Revisiting Earth’s Past: Scientists Uncover Startling New Insights Into the Devastating End-Triassic Mass Extinction

A research team from USC<span class="st">Founded in 1880, the <em>University of Southern California</em> is one of the world's leading private research universities. It is located in the heart of Los Angeles.</span>” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]” tabindex=”0″ role=”link”>USC Dornsife has made significant discoveries regarding the drastic changes caused by a surge in greenhouse gases and escalating temperatures, which resulted in a mass extinction event, paving the way for the emergence of JurassicThe Jurassic period is a geologic time period and system that spanned 56 million years from the end of the Triassic Period about 201.3 million years ago to the beginning of the Cretaceous Period 145 million years ago. It constitutes the middle period of the Mesozoic Era and is divided into three epochs: Early, Middle, and Late. The name "Jurassic" was given to the period by geologists in the early 19th century based on the rock formations found in the Jura Mountains, which were formed during the Jurassic period.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]” tabindex=”0″ role=”link”>Jurassic dinosaurs.

Startling new insights into the catastrophic impact of one of the most devastating events in Earth’s history have been revealed by a team led by researchers with the USC Dornsife College of Letters, Arts and Sciences. Their findings not only deepen our understanding of the end-TriassicThe Triassic is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.9 million years ago, to the beginning of the Jurassic Period 201.3 million years ago. It is the first and shortest period of the Mesozoic Era and is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]” tabindex=”0″ role=”link”>Triassic mass extinction but also provide crucial lessons for addressing today’s environmental challenges.

About 200 million years ago, Earth experienced its fourth major mass extinction event. Triggered by a dramatic rise in greenhouse gases due to volcanic activity, the event led to rapid global warming and a significant shift in the planet’s biosphere, ending the Triassic period and launching the Jurassic. Many scientists now believe Earth is in the midst of another mass extinction, driven in large part by similar climate changes.

Earth scientists at USC Dornsife took a unique approach to analyzing the impact of this extinction event on both ocean and land ecosystems, using a novel “ecospace framework” method that categorizes animals beyond just their speciesA species is a group of living organisms that share a set of common characteristics and are able to breed and produce fertile offspring. The concept of a species is important in biology as it is used to classify and organize the diversity of life. There are different ways to define a species, but the most widely accepted one is the biological species concept, which defines a species as a group of organisms that can interbreed and produce viable offspring in nature. This definition is widely used in evolutionary biology and ecology to identify and classify living organisms.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]” tabindex=”0″ role=”link”>species. It accounts for ecological roles and behaviors — from flying or swimming predators to grazing herbivores and from ocean seafloor invertebratesInvertebrates are animals that do not have a backbone. They make up the majority of the animal kingdom and include animals such as insects, worms, mollusks, and arachnids. Invertebrates are found in almost every habitat on Earth, from the depths of the oceans to the highest mountains. They play important roles in the ecosystem as decomposers, pollinators, and as a food source for other animals. Invertebrates have a wide range of body shapes, sizes, and behaviors, and they have evolved a variety of ways to survive and thrive in their environments.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]” tabindex=”0″ role=”link”>invertebrates to soil-dwelling animals on land.

Reconstruction of a Late Triassic ecosystem from Ghost Ranch, New Mexico. Published specimens and species preserved at Ghost Ranch were incorporated into the research team’s global ecological dataset. Credit: Viktor O. Leshyk/Natural History Museum of Los Angeles County

“We wanted to understand not just who survived and who didn’t, but how the roles that different species played in the ecosystem changed,” said David Bottjer, professor of Earth sciences, biological sciences and environmental studies at USC Dornsife and a study senior author. “This approach helps us see the broader, interconnected ecological picture.”

The study — a collaboration between students and faculty at USC Dornsife and the Natural History Museum of Los Angeles County — was recently published in the journal Proceedings of Royal Society B.

Sea life suffered, but not as much as land animals

The research revealed a stark difference in the impact on marine and terrestrial ecosystems. While both realms suffered greatly, the findings suggest that land-based ecosystems were hit harder and experienced more prolonged instability.

In the oceans, nearly 71% of categories of species, called genera, vanished. Surprisingly, despite this massive loss, the overall structure of marine ecosystems showed resilience. Predators like sharks, mollusks known as ammonites, and filter feeders like sponges and brachiopods, though severely affected, eventually bounced back.

