The oldest ancestor fossil of mammals has been discovered on Mallorca, one of the Balearic Islands in Spain. This discovery reveals the most distant ancestors of all mammal animals, including humans.
An international joint research team, including Princeton University and the Field Museum of Natural History, announced on the 17th that it has discovered fossils of Gorgonopsia, which lived during the time of the supercontinent Pangaea when all today's continents were connected, on Mallorca. The research results were published in the international journal Nature Communications on the same day.
Gorgonopsia was a thriving animal during the Permian period, between 300 million and 250 million years ago, at the end of the Paleozoic Era. While it had some reptilian characteristics, it was closer to mammals and is considered an ancestor of modern mammals.
The research team found the Gorgonopsia fossils in the Banyalbufar area of western Mallorca. The fossil is approximately 1 meter long and consists of the skull, spine, ribs, and femur. The researchers explained that the dating of this fossil is 270 million years ago, making it the oldest recorded Gorgonopsia fossil to date.
Gorgonopsia was warm-blooded like mammals and had sharp, sword-like canine teeth similar to those of saber-toothed cats, which appeared about 40 million years ago. Its overall appearance resembled that of a dog without ears and fur, but its skeleton was an intermediate form between mammals and reptiles. It also differed from mammals in that it laid eggs. While it had some reptilian traits, it was closer to mammals.
This discovery overturns the existing theory that the main habitat of Gorgonopsia was in the high-latitude regions of the supercontinent Pangaea, which included present-day Russia and South Africa. This is because Mallorca was located in a low-latitude area near the equator of Pangaea 270 million years ago. Raquel Matamales Català, a researcher from the Research Institute, noted, "Finding so many Gorgonopsia fossils in Mallorca was unexpected."
The research team analyzed almost complete Gorgonopsia legs and inferred that this animal walked upright like modern mammals. Angel Galobat, a researcher from the Research Institute, stated, "The sword-like teeth indicate that this animal was a predator," adding, "It was likely the top predator in the ecosystem at the time, preying on herbivorous ancient reptiles."
So far, important fossils such as the world's oldest mosquito, ancient ancestors of horses and hippos, and giant shark and coral reef fossils have been discovered in the Balearic Islands, where Mallorca is located. The research team stated, "This study adds important fossil records to the Balearic Islands," and emphasized, "Research on Mallorca's ancient ecosystem has only just begun."
Reference materials
Nature Communications (2024), DOI: https://doi.org/10.1038/s41467-024-54425-5