November 12, 2010

Ancient Embryos Reveal Much About Dino Development

Attempts to identify the oldest known dinosaur embryos have resulted in some stunning new discoveries about the early development of the ancient creatures, according to a new study published this week in the Journal of Vertebrate Paleontology.

The dinosaur eggs in question, which were discovered in Cape Town, South African back in 1976, came from the species Massospondylus, a predecessor of plant-eating sauropods such as the Brontosaurus, according to BBC News Science Reporter Katia Moskvitch.

The embryos contained within their shells are not only older than any other dinosaur embryo yet discovered, but they also are the oldest known of any land dwelling animal to date, according to Canadian researcher Robert Reisz and colleagues.

Reisz, a professor with the University of Toronto Mississauga, told Moskvitch that the project "opens an exciting window into the early history and evolution of dinosaurs"¦ Prosauropods are the first dinosaurs to diversify extensively, and they quickly became the most widely spread group, so their biology is particularly interesting as they represent in many ways the dawn of the age of dinosaurs."

According to a Wednesday report from CBC News, the researchers noted that the embryos "are unusually well-preserved, allowing for a complete reconstruction of the skeleton and detailed interpretations of their anatomy."

"They show that infancy for the Massospondylus was an awkward period, during which the young were oddly proportioned compared to adults, as is the case among human infants, which have disproportionately large heads. And just like us, Massospondylus babies started out on all fours, until they were able to walk on two legs," CBC News added.

Thus, Reisz and his colleague say that the baby dinosaurs, which were approximately 20 centimeters long and likely would have hatched before much longer, would likely have needed parental care as infants. As they matured, their necks and hind limbs would have grown at a much faster pace than their head and forelimbs, resulting in a vastly different looking adult.


Image Caption: An artist's reconstruction shows a curled-up dinosaur embryo inside an egg. Credit: Kevin Dupuis, UTM 


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