Phrynomedusa Miranda-Ribeiro, 1923 [Type species, Phrynomedusa fimbriata Miranda-Ribeiro, 1923, by subsequent designation].
Bradymedusa Miranda-Ribeiro, 1926 [Type species, Bradymedusa moschada Miranda-Ribeiro, 1926 (=Phyllomedusa rohdei Mertens, 1926) by subsequent designation].
Definition.—Fingers and toes having greatly reduced webbing or lacking webs; terminal discs small; first toe shorter than, equal to, or longer than second, opposable or not; skin smooth or rugose having osteoderms or not; parotoid glands present, in most species, usually distinct and elevated; palpebral membrane not reticulate; iris uniformly silvery white to orange-bronze with black reticulations; skull moderate to deep, depth more than 38 per cent of length; nasals moderately small; frontoparietal fontanelle present, variable in size; quadratojugal reduced in some species; prevomerine teeth present or absent.
Range.—Low and moderate elevations in South America east of the Andes from the Caribbean (including Trinidad) to northern Argentina; Costa Rica and Panamá in Central America.
Content.—Thirty-one species [synonyms in brackets]: aspera (Peters, 1872); ayeaye (B. Lutz, 1966); bahiana A. Lutz, 1925; bicolor (Boddaert, 1772) [scleroderma Cope, 1868]; blombergi Funkhouser, 1957; boliviana Boulenger, 1902; buckleyi Boulenger, 1882; burmeisteri burmeisteri Boulenger, 1882; burmeisteri distincta B. Lutz, 1950; centralis Bokermann, 1965; cochranae Bokermann, 1966; coelestis (Cope, 1874); edentula Andersson, 1945; feltoni Shreve, 1935; fimbriata (Miranda-Ribeiro, 1923) [appendiculata A. Lutz, 1925]; guttata A. Lutz, 1925; hypochondrialis (Daudin, 1803) [azurea Cope, 1862; megacephala (Miranda-Ribeiro, 1926)]; iheringi Boulenger, 1885; lemur Boulenger, 1882; loris Boulenger, 1912; medinae Funkhouser, 1962; nicefori Barbour, 1926; orcesi Funkhouser, 1957; pailona Shreve, 1959; perlata Boulenger, 1882; rohdei Mertens, 1926 [moschada (Miranda-Ribeiro, 1926)]; sauvagei Boulenger, 1882 [rickettsii Günther, 1897]; tarsius (Cope, 1868); tomopterna (Cope, 1868) [palliata Peters, 1872]; trinitatis Mertens, 1926, vaillanti Boulenger, 1882, venusta Duellmann and Trueb, 1967.
Remarks.—Phyllomedusa includes 1) a series of large species (bicolor-burmeisteri) showing progressive specialization of the feet; 2) a series of small species having grasping feet (ayeaye, centralis, cochranae, guttata, hypochondrialis, and rohdei); 3) a series of small, relatively unspecialized species (lemur, loris, and medinae); and 4) several other species of questionable affinities. Lutz (1966) resurrected Cope's (1866) Pithecopus for 12 species (ayeaye, boliviana, burmeisteri, coelestis, hypochondrialis, nicefori, rohdei, sauvagei, tarsius, tomopterna, trinitatis, and vaillanti). Adequate material is not available for detailed study of all South American species; consequently, a firm classification cannot be established at this time. Nevertheless, it is obvious that Lutz's arrangement is unnatural. If subsequent investigations show, as seems likely, that the small specialized phyllomedusines are a natural phyletic unit, the generic name Pithecopus is available. However, species such as boliviana, burmeisteri, nicefori, and trinitatis do not belong in Pithecopus. As noted by Funkhouser (1962), the small, relatively unspecialized species (lemur, loris, and medinae) form a natural group; possibly this group should be accorded generic recognition. Until more evidence on the interspecific relationships is acquired, the maintenance of the current classification is desirable.
DISCUSSION
Noble (1931) considered the species of Phyllomedusa having opposable digits, reduced terminal discs, and no webbing to be advanced and such species as Agalychnis moreleti, calcarifer, and spurrelli to be primitive. Funkhouser (1957) followed Noble's suggestion and attempted to explain the evolution of the species of Phyllomedusa (sensu lato) by assuming that they evolved from an advanced Hyla-like ancestor. Therefore, she placed those species having large, fully webbed hands and feet near the base of her phylogenetic scheme and hypothesized that evolutionary sequences involved stages of reduction and eventual loss of webbing, followed by the development of grasping toes. Such an evolutionary history is highly unlikely. The Agalychnis phyletic line has one kind of specialization for an arboreal existence. It is contrary to evolutionary theory that a specialized group would evolve into a generalized form and then evolve new kinds of specializations to meet the needs imposed by the same environmental conditions affecting the earlier specialized group. A more reasonable hypothesis is that the evolution of opposable digits took place in a phyletic line that had as its ancestral stock a frog with generalized hands and feet. If this assumption is correct, Phyllomedusa and Agalychnis represent different phyletic lines; each exhibits divergent modes of adaptation for arboreal habits, whereas Pachymedusa probably remains relatively little changed from the basic phyllomedusine stock.