Aplastodiscus callipygius

Aplastodiscus albosignatus: The Bocaina Treefrog

The Bocaina treefrog, scientifically known as Aplastodiscus albosignatus, is a distinctive amphibian species endemic to Brazil. This treefrog is notable for its striking green coloration, which extends not only to its external skin but also to its muscles and bones, a rare trait among amphibians. It is primarily found in the mountainous regions of southeastern Brazil, preferring the humid environments of subtropical and tropical moist lowland and montane forests.

Description and Identification

Adult Bocaina treefrogs typically measure around 5 cm (2.0 inches) in snout-to-vent length. They possess a broad head and a pointed snout, with vomerine teeth located on the roof of their mouths. Their eyes are large and prominent, featuring golden irises and a characteristic horizontal slit pupil, while the tympanum is easily discernible. A single vocal sac is present in the throat. Perhaps the most unique physical characteristic, aiding in its identification, is the presence of large granulations around its cloacal vent, setting it apart from closely related species.

Habitat and Distribution

This arboreal species is found in undisturbed habitats, typically at elevations up to 1,800 meters (5,900 feet) above sea level. Its natural range includes both pristine old-growth forests and secondary growth forests, particularly in proximity to mountain streams. The Bocaina treefrog is known to inhabit areas within national parks, such as the Serra da Bocaina National Park, from which it was first described. Critically, it generally avoids agricultural areas and human settlements, indicating a reliance on intact forest ecosystems.

Reproduction and Life Cycle

Breeding activities for the Bocaina treefrog commence between September and February. During this period, males can be heard calling at night, typically from rocky outcrops or the edges of forest streams. The reproductive strategy involves the female laying eggs in underground nests constructed within the muddy banks of these watercourses. The tadpoles develop within these nests and then inhabit the bottom of the stream. They undergo metamorphosis into juvenile frogs when they reach approximately 21 mm (0.83 inches) in length.

Conservation Status

The International Union for Conservation of Nature (IUCN) Red List classifies Aplastodiscus albosignatus as Least Concern. While population declines have been observed, they have not occurred at a rate deemed sufficient to warrant a higher threat categorization. Its presence within protected areas likely contributes to its current status, though habitat loss remains a general threat to amphibians in the region.