US EditionFirst-Ever Egg from a Mammal Ancestor Found in 250M-Year-Old Fossil
High-resolution scans show the embryo died before hatching, giving researchers the first confirmed evidence that mammal ancestors laid eggs.
- Researchers published findings in PLOS ONE confirming the first identified therapsid egg, belonging to the ancient species Lystrosaurus and providing direct evidence that mammal ancestors laid eggs.
- Paleontologists discovered the specimen in South Africa's Karoo Basin almost 17 years ago, but imaging technology available in 2008 could not confirm the embryo's presence until modern synchrotron X-ray scans resolved the fossil's identity.
- University of Witwatersrand paleobiologist Julien Benoit noted that high-resolution scans revealed an incomplete mandibular symphysis, proving the embryo died before hatching because the jaw halves had not yet fused.
- Evidence suggests Lystrosaurus laid relatively large, soft-shelled eggs rich in yolk, supporting full development without parental feeding and helping the species survive the harsh climate following the End-Permian Mass Extinction about 252 million years ago.
- Benoit said the discovery is "not just a breakthrough in paleontology," as the work offers a deep-time perspective on resilience, helping researchers understand how species respond to extreme environmental change.
23 Articles
23 Articles
250-Million-Year-Old Fossil Confirms That Mammal Ancestors Laid Eggs, Solving a Long-Standing Mystery
A 250-million-year-old fossil has just answered one of evolution’s biggest mysteries. Long before modern mammals evolved, their distant ancestors were already reproducing in a radically different way, and scientists now have the first direct proof. Published in PLOS ONE, the discovery reveals that…
Palaeontology breakthrough: 'Thrilled' scientists discover eggs laid by humans' distant ancestors
Scientists have confirmed for the first time that the ancestors of mammals reproduced by laying eggs, following the discovery of a 250-million-year-old fossilised embryo in South Africa.Therapsids, which existed roughly 250 million years ago, are considered the closest ancient relatives of modern mammals, earning them the description "mammalian ancestors". For over 150 years of South African palaeontology, no fossil had ever been conclusively id…
The Independent
The Independent (US)250-million-year-old fossil egg reveals survival secrets of ancient mammal ancestors
The plant-eating creature is famous for living through the ‘Great Dying’
The strategists who have lived for 250 million years have been mutilated by eggs or giving birth to babies? Analyzing an embryo of Lystrosaurus finally answers this question, writes the AFP agency named Agerpres. It is a mystery that concerns paleontologists for many decades: it is believed...
Africa: Embryo Fossil Found in South Africa Is World's Oldest Proof That Mammal Ancestors Laid Eggs
Analysis - Between 280 and 200 million years ago, a group of animals evolved which would eventually give rise to mammals, including humans: the therapsids. They were first described more than 150 years ago, based on fossils from South Africa. Since then, many more fossils have been discovered.
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