation, in Yunnan, China, dating to 195 million years ago. The new fossil species, Hadrocodium, has distinctly mammalian features, predating the previous oldest-known mammal-like specimen by 45 million years.
Zhe-Xi Luo, of the Carnegie Museum of Natural History, and colleagues describe the find -- a 12-mm-long skull -- in today's issue of Science. Extrapolating from the skull size, the researchers estimate that Hadrocodium weighed only 2 grams -- the size of a large paper clip. The smallest living ground-dwelling insectivorous placental mammal weighs 2.5 grams, the smallest bat, 2 grams.