Releases | New Mexico Department of Cultural Affairs

The one true king

August 4th, 2022

Albuquerque, NM - The mighty Tyrannosaurus rex should continue to be classified as a single unique species, according to a new report co-authored by a researcher from the New Mexico Museum of Natural History & Science (NMMNHS).  

The new paper, published recently in the journal Evolutionary Biology and headed by paleontologists at the American Museum of Natural History and Carthage College, refutes a provocative claim made earlier this year that fossils classified as the iconic dinosaur T. rex represent three separate species. The new study finds that the earlier proposal lacks sufficient evidence to split up the iconic species.   

“There appears to be only one species of the ‘Tyrant Lizards’, and that’s the king, T. rex,” said Dr. Thomas Williamson, paleontology curator for NMMNHS and co-author of the study. 

In March 2022, authors of a controversial study, also published in Evolutionary Biology, made the case that T. rex should be reclassified as three species: the standard T. rex, the bulkier “T. imperator,” and the slimmer “T. regina.” The study was based on analysis of the leg bones and teeth of 38 T. rex specimens.  

The authors of the new study revisited the data presented in the earlier paper and added data points from 112 species of living dinosaurs — birds — and from four non-avian theropod dinosaurs. They found that the multiple species argument was based on a limited comparative sample, non-comparable measurements, and improper statistical techniques. 

“When compared to data from hundreds of living birds, we actually found that T. rex is less variable than most living theropod dinosaurs, said James Napoli, co-lead author of the new study and a graduating doctoral student in the Museum’s Richard Gilder Graduate School. “This line of evidence for proposed multiple species doesn’t hold up.” 

Dr. Williamson at NMMNHS applied his extensive body of research on tyrannosaurs to the study. He previously collected Bistahieversor sealeyi (a.k.a., “The Bisti Beast”), an earlier cousin of T. rex, from the San Juan Basin of northern New Mexico in the late 1990s.  

He later teamed up with Dr. Thomas Carr of Carthage College to describe and name the dinosaur and two additional tyrannosaur genera and species. In their research, Dr. Carr and Dr. Williamson examined many specimens of Tyrannosaurus and other tyrannosaurs housed in major museums in the U.S. and Canada, placing them among North America’s top tyrannosaur experts. 

About the New Mexico Museum of Natural History and Science The New Mexico Museum of Natural History and Science is a division of the Department of Cultural Affairs, under the leadership of the Board of Trustees of the New Mexico Museum of Natural History & Science. Programs and exhibits are generously supported by the New Mexico Museum of Natural History Foundation, through the generous support of donors. Established in 1986, the mission of the New Mexico Museum of Natural History & Science is to preserve and interpret the distinctive natural and scientific heritage of our state through extraordinary collections, research, exhibits, and programs designed to ignite a passion for lifelong learning. The NMMNHS offers exhibitions, programs, and workshops in Geoscience, including Paleontology and Mineralogy, Bioscience, and Space Science. It is the Southwest’s largest repository for fossils and includes a Planetarium and a large format 3D DynaTheater. 

# # #

Bisti Beast Skull, Courtesy of NM Museum of Natural History & Science.

New Mexico CulturePass

Your ticket to New Mexico's exceptional Museums and Historic Sites.
From Indian treasures to space exploration, world-class folk art to awesome dinosaurs—our museums and monuments celebrate the essence of New Mexico every day.
More Info »

The wallet size version of the CulturePass showing the $30 price
An animated image of a cell phone showing various topics presented in the Encounter Culture podcast

Encounter Culture

Take a look inside the museums and historic sites of New Mexico without leaving home. Join host Charlotte Jusinski, and a variety of guest curators, artists, and exhibitors in exploring the art and culture of the state in Encounter Culture, a new podcast from the New Mexico Department of Cultural Affairs.

Logo and Link to Google Podcasts Logo and Link to Apple Podcasts Logo and Link to Spotify Podcasts

Featured DCA Exhibitions

A photo featuring items representing the Early Agriculture exhibition

Early Agriculture

People have been growing food in what is now New Mexico for 4,000
more »

A photo featuring items representing the Música Buena: Hispano Folk Music of New Mexico exhibition

Música Buena: Hispano Folk Music of New Mexico

The exhibition Música Buena: The exhibition will focus on the rich history of traditional Hispano music from the
more »

A photo featuring items representing the Transgressions and Amplifications: Mixed-Media Photography of the 1960s and 1970s exhibition

Transgressions and Amplifications: Mixed-Media Photography of the 1960s and 1970s

What defines a photograph? The dynamic new exhibition Transgressions and Amplifications: Mixed-Media Photography of the
more »

A photo featuring items representing the Curative Powers: New Mexico’s Hot Springs exhibition

Curative Powers: New Mexico’s Hot Springs

The New Mexico History Museum is pleased to present Curative Powers: New Mexico’s Hot Springs, a
more »