Short-tailed pterosaurs, like this Balaenognathus, were adapted to a life on the ground. This strange creature had nearly 500 needle-like teeth in its jaws and likely used them to filter tiny foods from shallow water, similar to the feeding habits of modern flamingos. Credit: Rudolf Hima
The evolutionary adaptations that allowed ancient pterosaurs to reach enormous sizes have been identified for the first time by palaeontologists from the Center for Paleobiology and Biosphere Evolution at the University of Leicester.
The discovery revealed a surprising twist: The ability to walk efficiently on the ground played a crucial role in determining the size of the largest flying animals, with some reaching wingspans of up to 10 meters.
In a new study published October 4 in Current biologyA team of researchers led by the University of Leicester examined the hands and feet of pterosaurs from around the world and throughout their evolutionary history.
They discovered a surprising level of variation similar to that seen in living birds. This discovery indicates that pterosaurs were not limited to a life in the sky, but were also adapted to a wide range of terrestrial lifestyles, from tree climbing in early species to more terrestrial lifestyles in early species. later species.
The evolution of pterosaurs, the first true flying vertebrates, features some of the most remarkable adaptations in the history of life. Although these creatures are best known for their ability to soar through the prehistoric skies of the Mesozoic era (252 to 66 million years ago), a new study has revealed a surprisingly high degree of diversity in the location and the way pterosaurs lived when they were not in flight. .
Long-tailed pterosaurs, like Scaphognathus, had large, curved claws on their hands and feet, specially adapted for climbing. Equipped with sharp teeth, they probably fed on insects and other small animals. Credit: Rudolf Hima
Lead author Robert Smyth, a PhD researcher at the Center for Paleobiology and Biosphere Evolution (School of Geography, Geology and Environment, University of Leicester), explained: “Early pterosaurs were highly specialized for climbing, with extreme modifications in their hands and feet, similar to those found today in climbing lizards and birds like woodpeckers.
“Hanging on to vertical surfaces with your fingertips for long periods of time is hard work. It’s much easier for small, lightweight animals.”
These early pterosaurs were likely restricted to arboreal habitats and, therefore, small body sizes. However, a major evolutionary change occurred during the Middle Jurassic period, when the hands and feet of pterosaurs changed to much more closely resemble those of ground-dwelling animals.
These adaptations to land travel have opened up new ecological opportunities, leading to a wide variety of dietary strategies. Freeing themselves from the size constraints imposed by vertical life allowed certain pterosaurs to evolve towards gigantic size with wingspans of up to 10 meters.
Co-author Dr David Unwin from the University of Leicester added: “In early pterosaurs, the hind limbs were connected by a flight membrane which severely impeded walking and running. In more advanced pterosaurs, this membrane separated along the midline. allowing each hind limb to move independently. This was a key innovation that, combined with modifications to their hands and feet, greatly improved the pterosaurs’ mobility on the ground.
“Freed from the constraints of climbing, these later pterosaurs could reach enormous sizes, with some species becoming veritable giants of the Mesozoic.”
This evolutionary tree illustrates the remarkable transformation of pterosaur hands as they adapted from a climbing lifestyle to one adapted to terrestrial movement. Early long-tailed pterosaurs, which relied on climbing, were limited to smaller body sizes. In contrast, later, short-tailed species that adapted to walking on land were able to grow freely, allowing some to reach giant sizes. Credit: Rudolf Hima
The details of the hands and feet are an obvious giveaway. In early pterosaurs, the bones at the base of the fingers and toes were relatively short, while those furthest from the body were very elongated, ending in large, curved claws. Together, these modifications resulted in a powerful grip, ideal for climbing.
In contrast, later, more advanced pterosaurs showed the opposite pattern: the bones at the base of their fingers and toes were much longer, while those closer to the extremities were shorter. Their claws were also flatter and less curved, suggesting that they were better adapted to walking than climbing.
Smyth added: “These findings highlight the need to examine all aspects of pterosaur locomotion, not just flight, to fully understand their evolution. The fact that pterosaurs could fly is only part of their story. By exploring how they lived in the trees or on the ground. on the ground, we can begin to understand the roles they played in ancient ecosystems. »
When pterosaurs arrived on earth, it was already inhabited by a wide range of animals, including dinosaurs and many other reptiles. Pterosaurs cleverly avoided competition with these established groups by exploiting ecological niches that required both flight and walking capabilities.
This resulted in bizarre feeding strategies, such as the appearance of hundreds of fine, needle-like teeth that were used for filter feeding. This remarkable feature, which resembles the feeding method of modern flamingos, appeared at least 120 million years before the first flamingos evolved.
More information:
Hand and foot morphology maps the invasion of terrestrial environments by pterosaurs in the mid-Mesozoic, Current biology (2024). DOI: 10.1016/j.cub.2024.09.014. www.cell.com/current-biology/f… 0960-9822(24)01226-0
Provided by University of Leicester
Quote: Study determines when and how pterosaurs evolved from tiny tree climbers to towering terrestrial titans (October 4, 2024) retrieved October 4, 2024 from
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