china dinosaur egg

Paleontologists earlier believed this long-snouted species was more intellectually mature than other prehistoric flyers, but the conclusions, published Thursday in Science, suggest pterosaur newborns were underdeveloped at birth and needed more parental care than previously thought. This class existed during the Lower Cretaceous geological period, so sometime between 145 million years ago and 100 million years ago.

The latest invention in northwestern China of hundreds of fossilised pterosaur eggs is giving a fresh knowledge of the flying reptiles that lived alongside the dinosaurs, including a sign that their babies were born flightless and needed parental care. A treasure trove of old 215 eggs reveals how winged reptiles called pterosaurs evolved in infanthood and how their parents took care of these newborn children.

Such a huge collection of old eggs is a rare find. In recent years, palaeontologists discovered five eggs from China and one egg from Argentina. Typically, a “clutch size” the number of eggs laid together comes in twos. So why did they find 215 eggs in one place?

Illustration of a Pterosaur and Pterosaur eggs by Zhao Chuang
Illustration of a Pterosaur and Pterosaur eggs by Zhao Chuang

The researchers consider a tornado might have hit a large group of pterosaur nests hidden in mud and washed them into a lake. This is likely why the investigators found the eggs in sandstone sediments. But even without this storm, it appears pterosaurs were living in large numbers in this area.

The eggs, though they remained this long, are weak. To look inside without inducing damage, the team used CT scans and found 16 of the eggs still had remains of their fetuses. Each embryo varied in its stage of growth, but all the eggs had well-developed thigh bones and underdeveloped pectoral muscles. One fetus, which the team named as the most mature, had partly developed wings and skull bones, as well as a whole lower jaw.

Before this wealth of pterosaur samples, palaeontologists questioned how these prehistoric creatures combined. So viewing, for the first time, a large colony of nests sparks some exciting ideas. Could raise their young together mean pterosaurs were social and nurtured approaching one another? The team wishes to use these eggs, and any others they uncover, to learn even more insight into pterosaur parenting and communal life.

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