Scientists have identified a new species of marine dinosaur, Tylosaurus rex, which grew up to 43 feet long and terrorised the seas over 80 million years ago. The massive mosasaur reptile, whose name means 'king of the tylosaurs', lived primarily in what is now northern Texas.
According to a study published in the Bulletin of the American Museum of Natural History, Tylosaurus rex was roughly twice the length of the largest great white sharks and appeared to be a much meaner animal than other mosasaurs. Researchers analysed well-preserved fossils from north Texas and found evidence of violence within the species to a degree not previously seen in other Tylosaurus specimens.
The fossils had finely serrated teeth, a trait uncommon among mosasaurs, and were four million years younger than the species Tylosaurus proriger, to which they were originally thought to belong. The species was named in homage to palaeontologist John Thurmond, who first recognised tylosaurs as a new species in the late 1960s.
One specimen, nicknamed 'The Black Knight', shows damage to the snout and lower jaw that scientists believe could only have been inflicted by its own species, suggesting powerful jaw and neck muscles. The findings highlight the need to re-examine relationships among known mosasaur species, as most prior studies relied on outdated datasets.
Researchers have now assembled a comprehensively revised mosasaur fossil dataset, which could lead to a new arrangement of evolutionary relationships among tylosaurs. Co-author Amelia Zietlow noted that the study 'highlights the need to revisit long-standing assumptions about mosasaur evolution', while Michael Polcyn added that Texas is a key region for understanding ancient marine ecosystems.
