Juramaia sinensis: Great Grandmother of all placental mammals

November 4, 2011

Juramaia is an extinct genus of a eutherian mammal from late Middle Jurassic deposits of western Liaoning, China.
Its well-preserved fossil, unearthed in the fossil-rich region of Liaoning Province, is believed to be the oldest ever found of a group of eutherians, or placental animals that give birth to live offspring.
Recently, a statement of Zhe-Xi Luo of the Carnegie Museum of Natural History in Pittsburgh was published in Daily Mail in which it was said that Juramaia, from 160 million years ago, is either a ‘greatgrand-aunt’, or a ‘great-grandmother’ of all placental mammals that are thriving today.
The researchers say that this fossil represents a new milestone in mammal evolution that was reached 35 million years earlier than previously thought, thus filling an important gap in the record of Mammalian Evolution.