A new species of Ice Age toad discovered at La Brea Tar Pits: the spadefoot toad Spea labreae
Along with the first description of an extinct species of amphibian, the paper also identifies the first record of the Mexican burrowing toad at the Tar Pits, shedding light on climate change impacts on species distributions past, present, and future
Natural History Museum of Los Angeles County
image:
Reconstruction of Spea labreae, sp. nov. (dark spadefoots, center and right) in La Brea Tar Pits compared with Spea hammondii (light spade-foot, left), the species currently present in the area, and the presence of the Mexican burrowing toad (Rhinophrynidae, bottom). Courtesy of La Brea Tar Pits
Credit: Artwork by Arturo Dávalos
Los Angeles, CA (August 5, 2026)—For the first time, researchers have discovered a new species of extinct amphibian from Ice Age Los Angeles at La Brea Tar Pits: a spadefoot toad which they have named Spea labreae. Only one other extinct Pleistocene amphibian from North America has ever been found (a tree frog from Florida). While the toad may be much smaller than the mammoths and saber-toothed cats that made the Tar Pits famous, this discovery has a big impact on our understanding of the climate at the end of the last ice age. Described in the Journal of Vertebrate Paleontology, S. labreae spotlights the ongoing daily discoveries at the Samuel Oschin Global Center for Ice Age Research at La Brea Tar Pits as the iconic museum begins a historic transformation.
The study’s lead author, Dr. Alberto Cruz, wasn’t looking for new species when he began his review of the Tar Pits’ understudied collections of amphibians and reptiles as a Postdoctoral Fellow working at La Brea Tar Pits, where he remains a Research Associate while working full time as Researcher for Mexico’s SECIHTI-Centro de Investigación Paleontológica Quinametzin (CIPAQ), Instituto Nacional de Antropología e Historia (INAH).
“I'm really more of a paleoecologist, paleogeographer, not a taxonomist,” says Dr. Cruz, who first noticed the distinctive features that separate S. labreae from known spadefoot toads while reviewing the Tar Pits’ collection of reptiles and amphibians. His first thought on seeing the new species was that the specimen had been sick or injured during its life, an example of paleopathology, rather than a new species. However, further comparisons to modern spadefoot toads left no doubt. “I reviewed and reviewed a lot of specimens until I was convinced. I thought, ‘Oh my gosh, this is a new species.’ This material is originally from the 1950s, but when you study it again, you can find gold in these specimens. It's very cool.”
“It’s a great example of how we’re still finding new things at La Brea Tar Pits, even after a century of ongoing excavation and research,” says Dr. Emily Lindsey, Curator and Excavation Site Director at the Samuel Oschin Center for Global Ice Age Research at La Brea Tar Pits. “There’s definitely more to come.”
Ancient Climate Through the Lens of Amphibians
While the iconic large mammals often grab headlines and capture our imagination, the small reptiles and amphibians Cruz studies can tell scientists much more about ancient climate and environmental change.
Amphibians don’t travel very far within their lifetimes and are extremely sensitive to environmental conditions. This limited movement and high sensitivity makes amphibians excellent climate proxies, whose presence or absence can help scientists discern changes in climate at a smaller scale.
“If you change the environment, you change the vegetation, the climate is warmer or colder, it affects these animals directly,” says Cruz.
Due to their fragile skeletons, amphibians like frogs, toads, and salamanders rarely make it into fossil records outside of asphaltic sites like the Tar Pits. The discovery of a new species—particularly a small amphibian like S. labreae—is an extraordinary find at the Tar Pits.
Their fragility and sensitivity to environmental changes also make researchers like Dr. Cruz suspect that there are many more extinct amphibians and reptiles whose remains were too delicate to make it into the fossil record.
To identify the new species, Dr. Cruz examined the bones of Tar Pits amphibians, a collection that had not been carefully assessed in nearly 30 years. Making detailed observations of their shape and size. Dr. Cruz compared Tar Pits amphibians to 80 specimens at the Herpetology Collections at the Natural History Museum of Los Angeles County and the Museum of Vertebrate Zoology at the University of California, Berkeley.
Along with the newly described species, the study identifies the first record of the Mexican burrowing toad, Rhinophrynus, from the southwestern United States. These living toads are no longer found in modern Los Angeles, and in fact, their nearest populations are nearly 2,500 km away in southern Mexico. This significant range shift, along with the extinction of S. labreae, further illuminates the multifaceted story of environmental change at the end of the last Ice Age, and helps us understand how they might cope with the human-caused climate change of today.
About the Samuel Oschin Global Center for Ice Age Research
A global center for pioneering science, the Samuel Oschin Global Center for Ice Age Research encompasses research, excavation, scientific analysis, publishing, and collections management. This work will be woven into the landscape of Hancock Park, integrated into the George C. Page Museum, and infused into every La Brea Tar Pits program, driving the educational and visitor experience, while advancing scientific research around the world. Founded in 2026 with a transformative gift from the Mr. and Mrs. Samuel Oschin Family Foundation, the Samuel Oschin Global Center for Ice Age Research embodies the core principles of the reimagined La Brea Tar Pits, which is set to open in 2028.
Journal
Journal of Vertebrate Paleontology
Method of Research
Observational study
Subject of Research
Animals
Article Title
A NEW EXTINCT PLEISTOCENE SPECIES OF SPADEFOOT TOAD AND COMMENTS ON THE PALEOECOLOGY AND PALEOBIOGEOGRAPHY OF ANURANS FROM RANCHO LA BREA, Q1 CALIFORNIA
Article Publication Date
5-Aug-2026
Coauthors Dr. Alberto Cruz (right) and Dr. Emily Lindsey at the Talara asphaltic site in Piura, Peru, looking for more amphibians, reptiles, and other climate-sensitive microvertebrates. Courtesy of La Brea Tar Pits
Credit
Photo by Tyler Hayden
This incomplete sacro-urostyle bone (base of the spine that connects to the hips) is the holotype specimen used to describe the new species, Spea labreae. Courtesy of La Brea Tar Pits
A nearly complete sacro-urostyle of a possibly juvenile individual Spea labrae. Courtesy of La Brea Tar Pits
Credit
Photo by Dr. Alberto Cruz
An iNaturalist observation of the Mexican burrowing toad, Rhinophrynidae dorsalis, recorded in Costa Rica. Though now known to have inhabited Los Angeles during the last Ice Age, the closest modern populations are found in southern Mexico.
Credit
Photo by Curtis Eckerman
Lead author Dr. Alberto Cruz in the field at the Talara asphaltic site in Piura, Peru. As a researcher with the Instituto Nacional de Antropologia y Historia in Mexico City, Dr. Cruznow leads research on the microvertebrate communities associated with the Santa Lucia Quinametzin mammoth site. Courtesy of La Brea Tar Pits
Credit
Photo by Tyler Hayden
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