Overview
- Researchers published the formal description of Spea labreae in the Journal of Vertebrate Paleontology on Wednesday after reexamining long-neglected amphibian material from the La Brea Tar Pits.
- The identification rests on distinctive sacro-urostyle (hip) bones that differed from modern spadefoot toads after comparisons with dozens of museum specimens.
- The fossils are fragile and cannot be directly radiocarbon-dated without damage, so authors estimate a Late Pleistocene age of about 45,000 years by association with dated material in the same deposits.
- The study also reports the first Rancho La Brea record of the Mexican burrowing toad, a species whose nearest living populations are roughly 1,500 to 2,500 miles to the south, signaling a large late-Quaternary range shift.
- Because amphibians stay close to water and respond strongly to temperature and moisture, the finds underscore the scientific value of museum archives and asphaltic sites for reconstructing past climates and informing modern conservation work.