The sharpest look yet at the oldest known dinosaur embryos (pictured, one of the eggs and its inhabitant) has revealed some "big surprises," a scientist says.
For one thing, the 190-million-year-old babies of Massospondylus—a two-legged dinosaur that preceded the well-known sauropods, such as Diplodocus—do not resemble their parents, according to study co-author Hans-Dieter Sues, a paleontologist at the National Museum of Natural History in Washington, D.C. (See more dinosaur-embryo pictures.)
The 8-inch-long (20-centimeter-long) youngster, for example, had long front legs for walking on all fours, and its overall body proportion—such as a short snout—made it "look like a dwarf version of a sauropod dinosaur," the largest animals to walk Earth. (See a sauropod picture.) The babies would have lost these traits as they matured.
Photograph courtesy Diane Scott, University of Toronto
The Massospondylus babies were ready to hatch (pictured, in an artist's reconstruction) when an early Jurassic flood likely entombed them in sediment, Sues noted.
High-powered microscopes allowed scientists to finally prepare and examine the "beautifully preserved" embryos, which were found near South Africa's border with Lesotho in 1976 and have since been stored in collections, he added.