Researchers have identified a new species of rocket frog, named Dryadobates erythropus, based on a single specimen collected in 1963. This discovery highlights the likely extinction of the species in the wild. The study, published in the journal Zootaxa, involved collaboration between scientists from the University of São Paulo in Brazil and the Smithsonian Institution in the United States.
The only known specimen of D. erythropus was collected by American herpetologist Doris M. Cochran during her visit to Brazil alongside entomologist Doris H. Blake. This specimen is housed at the Smithsonian’s National Museum of Natural History in Washington D.C. It measures approximately 14 millimeters in length and is described as “probably extinct” due to the absence of any additional specimens found in the wild or in museum collections over the past six decades.
Curitiba, the capital of the state of Paraná, was once a rich habitat for diverse species, including this newly identified frog. However, urban development has drastically altered the landscape, making it difficult to envision its former biodiversity. According to Taran Grant, a professor at the Institute of Biosciences at USP and the lead author of the study, extensive surveys in São Paulo and Paraná have yielded no further sightings of the species.
Historical Context and Identification
The genus Dryadobates is relatively new, with at least 13 species recognized to date. Of these, four are believed to have gone extinct between the 1960s and 1980s. The name Dryadobates is derived from Greek mythology, while erythropus translates to “red foot,” a reference to rural workers in northern Paraná who worked barefoot on the region’s reddish soil.
Grant’s investigation into the precise location of the frog’s collection involved examining Cochran’s travel diary. This document provided critical insights into the environment where the frog was found. “The notes from January 9, 1963, clearly state that two frogs were captured in a ‘large field full of anthills and cow-chewed bushes,'” Grant explained. The noted location is approximately 550 kilometers south of the nearest known related species, D. olfersioides, which is also presumed extinct.
Challenges in Genetic Analysis
Efforts to extract historical DNA (hDNA) from the specimen have posed significant challenges. Grant attempted to obtain genetic material from the frog but encountered contamination from human DNA and bacteria instead. The condition of the specimen suggested it had deteriorated before being preserved properly, which hindered any chance of successful genetic identification.
While the extraction of hDNA has successfully facilitated the identification of other species from museum specimens, the degraded state of Cochran’s frog specimen rendered molecular identification impossible. Grant noted that advancements in technology might one day allow for genetic identification of such specimens in the future.
Despite the absence of genetic data, the researchers were able to classify D. erythropus based on its morphological features, distinguishing it from its northern relatives. This work serves as a reminder of the importance of preserving natural habitats and documenting biodiversity. Grant emphasized the contributions of Cochran and Blake, stating, “If it weren’t for them, we wouldn’t know that we once had this species.”
The findings not only enhance the understanding of this particular frog but also underscore the broader implications of habitat destruction, as many species may have already disappeared without ever being documented. The study reinforces the critical need for ongoing conservation efforts and the protection of natural ecosystems.
