The discovery of more than 250 fossilized eggs reveals intimate details about the lives of тιтanosaurs in the Indian subcontinent, according to a study published in the journal PLOS ONE by Harsha Dhiman of the University of Delhi, New Delhi, and colleagues.

An artist’s rendering of what a тιтanosaur may have looked like. Credit: Lameta formation, CC BY-NC-SA 3.0

The Lameta Formation in central India is well-known for its fossils of dinosaur skeletons and eggs of the Late Cretaceous Period.  Recent work in the area uncovered 92 nesting sites containing a total of 256 fossil eggs belonging to тιтanosaurs, which were among the largest dinosaurs ever to live. Dhiman and colleagues were able to make inferences about these dinosaurs’ life habits after thoroughly examining these nests.

The authors identified six different egg species (oospecies), suggesting a greater diversity of тιтanosaurs than is represented by skeletal remains from this region. The team inferred from the layout of the nests that these dinosaurs buried their eggs in shallow pits like modern-day crocodiles.

(A) Completely unhatched egg from the clutch P43. (B) Almost fully intact circular outline of egg possibly indicating it to be unhatched and no loose eggshells are found in the clutch P6. (C) Compressed egg from clutch DR10 showing hatching window (arrow showing gap) and few eggshells collected just around the hatching window (circled) which possibly represent the remnants of hatching window. (D) Egg from clutch P26 showing curved outline. (E) Deformed egg from clutch P30 showing egg surfaces slipping past each other. Credit: Dhiman et al., 2023, PLOS ONE

Certain pathologies found in the eggs, such as a rare case of an “egg-in-egg,” suggest that тιтanosaur sauropods had a reproductive physiology similar to that of birds and possibly laid their eggs sequentially, as seen in modern birds. The presence of multiple nests in the same area suggests that these dinosaurs exhibited colonial nesting behavior like many modern birds. However, the close spacing of the nests left little room for adult dinosaurs, supporting the idea that adults left the hatchlings (newborns) to fend for themselves.

A block diagram showing the interpreted depositional environment of the Lameta Formation in the study areas. Credit: Dhiman et al., 2023, PLOS ONE

Details of dinosaur reproductive habits can be difficult to determine. These fossil nests contain a wealth of information about some of the largest dinosaurs in history, and they come from just before the dinosaur extinction. The findings of this study add significantly to paleontologists’ understanding of how dinosaurs lived and evolved.

“Our research has revealed the presence of an extensive hatchery of тιтanosaur sauropod dinosaurs in the study area and offers new insights into the conditions of nest preservation and reproductive strategies of тιтanosaur sauropod dinosaurs just before they went extinct,” says lead author Harsha Dhiman.

“Together with dinosaur nests from Jabalpur in the upper Narmada valley in the east and those from Balasinor in the west, the new nesting sites from Dhar District in Madhya Pradesh (Central India), covering an east-west stretch of about 1000 km, consтιтute one of the world’s largest dinosaur hatcheries,” says Guntupalli V.R. Prasad, co-author and leader of the research team.

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More information: Harsha Dhiman et al,. (2023). New Late Cretaceous тιтanosaur sauropod dinosaur egg clutches from lower Narmada valley, India: Palaeobiology and taphonomy, PLoS ONE. DOI: 10.1371/journal.pone.0278242