Utah State University Eastern provides life-changing experiences for students in all stages of life. Let USU Eastern transform your life for good.
Maintained by pioweb@ucsc.edu. The common ancestor of placental mammals probably looked like Eomaia scansoria, the earliest known placental mammal, shown here in an artist's reconstruction based on a 125-million-year-old fossil skeleton found in China in 2002.aintained by pioweb@ucsc.edu. The common ancestor of placental mammals probably looked like Eomaia scansoria, the earliest known placental mammal, shown here in an artist's reconstruction based on a 125-million-year-old fossil skeleton found in China in 2002.
We found the earliest ancestor, perhaps a great uncle or aunt, or perhaps a great grandparentalbeit 125 million years removedto all placental mammals,  said Zhe-Xi Luo, a paleontologist at the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania.t is an early, primitive representative of the lineage that eventually led to placental mammals,  said Weil. Properly, it is called a eutherian mammala mammal that is more closely related to living placentals than to living marsupials.. Fossil evidence dates the earliest mammals to 220 million years ago.