[Rockhounds] Controversial idea that T. rex was three species comes under fire

[Kreigh Tomaszewski]

A controversial claim made earlier this year that *Tyrannosaurus rex* should
be split into three separate species has been rejected by another group of
researchers.

In March, after analysing teeth and leg bones of 38 *T. rex *fossils, Scott
Persons
<https://geology.cofc.edu/about-the-department/faculty-and-staff/persons-scott.php>
at
the College of Charleston in South Carolina and his colleagues proposed
that rather than there just being one iconic *“*tyrant lizard king*”, *there
were three species.

According to Persons’s team, there was an early species, *Tyrannosaurus
imperator *(tyrant lizard emperor), which subsequently evolved into two
more recent species, one of which had a slender frame and thin thigh bones
– called *Tyrannosaurus regina *(tyrant lizard queen). The other was more
heavily built with stout thighs and retained the name *T. rex*. The team
also found variation in the shape of teeth in fossilised lower jaws, saying
this further supported the idea that *T. rex* should be considered as three
species.

Now, a study by James Napoli
<https://www.researchgate.net/profile/James-Napoli-2> at the American
Museum of Natural History in New York and his colleagues has criticised the
earlier work. His team found issues with the methods used by Persons’s
group to separate the *T. rex* fossils into groups, based on thigh bone
measurements.

By reanalysing the data with a method that makes fewer assumptions about
how the specimens might be split into groups, Napoli’s team found that the
fossils clustered as one group, rather than as separate species.

“I don’t think the data they provided is convincing,” says Napoli. “We
found that the specimens simply cluster as one group, indicating a single
species.”

https://www.newscientist.com/article/2330552-controversial-idea-that-t-rex-was-three-species-comes-under-fire/