Paleontologists have discovered a new species of early gorgonopsian therapsid that was part of an ancient summer wet biome of equatorial Pangea.
Life reconstruction of the gorgonopsian from Mallorca in a floodplain setting. Image credit: Henry Sutherland Sharpe.
Therapsids were a dominant component of Permian terrestrial ecosystems worldwide, eventually giving rise to mammals during the early Mesozoic.
However, little is currently known about the time and place of their origin.
“Therapsida is a clade of diverse and ecologically successful tetrapods, with mammals as their modern representatives,” said Dr. Rafel Matamales, a paleontologist at the Museu Balear de Ciències Naturals and the Institut Català de Paleontologia Miquel Crusafont, and colleagues.
“The roots of the clade extend back to the Late Paleozoic, when non-mammalian therapsids were important components of terrestrial ecosystems.”
“Until now, the oldest known unequivocal therapsid was Raranimus dashankouensis, from probable Roadian (lower Middle Permian) deposits of central-east Asia.”
“Yet, phylogenetic analyses consistently suggest that therapsids are the sister group of sphenacodontid ‘pelycosaur’-grade synapsids, which originated in the Pennsylvanian (ca. 320 million years ago).”
“This implies a long therapsid ghost lineage spanning about 40 million years.”
The newly-discovered therapsid is the oldest of its kind, and maybe the oldest therapsid ever discovered.
This dog-like saber-toothed animal, which doesn’t have a species name yet, belongs to a group of therapsids called the gorgonopsians.
“Gorgonopsians are more closely related to mammals than they are to any other living animals,” said Dr. Ken Angielczyk, a paleontologist at Field Museum.
“They don’t have any modern descendents, and while they’re not our direct ancestors, they’re related to species that were our direct ancestors.”
“Until now, the oldest known gorgonopsians lived roughly 265 million years ago; however, the new fossil is from 270-280 million years ago.”
“It is most likely the oldest gorgonopsian on the planet,” said Dr. Josep Fortuny, a paleontologist at the Institut Català de Paleontologia Miquel Crusafont.
The fossil was found in Mallorca, a Spanish island in the Mediterranean Sea. But in the time of the gorgonopsians, Mallorca was part of the supercontinent Pangea.
“The large number of bone remains is surprising,” Dr. Matamales said.
“We have found everything from fragments of skull, vertebrae, and ribs to a very well-preserved femur.”
“In fact, when we started this excavation, we never thought we would find so many remains of an animal of this type in Mallorca.”
“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, but it wouldn’t be quite right,” Dr. Angielczyk said.
“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.”
“These saber teeth suggest that this gorgonopsian was a top predator in its day.”
The fact that this gorgonopsian predates its closest relatives by tens of millions of years changes scientists’ understanding of when therapsids evolved, an important milestone on the way to the emergence of mammals, and in turn it tells us something about where we come from.
“Before the time of dinosaurs, there was an age of ancient mammal relatives,” Dr. Angielczyk said.
“Most of those ancient mammal relatives looked really different from what we think of mammals looking like today.”
“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.”
The discovery is reported in a paper published in the journal Nature Communications.
_____
R. Matamales-Andreu et al. 2024. Early-middle Permian Mediterranean gorgonopsian suggests an equatorial origin of therapsids. Nat Commun 15, 10346; doi: 10.1038/s41467-024-54425-5