Jurassic Mammal Fossil Hints At Earlier Split Between Placental Mammals and Marsupials
Jurassic Shrew Juramia sinensis, a shrew-like mammal, is the earliest placental mammal found to date. Mark A. Klingler/Carnegie Museum of Natural HistoryOur ancestors evolved from "Jurassic Mother" This pointy-nosed shrew, a new fossil find from China, may be the earliest grandmother of all placental mammals, scientists report in a new study. Or perhaps she is the oldest great-aunt. Either way, it's another big find this week in paleontology. The new shrew, Juramia sinensis, is the earliest known example of a placental mammal, which (unlike egg-laying monotremes and pouch-carrying marsupials) gives live birth. All placental mammals - from you to dolphins to bats - diverged from an animal like this one. Its discovery pushes back the marsupial-placental mammal evolutionary divergence by about 35 million years, to 160 million years ago, according to researchers in China and the U.S. This corresponds with DNA research that predicted an earlier divergence than the oldest previously known...