Fossilized eggshells presumed to be from some of the largest dinosaurs ever discovered have been unearthed in a surprisingly cool climate, distant from the equator. Despite their tremendous size, these titanosaurs could not warm their volleyball-sized eggs by brooding over them due to their massive stature. A recent study conducted by paleontologist Darla Zelenitsky from the University of Calgary, in collaboration with researchers from Japan and Argentina, has delved into how these titanosaurs managed to keep their eggs warm enough for successful hatching without direct nest incubation.
Through a microscopic examination of the eggshells’ pores, the researchers propose that titanosaurs likely utilized a similar incubation technique to modern crocodiles by burying their eggs in warm mounds of decaying vegetation. This study, led by University of Tsukuba paleontologist Kohei Tanaka, a former student of Zelenitsky, was published in the Royal Society Open Science journal.
Belonging to a group of colossal, herbivorous dinosaurs known as titanosaurs, these long-necked, long-tailed creatures moved on four legs and weighed up to 75 tonnes, approximately half the mass of a blue whale. Fossilized volleyball-sized eggs associated with titanosaurs, named Fusioolithus, were previously discovered in warmer regions but were later found in the Chorrillo Formation in southern Argentina, dating back to the Late Cretaceous period, 72 to 66 million years ago.
The Chorrillo Formation, once situated at a latitude akin to Red Deer, Alta., experienced a climate resembling that of present-day New York City. This region housed various dinosaurs, including the gigantic titanosaur Nullotitan glaciaris and the smaller herbivore Isasicursor santacrucensis, alongside megaraptors, small birds, crocodiles, and other diverse fauna.
Zelenitsky expressed surprise at the titanosaurs’ egg findings in such a distant location from the equator, emphasizing the challenges faced by larger animals in terms of survival and reproduction. The study sheds light on the innovative incubation methods employed by dinosaurs, showcasing their adaptability in different environments.
The researchers determined that titanosaurs likely buried their eggs based on the porous nature of the eggshells, allowing sufficient oxygen exchange for proper incubation. This discovery underscores the remarkable abilities of dinosaurs to thrive and reproduce in various climates and habitats. Further research on titanosaurs’ nesting behaviors may provide valuable insights into their evolutionary success during the Late Cretaceous period.
