Sometimes new species are hiding in plain sight, in our museum drawers. Some new species are morphologically obvious, or we can identify them by looking at their features visible to the naked eye, such as color and body shape. Others are cryptic, and we often need molecular or genetic data as well as morphology to set these apart from known species.
Researchers at the LSU Museum of Natural Science recently used just these types of data, including DNA sequences from various organisms, to explore the genetic diversity and population structure of New Guinea ground snakes of the genus Stegonotus. Little is known about how these snakes are related to one another and to other snakes. This is partly due to the fact that Stegonotus snakes are relatively inconspicuous, often drably colored in shades of brown and grey, and can be difficult to study because they are active at dusk or night. Field work in New Guinea is also infamously difficult.
“The island of New Guinea has been identified as biologically megadiverse; however, it remains one of the least studied regions of the world,” Rutgers University snake researcher Sara Ruane and collaborators write in a research article published this month in the Journal of Natural History. “Most groups of snakes in New Guinea have been poorly studied and are in dire need of taxonomic revision.”
In the hopes of identifying undescribed taxa, Sara Ruane, an assistant professor in the Department of Biological Sciences at Rutgers University and a former postdoctoral researcher in the LSU Museum of Natural Science (LSUMNS), and collaborators including LSUMNS Curator of Herpetology Chris Austin analyzed molecular data from 49 individuals representing New Guinea Stegonotus species. Using both genetic (DNA) data and morphological data from museum specimens where available, Sara and colleagues found molecular evidence for a whopping four new species of Stegonotus, both morphologically obvious and cryptic.
Did you know: Many Stegonotus snakes have enlarged rear maxillary teeth that likely help them consume a diet of reptile eggs.
The newly described New Guinea ground snake species include the darkly colored Stegonotus melanolabiatus and the reddish brown Stegonotus admiraltiensis, both collected by LSU Science’s own Christopher Austin in Papua New Guinea, as well as the striking white-bodied Stegonotus iridis and the grey-brown Stegonotus derooijae, collected by co-author Stephen Richard. Stegonotus derooijae was named in honor Dr. Nelly De Rooij, a researcher who described many new species from New Guinea and Indonesia including Stegonotus florensis.
S. admiraltiensis and S. iridis have noticeable morphological characteristics that differentiate them from other snakes in this genus, while the other two snakes are a bit more difficult to differentiate as new species at first glance.
One of the cryptic Stegonotus species that Sara and colleagues describe in their new paper is named in honor Dr. Petronella Johanna Nelly de Rooij (1883 – 1964). Nelly de Rooij was a Dutch zoologist and herpetologist and curator at the Museum of Zoology at the University of Amsterdam. Discriminated against in Amsterdam as a woman and not allowed to pursue higher education, de Rooij studied and earned her doctorate in Zurich at the University of Zurich. For her dissertation, she studied the cardiovascular system of the Japanese giant salamander. Despite a relatively short scientific career, Dr. de Rooij published the most complete work to this day on the reptiles of the Indo-Australian region, a two-volume set titled The Reptiles of the Indo-Australian Archipelago, as well as a dozen scientific paper papers.
“To honor Dr. de Rooij’s important contributions to this still poorly explored region of the world, we named a new ground snake for her, Stegonotus derooijae,” Sara Ruane said. “She described a species of Stegonotus from the Indonesian island of Flores in her own work on the region (Stegonotus florensis), and so it seemed fitting to name one of these new species after her.”
Stegonotus derooijae can be found in the Raja Ampat Regency in eastern Indonesia. The snake is small and slender, with a gray-brown dorsal color, a cream-colored venter and yellow mottling on the head. It likely preys on frogs and reptile eggs, common prey among other ground snakes. It is not clear what the full geographic range of this snake may be, as the only specimens are those collected from the Raja Ampat islands of Batanta, Salawati and Waigeo.
Sara and colleagues also found that different Stegonotus species seem to have invaded the same regions of New Guinea more than once and often co-exist in the same geographic areas. However, to partition resources these snakes may be specializing on different prey items, and they have different body shapes perhaps best suited for their prey of choice.
The hunt for new Stegonotus species is likely not finished. Sara and colleagues think this genus includes additional undescribed species and plan to further sample across New Guinea to examine more fully the pattern and tempo of diversification within Stegonotus.
“These ground snakes have not garnered much attention, and we expect that additional species remain to be discovered,” Sara said.
Read more about the newly discovered Stegonotus species in the Journal of Natural History online: “Cryptic and non-cryptic diversity in New Guinea ground snakes of the genus Stegonotus Duméril, Bibron and Duméril, 1854: a description of four new species (Squamata: Colubridae).”