T. Zweifel 1953 Rana 14 mi SW El Batel, 4200', Sinaloa, Mexico 2475-81 R2 July 12 Small stream, seldom more than 4 feet wide. Pools up to 3' deep, 10' in diameter. Stream gradient is relatively steep with numerous small waterfalls. Stream is on bedrock much of course. Water temp 23.5° C. Tropical Deciduous Forest, but some pines on adjacent hillsides. Some frogs were on boulders several feet above the water, others in the water when first seen. Dorsal coloration is brown. In light phase, the dorsolateral folds are white, contrasting sharply with the background. The lateral body walls below the dorsolateral fold is dark brown, almost black. A distinct light line from snout along upper lip, passing beneath eardrum and connecting with light lateral ventral color behind foreleg. Ventral surfaces white. In dark phase, melanophores on ventral surface form no definite pattern. A few small dark spots are present dorsally. Superficial examination places this frog with the group including R. palmipes, R. macroglossa and R. sierramadreensis. The geographically closest form, sierramadreensis, occurs some 575 miles south in Guerrero.