Description: The Tarahumara Frog has a maximum snout-vent length of 4 inches. Its distinquishing characteristics include an inner but no outer metatarsal tubercle, dorsolateral folds usually absent but occasionally present and poorly developed, an indistinct usually tympanium, and no vocal sacs in males. In addition, R. tarahumarae is pustulose and has a brown dorsum with small black or brown spots on the body, with white crossbars on the fron and hind limbs. The ventral body surface is white, the throat and chest can sometimes by gray with an indefinite melanophore pattern, and yellow con be present in the groin area. The tips of the toes are just a little bit expanded, and the toes are broadly webbed to the tips. In males, the first digit is enlarged and has a nuptial pad, but they lack vocal sacs.
Habitat: This species inhabits rocky/gravelly streams and banks in areas of oak or pine-oak woodland or Sinaloan thornscrub and tropical deciduous forest on the edge of the desert; typically associated with canyons and deep plunge pools; found on banks of plunge pools or in riffles. During the dry season it is found at quiet pools and springs. It is usually in or near water, but may take cover under rocks or in cliff crevices. Favorable breeding sites include areas with low mean flows (less than 0.2 cfs) and relatively steep gradients (more than 160 feet/mile); permanent water is probably necessary for metamorphosis.
Range: Occurs in the Sierra Madre Occidental and sky island mountain ranges west of the continental divide. The historical range of this species included Arizona (Santa Rita Mountains, Atascosa-Pajarito-Tumacacori mountain complex), Sonora, and Chihuahua: extreme south-central Arizona (known from Tinaja and Sycamore canyons; near Pena Blanca Springs and Alamo Spring; Gardner, Blanca, and Adobe canyons; Rio Altar and Santa Cruz drainages), south in Sierra Madre Occidental to northern Sinaloa and southwestern Chihuahua, Mexico. It has recently been extirpated from the United States and from certain localities in northern Sonora in Mexico. Most occurrences are in the mountains of eastern Sonora.
Diet: Adults mainly invertivorous. Larvae eat algae, organic debris, plant tissue, and minute organisms in water.
Reproduction: In Arizona, breeding takes place betweeen July and August. Breeding occurs during the summer rains.
Status: The decline of Tarahumara frog populations has many reasons and may include chytridiomycosis and introduced species.
Subspecies: None
Taxonomy: This species was placed in the genus Lithobates by Frost et al. (2006). However, Yuan et al. (2016, Systematic Biology, doi: 10.1093/sysbio/syw055) showed that this action created problems of paraphyly in other genera. Yuan et al. (2016) recognized subgenera within Rana for the major traditional species groups, with Lithobates used as the subgenus for the Rana palmipes group. AmphibiaWeb recommends the optional use of these subgenera to refer to these major species groups, with names written as Rana (Aquarana) catesbeiana, for example.
Disclaimer: ITIS taxonomy is based on the latest scientific consensus available, and is provided as a general reference source for interested parties. However, it is not a legal authority for statutory or regulatory purposes. While every effort has been made to provide the most reliable and up-to-date information available, ultimate legal requirements with respect to species are contained in provisions of treaties to which the United States is a party, wildlife statutes, regulations, and any applicable notices that have been published in the Federal Register. For further information on U.S. legal requirements with respect to protected taxa, please contact the U.S. Fish and Wildlife Service.
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