Guinle Treefrog

Aplastodiscus leucopygius is a green tree frog that belongs to the A. albosignatus species group (Faivovich et al. 2005), in the Aplastodiscus (Hyla) albosignata complex (Cruz and Peixoto 1985). It is a medium size species for the group (35-45 mm SVL). Snout rounded in profile. Tympanum large, diameter about 2/3 to ¾ of the eye diameter, moderate tympanic fold; single vocal sac. Finger discs large. Dorsum smooth; diffuse glands along the entire flank. Venter granular. A white outlined transverse ridge above the vent composes the cloacal ornamentation. Prominent ovate inner metatarsal tubercle; heel with a fold and well-developed white calcar (Heyer et al. 1990). Coloration: Dorsum bright green with small white spots. Belly creamy yellow with bits of white pigment flecks. Tarsal and supra-vent folds white highlighted, with dots spread laterally. Posterior surface of thigh unpigmented. Iris gold centrally and red or orange peripherally. Bones green (Heyer et al. 1990). The tadpole has a mean total length of 52.4 mm at Gosner stage 28. Body elliptical in dorsal view, gray or light brown. Eyes dorsal. Snout rounded; nares kidney-like, closer to the eye than to the snout. Oral apparatus ventral. Marginal papillae in a single row; submarginal papillae present. LTRF 2(2)/4(1). Lower jaw V-shaped. Spiracle sinistral, directed upward, with the end point white. Vent tube dextral. Tail 69% of the total length, being the highest point at the first third, with rounded tip. Moderate tail musculature, with dark transverse bars. Fins reddish; ventral fin lower than the dorsal (Gomes and Peixoto 2002).The epithet of this species (leucopygius) is related to the white parts of the cloaca and the calcaneous appendix.

Aplastodiscus leucopygius is found in the Atlantic Rainforest of Brazil, in the states of Rio de Janeiro, southern Minas Gerais, and eastern São Paulo. It lives near streams or temporary ponds associated with woodlands in the coastal mountains of southeastern Brazil, from 800 m up to 1,600 m a.s.l.

Males of this species call at night from high branches and leaves of trees (above 2 m), near permanent forest streams and rivulets, and less commonly at the forest edge (Heyer et al. 1990; Haddad and Sawaya 2000; Ribeiro et al. 2005). Each chorus can be composed of 4 or 5 calling males (Heyer et al. 1990). Males give three different vocalization types: advertisement calls, courtship calls, and multi-note (aggressive) calls. The advertisement call is the most common vocalization (Haddad and Sawaya 2000), which sounds like a horn (vocalizations can be heard on Haddad et al. 2005). Calling males use only one pond per reproductive period (Haddad and Sawaya 2000).A. leucopygius is acoustically active throughout the year, but with a peak in activity during the rainy season, between October and March (Feio 1990; Haddad and Sawaya 2000). Gravid females and effective reproduction, however, were observed only from December to February in the Serra do Japi (Haddad and Sawaya 2000). An elaborate courtship takes place with a sequence of stereotypical mutual touches between the male and female, and the male eventually guides the female to the concealed subterranean nest (Haddad and Sawaya 2000). The female apparently inspects the nest before accepting the male (Haddad and Sawaya 2000), as is the case for another hylid species, Hypsiboas faber (Martins and Haddad 1988). A. leucopygius lays unpigmented eggs in a floating layer in these subterranean constructed nests, where the larvae also spend their early lives after hatching (Haddad and Sawaya 2000). Nests are made in muddy soil or banks near ponds and rivulets (Haddad and Sawaya 2000). Flooding washes the exotrophic tadpoles out of the nests, after which they occupy temporary ponds or streams (Haddad and Sawaya 2000; reproductive mode 5 of Haddad and Prado 2005). Tadpoles can inhabit streams varying in depth from 0.5 to 1 m, with the bottom composed of silt and litter. A detailed description and discussion of the elaborate courtship behaviour can be found in Haddad and Sawaya (2000), including a description of the three types of vocalization, sexual selection, and the egg clutches, along with a discussion on the evolution of these behaviours and oviposition site.

Its range is within protected areas, like the Parque Estadual Nova Baden, at Lambari-MG, RPPN Ovidio Pires, at Bom Jardim-MG, Parque Estadual do Ibitipoca, at Lima Duarte-MG, Serra do Japi, at Jundiaí-SP, Parque Municipal do Itapetinga, at Atibaia-SP, Estação Biológica de Boracéia, at Salesópolis-SP, Parque Água Funda, at São Paulo, APA Federal da Bacia do Rio Paraíba do Sul, at Arujá-SP, Parque Nacional da Serra dos Órgãos, at Teresópolis-RJ, and Parque Nacional de Itatiaia, at Itatiaia-RJ (Cruz and Peixoto, 1985; Feio, 1990; Heyer et al., 1990; Haddad and Sawaya, 2000). A. leucopygius was apparently not affected by factors producing a drastic drop in abundance of several other anuran species in the Estação Biológica da Boracéia in 1979, as reported by Heyer et al. (1988).