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Sauropod Nesting Behaviour in PLoS ONE

I haven't seen this mentioned on the list before:

Bernat et all 2010 "3-D Modelling of Megaloolithid Clutches: Insights about 
Nest Construction and 
Dinosaur Behaviour" PLoS May 2010

Background: Megaloolithid eggs have long been associated with sauropod 
dinosaurs. Despite their 
extensive and worldwide fossil record, interpretations of egg size and shape, 
clutch morphology, 
and incubation strategy vary. The Pinyes locality in the Upper Cretaceous Tremp 
Formation in the 
southern Pyrenees, Catalonia provides new information for addressing these 
issues. Nine horizons 
containing Megaloolithus siruguei clutches are exposed near the village of Coll 
de Nargo. Tectonic 
deformation in the study area strongly influenced egg size and shape, which 
could potentially lead 
to misinterpretation of reproductive biology if 2D and 3D maps are not 
corrected for bed dip that 
results from tectonism.

Methodology/Findings: Detailed taphonomic study and three-dimensional modelling 
of fossil eggs 
show that intact M. siruguei clutches contained 20?28 eggs, which is 
substantially larger than 
commonly reported from Europe and India. Linear and grouped eggs occur in three 
levels and form an asymmetric, elongate, bowl-shaped profile in lateral view. 
tomography data support previous interpretations that the eggs hatched within 
the substrate.
Megaloolithid clutch sizes reported from other European and Indian localities 
are typically less than 
15 eggs; however, these clutches often include linear or grouped eggs that 
resemble those of the 
larger Pinyes clutches and may reflect preservation of incomplete clutches.

Conclusions/Significance: We propose that 25 eggs represent a typical 
megaloolithid clutch size 
and smaller egg clusters that display linear or grouped egg arrangements 
reported at Pinyes and 
other localities may represent eroded remnants of larger clutches. The 
similarity of megaloolithid 
clutch morphology from localities worldwide strongly suggests common 
reproductive behaviour. 
The distinct clutch geometry at Pinyes and other localities likely resulted 
from the asymmetrical,
inclined, and laterally compressed titanosaur pes unguals of the female, using 
the hind foot for 
scratch-digging during nest excavation.



Dann Pigdon
Spatial Data Analyst               Australian Dinosaurs
Melbourne, Australia               http://home.alphalink.com.au/~dannj