The discovery of the oldest dinosaur embryos Massospondylus ever found is enabling scientists to piece together the lifetime growth of a type of long-necked giant that lived about 190 million years ago.
The embryo Massospondylus died as it had lived, curled up inside its 6cm egg, in sediments baked by the sunshine of South Africa.
The egg was discovered 25 years ago - but only now has the little hatchling emerged, unblinking, before the world's gaze.
The embryo had four legs, a short tail, and a huge head, researchers report Friday in Science. It had no teeth. The unborn baby is yet more evidence that at least some dinosaurs must have been caring parents.
Robert Reisz, of the University of Toronto, Mississauga, was quoted as saying by Guardian: "These embryos had overall awkward body proportions and no mechanism for feeding themselves. If this interpretation is correct, we have the oldest known indication of parental care."
James Clark, a biology professor at George Washington University in Washington who was not part of the research group, was quoted as saying by AP: "The importance of the discovery is that they are from a primitive member of the sauropodomorphs, a large group that includes the biggest land animals that ever lived."