The animal lived at the beginning of the Cretaceous period, reached 5 meters in length and hunted for large prey.
An international team of researchers led by Valentin Fisher from the University of Oxford have found fossils of a new species of pliosaurus in Russia, named Makhaira rossica. A detailed description of the find was published in the journal Royal Society Open Science.
The fossils found included fragments of the skeleton of a young animal, enclosed in limestone rocks in the Ulyanovsk region on the banks of the Volga River. Makhaira rossica lived in the early Cretaceous period and belonged to the Brahauchenius group, which lasted until the end of the Mesozoic era. However, the new pliosaurus was smaller than its later relatives.
Little remains of the Russian pliosaurus: part of the premaxillary bone, the anterior part of the lower jaw, several teeth, three thoracic vertebrae, parts of the ischium and ilium. The most interesting feature of the Russian pliosaur was its teeth. They were arranged in pairs along the jaw, their edges were covered with tiny teeth, and their size was large, which resembled the teeth of terrestrial predators of the time, such as theropod dinosaurs. Overall, the structure of the teeth and the size of the jaw indicated that Makhaira rossica was approximately five meters long and specialized in large prey. This type of feeding was thought to have been lost in Cretaceous pliosaurs, but the find suggests that at least one species was still a macrophage.
Pliosaurs are marine lizards, a short-necked plesiosaur that appeared in the early Jurassic and disappeared in the late Cretaceous along with many groups of vertebrates, including dinosaurs. Among the pliosaurs, there were some of the largest known marine predators, such as the Pliosaurus funkei, known as Predator X and reaching a length of up to thirteen meters.