A fossil pulled from Los Angeles's La Brea Tar Pits in 1929 has been identified as a new species of extinct toad, nearly a century after it was dug up. Researchers named it Spea labreae, a spadefoot toad that lived in the region during the last Ice Age.
The discovery, published Aug. 5 in the Journal of Vertebrate Paleontology, is only the second extinct Pleistocene amphibian species ever identified in North America. The fossil itself — an incomplete sacro-urostyle, the bone connecting the lower spine to the hips — had sat in a museum drawer since the excavation, one of thousands of smaller specimens that drew less attention than the tar pits' famous mammoths and saber-toothed cats.
A find in the drawer
Paleontologist José Alberto Cruz identified the bone as belonging to an unrecognized species while reviewing the museum's amphibian and reptile collections during his postdoctoral research.
Oh my god, this is a new species that is being kept in a drawer. And now it's in the light to the world.
José Alberto Cruz, La Brea Tar Pits
Measurements showed the extinct species was somewhat larger than living spadefoot toads found in the region today, according to researchers' findings. Co-author Emily Lindsey said the fossil helps reconstruct the area's Ice Age ecosystem.
If we're trying to understand what Los Angeles looked like during the Ice Age, these are some of our best clues.
Emily Lindsey, La Brea Tar Pits
The same collections review turned up a second surprise: bones from a Mexican burrowing toad, a species whose living populations are now found roughly 1,550 miles south, in southern Mexico. Its presence in Ice Age Los Angeles suggests the region's climate and species ranges have shifted substantially since the Pleistocene, giving researchers another data point for how amphibians respond to long-term climate change.
