Written by Will Dunham
WASHINGTON (Reuters) – It was a trying moment for life on Earth. Runaway global warming caused by catastrophic volcanoes in Siberia caused the worst-ever mass extinction – possibly wiping out 90% of species – roughly 252 million years ago at the end of the Permian period.
Unlike the asteroid 66 million years ago that destroyed the dinosaurs, this extinction occurred over a long period of time, with species decimated one by one as conditions worsened. Fossils unearthed in South Africa offer a peek into the drama, scientists said Monday, telling the tale of a predator that over several generations migrated halfway around the world in a desperate, and ultimately failed, attempt to survive.
This beast, a tiger-sized, saber-toothed mammal called Inostrancevia, was only known from fossils excavated in the northwest corner of Russia bordering the Arctic Sea until new remains were discovered on a farm in central South Africa.
Fossils indicate that Inostrancevia left its place of origin and migrated over time—perhaps hundreds or thousands of years—about 7,000 miles (12,000 km) across Earth’s ancient supercontinent at a time when today’s continents were united. Inostrancevia filled the ecological niche of apex predator in southern Africa that was left vacant after four other species had already disappeared.
“However, it didn’t last there long,” said paleontologist Christian Kammerer of the North Carolina Museum of Natural Science, lead author of the research published in the journal Current Biology, noting that Inostrancevia and all its close relatives disappeared in the mass extinction. It is called “The Great Dying”.
“Therefore, they do not have living descendants, but are members of a larger group called synapsids, which includes mammals as living representatives,” Kammerer added.
Inostrancevia is part of a group of animals called protomammals that combine reptile- and mammal-like features. It was 10 to 13 feet (3–4 m) long, roughly the size of a Siberian tiger, but with a relatively larger and elongated skull as well as massive, razor-like teeth.
“I suspect these animals primarily killed prey with their saber-like fangs and either cut off chunks of flesh with the serrated incisors or, if small enough, swallowed the prey whole,” Kammerer said.
Inostrancevia’s body had an unusual posture typical of proto-mammals, not quite sprawling like reptiles or erect like mammals but something in between, with extended forelimbs and mostly erect hind limbs. They also lack mammalian facial muscles and will not produce milk.
“Whether or not these animals are furry remains an open question,” Kammerer said.
The mass extinction, which occurred over a period of a million years or so, paved the way for the advent of dinosaurs in the later Triassic period. Supervolcanoes unleashed lava flows across large parts of Eurasia and pumped carbon dioxide into the atmosphere for thousands of years. This caused global warming, oxygen depletion in the seas and atmosphere, ocean acidification and global desertification.
The apex predators were particularly vulnerable to extinction because they require the most food and space.
“They tend to take a relatively long time to mature and have few offspring. When ecosystems are disrupted and prey supplies are reduced or available habitats are limited, large predators are disproportionately affected,” Kammerer said.
Researchers see similarities between the Permian crisis and human-induced climate change.
“The hardships these species faced were a direct result of the global warming climate crisis, so they really had no choice but to adapt or go extinct. This is evidenced by their brief perseverance despite these conditions, but paleontologist and study co-author Pia Viglietti of the Museum of Natural Sciences said. Field in Chicago: “They eventually disappeared one by one.”
Viglietti added, “Unlike our Permian ancestors, we actually have the ability to do something to prevent this kind of ecosystem crisis from happening again.”
(Reporting by Will Dunham; Editing by Rosalba O’Brien)
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