Abstract
Cryptic species are a challenge for systematics, but their elucidation also may leave critical information gaps about the distribution, conservation status, and behavior of affected species. We use the leopard frogs of the eastern U.S. as a case study of this issue. We refined the known range of the recently described Rana kauffeldi, the Atlantic Coast Leopard Frog, relative to the region’s two other leopard frog species, conducted assessments of conservation status, and improved methods for separating the three species using morphological field characters. We conducted over 2,000 call and visual surveys and took photographs of and tissue samples from hundreds of frogs. Genetic analysis supported a three-species taxonomy and provided determinations for 220 individual photographed frogs. Rana kauffeldi was confirmed in eight U.S. states, from North Carolina to southern Connecticut, hewing closely to the Atlantic Coastal Plain. It can be reliably differentiated in life from R. pipiens, and from R. sphenocephala 90% of the time, based on such characters as the femoral reticulum patterning, dorsal spot size and number, and presence of a snout spot. However, the only diagnostic character separating R. kauffeldi from R. sphenocephala remains the breeding call described in 2014. Based on our field study, museum specimens, and prior survey data, we suggest that R. kauffeldi has declined substantially in the northern part of its range, but is more secure in the core of its range. We also report, for the first time, apparent extirpations of R. pipiens from the southeastern portion of its range, previously overlooked because of confusion with R. kauffeldi. We conclude with a generalized ecological research agenda for cryptic species. For R. kauffeldi, needs include descriptions of earlier life stages, studies of niche partitioning with sympatric congeners and the potential for hybridization, and identification of conservation actions to prevent further declines.
Highlights
Conservation biologists agree that a clear understanding of a region’s species is essential for biodiversity conservation [1,2,3]
Sampling occurred in the following U.S states: Connecticut (CT), Delaware (DE), Maryland (DE), Massachusetts (MA), New Jersey (NJ), New York (NY), North Carolina (NC), Pennsylvania (PA), Rhode Island (RI), and Virginia (VA)
Permits for frog handling and tissue collection were issued by the following agencies: New York State Department of Environmental Conservation, Pennsylvania Fish and Boat Commission, Massachusetts Division of Fisheries and Wildlife, North Carolina Wildlife Resources Commission, Connecticut Department of Energy and Environmental Protection, Delaware Division of Fish and Wildlife, and Maryland Department of Natural Resources
Summary
Conservation biologists agree that a clear understanding of a region’s species is essential for biodiversity conservation [1,2,3]. Biological inventories combined with detailed natural history observation are important tools for this, not just to enumerate a region’s species, and—in some cases—for revealing evidence of new species. Cryptic species represent two or more species that are morphologically similar and confused with one another, but are phylogenetically distinct. For frogs as well as some other vocalizing taxa (e.g., insects, birds), otherwise cryptic species can often be differentiated by their audial signature, and bioacoustic analysis is an important tool for recognizing new or overlooked species [9]. Investigations have uncovered cryptic species in a variety of settings, including surprising locations and among presumably well-known taxa [8,10,11,12]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
