Paleontologists have identified the myriad of animals — saber-toothed predators, burrowing foragers and a large, salamander-like creature — that thrived in southern Pangea just before the end-Permian mass extinction, about 252 million years ago.
An artistic rendering of an evening approximately 252 million years ago during the Late Permian epoch in the Luangwa Basin of Zambia. The scene includes several saber-toothed gorgonopsians and beaked dicynodonts. Image credit: Gabriel Ugueto.
“The end-Permian mass extinction was nothing short of a cataclysm for life on Earth, and changed the course of evolution,” said University of Washington’s Professor Christian Sidor.
“But we lack a comprehensive view of which species survived, which didn’t, and why.”
“The fossils we have collected in Tanzania and Zambia will give us a more global perspective on this unprecedented period in our planet’s natural history.”
All new fossils were excavated in three basins across southern Africa: the Ruhuhu Basin in southern Tanzania, the Luangwa Basin in eastern Zambia and the Mid-Zambezi Basin in southern Zambia.
Most were discovered by team members on multiple, month-long excavation trips to the region over the past 17 years.
Others were analyses of specimens dug up decades prior that had been stored in museum collections.
“These parts of Zambia and Tanzania contain absolutely beautiful fossils from the Permian,” Professor Sidor said.
“They are giving us an unprecedented view of life on land leading up to the mass extinction.”
The Permian period is the endpoint of what paleontologists call the Paleozoic Era.
During this time, animal life — which evolved first in Earth’s oceans — began to colonize land and complex terrestrial ecosystems developed.
By the Permian, a diverse array of amphibian and reptile-like creatures roamed environments ranging from early forests to arid valleys.
The end-Permian mass extinction obliterated many of these ecosystems and ushered in the Mesozoic Era, which saw the evolution of dinosaurs, as well as the first birds, flowering plants and mammals.
For decades, scientists’ best understanding of the Permian, the end-Permian mass extinction and the start of the Mesozoic came from the Karoo Basin in South Africa, which contains a near-complete fossil record of periods before and after the mass extinction.
But beginning in the 1930s, paleontologists realized that basins in Tanzania and Zambia contain fossil records of this time range that are almost as pristine as the Karoo’s.
The excavation trips by the authors represent the largest analysis to date of the region’s fossil record from before and after the end-Permian mass extinction.
“The number of specimens we’ve found in Zambia and Tanzania is so high and their condition is so exquisite that we can make species-level comparisons to what paleontologists have found in South Africa,” Professor Sidor said.
“I know of no better place on Earth for getting sufficient detail of this time period to make such detailed conclusions and comparisons.”
In a series of 14 articles in the Journal of Vertebrate Paleontology, the researchers describe a number of new species of dicynodonts.
These small, burrowing, reptile-like herbivores first evolved in the mid-Permian.
By the time of the mass extinction, dicynodonts — many of whom sported a beak-like snout with two small tusks that likely aided burrowing — were the dominant plant-eaters on land.
The findings also include several new species of large, saber-toothed predators called gorgonopsians, as well as a new species of temnospondyl, a large salamander-like amphibian.
“We can now compare two different geographic regions of Pangea and see what was going on both before and after the end-Permian mass extinction,” Professor Sidor said.
“We can really start to ask questions about who survived and who didn’t.”