Distribution.—From Tamaulipas and Sinaloa, México, exclusive of the Mexican Plateau, to at least Peru and southernmost Brazil and throughout the West Indies. Introduced into Florida.
Etymology.—Greek (eleuthero + dactylus) meaning free-toed.
Genus Engystomops Jiménez de la Espada, 1872
Type species.—Engystomops petersi Jiménez de la Espada, 1872
Diagnosis and definition.—Small frogs (20 to 40 mm. snout-vent length) having undilated digital tips lacking transverse grooves; lumbo-inguinal or inguinal glands absent; plantar supernumerary tubercles present, extending between metatarsal tubercles; tarsus bearing spinelike tubercle on inner edge; toes free; terminal phalanges pointed; sternum bearing bony style; spenethmoid not truncate anteriorly; nasals in contact medially; maxillary and quadratojugal in articular contact; anterior arm of squamosal not in contact with maxillary; dermal cranial elements not involved in integumentary-cranial co-ossification; prevomers moderate in size, lacking teeth; maxillary and premaxillary bones edentate; occipital condyles separated; tadpole free living.
Composition.—Four nominal species (E. petersi, E. pustulatus, E. pustulosus and E. schereri).
Distribution.—Central Veracruz and eastern Oaxaca, México, to Trinidad, Bolivia, and Peru, east of the Andes.
Etymology.—Greek (engys + stoma) meaning narrow-mouthed.