(Santa Barbara, Calif.) Paleontologists have discovered three tiny teeth embedded in a piece of lower jawbone from a small Jurassic period mammal on the island of Madagascar, evidence that some of our mammalian ancestors roamed the Earth at exactly the same time as the dinosaurs, according to an article in the Sept. 2 Nature.
The finding more than doubles the age of the oldest known mammal from Madagascar. Until now, terrestrial fossils were all but unknown from Madagascar for this time interval.
These small, furry creatures, the size of a house mouse, lived in Madagascar during the Middle Jurassic period -- about 165 million years ago -- scampering under the feet of allosaurs and brachiosaurs, much earlier than scientists had previously thought. The findings also show that an advanced subgroup of mammals evolved in the Southern hemisphere, challenging the prevailing notion that it came from the north.
"Smack in the middle of the dinosaurs' heyday, our ancestors were living as well -- it's just that they were small and inconspicuous," said Andre R. Wyss, associate professor of geology at the University of California, Santa Barbara, and one of the authors of the article.
The National Geographic Society funded the research, a collaboration that included John J. Flynn and William F. Simpson, of the department of geology, the Field Museum of Natural History in Chicago; J. Michael Parrish of the department of biology, Northern Illinois University, DeKalb; Berthe Rakotosamimanana of the department of Paleontology, University d'Antananarivo, Madagascar; and, Andre R. Wyss, of the department of geology, UC, Santa Barbara.
"The most conspicuous and hence the most famous land animals of the
Mesozoic Era were of course the dinosaurs," explained Wyss. "Less widely
appreciated is the fact that furry animals -- mammals -- and dinosaurs sprang on
an evolutionary scene at about the same time; the t
Contact: Bill Schlotter
University of California - Santa Barbara