Researchers at the University of Kansas have uncovered a long-standing error in the classification of a poison frog species from Peru. The frog, originally described in 1999 based on a photograph, was linked to the wrong preserved specimen, leading to its misidentification for over two decades. The correction reclassifies it as a variant of an existing species.
In 1999, a researcher described a new poison frog species, Dendrobates duellmani, using a photograph of a brightly colored specimen from the Peruvian rainforest near the Ecuadorian border. The specimen was housed in the University of Kansas herpetology collection and assigned catalog number KU 221832 as the holotype—the key preserved example defining the species. However, a mix-up occurred: the researcher requested the catalog number instead of the physical specimen and received the wrong one, which belonged to a brown frog rather than the vibrant one in the photo.
The error persisted until recently, when visiting herpetologists examined the supposed holotype at the Biodiversity Institute and Natural History Museum. "They got the specimen with the described number, they realized: This is not it. The frog is very colorful, and the numbered one was brown," said Ana Motta, lead author and collection manager of herpetology.
Motta and her team delved into field notes, photo records, and historical documentation to trace the correct specimen. They found that the original photo matched a different catalog number, resolving the discrepancy. Their findings, published in the journal Zootaxa in 2025, reclassify Dendrobates duellmani as a color variant of the Amazon poison frog, Ranitomeya ventrimaculata. "Things that look different morphologically can be the same species genetically," Motta explained. "The populations have different colorations but are not reproductively isolated. They share a lot of genetics."
This case highlights the importance of holotypes in taxonomy. "The holotype is the specimen that represents the species," Motta noted, emphasizing how it allows global scientists to compare and verify identifications. In an era of rapid biodiversity loss, the incident underscores the need for verifiable physical specimens over photos alone. "Having the specimen is the only way you can reproduce or verify data," she added. Motta, who manages the world's fourth-largest herpetology collection, described the resolution as a rewarding puzzle, revealing the dynamic nature of museum collections.