New fossil discovery reveals Inostrancevia’s incredible journey

252 million years ago, a cataclysmic event known as “the Great Dying” caused a mass extinction on Earth. This devastating event, which occurred at the end of the Permian period, wiped out 90% of species and eventually paved the way for the rise of dinosaurs. The Great Dying unfolded over a span of up to a million years, marked by dramatic changes and turmoil as organisms struggled to adapt to shifting environments. Among the creatures that exemplify this era of instability is Inostrancevia, a saber-toothed predator resembling a tiger in size.

A recent fossil discovery sheds light on Inostrancevia's remarkable journey and its role in filling an ecological void on the supercontinent Pangaea. Prior to this finding, Inostrancevia fossils had only been found in Russia. However, a study conducted in South Africa's Karoo Basin unearthed the remains of two large predatory animals that differed from the typical species found in the region. Pia Viglietti, a research scientist at the Field Museum in Chicago and co-author of the study published in Current Biology, explains that these unexpected fossils belonged to Inostrancevia.

Inostrancevia belonged to a group of proto-mammals known as gorgonopsians, which included the first saber-toothed predators on Earth. Despite its reptilian appearance, Inostrancevia was part of the lineage that led to modern mammals. It likely had a rhino or elephant-like skin texture and possessed the characteristics of a top predator.

The migration of Inostrancevia over a distance of 7,000 miles across Pangaea highlights the species' adaptability and its ability to exploit opportunities in new ecosystems. In this case, Inostrancevia filled a niche in South Africa's ecosystem that had lost its top predators due to earlier extinctions. However, Inostrancevia's tenure in this foreign habitat was short-lived, as it eventually faced its own extinction.

The exact mechanisms by which Inostrancevia made its journey from Russia to South Africa remain unclear. Nevertheless, the discovery of these fossils not only adds to our understanding of prehistoric ecosystems but also underscores the dynamic nature of life during the late Permian period.

Inostrancevia fossils in the field. Credit: Jennifer Botha.

Upon analyzing the typical ranges and ages of the rubidgeine gorgonopsians, the local top predators in the area, in conjunction with the newly discovered Inostrancevia fossils, the researchers made an exciting revelation. “We found something quite remarkable,” she explains. “The local carnivores actually became extinct well before the main extinction event that we observe in the Karoo. By the time the extinction began affecting other animals, these predators were already gone.”

The arrival of Inostrancevia from a distance of 7,000 miles and its subsequent extinction suggests that these top predators acted as early indicators or “canaries in the coal mine” for the impending larger-scale extinction event.

“This discovery underscores the South African Karoo Basin's continued contribution to providing crucial data for comprehending the most catastrophic mass extinction in Earth's history,” asserts co-author Jennifer Botha, who serves as the director of the GENUS Centre of Excellence in Palaeosciences and a professor at the Evolutionary Studies Institute, University of the Witwatersrand, Johannesburg.

Paul October, a now retired field technician from Iziko South African Museum, with Inostrancevia fossils in the field. Credit: Jennifer Botha.

The study's first author, Christian Kammerer, a research curator of paleontology at the North Carolina Museum of Natural Sciences and research associate at the Field Museum, highlights the unprecedented nature of the shifts in apex predator roles during the Permian-Triassic mass extinction. He states, “We have demonstrated that the transition of different animal groups assuming apex predator roles occurred four times within a span of less than two million years surrounding the Permian-Triassic mass extinction. This is unparalleled in the history of terrestrial life, emphasizing the extreme nature of this crisis, with even fundamental ecological roles undergoing drastic fluctuations.”

The vulnerability of these apex predators draws parallels to present-day circumstances. Kammerer explains, “Modern apex predators are often highly susceptible to extinction, being among the first species to be locally eradicated due to human-induced activities like hunting or habitat destruction. Consider the wolves in Europe or the tigers in Asia, species with slow reproduction and growth rates, dependent on vast territories for hunting and roaming, and now absent from much of their historical ranges. We should anticipate that ancient apex predators shared similar vulnerabilities and were among the first casualties of mass extinction events.”

In addition to providing insights into the extinction event that paved the way for the ascent of dinosaurs, the study holds significance in its ability to educate us about ongoing ecological crises faced by our planet today.

Pia Viglietti emphasizes the importance of the study in understanding the ecological disasters unfolding in the present, stating, “In addition to shedding new light on the extinction event that helped lead to the rise of the dinosaurs, this research holds significance in its ability to offer valuable lessons about the environmental catastrophes that our planet is presently undergoing.”

The field location where the Inostrancevia were found (a farm called Nooitgedacht in the Free State Province of South Africa's Karoo Basin). Credit: Pia Viglietti.

Viglietti emphasizes the value of gaining a deeper comprehension of how mass extinctions impact ecosystems, particularly due to the striking parallels between the Permian extinction and our current circumstances. She states, “It is crucial to enhance our understanding of how mass extinction events shape ecosystems, particularly because the Permian event serves as a mirror to the challenges we face today. We lack modern analogs that can precisely predict the outcomes of the ongoing mass extinction and climate crisis. The Permian-Triassic mass extinction event stands as one of the most prominent examples of what we might encounter in terms of climate-related crises and extinctions. However, there is one fundamental difference – we possess the knowledge and means to prevent it from happening.”

In highlighting this distinction, Viglietti suggests that unlike the ancient world, we now have the awareness and tools to address and mitigate the current environmental challenges we face.

Source: Field Museum

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