Fossilized remains estimated to be 225 million years old have been identified as a new species, also recognized as the oldest mammal species ever discovered in the world.
With this age, the newly named species Brasilodon quadrangularis coexisted with the first dinosaurs that roamed the Earth.
According to CNN, the fossil remains of Brasilodon quadrangularis are 20 million years older than the previously known ancient mammal species that held the record. This discovery has been praised by researchers as “extremely significant.”
Portrait of the oldest mammal ever discovered – (Photo: Journal of Anatomy)
The ancestor at the top of the genetic tree of the mammal lineage we belong to resembled a shrew, measuring about 20 cm in length, and is considered to “illuminate the evolution of modern mammals.”
This discovery was made by researchers from the Natural History Museum in London, King’s College London, and the Federal University of Rio Grande do Sul in Porto Alegre, Brazil.
While mammary glands cannot be preserved as fossils, the well-preserved hard tissues such as bones and teeth of the remains have enabled scientists to identify the species. It belongs to a group of animals that emerged after the Permian-Triassic extinction event, the largest mass extinction in Earth’s history, which wiped out 90% of marine life and 70% of terrestrial animals.
However, this mass extinction also gave rise to a completely new group of organisms, including dinosaurs and mammals. Brasilodon quadrangularis appeared 25 million years after this catastrophic event.
Brasilodon quadrangularis is also the oldest vertebrate with two sets of teeth that grow in succession—milk teeth and permanent teeth—similar to how humans develop teeth today.
The research has just been published in the scientific journal Journal of Anatomy.
