Paleontologists Discover a New Species of Ice Age Toad at the La Brea Tar Pits, Offering Clues About the Area's Ancient Climate

Over the past tens of thousands of years, the La Brea Tar Pits in modern-day Los Angeles became the final resting place for millions of animals that got stuck in its dark, sticky pools. Today, some of the fossil site’s most famous victims include mammoths, giant ground sloths, dire wolves and saber-toothed cats. But tiny creatures also met their doom in the bubbling pits of asphalt.

Now, these often overlooked animals are spilling secrets about what southern California looked like long ago. In a study published August 4 in the Journal of Vertebrate Paleontology, researchers have identified a fossil of a never-before-seen species of spadefoot toad. This creature, dubbed Spea labreae after the tar pits, is the first extinct Ice Age amphibian found at La Brea and only the second discovered in North America.

Alberto Cruz, a paleoecologist at La Brea and Mexico’s National Institute of Anthropology and History, tells Scientific American’s Damien Pine. A few years ago, Cruz began to analyze La Brea’s relatively understudied reptile and amphibian collections. But some unusual-looking specimens stumped him.

He initially thought they might have belonged to a sick or injured animal, according to a statement. So he and his co-author Emily Lindsey, also a paleoecologist at La Brea, compared the remains—recovered in 1929—to others in the collection. They also looked at fossils at the Natural History Museum of Los Angeles County and the Museum of Vertebrate Zoology at the University of California, Berkeley.

Unique features in the fossilized bones hinted that they came from a previously undescribed species: S. labreae. It’s an important addition to the fossil record because delicate skeletons of toads and other frogs don’t fossilize easily, so they’re rarely unearthed outside of asphaltic goo. Researchers don’t know exactly how old the toad is, since they’d have to use a destructive technique to find out.

But based on other remains found in the pool of tar where it was found, the team suspects it lived at least around 45,000 years ago, during the last Ice Age, which took place around 11,700 to 2.6 million years ago, reports Scientific American. Quick fact: La Brea’s saber-toothed cats In July, researchers reported signs of tumors and other spinal deformities in saber-toothed cat fossils found at La Brea. The findings hint at inbreeding among the now-extinct predators as their numbers dwindled.