The discovery sheds light on “cryptic” species, which are described as those lacking obvious differences separating evolutionarily distinct populations. According to the researchers, black-bellied salamanders were known as a single species for more than 100 years, but nonetheless have subtle differences between them.
“Black-bellied salamanders have been commonly studied for over 100 years,” Pyron said. “In 2002, a cryptic dwarf species was discovered, and, in 2005, DNA evidence began to suggest there were still more. It wasn’t until our NSF-funded research in 2020 that we were able to sequence genome-scale data to figure out there were actually five similar-looking species.”
The researchers began by observing Desmognathus quadramaculatus, a species of salamander that has been poorly characterized throughout its history. They noticed that certain morphological, genetic and geographic aspects differed among the specimens, including variation in size, shape and color pattern. After sequencing the genome from D. quadramaculatus, the researchers discovered five separate species, three of which are new to researchers. The new species are now known as D. gvnigeusgwotli, D. kanawha, and D. mavrokoilius.
“After looking at multiple specimens, we see obvious and substantial phenotypic variation between most lineages,” Pyron said. “In fact, the name ‘quadramaculatus,’ which was used for over 120 years, is not the correct name for any of these five species. We tracked down the original specimens at museums in Philadelphia and Paris and found that they belonged to a totally separate species. This raises the question of how ‘cryptic’ they ultimately are.”
According to the researchers, future studies should offer substantial additional insights into the evolutionary history, geographic distribution, ecological interactions, and other aspects of the new black-bellied salamanders.
The study, “Nomenclatural solutions for diagnosing ‘cryptic’ species using molecular and morphological data facilitate a taxonomic revision of the Black-bellied Salamanders (Urodela, Desmognathus ‘quadramaculatus’) from the southern Appalachian Mountains” was published July 19, 2022, in the journal Bionomina. The research team also included David Beamer of Nash Community College.
The National Science Foundation (DEB-1655737, DEB-0808451, DEB-1656111) supported this research.