A single bone, roughly the size of a fingernail, sat in a drawer at the La Brea Tar Pits for close to a century before anyone noticed it belonged to something science had never named. That bone, excavated back in 1929 and left largely unstudied for the following decades, is now the holotype specimen for Spea labreae, a newly described extinct spadefoot toad and only the second Ice Age amphibian species ever identified anywhere in North America.

A collection nobody had carefully checked in 30 years

The discovery, described in a paper published August 4, 2026, in the Journal of Vertebrate Paleontology, came from Dr. J. Alberto Cruz, a postdoctoral fellow at La Brea Tar Pits, who wasn't actually hunting for a new species when he began the project that led to it. Cruz had set out to review the museum's understudied collection of amphibian and reptile fossils, material that, by his own account, "had not been carefully assessed in nearly 30 years."

That kind of long-overlooked museum backlog is common at major fossil sites, where large, dramatic specimens, mammoths, saber-toothed cats, dire wolves, tend to receive the bulk of research attention, while smaller and more fragile fossils sit comparatively neglected in storage. La Brea Tar Pits happens to be a particularly rich source of exactly that kind of overlooked material, given how effectively its natural asphalt seeps preserved even delicate skeletal remains that would have disintegrated entirely at most other fossil sites.

The bone that looked wrong before it looked new

While working through the collection, Cruz's attention caught on an incomplete sacro-urostyle, a bone forming the base of an amphibian's spine where it connects to the hips. It was clearly a spadefoot toad bone, but something about its proportions didn't match any known species. His first instinct wasn't that he'd found something new to science, but that the animal might simply have been sick or injured during its life, a kind of individual abnormality paleontologists call paleopathology rather than evidence of a distinct species.

"I'm really more of a paleoecologist, paleobiogeographer, not a taxonomist," Cruz said, describing his own background as somewhat outside the specific discipline of formally identifying and naming new species. But repeated comparison against modern spadefoot toad specimens ruled out the injury explanation entirely. "I reviewed and reviewed a lot of specimens until I was convinced," Cruz said. "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."

A genuinely rare category of fossil to find at all

What makes Spea labreae scientifically significant extends well beyond simply adding one more name to the tar pits' already extensive species list. Amphibians possess extremely fragile, lightly built skeletons that rarely survive the fossilization process under ordinary conditions, meaning frogs, toads, and salamanders are drastically underrepresented in the fossil record generally, even in eras and regions where they likely lived in considerable abundance. "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," Cruz and co-author Dr. Emily Lindsey noted in describing the find.

That scarcity is precisely why Spea labreae's discovery carries outsized significance for a bone this small: prior to this description, only one other extinct Pleistocene amphibian species had ever been formally identified anywhere in North America, a tree frog previously found in Florida. Spea labreae now becomes just the second, and the very first from anywhere in the western half of the continent.

Slightly bigger, and living somewhere its relatives no longer do

Physically, Spea labreae was measurably larger than its closest living relatives, estimated at roughly 7% bigger than modern spadefoot toad species in the genus Spea. The species inhabited the Los Angeles region during the tail end of the last Ice Age, at a time when the area's climate ran considerably colder and wetter than it does today, conditions reflected in the broader mix of species found alongside it within the tar pits' fossil record.

What one small toad reveals about a much bigger climate story

Beyond its taxonomic novelty, the discovery carries meaningful weight for understanding how Southern California's climate and ecosystems shifted as the last Ice Age came to an end. Amphibians as a group are unusually sensitive to environmental conditions, particularly moisture and temperature, making their presence or absence at a given fossil site a comparatively reliable indicator of past climate conditions compared to more environmentally tolerant species.

That sensitivity extends to a related finding described alongside Spea labreae's formal identification: evidence of a significant range shift among another amphibian species found in the same tar pits deposits, the Mexican burrowing toad. Fossils confirm this species once lived in the Los Angeles area during the Ice Age, even though its closest modern populations are today found far south, in southern Mexico and Central America, according to iNaturalist observation records cited alongside the study. That kind of dramatic northward-to-southward range contraction, paired with Spea labreae's own eventual extinction, offers researchers a more detailed picture of how thoroughly Southern California's amphibian communities reorganized as regional climate conditions warmed and dried out toward the modern era, a process researchers suggest may hold relevance for understanding how amphibians could respond to current, human-driven climate change as well.

Part of a bigger, ongoing transformation at the Tar Pits

The discovery arrives as La Brea Tar Pits undergoes what the museum describes as a historic institutional transformation, centered on its newly established Samuel Oschin Global Center for Ice Age Research, a dedicated hub for research, excavation, scientific analysis, and collections management built specifically to support this kind of detailed, ongoing reexamination of the site's enormous existing fossil holdings. Spea labreae's identification is being highlighted by the museum as a direct example of the daily discoveries that kind of dedicated research infrastructure is designed to keep producing, even from material excavated nearly a century earlier and sitting quietly in storage ever since.

A reminder that old collections still hold new species

Cruz and Lindsey's broader assessment following the discovery points toward a genuinely open-ended possibility: given how fragile amphibian and reptile remains are, and how easily such delicate fossils can be overlooked or misidentified during less detailed collection reviews, researchers suspect considerably more extinct amphibian and reptile species likely remain undiscovered within the tar pits' existing archives, sitting misidentified or entirely unexamined among specimens excavated decades ago.

That pattern, a genuinely new species hiding in plain sight within a nearly century-old museum drawer, echoes a recurring theme across paleontology more broadly this year, where careful modern reanalysis of previously excavated material has repeatedly turned up species nobody had recognized the first time around. For Spea labreae specifically, that means a toad that died sometime during the last Ice Age, was dug out of asphalt-soaked sediment in 1929, and then waited nearly a hundred years for someone to finally look closely enough to notice it had never actually had a name.

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*Sources cited in this article include the peer-reviewed study "A new extinct Pleistocene species of spadefoot toad and comments on the paleoecology and paleobiogeography of anurans from Rancho La Brea, California," published August 4, 2026, in the Journal of Vertebrate Paleontology, and reporting from La Brea Tar Pits' official press release, Phys.org, Sci.News, Nautilus, and LAist covering research led by Dr. J. Alberto Cruz and Dr. Emily Lindsey. All figures reflect reporting available as of August 17, 2026.*