It’s small, furry, and—125 million years ago—made its home in bushes and shrubs. And it wouldn’t be too far off to call it “grandma.” A team of Chinese and American scientists recently discovered Eomaia scansoria “the most primitive ancestor of all placental mammals” in China’s fossil-rich Liaoning Province. Its name comes from the Greek words for dawn (eo), mother (maia), and climbing (scansoria).
Unlike earlier non-placental mammals, the bones of this animal show that it was adapted for life in bushes and shrubs. Its age extends the record of placental mammals by 40 to 50 million years further into the past. Neither the fossil record nor molecular data had predicted such an early appearance for this group.
Three groups of mammals live today and are distinguished by how—among other things—they bear their young. Monotremes, represented by the platypus and echidna, lay eggs. Marsupials, which include the kangaroo and opossum, carry their newborn in pouches. The third group, placental mammals, nourish their young before birth within their bodies through the placenta. Diverse members of this group include whales, deer, bats, pigs, apes, and humans.
The five-inch-long (14-centimeter-long) skeleton is in an astonishing state of preservation, with a remarkable “fur halo” surrounding the bones. It was originally examined by Qiang Ji of the Chinese Academy of Geological Sciences and then studied further by Zhe-Xi Luo and John R. Wible at the Carnegie Museum of Natural History in Pittsburgh. Research was funded by the National Geographic Society together with the National Science Foundation, the Carnegie Museum of Natural History, the National Natural Science Foundation of China, and the Ministry of Land Resources of China.
Related Web links
National Geographic
news.nationalgeographic.com/news/2002/04/0423_020425_firstmammal.html
Visit NG News for more about “the earliest ancestor.”
Carnegie Museum of Natural History
www.carnegiemuseums.org/cmnh/news/02-mar-apr/042502eomaia.html
Read the official press release.
www.carnegiemuseums.org/cmnh/vp/luo.html
Visit Zhe-Zi Luo’s professional website.
