New Species of Minute Leptodactylid Frogs from the Andes of Ecuador and Peru

Resumen

--A new species of Phyllonastes (P. heyerl) is named from the Andean ridges in the Huancabamba Depression in southern Ecuador and northern Peru. A similar species is described as a new species of Phrynopus (P. bagrecito) from the Andes of Cuzco, Peru. Based on the similarities in skeletons, Phyllonastes may share a common ancestry with frogs of the Phrynopus peruvianus group. An additional record is provided for Adelophryne adiastola (Amazonas, Colombia). A suite of minute (adults less than 20 mm SVL) leptodactylid frogs has been described from the lowlands of northern South America and along the eastern Andean flanks in Ecuador (Lynch, 1976; Heyer, 1977; Hoogmoed and Lescure, 1984). Lynch (1976) described the first two as species of the genus Euparkerella (previously known only from southeastern Brazil). Heyer (1977) placed these two species in a new genus (Phyllonastes) and named another new genus (Phyzelaphryne) from Amazonian Brazil. Lynch (1980) treated Phyzelaphryne miriamae as a synonym of Eleutherodactylus nigrovittatus. Lastly, Hoogmoed and Lescure (1984) revalidated Phyzelaphryne miriamae and proposed a new genus with two new species (Adelophryne). At present, all of these minute frogs are placed in the tribe Eleutheradactylini. The five Amazonian species are placed in three genera: Adelophryne (A. adiastola and A. gutturosa), Phyllonastes (P. lochites and P. myrmecoides), and Phyzelaphryne (P. miriamae). These small frogs are rather imperfectly known, being separated generically on the basis of (1) presence/absence of vomerine dentition, (2) presence/absence of a tarsal tubercle, (3) digits flattened/round in cross section, and (4) reduction of fourth finger of hand (sometimes with reduction in number of phalanges). Hoogmoed and Lescure (1984) suggested that Adelophryne and Phyzelaphryne might be closely related because each has a peculiar form to the digital pads (lateral grooves not united at tip). They cautioned however that it was difficult to distinguish features that reflect adaptation to a leaf-litter habitat from t ose that are correlates of achieving very small size from those reflecting relationships. As Hoogmoed and Lescure noted, these frogs are all quite rare and too few specimens are available to permit skeletal preparations. The two new species described here are represented by sufficient material to permit osteological preparations. MATERIALS AND METHODS Specimens are identified with a catalogue number and museum abbreviation (following list in Leviton et al., 1980). Measurements were made with dial calipers (under magnification) and recorded to the nearest 0.1 mm. Specimens were cleared and stained (Alizarin and Alcian Blue) using the methods of Dingerkus and Uhler (1977). All drawings were made using a Wild M-5 with a drawing tube attachment. Terminology and measurements follow Lynch (1975).