Researchers have made a new finding hailed as “extremely significant.” The discovery was made by studying fossil tooth records to identify the world’s oldest mammal. This discovery predates the previously reported earliest mammal by around 20 million years.
According to a team of Brazilian and British scientists, Brasilodon quadrangularis was a small shrew-like creature that walked the earth 225 million years ago at the same time as some of the oldest dinosaurs. It was approximately 20 centimeters (8 inches) long and shed light on the evolution of modern mammals.
According to a statement made by Martha Richter, a scientific associate at the museum and senior author of the article, the Brasilodon quadrangularis was formerly thought to be an “advanced reptile.” However, an examination of its teeth shows “definitively” that it was a mammal.
“If you consider reptiles, you’ll see that they have a wide variety of replacement teeth throughout their lifespan, in contrast to mammals with only two sets of teeth. The primary teeth come in first, followed by the secondary dentition, which ultimately takes the place of the primary teeth. This is what separates mammals from other animals, “Richter remarked.
According to the news release, Brasilodon is the oldest known extinct animal to have had two sets of teeth (one set of baby teeth and one set of permanent teeth), also known as a diphyodonty. The first set begins to develop while the embryo is still in the womb and the second set continues to grow after the baby is born.
Richter and her colleagues investigated three lower jaws of the species found in the region now the most southern part of Brazil. She explained that the team had found “the type of replacement teeth that are exclusively present in animals” while examining the specimen with a microscope.
Richter continued by saying, “this was a very, very little mammal that was probably a burrowing species living in the shadows of the oldest dinosaurs that we know from that period.”She stated that the group had worked on the project for more than five years and referred to their discovery as “extremely significant.”
Richter noted that the discoveries contributed “to our understanding of the ecological landscape of this epoch and the emergence of contemporary mammals” in the press statement that accompanied the findings.
“Our paper raises the level of debate about what defines a mammal and shows that it was a much earlier time of origin in the fossil record than previously known,” said Moya Meredith Smith, a contributing author and professor of endoskeletal evolutionary biology at King’s College London, in the release.
Researchers from the Natural History Museum in London, King’s College London and the Federal University of Rio Grande do Sul in Porto Alegre are credited with making the discovery. The fossilized remains of hard tissues, such as bones and teeth, were an essential source of information for scientists. This is because mammalian glands responsible for milk production have never been preserved in any fossils discovered to date.
Stay tuned for more updates, Nog Magazine.