Preterm birth
James Elgin Gill (born on 20 May 1987 in Ottawa, Ontario, Canada) was the earliest premature baby in the world, until that record was broken in 2014. He was 128 days premature (21 weeks and 5 days' gestation) and weighed . He survived.
Birth
A more developed form of viviparity called placental viviparity is adopted by some species of scorpions and cockroaches, certain genera of sharks, snakes and velvet worms. In these, the developing embryo is nourished by some form of placental structure. The earliest known placenta was found recently in a group of extinct fishes called placoderms, which are ancestral to mammals. A fossil from Australia's Gogo Formation, laid down in the Devonian period, 380 million years ago, was found with an embryo inside it connected by an umbilical cord to a yolk sac. The find confirmed the hypothesis that a sub-group of placoderms, called ptyctodontids, fertilized their eggs internally. Some fishes that fertilize their eggs internally also give birth to live young, as seen here. This discovery moved our knowledge of live birth back 200 million years. The fossil of another genus was found with three embryos in the same position. Placoderms are a sister group of the ancestor of all living jawed fishes (Gnathostomata), including both chondrichthyians, the sharks & rays, and Osteichthyes, the bony fishes.