Shell Of A Find: Scientists Find Massive Haul Of 80-Million-Year-Old Titanosaur Eggs

Selected titanosaurian eggs and egg-clutches collected from the Late Cretaceous Serra da Galga Formation (Bauru Group) at Ponto Alta nesting site, Uberaba Municipality, Minas Gerais State, Brazil. (Dr. Agustin G. Martinelli/Zenger)

By Joseph Golder

Scientists found about 20 large 80-million-year-old dinosaur eggs when they unearthed a titanosaur nesting site in Brazil.

The dinosaur egg nest, which dates back to the Cretaceous period, approximately 145 to 66 million years ago, was discovered in an abandoned limestone mine in the rural area of Ponte Alta, in the southeastern Brazilian state of Minas Gerais.

Joao Ismael da Silva, a paleontology technician at the Federal University of Triangular Mineiro Ivor Price Paleontological Research Center, made the discovery in the 1990s, but the results of the analysis of the fossilized eggs have just been published.

Researcher Joao Ismael da Silva, from the Cultural Foundation of Uberaba in Brazil, made the discovery of the dinosaur eggs in the 1990s. But the results of the analysis of the fossilized eggs have only recently been published. (Dr. Agustin G. Martinelli/Zenger)

“In the 1990s, I became aware of the occurrence of dinosaur eggs in Ponte Alta. In conversation with friends of mine who worked in limestone mining, I was able to recover some isolated eggs and, finally, an association of ten spherical eggs.,” Da Silva said in a statement.

A study on the discovery, published in the journal Scientific Reports, was authored by da Silva, his UFTM colleagues Luiz Carlos Borges Ribeiro and Thiago Marinho, and Argentine researchers Lucas Fiorelli and Agustin Martinelli, from the Regional Center for Scientific Research in La Rioja and the Argentine Museum of Natural Sciences.

“From the associations of shells and eggs, and the macro and microscopic characteristics, it was possible to compare them with nests and fossil eggs from other parts of the world, mainly from the important sites already known in Argentina,” the UFTM statement said.

CT scans of the best-preserved egg-clutch (CPPLIP 1798). (a) 3D rendering of the bottom of the clutch in CPPLIP 1798. (b) General view of the clutch at the same orientation, showing the external part of the lower hemisphere of the eggs. (c) Top view of the lower egg row, showing the inner part of the lower hemisphere of the eggs. (d) Lateral view of CPPLIP 1798, showing lower egg row with higher shells at both ends and part of the upper egg row. In dark orange, eggshell fragments within the eggs. Note that the incompleteness (“holes”) of some eggs in B and C are due to the lack of the eggshells and/or poor resolution of the CT scan. In A the shape of each egg is maintained due to the sedimentary internal mold. Scale bar 10 cm. (Dr Agustin G. Martinelli/Zenger)

“Titanosaurs were the largest land animals of all time” Marinho said. “The titanosaurs from Uberaba reached up to 25 m [82 feet] in length, which is very striking and contrasts with the size of their eggs (about 12 cm [4.75 inches] in diameter).”

“The titanosaurs,” he said “would have been colonial and generalist in their reproductive aspects, nesting in a herd in a huge area, building massive nests with dozens of eggs, and possibly they would have had philopatric behaviors, something similar to sea turtles that periodically return to nest at the same sites.”

Model of events of titanosaur egg laying in two levels (L1 and L2), preservation and subsequent sedimentation in the Ponte Alta nesting site. (a) First level of eggs. (b) Repeated selection of the laying area (by philopatry or breeding-site fidelity), excavation, and laying the eggs. (c) Covered eggs and a new deposition. (Dr. Agustin G. Martinelli/Zenger)

The dinosaurs would bury approximately 10 eggs at a time, in what is known as a brood, in order for the temperature to remain controlled until the babies hatched, not unlike many reptiles today.

“This publication reinforces the importance of the municipality of Uberaba in the field of paleontology, especially dinosaurs, and strengthens the relevance of the Uberaba Geopark Project with UNESCO, [the United Nations cultural agency] since this plurality of discoveries most relevant international geological heritage present in the municipality,” Borges Ribeiro said.

Remains belonging to titanosaurs have been found all over the world. They were a diverse group of dinosaurs and the last of the long-necked sauropods, believed to have been wiped out in the extinction-level at the end of the Cretaceous period.

Edited by Richard Pretorius and Kristen Butler