Lowland Leopard Frog (Rana yavapaiensis)

Photo by Jim Rorabaugh

Lowland Leopard Frog, cattle tank, Sierra Azul, Sonora. Photo by Jim Rorabaugh

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Description

Editor’s Note: We follow Amphibiaweb and Yuan et al. (2016: Systematic Biology, doi: 10.1093/sysbio/syw055) in our usage of Rana rather than Lithobates for Arizona’s ranid frogs.

The Lowland Leopard Frog is a relatively small leopard frog (< 87 mm SVL) that is distinguished from other Arizona leopard frogs by a combination of characters, including dorsolateral folds that, towards the rear, are broken and inset medially, usually no spots on the snout anterior to the eyes, and a pattern on the rear of the thigh consisting of a dark brown to gray brown, relatively tight reticulation. Adult males lack prominent vocal sacs.  This is typically a brown or gray-brown frog with dark spots dorsally, although some are green, particularly on the head. There is often a yellowish wash to the groin area. The Lowland Leopard Frog is very similar and closely related to the Relict Leopard Frog.  In the 100-Mile Circle, the Lowland Leopard Frog is distributed patchily in the Pajarito, Whetstone, Catalina, Rincon, and Galiuro Mountains, several sierras in Sonora, as well as a number of rivers and streams such as lower Cienega Creek, the lower San Pedro River, the Río Cocóspera, and Arnett Creek near Superior.  The species has declined and disappeared from a number of areas in southern Arizona.  For instance, it formerly inhabited Pantano Wash, the Santa Cruz River in the Tucson area, and agricultural ditches and canals in the Avra Valley.  In the 100-Mile Circle, this species occurs or occurred in the permanent or nearly permanent waters of streams, rivers, ciénegas, cattle tanks, and other impoundments in Sonoran desertscrub, semi-desert grassland, and upslope into oak woodlands, as well as agricultural lands.  However, dispersing individuals may be found in uplands or ephemeral waters.

The species breeds primarily from January through April, and again in late summer or early fall.  Egg masses are laid in shallow water and are attached to vegetation, bedrock, or gravel.  Adult males give a distinctive advertisement call consisting of a series of chuckles that are not very loud and are similar to that of the Plains and Relict Leopard Frogs.  Chuckles may be interspersed with sounds akin to someone rubbing an inflated balloon.  The call can be heard by following this link:

http://amphibiaweb.org/sounds/Rana_yavapaiensis83.mp3

Tadpoles take 3-9 months to develop and metamorphose, and some overwinter.  Compared to other leopard frogs, late stage Lowland Leopard Frog tadpoles are relatively dark (brown or gray), mottled, and stocky.  Tadpoles grow to 75-90 mm total length prior to metamorphosis.

This is more of a stream frog than the Chiricahua and some other leopard frogs, which need deep pools for breeding.  The Lowland Leopard Frog’s ability to breed in relatively shallow, flowing water is likely a key factor in its propensity to coexist with non-native American Bullfrogs, sport fishes, and crayfish, which thrive in deep pools but not shallow, flowing water.  Lowland Leopard Frogs are susceptible to the fungal skin disease, chytridiomycosis.  Some populations persist with the disease while others have been extirpated.  Although the precise cause of extirpation is often unknown and may include multiple factors, die offs associated with chytridiomycosis no doubt contribute to population loss.  A successful reestablishment program has created numerous backyard pond populations in the Tucson area. The Lowland Leopard Frog is a species of least concern on the IUCN Red List, but it is illegal to collect them in Arizona and Sonora without appropriate permits.  Most of the literature on this species is under the name Rana yavapaiensis.

Suggested Reading:

Brennan, T.C., and A.T. Holycross. 2006. Amphibians and Reptiles in Arizona. Arizona Game and Fish Department, Phoenix, AZ.

Rorabaugh, J.C., and J.A. Lemos Espinal. 2016. A Field Guide to the Amphibians and Reptiles of Sonora, Mexico. ECO Herpetological Publishing and Distribution, Rodeo, New Mexico, USA.

Sartorius, S.S., and P.C. Rosen. 2000. Reproductive and population phenology of the lowland leopard frog in a semi-desert canyon. Southwestern Naturalist 45:267-273.

Savage, A.E., M.J. Sredl, and K.R. Zamudio. 2011. Disease dynamics vary spatially and temporally in a North American amphibian. Biological Conservation 144:1910–1915.

Sredl, M.J. 2005.  Rana yavapaiensis: Platz and Frost, 1984 Lowland leopard frog.  Pages 596-599 in M.J. Lannoo (editor), Amphibian Declines: The Conservation Status of United States Species.  University of California Press, Berkeley.

Wallace, J.E., R.J. Steidel, and D.E. Swann. 2010. Habitat characteristics of Lowland Leopard Frogs in mountain canyons of southeastern Arizona. Journal of Wildlife Management 74(4):808-815.

Author:  Jim Rorabaugh

For additional information on this species, please see the following volumes and pages in the Sonoran Herpetologist: 2004 Sep:87; 2005 Nov:128; 2008 Jul:78-79.

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