When Did Animals Start Giving Birth to Live Young? This 236-Million-Year-Old Fossil Might Rewrite Mammals' Evolutionary History
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5 Articles
When Did Animals Start Giving Birth to Live Young? This 236-Million-Year-Old Fossil Might Rewrite Mammals' Evolutionary History
A bone feature found in a mammal ancestor hints that the creature was relatively large as a newborn, more in line with the size of a creature birthed live than hatched from an egg. Still, it provides only indirect evidence
Scientists found a mysterious mark inside a 236-million-year-old fossil in Argentina that may reveal ancient mammal relatives gave birth instead of laying eggs
Science News: A 236-million-year-old fossil from Argentina may have provided the earliest evidence yet that an animal on the evolutionary lineage leading to mammals.
A new study provides the first fossil evidence that mammal-like reptiles, or cynodonts, gave birth to live offspring. Analysis of the bone tissue of Chiniquodon theotonicus, which lived nearly 236 million years ago, shows that the animal's cub-to-adult body mass ratio was similar to that of modern mammals, pushing back the evolutionary onset of birth by up to 95 million years.
The discovery of paleontologists in Argentina, announced on August 13, 2026, revealed new information about the evolution of mammals. When examining a cynodont fossil of 236 million years old, the team found the oldest recorded evidence of viviparity — the birth of live cubs — in the ancestral lineage that gave [...]
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