Researchers have identified a new extinct species of Ice Age spadefoot toad, named Spea labreae, from fossils found at the La Brea Tar Pits in Los Angeles [1, 2].
The discovery is significant because it provides rare data on the ancient climate and ecosystems of the Los Angeles region during the Pleistocene epoch [4, 5].
Amphibians are rarely preserved in the fossil record due to their small size and fragile skeletons. This find marks only the second Ice Age amphibian discovered in North America [3]. The only other known extinct Pleistocene amphibian from the continent is a tree frog found in Florida [2].
The fossil specimen dates back more than one million years [4]. Other data indicates the fossil represents the beginning of the end of the last Ice Age [6].
Scientists studying the collection said that the toad lived exclusively in the Los Angeles area [4]. The preservation at the La Brea Tar Pits allows researchers to reconstruct the environmental conditions that supported such species, conditions that differ vastly from the modern urban landscape of Southern California.
By analyzing the physical characteristics of Spea labreae, researchers can better understand how spadefoot toads adapted to the shifting temperatures and water availability of the prehistoric West Coast. The find adds a critical piece to the biological map of the Ice Age, filling a gap in the understanding of small vertebrate populations during this era [5].
“Only the second Ice Age amphibian found in North America”
The discovery of Spea labreae highlights the unique preservative qualities of the La Brea Tar Pits, which capture a broader spectrum of biodiversity than typical fossil sites. Because amphibians are highly sensitive to environmental changes, this fossil serves as a biological proxy for understanding the specific humidity and temperature fluctuations of the Pleistocene era in California.
