A group of paleobiologists analyzed the structure and proportions of many known forms of pterosaurs, covering their entire evolutionary history, and discovered why flying lizards were able to reach gigantic sizes, occupy many ecological niches, and acquire unusual structural features. Pterosaurs were the first vertebrates on Earth and lived very long lives as a group, from the late Triassic period (227 million years ago), throughout the Jurassic period, and until the end of the Cretaceous period (66 million years ago). experienced a mass extinction.

During this long period, pterosaurs achieved a striking diversity and anatomical features. For example, a perfectly preserved skeleton of a flying lizard was discovered in Bavaria in early 2023. Balaenognathus maeuseriTheir jaws were adorned with small, hair-like teeth, like combs. A pterosaur (pterodaustro) with similar features has been found before, but it only had hairs on its lower jaw.

These lizards were relatively small: the first had a wingspan of just over a meter, and the pterodaustro was two and a half. The real giants of the Cretaceous period were some azhdarchids; The wingspan of Aramburgian or Hotigopteryx sometimes equaled 11 meters. Considering that the length of the skull is three meters, it is difficult to imagine such a huge beast.

It is even more difficult to imagine the flight of such large animals. Paleontologists are still finding details that reveal the mechanics of pterosaur locomotion and the features of some species’ wings. This time, a group of British and American paleobiologists studied the history of changes in the limbs of almost all known pterosaurs to reconstruct the development of their musculoskeletal systems. During the study, researchers discovered an evolutionary reason that allowed pterosaurs to occupy a wide variety of ecological niches. The article was published in the magazine Current Biology.

Experts analyzed the structure, length and proportions of the phalanges of the first three fingers on the front legs, which end in claws (the fourth finger usually holds the wing), and the bones of the first four fingers on the hind legs of pterosaurs. It was these fingers that came into contact with the substrate (trees, ground, and other surfaces) when pterosaurs moved.

The sample covered more than 60 taxa and the entire known evolutionary history of lizards, from the Late Triassic to the Late Cretaceous. The finger bones of some pterosaur groups are either unknown or poorly preserved, so they were not included in the analysis. The scientists also compared them to the proportions of neptrodactylomorphs, animals that are not flying lizards. This group included modern birds, lepidosaurs (lizards, snakes, crocodiles), flightless dinosaurs, pseudosuchians, and other species.

As paleobiologists discovered, the limbs of early pterosaurs were adapted for climbing; Its fingers were prehensile and resembled the structure of the claws of modern birds. Climbing was an ancestral method of locomotion that severely limited the mass of lizards because it is much more difficult to move a heavy object up a tree, for example.

However, there are two species that reflect the transition between pterosaurs and the more specialized pterodactyloids: propterodactylus And douzhanopterus – extinct animals had a limb configuration that allowed them to move on the ground. The front and hind legs of Douzhanopterus already prevented it from climbing trees – it was more convenient to walk on all four limbs with strong support from the front parts (this was especially indicated by deeper thrusts).

The transition to a terrestrial lifestyle, which occurred in the middle part of the Jurassic period about 160 million years ago, brought about many other changes in the structure of pterodactyloids. Some taxa, such as ornithocheirids, returned to the old mode of movement, and as experts emphasize, the treasures of ctenochasmatids were terrestrial pterosaurs (among them, by the way, there were also those mentioned above) B. maeuseri with chin comb).

Land expansion provided pterosaurs with a wide range of ecological niches. Some fixed themselves on trees, others moved voluntarily on the ground (for example, to take off), others were committed to terrestrial life. Climbing no longer limited the size of pterosaurs – as a result, ten-meter giants were born who lived at the end of the Mesozoic. Thanks to this versatility, pterosaurs successfully competed with other lizards and acquired unusual adaptations.

“These findings highlight the need to study all aspects of pterosaur movements, not just flight, to fully understand the evolution of pterosaurs. The ability of pterosaurs to fly is only part of their story. By studying how they lived in trees or on the ground, we will be able to understand what role they played in ancient ecosystems.” added the paper’s author, a researcher at the University’s Center for Paleobiology and Evolution of the Biosphere. Leicester (Great Britain) Robert Smith.