When the world almost ended 252 million years ago, a unique group of amphibians not only survived, but also flourished after the most devastating giant extinction in the history of the planet. New research reveals their secret weapon: the ability of freshwater prey to avoid ecological damage that takes place on land.
The last round of the giant extinction exterminates up to 90% of the species on Earth, thus forming a burning landscape where few living things can survive. However, a group of ancient amphibians called temnosphyls managed to thrive and quickly diversify in what would have been a desolate world.
“One of the great mysteries is the survival and prosperity of a group of amphibians called Temnospondyls,” explains lead author Aamir Mehmood, Bristol College of Biological Sciences. “These are predators that feed fish and other prey, but are mainly related to water, just like modern amphibians like frogs and sals. We know the climate was very hot at the time, especially after the extinction incident. How could these water-loving animals be so successful?”
The study, published on March 5 in the journal Royal Society’s Open Science, analyzed 100 temnospondyl species throughout the Triassic period, which was the time of subsequent extinction. By measuring body size and examining skull and teeth characteristics that reveal feeding functions, researchers have discovered how these animals adapt to the world in crisis.
“To our surprise, we found that they didn’t change much in the crisis,” said co-author Dr. Armin Elsler. “Temnospondyls show the same range of body size as the Permian, some of which are small and feed on insects and others larger. These larger forms include long-term harsh animals that capture fish and broad generalist feeders.”
The early Triassic was a hell landscape of repeated volcanic activity that triggered global warming, acid rain, atmospheric oxygen and extensive wildfires. The conditions are so extreme that tropical areas are almost inhabited by many species – a phenomenon that scientists call “tropical dead zones.”
However, temnospondyls manage to navigate this apocalyptic world. Professor Mike Benton explained: “Our work shows that Temnospondyls unexpectedly crossed the tropical death zone. It is well known from South Africa and the South and Australia in North America, Europe and Russia. Temnospondyl must be able to crisscross the tropical zones during cooler attacks.”
The team found that these amphibians flourished because they are ecological generalists in eating habits, allowing them to take advantage of any available food resources as the environment fluctuates violently. When land ecosystems are damaged, their connection to water bodies gives them a relatively stable source of food.
Throughout the crisis, Temnospondyls stayed away from the professional physiology we might expect from disaster survivors, and they maintained a wide variety of feeding methods. Some have narrow noses and are specifically used for fishing, while others have a wider skull to consume more prey, similar to the difference between modern gharials and crocodiles.
This versatility proves crucial because the ecosystem rebuilds itself after mass extinction. Despite the struggles of strict land predators with a meager, unpredictable food source, Temnospondyls enjoy the relative stability of freshwater habitats.
After extinction, the temnospondyls experienced a significant diversification, peaking in the early Triassic period before starting a long-term decline. By studying the morphological characteristics of the skull over time, the researchers found that their ecological changes peaked about 5 million years after the crisis.
This study provides insights on how some animals survive while many others die. Instead of developing new professional adaptations, Temnosphyls have achieved success by maintaining ecological flexibility and utilizing habitats, thus providing some protections for habitats that invade extreme conditions.
“They probably deal with hot conditions by being on the food, being able to eat most prey and hiding in sparse bodies of water,” Memod concluded. “But when the ancestors of dinosaurs and mammals began to diversify during the Middle Triassic, Temnosphyls began to decline for a long time.”
These findings contribute to our understanding of extinction and recovery dynamics, showing how some groups thrive after mass extinction by leveraging ecological opportunities rather than developing novel adaptations.
Despite their early Triassic success, the Temnospondyls will eventually disappear with the emergence of new vertebrate groups. However, their story is still important today because it shows how ecological versatility and habitat choices determine which species survives when climate changes dramatically.
For paleontologists, these ancient amphibians provide a window for the evolutionary response to global catastrophes. As our planet faces its own biodiversity crisis, understanding how certain creatures face environmental turmoil and how the planet’s greatest apocalypse may provide clues about ecological resilience.
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