The few specimens indicate that this species occurs at moderate to high elevations in the state. The specimens from Cherán and Uruapan were obtained in pine forests; the specimen from Coalcomán was found on a rocky hillside covered with dense forest and located about 100 meters below the lower limits of the pine forest in the area. A specimen from Rancho Reparto (elevation 1850 meters) on the west slope of Cerro Barolosa was lost.
The specimen from Coalcomán (UMMZ 104728) is a juvenile having a snout-vent length of 25.0 mm. In life it was tan above, mottled with olive-green. The ventral surfaces were gray; the hind limbs were distinctly barred with yellow and brown, and the lips were barred with yellow and black.
Eleutherodactylus occidentalis Taylor
Eleutherodactylus occidentalis Taylor, Proc. Biol. Soc. Washington, 54:91, July 31, 1941.—Hacienda El Florencio, Zacatecas, México.
Arteaga (2); Cascada Tzararacua; Coalcomán (2); 19 km. SW of Coire (3); La Placita (7); Los Reyes; Ostula (4); Pómaro (2).
The locality records for this species suggest that it is a member of a group of animals, the distribution of which includes the western part of the Mexican Plateau and the Pacific lowlands. In Michoacán this frog has been collected in pine-oak forest at Cascada Tzararacua and at Los Reyes, in arid scrub forest at Arteaga and Coalcomán, and in tropical semi-deciduous forest on the lower Pacific slopes of the Sierra de Coalcomán. On July 5, 1950, James Peters (1954:6) found calling males at La Placita.
Most of the specimens are immature; four adult males have snout-vent lengths of 30.9-33.0 (32.2) mm. In all specimens the first finger is noticeably longer than the second; the inner metatarsal tubercle is large, flat, and cream-colored, contrasting with the dark brown sole of the foot. When the hind limbs are adpressed, the heels broadly overlap. Characteristically, a dark line extends from the snout, through the eye, above the tympanum, to a point above the insertion of the forelimb. Usually there is a dark bar behind the tympanum, two dark brown bars from the eye to the mouth and thence onto the lower jaw, and another dark bar on the upper lip between the eye and nostril. One adult from Arteaga, an adult and a juvenile from La Placita, and one juvenile each from Coire, Ostula, and Pómaro, have the lower lip barred with dark brown and white, and have a white stripe extending the length of the upper lip. In life the dorsum varies from dark gray or olive-brown to tan or reddish brown.
This species belongs to a group containing two other populations that are currently recognized as species—calcitrans, known only from Omiltemi, Guerrero, and mexicanus, reported from the mountains of Oaxaca. Another apparently undescribed member of this group has been collected in the mountains of northern Puebla. The locality records indicate that the group inhabits the mountains on the periphery of the Mexican Plateau, except in western México, where Eleutherodactylus occidentalis extends to the Pacific lowlands.
Eleutherodactylus rugulosus vocalis Taylor
Eleutherodactylus vocalis Taylor, Univ. Kansas Sci. Bull., 26:401, November 27, 1940.—Hacienda El Sabino, Michoacán, México.