70% of all terrestrial vertebrate species and 96% of marine organisms perished during the Great Dying, 252 million years ago. The causes that led to this mass extinction, the most devastating the planet has experienced, are not clear, but, according to a new study, marine reptiles managed to seize many of the ecological niches that were left empty in the oceans in a very short time.
During the Mesozoic, the geological era that followed the aforementioned Permian-Triassic extinction and that lasted until 66 million years ago, dinosaurs spread through the landmass and marine reptiles, such as ichthyosaurs, plesiosaurs or mosasaurs , they became the dominant predators in their environment . However, it is unknown how they did so so successfully.
Now, a team of researchers coordinated by paleobiologist Tom Stubbs, from the Faculty of Earth Sciences at the University of Bristol, in the United Kingdom, assures that these animals did not spread little by little through ecosystems, but instead so to speak, they burst onto the scene. “We know that when marine reptiles were distributed throughout the oceans during the Triassic – between 252 and 201 million years ago – they developed very quickly different morphological adaptations that allowed them to feed on very diverse prey. Nothing like it was seen during the rest of the Mesozoic. In a relatively short space of time, they began to feed on all kinds of fish, invertebrates and even other reptiles, ”says Stubbs.
To determine this, this expert and his collaborators studied the variations in the structure of the jaws and teeth of these animals . Thus, they discovered that species of very different sizes and eating habits emerged much faster than previously believed. However, just 30 million years after this evolutionary bombshell, a series of extinctions in the late Triassic wiped out most of all groups of marine reptiles. In this way, many of these adaptations were lost, which determined the evolution of these animals in the long term.
Image: Dmitry Bogdanov / GNU / CC
