Part 10

Distribution.--Pacific lowlands of Sinaloa, Mexico (Fig. 20).

Specimens examined.--(10). MEXICO, Sinaloa: 36 mi. N Mazatlan, UIMNH 38094-96, 67061 (holotype), 71970-74; 65 mi. N Mazatlan, LACM 13773.

=Syrrhophus modestus= Taylor

Syrrhophus modestus Taylor, 1942:304-06, pl. 29 [Holotype.--FMNH 100048 (formerly EHT-HMS 3756), from Hacienda Paso del Rio, Colima, Mexico; collected on July 8, 1935, by Hobart M. Smith]. Smith and Taylor, 1948:49-50.

Syrrhophus modestus modestus: Duellman, 1958:2-5, 7, 14, pl. 1, fig. 1. Gorham, 1966:166.

Diagnosis.--Small frogs, males 15.8-20.1 mm. snout-vent length, single female 18.5 mm.; 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 shagreened, that of venter smooth; tympanum concealed; pale cream in preservative with dark brown spots; limbs banded; bands on forearm and thigh poorly developed or absent; interorbital bar absent.

Remarks.--The tympanum is concealed in S. modestus, S. nivocolimae, S. pallidus, S. teretistes, and to a lesser degree in S. interorbitalis. However, if the specimen is permitted to dry slightly, the annulus tympanicus becomes visible through the skin and a tympanum/eye ratio can be computed.

One of the few cases of sympatry within the genus Syrrhophus involves this species; modestus and nivocolimae are known to be sympatric at one locality in southwestern Jalisco, Mexico.

Duellman (1958) used the trinomial for this population and named a new subspecies, pallidus, from Nayarit. I consider pallidus to be specifically distinct from modestus because there is no evidence of genetic exchange, and there is no overlap in the distinguishing morphological features. I do consider the two populations to be closely related but feel the interrelationships between modestus, pallidus, nivocolimae, and teretistes are more complex than would be indicated by the use of trinomials. The sympatric occurrence of modestus and nivocolimae is significant; morphologically, they might otherwise be regarded as subspecies. Although allopatric, similar arguments could be advanced for the morphologically similar pallidus and teretistes. The four are here afforded species rank since morphological similarity and allopatry are not sufficient grounds for the assumption of genetic exchange.

Etymology.--Latin, meaning unassuming, modest, in reference to the small size of the species.

Distribution.--Low elevations (up to 700 meters) in the lowlands and foothills of Colima and southwestern Jalisco, Mexico (Fig. 20).

Specimens examined.--(14). MEXICO, Colima: Hda. Paso del Rio, 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; Bahia 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, Mexico, 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.

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).

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, Mexico, at moderate to high elevations (600-2400 meters).

Specimens examined.--(48) MEXICO, Jalisco: 17.6 km. SW Autlan, 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, Mexico, 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.

Etymology.--Latin, in reference to the pale ground color in comparison with that of S. modestus.