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Re: Massospondylus nest site found in South Africa



From: Ben Creisler
bcreisler@gmail.com


Here's the official abstract and link:


Robert R. Reisz, David C. Evans, Eric M. Roberts, Hans-Dieter Sues,
and Adam M. Yates (2012)
Oldest known dinosaurian nesting site and reproductive biology of the
Early Jurassic sauropodomorph Massospondylus.
Proceedings of the National Academy of Sciences (advance online publication)
doi: 10.1073/pnas.1109385109
http://www.pnas.org/content/early/2012/01/23/1109385109.abstract?sid=f96b012d-8091-4324-b12d-0e9d333882be



Abstract

The extensive Early Jurassic continental strata of southern Africa
have yielded an exceptional record of dinosaurs that includes scores
of partial to complete skeletons of the sauropodomorph Massospondylus,
ranging from embryos to large adults. In 1976 an incomplete egg clutch
including in ovo embryos of this dinosaur, the oldest known example in
the fossil record, was collected from a road-cut talus, but its exact
provenance was uncertain. An excavation program at the site started in
2006 has yielded multiple in situ egg clutches, documenting the oldest
known dinosaurian nesting site, predating other similar sites by more
than 100 million years. The presence of numerous clutches of eggs,
some of which contain embryonic remains, in at least four distinct
horizons within a small area, provides the earliest known evidence of
complex reproductive behavior including site fidelity and colonial
nesting in a terrestrial vertebrate. Thus, fossil and sedimentological
evidence from this nesting site provides empirical data on
reproductive strategies in early dinosaurs. A temporally calibrated
optimization of dinosaurian reproductive biology not only demonstrates
the primary significance of the Massospondylus nesting site, but also
provides additional insights into the initial stages of the
evolutionary history of dinosaurs, including evidence that deposition
of eggs in a tightly organized single layer in a nest evolved
independently from brooding.


==========
A news story [WITH VIDEO] about a Massospondylus nest with eggs and embryos. The
article in the Proceedings of the National Academy of Sciences has not
been posted yet on the journal website so I can't provide the official
abstract.


http://www.cbc.ca/news/technology/story/2012/01/23/sci-dinosaur-nesting-site.html