Image copyright Dinghua Yang Image caption Dinocephalosaurus was adapted for a fully aquatic lifestyle Scientists have uncovered the first evidence of live births in the group of animals that includes dinosaurs, crocodiles and birds. All examples of this group, known as the Archosauromorpha, lay eggs. This led some scientists to wonder whether there was something in their biology that prevented live births. But examination of the fossil remains of a very long-necked, 245 million-year-old marine reptile from China revealed it was carrying an embryo. Jun Liu, first author of the new study, told BBC News that the animal would have measured between three and four metres long, with a neck that was about 1.7m long. The embryo may have been around half a metre long and is positioned inside the rib cage of the adult Dinocephalosaurus fossil, which was discovered in 2008. Researchers had to consider whether the smaller animal might have been part of the adult’s last meal. But it’s facing forward, whereas swallowed prey generally face backwards because predators usually consume the animal head first to help it go down its throat. Another line of evidence in favour of the live birth idea is that the small reptile inside the mother is clearly an example of the same species. Prof Liu, from Hefei University of Technology in China, said the discovery pushes back evidence of reproductive biology in the archosauromorphs by 50 million years. The mode of reproduction in Dinocephalosaurus also points to how the sex of its…more detail
