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.
By Bob Strauss. Ask the average person (or high schooler) on the street, and heâll guess that the first mammals didn't appear on the scene until after the dinosaurs went extinct 65 million years ago--and that the last dinosaurs evolved into the first mammals.ozostrodon This Triassic critter may (or may not) have been the first true mammal. Fruitafossor The earliest digging mammal yet discovered. Hadrocodium This tiny mammal had an unusually large brain. Juramaia The earliest known placental mammal in the fossil record.