Fossilized eggs of the largest known dinosaurs have been unearthed in an unexpected place

Key Points:

• Titanosaurs, the largest dinosaurs, nested at high latitudes in southern Argentina around 68 million years ago, marking the highest-latitude nesting environment known for sauropods and the southernmost definitive evidence of dinosaur eggs.
• Unlike many dinosaurs and birds, titanosaurs likely did not brood their eggs; instead, they incubated eggs in mound nests made of vegetation and soil, where heat from decomposing plant material kept the eggs warm in cooler climates.
• The eggshells were highly porous, requiring burial in damp nests to prevent drying out and embryo death, illustrating an adaptive reproductive strategy for survival in colder, less sunny environments far from the equator.
• The discovery suggests titanosaurs may have stayed year-round or at least completed their reproductive cycle at high latitudes, challenging previous beliefs that they only migrated seasonally to these regions.
• Despite their massive adult size, titanosaur eggs were relatively tiny, and nesting sites could have been large, communal mounds, leaving noticeable impressions on the landscape and indicating complex reproductive behavior.