Explained: What is the Thanatotheristes, reaper of death?

The 79-million-year-old fossil that the researchers have found is the oldest tyrannosaur known from northern North America.

Thanatotheristes degrootorum. (Julius Scotonyi, Royal Tyrrell Museum)

Scientists at the University of Calgary and Royal Tyrrell Museum have found that a dinosaur fossil, found in Alberta in Canada in 2010, belongs to a new species of tyrannosaur. They have named it Thanatotheristes, which means “reaper of death”.

Tyrannosaurs were one of the largest meat-eating dinosaurs to have ever lived, with very large and high skulls, and the best known among them is the Tyrannosaurus rex, celebrated in the Jurassic Park series.

The 79-million-year-old fossil that the researchers have found is the oldest tyrannosaur known from northern North America.

Story continues below this ad

In a statement issued by the University of Calgary, the study’s lead author Jared Voris, whose analysis has identified the new species, said the fossil specimen is important to understand the Late Cretaceous period, which is the period when tyrannosaurs roamed the Earth.

📢 Express Explained is now on Telegram. Click here to join our channel (@ieexplained) and stay updated with the latest

The scientists named the genus and species Thanatotheristes degrootorum, after John and Sandra de Groot who found the fossil in 2010. They identified it from fragmentary fossil parts of the skull and the upper and lower jaw bones. Until last year, the specimen lay in a drawer at the Royal Tyrrell Museum.

Thanatotheristes preyed on large plant-eating dinosaurs such as the horned xenoceratops and the dome-headed colepiochephale. The research suggests that tyrannosaurs did not have one general body type; rather different tyrannosaur species evolved distinct body sizes, skull forms and other such physical features.