A Lost Toad From the Tar Pits
A new extinct Ice Age spadefoot toad, *Spea labreae*, has been described from bones stored at the La Brea Tar Pits since 1929 — only the second extinct Pleistocene amphibian ever found in North America.
For nearly a century, the asphalt seeps at the La Brea Tar Pits have been yielding up Pleistocene mammals — dire wolves, saber-toothed cats, ground sloths, mammoths — by the thousands. What they have not yielded, almost ever, is an amphibian. On August 5, 2026, a team led by Dr. J. Alberto Cruz broke that pattern: scientists announced the discovery of Spea labreae, a new extinct Ice Age spadefoot toad described from bones recovered at the site, only the second extinct Pleistocene amphibian ever formally identified in North America. The study was published in the Journal of Vertebrate Paleontology, with Dr. Emily Lindsey as coauthor.
The bones had been sitting in storage for the better part of a century. The toad was found in a 1929 excavation that had been barely touched, a run of sediment pulled out of Pit 91 in the early years of excavation and left in museum cabinets ever since. Spadefoot toads spend most of their lives underground, emerging only during the brief windows of seasonal rain — a behavioral quirk that makes them rare in the fossil record to begin with, and which probably explains why nothing like this has shown up in nearly 90 years of continuous work at one of the most heavily sampled Ice Age localities on the continent.
The find is genuinely small. A single species represented by a handful of bones is, in the La Brea context, almost a footnote compared with the tens of thousands of dire wolves and saber-toothed cats catalogued from the same pits. But the footnote lands harder than its size suggests, because it clears up a long-standing puzzle: which spadefoot toads actually lived in Pleistocene Los Angeles, and what the climate looked like when they did. Spea, the genus to which the new species belongs, is sensitive to moisture in ways that larger vertebrates are not. Confirming that a Spea species was present in Ice Age LA — and that it is its own species, not a southern population of something still alive today — gives paleontologists a tighter handle on what the basin would have felt like to a small, wet-skinned animal trying to breed in it.
The same study documents a second first: the first record of the Mexican burrowing toad (Rhinophrynus) in the southwestern United States, a species now found only around 2,500 kilometers away in southern Mexico. Rhinophrynus is its own one-species genus, an odd tongue-fed burrower whose modern range hugs the tropics. Pulling it out of Pleistocene sediment from what is now downtown Los Angeles pushes its historical distribution across almost the entire breadth of Mexico and into California, and it does so for an animal whose climate tolerances today would not put it anywhere near the site. The combined picture — a now-extinct Spea living alongside a now-tropical Rhinophrynus in Ice Age LA — is consistent with a cooler but wetter Ice Age California than the dry, fire-prone landscape the basin has become.
None of this rewrites the larger picture of Ice Age North America, which is dominated by charismatic mammals and reconstructed largely from them. What it does is plug a long-empty corner of the record. Amphibians are the animals most tightly bound to local moisture and temperature — they are, in a real sense, living hygrometers — and the La Brea asphalt has now produced two of them, separated by almost a century of digging. That the second one only just turned up, in dirt that had been on a shelf since before the Great Depression, is a useful reminder of how much pre-excavated fossil is still waiting to be re-read with the questions of the 2020s in mind.