The following accounts do not include complete descriptions of each taxon, because a more than adequate number of descriptions is available in the recent (1940-1966) literature. An abbreviated synonymy, in which are listed all combinations and emendations of names and significant contributions to our knowledge of the taxon, is given for each. For each species and subspecies the following are given: descriptive diagnosis, statement of range, remarks on taxonomy, list of specimens examined, illustration of color pattern, and distribution map.
Syrrhophus cystignathoides (Cope)
Phyllobates cystignathoides Cope, 1877:89-90 [Syntypes.—Originally USNM 32402-32409, (32405 now in MCZ) from Potrero, near Córdoba, Veracruz, México, Francis Sumichrast collector.]
Diagnosis.—Adults small, males 16.0 to 23.5 mm. in snout-vent length, females 16.0-25.8 mm. in snout-vent length; vocal slits present in males; finger tips slightly expanded; first finger longer than second; outer metatarsal tubercle one-half size of inner, conical, compressed; skin of dorsum weakly pustular, that of venter smooth to areolate; tympanum 44 to 69 per cent diameter of eye (mean 55.5 per cent); ground color yellow to brown in life with brown to black fleckings on dorsum and flanks; limbs banded; interorbital bar present or not.
Remarks.—Two geographic races (subspecies) are herein recognized; previously these were held by various authors to be species (campi and cystignathoides). Intergradation occurs in southern Tamaulipas and eastern San Luis Potosí, México. The two subspecies can be distinguished on the basis of color pattern and the condition of the skin of the venter.
Distribution.—Low to moderate elevations from the Río Grande embayment to central Veracruz, México ([Fig. 5]).
Syrrhophus cystignathoides campi Stejneger, New combination
Syrrhophus campi Stejneger, 1915:131-32. [Holotype.—USNM 52290, from Brownsville, Cameron Co., Texas; R. D. Camp collector, March 31, 1915]. Smith and Taylor, 1948:52. Martin, 1958:50.
Diagnosis.—Venter smooth; usually no interorbital light and dark bars present; ground color brown in life ([Fig. 4a]).