What is Eomaia?
Q: What is Eomaia?
A: Eomaia is an early fossil eutherian mammal that was discovered in rocks of the Yixian Formation, Liaoning Province, China. It dates back to the Lower Cretaceous period about 125 million years ago.
Q: How big and heavy was Eomaia?
A: The fossil of Eomaia is 10 centimetres (3.9 in) in length and weighed between 20–25 grams (0.71–0.88 oz).
Q: What distinguishes the Eutheria from metatherians?
A: The distinguishing features between the Eutheria and metatherians are various features of their feet, jaws and teeth.
Q: What features does Eomaia have that are not found in placental mammals?
A: Features that are unique to Eomaia which are not found in placental mammals include variations in the shin and ankles, an ancestral eutherian dental formula, a wide opening at the bottom of the pelvis which allows for larger offspring to pass through, as well as epipubic bones extending forwards from the pelvis which stiffen its body during locomotion.
Q: Does it have clear evidence of hair?
A: Yes, traces of fur can be seen on its fossilized remains.
Q: Is this earliest clear evidence of hair in mammalian lineage?
A: No, fossils of Castorocauda which date back to 164 mya also have traces of fur so it is not considered to be earliest clear evidence of hair in mammalian lineage.
