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. However, molecular data suggests that therians may have originated even earlier, during the Early Jurassic.