विशाल गोर्गोनोप्सियन इनोस्ट्रेन्सविया ने अपने डाइसिनोडोंट शिकार के साथ, बहुत छोटी अफ्रीकी प्रजाति साइनोसॉरस को भयभीत कर दिया। क्रेडिट: मैट सेलेस्की द्वारा कला
एक हालिया अध्ययन ने 252 मिलियन वर्ष पहले विनाशकारी विलुप्त होने की घटना “द ग्रेट डाइंग” में दिलचस्प अंतर्दृष्टि का खुलासा किया है, जो बाघ के आकार के कृपाण-दांतेदार जीव की भूमिका पर ध्यान केंद्रित करता है जिसे इनोस्ट्रेन्सविया कहा जाता है।
खोजे गए जीवाश्मों से संकेत मिलता है कि यह प्राणी पैंजिया में 7,000 मील की दूरी पर चला गया, विलुप्त होने से पहले दूर-दराज के पारिस्थितिकी तंत्र में विलुप्त शीर्ष शिकारियों द्वारा छोड़े गए शून्य को भर दिया। मूल रूप से केवल रूस में पाए जाने वाले इन जीवों को अप्रत्याशित रूप से दक्षिण अफ्रीका के कारू बेसिन में खोजा गया था। मुख्य कार्यक्रम से पहले उनके विलुप्त होने से पता चलता है कि एपेक्स प्रीडेटर्स आसन्न सामूहिक विलुप्त होने के शुरुआती संकेतक के रूप में काम कर सकते हैं। शोधकर्ता इन प्रागैतिहासिक प्रतिमानों और वर्तमान पर्यावरणीय संकटों के बीच समानताएं बनाते हैं, जो आज जैव विविधता के नुकसान की भविष्यवाणी करने और संभावित रूप से कम करने के लिए प्राचीन विलुप्त होने की घटनाओं को समझने के महत्व को रेखांकित करते हैं।
दो सौ बावन मिलियन वर्ष पहले, पृथ्वी ने एक बड़े पैमाने पर विलुप्त होने का अनुभव किया जो इतना विनाशकारी था कि इसे ग्रेट डाइंग के रूप में जाना जाने लगा। बड़े पैमाने पर ज्वालामुखीय विस्फोट विनाशकारी जलवायु परिवर्तन का कारण बनते हैं, दस में से नौ की मौत हो जाती है[{” attribute=””>species and eventually setting the stage for the dinosaurs. But the Great Dying was a long goodbye– the extinction event took place over the course of up to a million years at the end of the Permian period. During that time, the fossil record shows drama and upheaval as species fought to get a foothold in their changing environments. One animal that exemplifies this instability was a tiger-sized, saber-toothed creature called Inostrancevia: a new fossil discovery suggests that Inostrancevia migrated 7,000 miles across the supercontinent Pangaea, filling a gap in a faraway ecosystem that had lost its top predators, before going extinct itself.
“All the big top predators in the late Permian in South Africa went extinct well before the end-Permian mass extinction. We learned that this vacancy in the niche was occupied, for a brief period, by Inostrancevia,” says Pia Viglietti, a research scientist at the Field Museum in Chicago and a co-author of the new study in Current Biology.
Inostrancevia fossils in the field. Credit: Jennifer Botha
The prehistoric creature looked the part of “top predator.” “Inostrancevia was a gorgonopsian, a group of proto-mammals that included the first saber-toothed predators on the planet,” says Viglietti. It was about the size of a tiger and likely had skin like an elephant or a rhino; while vaguely reptilian in appearance, it was part of the group of animals that includes modern mammals.
Prior to this new paper, Inostrancevia had only ever been found in Russia. But while examining the fossil record of South Africa’s Karoo Basin, Viglietti’s colleague Christian Kammerer identified the fossils of two large predatory animals that were different from those normally found in the region. “The fossils themselves were quite unexpected,” says Viglietti. It’s not clear how they made it from what’s now Russia, or how long it took them to cross Pangaea and arrive in what’s now South Africa. But being far from home was just one element of what made the fossils special.
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
“When we reviewed the ranges and ages of the other top predators normally found in the area, the rubidgeine gorgonopsians, with these Inostrancevia fossils, we found something quite exciting,” she says. “The local carnivores actually went extinct quite a bit before even the main extinction that we see in the Karoo– by the time the extinction begins in other animals, they’re gone.”
The arrival of Inostrancevia from 7,000 miles away and its subsequent extinction indicates that these top predators were “canaries in the coal mine” for the larger extinction event to come.
“This shows that the South African Karoo Basin continues to produce critical data for understanding the most catastrophic mass extinction in Earth’s history,” says co-author Jennifer Botha, director of GENUS Centre of Excellence in Palaeosciences and 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
“We have shown that the shift in which groups of animals occupied apex predator roles occurred four times over less than two million years around the Permian-Triassic mass extinction, which is unprecedented in the history of life on land. This underlines how extreme this crisis was, with even fundamental roles in ecosystems in extreme flux,” said Christian Kammerer, the study’s first author and a research curator of paleontology at the North Carolina Museum of Natural Sciences and research associate at the Field Museum.
The vulnerability of these top predators matches what we see today. “Apex predators in modern environments tend to show high extinction risk, and tend to be among the first species that are locally extirpated due to human-mediated activities such as hunting or habitat destruction,” says Kammerer. “Think about wolves in Europe or tigers in Asia, species which tend to be slow to reproduce and grow and require large geographic areas to roam and hunt prey, and which are now absent from most of their historic ranges. We should expect that ancient apex predators would have had similar vulnerabilities, and would be among the species that first go extinct during mass extinction events.”
In addition to shedding new light on the extinction event that helped lead to the rise of the dinosaurs, Viglietti says that the study is important for what it can teach us about the ecological disasters the planet is currently experiencing.
“It’s always good to get a better understanding of how mass extinction events affect ecosystems, especially because the Permian is basically a parallel on what we’re going through now,” said Viglietti. “We don’t really have any modern analogs of what to expect with the mass extinction happening today, and the Permo-Triassic mass extinction event represents one of the best examples of what we could experience with our climate crisis and extinctions. I guess the only difference is, we know what to do and how to stop it from happening.”
Reference: “Rapid turnover of top predators in African terrestrial faunas around the Permian-Triassic mass extinction” by Christian F. Kammerer, Pia A. Viglietti, Elize Butler and Jennifer Botha, 22 May 2023, Current Biology.
DOI: 10.1016/j.cub.2023.04.007
