Researchers describe a new species of marine reptile, Tylosaurus rex, from Late Cretaceous-era fossils found primarily in northern Texas. The species is classified as a mosasaur, a group of ocean-dwelling predators that lived during the dinosaur age. According to the studies, the newly described mosasaur can reach about 43 feet (13 meters) in length, placing it among the largest mosasaurs known. The fossils date to roughly 80 million years ago, and the material has been available for decades before being re-examined and formally described by an international team. The researchers characterize T. rex as a top predator of ancient seas, emphasizing its large size and inferred powerful bite based on its skull and feeding adaptations. The species name, “Tylosaurus rex,” is presented as meaning “king of the tylosaurs.” Together, the reports highlight both the fossil origin in Texas and the identification of a major new apex predator within the mosasaur lineage.