Hylidae

Duellman, William E., Marion, Angela B. & Hedges, Blair, 2016, Phylogenetics, classification, and biogeography of the treefrogs (Amphibia: Anura: Arboranae), Zootaxa 4104 (1), pp. 1-109 : 54

Hylidae : Pseudinae

In the early Oligocene, 32.3 (25.8–38.7) Mya, the crown node time of this subfamily, a clade of aquatic and semiaquatic frogs with elongate, calcified intercalary elements in the digits gave rise to the semiaquatic Scarthyla in the upper Amazon Basin. The major component of the pseudine clade differentiated into the smaller Lysapsus and the larger Pseudis in the early Miocene about 21.5 (18.4–24.6) Mya. Both genera have broad distributions in the Guiana Region and tropical and subtropical South America east of the Andes.