Fossil eggshells from some of the largest dinosaurs ever discovered have been unearthed in a surprisingly cooler region far from the equator. Despite their immense size, these titanosaurs did not incubate their volleyball-sized eggs by sitting on them due to their large stature, as explained by University of Calgary paleontologist Darla Zelenitsky.
A recent study, led by Zelenitsky and an international team, delved into the microscopic details of the eggshells to uncover how titanosaurs maintained the necessary warmth for successful hatching without direct brooding. The research, published in Royal Society Open Science by University of Tsukuba paleontologist Kohei Tanaka and team, suggests that titanosaurs likely employed a similar incubation method as modern crocodiles—burying their eggs in warm heaps of decaying vegetation.
Titanosaurs, colossal herbivorous dinosaurs weighing up to 75 tonnes and resembling long-necked giants, roamed on four legs during the Late Cretaceous period. These creatures, a fraction of the mass of a blue whale, have been linked to volleyball-sized fossil eggs known as Fusioolithus, previously discovered in warmer environments.
Notably, fragments of Fusioolithus eggshells were recently found in the Chorrillo Formation in southern Argentina, dating back 72 to 66 million years. Despite the shifting landscape, the site’s historical climate, similar to present-day New York City, hosted diverse dinosaur species like Nullotitan glaciaris and Isasicursor santacrucensis, along with various other fauna.
To sustain the incubation process for months and aid embryo development, dinosaurs needed to maintain egg warmth. While smaller dinosaurs brooded their eggs like birds, titanosaurs resorted to alternative methods due to their immense size. The study of the Chorrillo Formation eggshells revealed their burial practice, as indicated by the porous nature of the shells necessary for oxygen exchange during incubation.
The adaptability of dinosaurs, even the largest among them, is exemplified by their nesting strategies in different environments. The research underscores the remarkable ability of titanosaurs to thrive in various latitudes, showcasing their evolutionary success. Further studies on titanosaur nesting behaviors across different time periods could unveil additional insights into their global spread during the Late Cretaceous era.