Research leads to discovery of Ice Age mammal

An Albuquerque museum curator was part of a team that identified a new species related to the muskox — one that roamed thousands of years ago and found its final resting place in what's now known as Carlsbad Caverns.

The fossils have been classified as Speleotherium logani, named for Lloyd Logan, the paleontologist who led the exploration uncovering the fossils inside Muskox Cave in Carlsbad Caverns National Park in 1976 and 1977. 

The fossils were identified as a relative of the muskox by New Mexico Museum of Natural History & Science paleontology curator Gary Morgan, and Richard White and Jim Mead of the Mammoth Site in South Dakota, who recently published their findings in the New Mexico Museum of Natural History & Science Bulletin.

The Speleotherium, which was up to 4 feet tall and weighed between 400 and 700 pounds, lived during the Late Pleistocene Period that ended less than 12,000 years ago, New Mexico Museum of Natural History & Science spokesperson Stephen Hamway said in a Dec. 10 news release.

"New Mexico is known as a hotbed for dinosaur fossils, but discoveries like this remind us that our state's fossil record extends long after the Cretaceous extinction," said Anthony Fiorillo, New Mexico Museum of Natural History & Science executive director.

In 2023, Morgan, White and Mead began studying the fossils and realized they belonged to a previously unknown relative of the muskox, Hamway said.  The horns, which resemble those of a modern muskox, played a "key role in helping researchers identify Speleotherium as a new species," Hamway said.

Additionally, comparisons with bones of both the front and hind legs in the Muskox Cave collection allowed researchers to identify bones of this new species from other fossil sites, including the U-Bar Cave in Hidalgo County and three other caves, two in Mexico and one in Belize, he said.

"Fossils of most large Ice Age mammals, such as mammoths, mastodons, ground sloths, and sabretooth cats, were discovered more than a century ago, with only a few new species, including Speleotherium logani, recognized within the past few decades," Morgan said in a statement. "The discovery of Speleotherium in Muskox Cave and U-Bar Cave attests to the extraordinary rich fossil record of Ice Age mammals in New Mexico."

Gregory R.C. Hasman is a general assignment reporter and the Road Warrior. He can be reached at ghasman@abqjournal.com or 505-823-3820.