Wednesday, March 13, 2013

[Paleontology / Ootaxa • 2013] Dinosaur eggs in the Upper Cretaceous of the Coll de Nargó area, Lleida Province, south-central Pyrenees, Spain | Oodiversity, biostratigraphy and their implications / Four dinosaur egg species identified in Lleida; Megaloolithus & Cairanoolithus

artist's impression of the egg laying of an Ampelosaurus.
Art: J.A. Penas - SINC.

The Coll de Nargó area (Lleida Province, south-central Pyrenees) has yielded thousands of dinosaur eggs distributed in more than 30 levels across 370 m of Upper Cretaceous Tremp Formation deposits. Two stratigraphic units yielding dinosaur eggshells, eggs and clutches, can be distinguished. Multiple eggshells were collected from up to 75 different in situ clutches, located in consecutive stratigraphical levels throughout the Mas de Pinyes section. Four different oospecies have been recognized: Megaloolithus aureliensis, Megaloolithus siruguei, Megaloolithus cf. baghensis and Cairanoolithus cf. roussetensis. In absence of typical biochronological markers, fossil eggshells may have potential as a tool for dating. Based on these ootaxa, three oozones can be established along the stratigraphic section. The lower assemblage is composed by M. aureliensis, M. siruguei and Cairanoolithus cf. roussetensis; the middle one consists only of M. siruguei, while the upper oozone is characterized by M. cf. baghensis. Results suggest that the age of Coll de Nargó rocks ranges from the latest Campanian to the beginning of the Late Maastrichtian. Also reported is the first evidence of the oogenus Cairanoolithus outside of France, where it was regarded as an endemic ootaxon. The Coll de Nargó area is considered to be one of the most important dinosaur nesting areas in Europe recurrently used by several dinosaurs during a long time span. Finally, the presence of fossilized eggshell membrane in several specimens from Coll de Nargó contributes to understanding the taphonomic process of megaloolithid eggs in this area.

Keywords: Dinosaur eggs; Nesting site; Megaloolithus; Upper Cretaceous; Coll de Nargó, Spain

Four dinosaur egg species identified in Lleida 
A study headed by the Miquel Crusafont Catalan Palaeontology Institute has for the first time documented detailed records of dinosaur egg fossils in the Coll de Nargó archaeological site in Lleida, Spain. Up until now, only one type of dinosaur egg had been documented in the region. 

Albert G. Sellés, Ana María Bravo, Xavier Delclòs, Ferran Colombo, Xavier Martí c, Jaume Ortega-Blanco, Carme Parellada, Àngel Galobart. 2013. Dinosaur eggs in the Upper Cretaceous of the Coll de Nargó area, Lleida Province, south-central Pyrenees, Spain: Oodiversity, biostratigraphy and their implications. Cretaceous Research. 40: 10 -20.