Etymology.—niv, Latin, and Colima (Nevado de), meaning high on the volcano, in reference to the higher distribution of this species (around 2000 meters) than other members of the group.
Distribution.—Known from southwestern Jalisco, México, at moderate to high elevations (600-2400 meters).
Specimens examined.—(48) MÉXICO, Jalisco: 17.6 km. SW Autlán, 606 m., KU 102626, 102631; 6.4 km. W Atenquique, 2060 m., KU 102628-30, 102632; 8 km. W Atenquique, 1970 m., LACM 3210-12; 9.6 km. W Atenquique, 2360 m., LACM 3200 (holotype), 3201-09; 14.5 km. W Atenquique, 2000 m., LACM 25424-36, 25439-41, 25446; 15 km. W Atenquique, LACM 37044-46, 37244-47; 16 km. W Atenquique, 2105 m., LACM 25443-45; 17 km. W Atenquique, 2180 m., LACM 25442.
Syrrhophus pallidus Duellman, New combination
Syrrhophus modestus: Davis and Dixon, 1957:146.
Syrrhophus modestus pallidus Duellman, 1958:2-3, 5-7, 14, pl. 3 [Holotype.—UMMZ 115452, from San Blas, Nayarit, México, sea level; collected on August 13, 1956, by William E. and Ann S. Duellman]. Zweifel, 1960:86-88, 91, 93-94, 118, 120-22. Gorham, 1966:166.
Syrrhophis modestus pallidus: Campbell and Simmons, 1962:194.
Diagnosis.—Small frogs, males 17.9-19.3 mm. snout-vent length; vocal slits in males; finger tips widely expanded; first finger shorter than second; inner metatarsal tubercle about three times size of outer; skin of dorsum shagreened, that of venter smooth; tympanum concealed, its diameter 27.0-35.6 per cent of eye in males; ground color cream vermiculated with brown, upper arm and thigh lacking, or with few, indistinct, bands; interorbital bar absent.
Remarks.—Considerable debate has been waged relative to the value of subspecies and to the reasons for recognizing distinct disjunct populations as species versus subspecies. Lacking evidence of genetic exchange, I prefer to retain disjunct populations that are distinctive as species.
All known specimens of pallidus can be separated from those of modestus by color pattern. The two nominal species exhibit overlap in proportions but the same can be said about nearly every species of Syrrhophus; therefore, overlap in proportions can be disregarded in assessing specific versus subspecific rank. Until contrary evidence is forthcoming, I consider the disjunct populations heretofore held to be subspecies of modestus to be specifically distinct. The specimens of the disjunct population of pallidus on the Tres Marias do not differ from the mainland population in Nayarit. This evidence, though perhaps secondary, supports my contention that two species should be recognized.