Scientists have discovered 280 million-year-old fossil remains of a predator that gave rise to all mammals.
This ancient animal, which does not yet have a species name, is the member of an evolutionary group known as the gorgonopsians — a distant relative of mammals – that are an extinct clade of saber-toothed therapsids.
They were four-legged, slightly reptilian-looking animals that eventually gave rise to mammals roughly 200 million years ago.
Co-author Ken Angielczyk said: ‘Gorgonopsians are more closely related to mammals than they are to any other living animals.
‘While they’re not our direct ancestors, they’re related to species that were our direct ancestors.’
The newly discovered fossils — which include fragments of skull, vertebrae, and ribs to a very well-preserved femur — belonged to a vaguely dog-like saber-toothed predator that the researchers believe may be the oldest therapsid ever discovered.
Until now, the oldest known gorgonopsians lived roughly 265 million years ago, but these fossils are roughly 15 million years older.
They were unearthed in Mallorca, a Spanish island in the Mediterranean sea. Back when gorgonopsians still roamed the Earth, Mallorca was part of the supercontinent Pangea.
Fossil remains of the oldest known gorgonopsians allowed researchers to reconstruct what these ancient proto-mammals may have looked like when they were alive
Gorgonopsians were vaguely dog-like saber-toothed predators that roamed the Earth up to 280 million years ago, this new discovery suggests
‘If you saw this animal walking down the street, it would look a little bit like a medium-sized dog, maybe about the size of a husky,’ Angielczyk, a paleobiologist at the Field Museum in Chicago, said in a statement.
‘But it wouldn’t be quite right. ‘It didn’t have any fur, and it wouldn’t have had dog-like ears. But it’s the oldest animal scientists have ever found with long, blade-like canine teeth,’ he added.
The saber teeth suggest this animal was a top-predator at the time it was alive, and confirmed its carnivorous diet.
The presence of a nearly complete leg also allowed researchers to surmise how the animal moved.
Analysis of the leg remains suggested that gorgonopsians ‘moved in a way that was intermediate between reptiles and mammals’ which was more efficient for walking and running than true reptilian movement.
Angielczyk and colleagues at the Field Museum partnered with researchers at the Catalan Institute of Paleontology Miquel Crusafont in Barcelona, Spain to excavate and analyze the fossils.
They published their findings today in the journal Nature Communications.
The gorgonopsian remains were recovered from a site located in the Mallorcan city of Banyalbufar.
The newly discovered fossils include fragments of skull, vertebrae, and ribs to a very well-preserved femur
The presence of a nearly complete leg also allowed researchers to surmise how the animal moved
The saber teeth suggest this animal was a top-predator at the time it was alive, and confirmed its carnivorous diet
‘The large number of bone remains is surprising. We have found everything from fragments of skull, vertebrae, and ribs to a very well-preserved femur,’ said lead author Rafel Matamales, a research associate at the Catalan Institute.
‘In fact, when we started this excavation, we never thought we would find so many remains of an animal of this type in Mallorca,’ he added.
What’s more, the researchers were surprised to find this kind of specimen in the Balearic Islands, as the known remains of gorgonopsians had been found in very high latitudes such as Russia or South Africa until now.
But this isn’t the first time that these small Spanish islands have yielded groundbreaking fossil discoveries.
The world’s oldest mosquito was recovered there, as well as nearly a thousands species of ammonoids, or cephalopods related to squids, ancestors of horses and hippos, giant sharks and large coral reefs, according to the researchers.
The fact that this newly discovered gorgonopsian predates its closest relatives by tens of millions of years changes scientists’ understanding of when therapsids evolved, the researchers concluded in the statement.
And because therapsids are the ancient ancestors of mammals, this finding also clarifies when and how humans evolved.
‘Before the time of dinosaurs, there was an age of ancient mammal relatives. Most of those ancient mammal relatives looked really different from what we think of mammals looking like today,’ Angielczyk said.
‘But they were really diverse and played lots of different ecological roles. The discovery of this new fossil is another piece of the puzzle for how mammals evolved.’
