Fossils of six new species of pterosaurs, giant flying reptiles that flew over the heads of dinosaurs, have been discovered by a research team led by the Milner Center for Evolution at the University of Bath, which reveals that this lineage was exterminated at its best An analysis of fossils, published on March 13 in the open access journal PLOS Biology shows that, contrary to previous studies, there was still a remarkable diversity among pterosaurs to the point of its extinction.
Pterosaurs, prehistoric reptiles popularly known as pterodactyls, were flying cousins of dinosaurs. Flying over the wings of the skin supported by a single huge finger, they were the largest animals that ever flew.
It was thought that pterosaurs were declining before the mass extinction at the end of the Cretaceous period, which was caused by an asteroid impact 66 million years ago. However, hundreds of new fossils from the Late Cretaceous, discovered at sites in northern Morocco, show that the region harbored seven species of pterosaurs from three different families. It was thought that the rarity of the fossils of pterosaurs from the end of the dinosaur era meant that they were slowly dying out. But the new study shows that the data had been deceptively biased by the shortage of fossils and that the pterosaurs at the moment were actually much more diverse than previously thought.
The new pterosaurs oscillated in a span of just over two meters to almost ten meters (6 to 30 feet) – almost three times larger than the largest living bird – and weighed up to 200 kg (440 pounds). The fossils date from a little more than 66 million years ago, at the end of the Cretaceous period, turning these pterosaurs into the last of their kind on Earth. In addition to the diversity in size, the authors were also able to demonstrate that the species differed significantly in the shape and size of the parts of their bodies (such as the shape of the beak, the length of the neck and the wing proportions), which Suggests that niches.
Dr. Nick Longrich, from the Milner Center for Evolution and the Department of Biology and Biochemistry at the University of Bath, and the lead author of the study, said: "To grow so big and able to fly, pterosaurs evolved Skeletons incredibly lightweight, with bones reduced to thin-walled hollow tubes like the frame of a carbon fiber racing bike.
"But unfortunately, that means these bones are fragile and almost none survive like fossils"  Longrich said that he had always found fascinating pterosaurs, and as a university student he had dreamed of studying them, years later in Morocco, he would come across a single small bone mixed with fossil fish dug out of a phosphate mine. ", He said. "I remembered the Illustrated Encyclopedia of Pterosaurs, a book I had practically memorized as a college student, and I thought, 'that's a nyctosaurus.'"
The Nyctosaurs, a family of small pterosaurs, have not been shown to survive until the end of the Cretaceous. For a premonition, he looked for more pterosaurs and found more species, including Tethydraco, a member of the pteranodontids, a family thought to be It would disappear fifteen million years before. In addition to the only species previously found in the area, six additional species appeared. "I think there are many more species to find," he said.
The co-author of the study, Professor David Martill of the University of Portsmouth said: "Exciting discoveries are being made all the time, and sometimes, only the smallest of bones can radically change our perception of the history of the life on Earth. "
Dr. Brian Andres, associate researcher at the University of Texas at Austin, also co-author of the study, added: "Moroccan fossils tell the last chapter in the history of pterosaurs, and tell us that pterosaurs dominated the skies on land and sea, as they had done for the last 150 million years. "
Moroccan paleontologist Professor Nour-Eddine Jalil del Muséum national d & # 39; Histoire naturelle, France commented: "This is a fabulous discovery of the pterosaurs of Morocco: they tell us their incredible diversity while we thought they were in decline." Moroccan phosphates are an open window at a key moment in the history of the Earth, one that shortly preceded the world crisis that swept, among others, dinosaurs and marine reptiles.
New research shows that birds and flying reptiles were friends, not enemies
Longrich NR, Martill DM, Andres B (2018) Pterosaurs of the late Maastrichtian of North Africa and the massive extinction of Pterosauria in the Cretaceous-Paleogene boundary. PLoS Biol 16 (3): e2001663. doi.org/10.1371/journal.pbio.2001663