Graphic representation of the study concept and findings. Credit: C. Henrik Woolley/Natural History Museum of Los Angeles County

On land, the scenario proved much bleaker. A staggering 96% of terrestrial genera went extinct, dramatically reshaping the landscape of life on Earth. Large herbivores like early dinosaurs and various small predators suffered greatly, with significant changes in their populations and roles within the ecosystem.

“This contrast between land and sea tells us about the different ways ecosystems respond to catastrophic events,” said co-lead author Alison Cribb, who earned her Ph.D. in geological sciences at USC Dornsife this year and is now at the University of Southampton in the U.K. “It also raises important questions about the interplay of biodiversity and ecological resilience.”

Climate change clues from ancient catastrophe 

The study’s findings spark more than just historical interest — they carry significant implications for our current environmental challenges. “Understanding past mass extinctions helps us to predict and possibly soften the impacts of current and future environmental crises,” said co-lead author Kiersten Formoso, who is finishing her doctoral studies in vertebrate paleobiology at USC Dornsife and will soon move to a position at Rutgers University.

The parallels between the rapid global warming of the end-Triassic and today’s climate change are particularly striking. “We’re seeing similar patterns now — rapid climate change, loss of biodiversity. Learning how ecosystems responded in the past can inform our conservation efforts today,” Bottjer said.

The research also provides a rare window into the world as it existed over 200 million years ago, he added. “It’s like a time machine, giving us a glimpse of life during a period of profound change.”

The study’s ecospace framework, with its focus on functional roles, offers a fresh perspective on ancient life, according to Frank Corsetti, professor of Earth sciences and chair of USC Dornsife’s Department of Earth Sciences. “It’s not just about identifying fossils,” he said. “It’s about piecing together the puzzle of ancient ecosystems and how they functioned.”

Future ventures will delve into the past’s lessons

As they plan further research, the scientists aim to explore how different species and ecosystems recovered after the extinction, and how these ancient events can parallel current biodiversity loss due to climate change.

Future studies are also planned to examine changes in ecospace dynamics across other periods of profound environmental change in deep time. 

“We’ve just scratched the surface,” said Cribb. “There’s so much more to learn about how life on Earth responds to extreme changes, and this new ecospace framework offers great potential for helping us do that.”

Pandemic sparks unique, collaborative project 

The study was conceived, and much of the work done, during the COVID-19First identified in 2019 in Wuhan, China, COVID-19, or Coronavirus disease 2019, (which was originally called "2019 novel coronavirus" or 2019-nCoV) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It has spread globally, resulting in the 2019–22 coronavirus pandemic.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]” tabindex=”0″ role=”link”>COVID-19 pandemic, when restrictions on many other types of research were in place, said Bottjer. “This produced unique conditions that fostered and led to the development and completion of this research involving individuals with expertise across a broad variety of paleobiological fields, from microbes to invertebrates to vertebratesVertebrates are animals that have a backbone and include mammals, birds, reptiles, amphibians, and fish. They have a more advanced nervous system than invertebrates, allowing them greater control over their movements and behaviors, and they are able to move and support their body weight using their spine. Vertebrates are found in many habitats and play important roles in the ecosystem as predators, prey, and scavengers.” data-gt-translate-attributes=”[{“attribute”:”data-cmtooltip”, “format”:”html”}]” tabindex=”0″ role=”link”>vertebrates, in marine and terrestrial environments, with everyone working together towards one goal,” he said. 

Reference: “Contrasting terrestrial and marine ecospace dynamics after the end-Triassic mass extinction event” by Alison T. Cribb, Kiersten K. Formoso, C. Henrik Woolley, James Beech, Shannon Brophy, Paul Byrne, Victoria C. Cassady, Amanda L. Godbold, Ekaterina Larina, Philip-peter Maxeiner, Yun-Hsin Wu, Frank A. Corsetti and David J. Bottjer, 6 December 2023, Proceedings of the Royal Society B.
DOI: 10.1098/rspb.2023.2232

Bottjer said Cribb and Formoso initially devised the collaboration with his and Corsetti’s supervision and essential contributions from the study’s other co-authors.

Researchers on the study include Cribb, Formoso, Bottjer, Corsetti, James Beech, Shannon Brophy, Victoria Cassady, Amanda Godbold, Philip-peter Maxeiner, and Ekaterina Larina (now at the University of Texas at Austin) of USC Dornsife’s Department of Earth Sciences as well as C. Henrik “Hank” Woolley, Paul Byrne, Yun-Hsin Wu of Earth sciences at USC Dornsife and the Natural History Museum of Los Angeles County.