Fossil redefines mammal history

The shrew-like creature is the earliest known example of an animal that used a placenta to provide nourishment to their unborn young.

Its features clearly set it apart from marsupial mammals, which adopt a very different reproductive strategy. The discovery pushes back the date the two groups took up their separate lines, according to Nature magazine. The journal carries a paper written by a team of palaeontologists led by Zhe-Xi Luo from the Carnegie Museum of Natural History, Pittsburgh, US.