Distribution.—Low elevations (up to 700 meters) in the lowlands and foothills of Colima and southwestern Jalisco, México ([Fig. 20]).
Specimens examined.—(14). MÉXICO, Colima: Hda. Paso del Río, FMNH 100048 (holotype), 100167, 100299, UIMNH 13300, UMMZ 110877 (2), USNM 139729; 7.2 km. SW Tecolapa, UMMZ 115477 (4); Jalisco: 17.6 km. SW Autlan, 606 m., KU 102627; 3.2 km. N La Resolana, UMMZ 102100; Bahía Tenacatita, UMMZ 84264.
Syrrhophus nivocolimae Dixon and Webb
Syrrhophus nivocolimae Dixon and Webb, 1966:1-4, Fig. 1 [Holotype.—LACM 3200, from Nevado de Colima (6 airline miles west of Atenquique), Jalisco, México, 7800 feet; collected on July 20, 1964, by Robert G. Webb].
Diagnosis.—Small frogs, males 18.5-21.1 mm. snout-vent length, only known female 24.1 mm. snout-vent; vocal slits present in males; finger tips widely expanded; first finger shorter than second; inner metatarsal tubercle about three times size of outer; skin of dorsum warty, that of venter smooth; tympanum concealed, its diameter 30.0-39.3 per cent that of eye in males; mid-dorsal brown band from interorbital bar to anus; bands on limbs narrow, dark bands less than one-half width of light bands, upper arm not banded; narrow interorbital light bar.
Remarks.—This species is closely related to S. modestus and differs in color pattern and degree of wartiness of the skin. Dixon and Webb (1966) held that nivocolimae had no close relatives, but the condition of the tympanum, size, nature of the outer palmar tubercle, relative sizes of the metatarsal tubercles, and shape and size of the digital pads all point to a close relationship between S. modestus, S. nivocolimae, and S. pallidus.
Fig. 20: Distribution of the species of the modestus group: interorbitalis (open circles), teretistes (solid circles), modestus (open triangles), pallidus (solid triangles) and nivocolimae (square). Arrow indicates locality of sympatry between modestus and nivocolimae. Solid line about the localities for interorbitalis is a range estimate based on call records and specimens examined.
Dixon and Webb (1966) reported that S. nivocolimae has a large tympanum (50.0-59.0 per cent diameter of eye). However, my examination of the type series and several other specimens from Jalisco reveals that the largest tympanum/eye ratio is 39.3 per cent. Therefore, the tympanum/eye ratio in S. nivocolimae is in agreement with those for S. modestus, S. pallidus, and S. teretistes ([Table 6]).