Ololygon Fitzinger, 1843

Ololygon Fitzinger, 1843:31. Type species: Hyla strigilata Spix, 1824, by original designation.

Definition. Small to medium-sized frogs with slightly truncate discs on fingers and toes, webbing reduced between fingers and absent between Fingers I and II (Figs. 10A and B); venter immaculate, eggs deposited in streams or terrestrial bromeliads.

Content. Forty-six species: Ololygon agilis * (Cruz & Peixoto), albicans* (Bokermann), alcatraz* (Lutz), angrensis* (Lutz), arduoa* (Peixoto), argyreornata* (Miranda-Ribeiro), ariadne* (Bokermann), aromothyella* (Faivovich), atrata* (Peixoto), aurata * (Wied-Neuwied), belloni* (Faivovich, Gasparini & Haddad), berthae (Barrio), brieni* (De Witte), canastrensis* (Cardoso & Haddad), carnevallii * Caramaschi & Kisteumacher, catharinae (Boulenger), centralis * (Pombal & Bastos), cosenzai* (Lacerda, Peixoto & Feio), faivovichi (Brasileiro, Oyamaguchi & Haddad), flavoguttata* (Lutz & Lutz), heyeri * Peixoto & Weygoldt, hiemalis* (Haddad & Pombal), humilis* (Lutz & Lutz), insperata* (Silva & Alves-Silva), jureia* (Pombal & Gordo), kautskyi* Carvalho-e-Silva & Peixoto, littoralis* (Pombal & Gordo), littorea* Peixoto, longilinea* (Lutz), luizotavioi* Caramaschi & Kisteumacher, machadoi* (Bokermann & Sazima), melloi* Peixoto, muriciensis * (Cruz, Nunes & Lima), obtriangulata (Lutz), peixotoi (Brasileiro, Haddad, Sawaya & Martins), perpusilla (Lutz & Lutz), pombali * (Lourenço, Carvalho, Baêta, Pezzuti & Leite), ranki * (Andrade & Cardoso), rizibilis* (Bokermann), skaios * (Pombal, Carvalho, Canelos & Bastos), skuki * (Lima, Cruz & Azevedo), strigilata * (Spix), trapicheiroi* (Lutz & Lutz), tripui* (Loureço, Nascimento & Pires), tupinamba* (Silva & Alves-Silva), and vsignata* (Lutz).

Distribution. Atlantic Coastal Forest of eastern Brazil, extending southward to northeastern Argentina and westward into gallery forests in the Brazilian Cerrado.

Etymology. The generic name is the Greek word, ololygon meaning the croaking of a frog. The gender is feminine.

Remarks. Throughout its recent history, Ololygon either encompassed the entire “ Hyla rubra ” Group (Fouquette & Delahoussaye 1977) or was considered to be a synonym of Scinax (Duellman & Wiens 1992; Faivovich 2002; Pombal & Gordo 1991). The identity of Hyla strigilata Spix, the type species of Ololygon, was uncertain until Pimenta et al. (2007a) discovered a population of frogs that fits the type description. Almeida and Cardoso (1985) suggested that the “ rubra group” and “ catharinae group” of Ololygon should be in separate genera. This separation was evident in the cladistics analyses of Faivovich (2002) and Faivovich et al. (2005).

Even though we have molecular data for only 30% of the species of Scinax (sensu lato), three distinct major clades are evident in the tree (Fig. 4). One of these recognized herein is Ololygon that contains the species in the “ catharinae clade,” as recognized by Faivovich (2002) and updated in Frost (2015). Faivovich (2002) and Faivovich et al. (2005) noted some myological and osteological differences between certain members of the “ catharinae clade” (= Ololygon) and the “ rubra clade” (= Scinax). However, the utility of these characters will be ascertained only after thorough comparisons of many more species in both genera.

Faivovich et al. (2005) recognized two groups of species in their “ catharinae clade.” One of these is the “ perpusilla ” group, first defined by Peixoto (1987). This group contains at least nine small species that breed in terrestrial bromeliads in coastal southeastern Brazil. Our tree contains three of these species that form a distinctive clade separate from the species in the “ catharinae group,” which breed in streams.