Theria (/ˈθɪəriə/; Greek: θηρίον, wild beast) is a subclass of mammals that give birth to live young without using a shelled egg, consisting of the eutherians (including the placental mammals) and the metatherians (including the marsupials). The only omitted extant mammal group is the egg-laying monotremes.The earliest known therian mammal fossil is Juramaia, from the Middle Jurassic of China.