WEDNESDAY, Jan. 25 (HealthDay News) -- Researchers who found the
earliest known dinosaur nesting site say it offers significant
clues about the evolution of complex reproductive behavior in
early dinosaurs. The 190-million-year-old site in South Africa
is 100 million years older than previously known nesting sites.
It contains clutches of eggs of the prosauropod dinosaur
Massospondylus, a relative of the giant, long-necked sauropods
of the Jurassic and Cretaceous periods. Many of the eggs contain
embryos. There are also tiny dinosaur footprints, which provide
the oldest known evidence that hatchlings remained at the
nesting site long enough to at least double in size. At least 10
nests, each with up to 34 round eggs in tightly clustered
clutches, have been found at several ground levels at the site.
The fact that there are nests at different levels in the
sediment indicates that the dinosaurs returned repeatedly to the
site and likely gathered in groups to lay their eggs. This is
the oldest known evidence of