Animal remains dating back about 33 million years were initially believed to have belonged to a sabre-toothed tiger, but new analysis has revealed that it was actually a previously unidentified species.
The remains were on display at Washington’s Smithsonian National Museum of Natural History but were taken down in 2017 when the building underwent renovations. That’s when University of Oregon graduate student Paul Barrett decided to examine the specimen in further detail.
Analysis of the remains revealed that the creature wasn’t a sabre-toothed tiger, but an entirely new species that has been named Eusmilus adelos. It was in fact a lot bigger and had sharper teeth than the sabre-toothed tiger, although they did live at the same time approximately 33 million years ago.
Eusmilus adelos was a member of a mammal group called nimravids that had bodies similar to cats and that lived between 40 million and 7 million years ago. While sabre-toothed animals were around the same size as today’s cougars and bobcats, Eusmilus adelos was about the size of a lion.
Barrett explained the newly identified creature in further details in the study, “Nimravids were the first carnivorans to evolve saber teeth, but previously portrayed as having a narrow evolutionary trajectory of increasing degrees of saber-tooth specialization,” adding, “For its time period, it was anomalously large.”
He even went a step further and looked at the evolution of nimravids. “Historically, our ideas of how nimravids evolved is that they got increasingly more saber-toothed until they went extinct.” But after he analyzed the animal’s teeth, skull, and other bones such as its spine and limbs, he realized that its evolution was a lot more complicated than previously thought.
Barrett claimed that nimravids split into two different groups – one of which evolved saber teeth, while the other evolved into several different species that looked like modern cats. The lineage of sabre-toothed cats eventually went extinct and the species that did survive evolved different teeth that are now seen in today’s cats.
He went on to say, “Here I present a novel hypothesis about the evolution of this group, including a description of Eusmilus adelos, the largest known hoplophonine, which forces a re-evaluation of not only their relationships, but perceived paleoecology.” His study was published in Scientific Reports where it can be read in full.
Pictures of some of the Eusmilus adelos bones can be viewed here.