Scientists have discovered a new marine dinosaur species that grew up to 43 feet and terrorised the seas over 80 million years ago. Named Tylosaurus rex, or T-rex for short, this massive mosasaur reptile lived primarily in what is now northern Texas.
The name means “king of the tylosaurs”, distinguishing it from the iconic land dinosaur Tyrannosaurus rex, which translates to “tyrant lizard”. Researchers say T-rex was roughly twice the length of the largest great white sharks and appeared to be a much meaner animal than other mosasaurs.
“Through our study and examination of well-preserved fossils collected throughout the north Texas region, we have evidence of violence within this species to a degree not previously seen in other Tylosaurus specimens,” said Ron Tykoski, author of a new study published in the Bulletin of the American Museum of Natural History.
Researchers analysed fossils kept at the American Museum of Natural History as well as more than a dozen similar samples held at other institutions, following suspicion that they represented a different animal. These fossils had finely serrated teeth, a trait uncommon among mosasaurs, and were four million years younger than the species Tylosaurus proriger to which the specimens were thought to belong.
One T-rex specimen housed in the Perot Museum’s collection, nicknamed “The Black Knight”, is missing the tip of the snout and has a fractured lower jaw, damage scientists claim could only be inflicted by its own species. The findings suggest that relationships of known mosasaur species need to be re-examined, as most prior studies relied on the same, minimally modified dataset for decades.
“These findings reshape both the physical and evolutionary picture of mosasaurs, underscoring Texas as a key region for understanding ancient marine ecosystems,” said Michael Polcyn, another study author. Researchers have now assembled a comprehensively revised mosasaur fossil sample dataset, which could lead to a new arrangement of evolutionary relationships among tylosaurs.
