Photograph courtesy D. Scott
An egg clutch recovered from the South African site in 1976 (pictured) had two exposed skeletons, including the embryo in the first picture of this gallery, which wasn't formally studied until 2005. These embryos have since given scientists valuable insights into dinosaur evolution.
For example, the Massospondylus embryo resembles "a dwarf version of a sauropod dinosaur," the largest animals to walk the Earth, Hans-Dieter Sues, a paleontologist at the National Museum of Natural History in Washington, D.C., said in 2010.
This means that Massospondylus had characteristics that "foreshadowed" the look of sauropods, which evolved later, he said.
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