Rana subaquavocalis: The Rarest Frog in the U.S. By Terry Gampper
According to Platz, the next steps are to determine how vulnerable this species is to extinction. They are known to live in two places. There are about 45 individuals living in Ramsey Canyon and about 55 living in nearby Brown Canyon. The frog is green and olive-brown in coloration and about 6 inches in length. Some of the individuals were at least 10 years old, about twice the age that most leopard frogs get. By the way, the age of frogs is determined by counting the annual rings found in the toe bones. The professor believes that the frogs were quite common about 17,000 years ago when glaciers covered most of the country and the climate was much cooler. As the glaciers retreated, the climate became hotter and dryer forcing the frogs to move to mountain streams. The frogs at the low altitudes perished but those who made it to the mountains survived. They were isolated from the gene pool of other leopard frogs for several thousands of years and eventually became a new species. Platz returned to the area in 1989 equipped with a tape recorder and hydrophones. He found several egg masses, which indicated that the frogs were breeding. However, one important factor was missing: there were no vocalizations. He placed the hydrophone in the water and was greeted by a plethora of frog calls. Why would frogs call from underwater? Platz offered these hypotheses:
1) A frog calling at the edge of the pond may be heard by a predator and thus placed at a disadvantage; In 1995, Platz and other conservationists began trying to increase the population of these frogs by collecting eggs and raising the tadpoles in large horse tanks for later reintroduction. Also, efforts to improve the habitat of the area are being planned. The frogs live in canyon ponds within the Nature Conservancy's Ramsey Canyon Preserve. As more people became involved in the project, a third population of the frogs was discovered. Dr. Platz is working with the conservancy, the ranch owner, the U.S. and Arizona fish and game departments, and the military to draft a recovery plan for the frog. The U.S. Army is involved because Ramsey Canyon borders a large military reservation. The plan also calls for the eventual establishment of 8 population groups that are close enough so the frog can migrate from place to place. The Nature Conservancy has a detailed article about Rana subaquavocalis in the September/October 1997 issue of Nature Conservancy Magazine. Sources: Omaha World-Herald, "Frog Lover Happens Onto Hoppers", October 9, 1993 Omaha World-Herald, "Frog Man Has Found New But Dying Species", July 14, 1995
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In 1988, Creighton University (Omaha, NE) professor of biology James Platz received a tip from a stranger on a desolate road in southeastern Arizona. At the end of the road, Professor Platz found a big frog. Although it looked very much like a typical leopard frog, it turned out to be a brand new species. The frogs reside in a couple of small ponds located in the Huachuca Mountains near Sierra Vista, Arizona. It is popularly known as the Ramsey Canyon Leopard Frog. Platz gave it the scientific name Rana subaquavocalis for their unusual vocalizing behavior -- the males call for their mates from three feet underwater. This species is described in the June 1993 issue of the Journal of Herpetology.
