Redescription of the Tadpole ofAmeerega hahneli(Boulenger, 1884) (Anura: Dendrobatidae) with Notes on Ontogenetic Variations and Development Habitats

Abstract

Ameerega hahneli is a terrestrial dendrobatid frog widely distributed in the Amazon region. The tadpole of this species was formally described based on eight specimens in the early developmental stage 25, when some of the morphological structures were still not fully developed. In this study, the tadpoles of A. hahneli are redescribed based on 78 individuals in 14 different developmental stages. Additionally, we provide data on the ontogenetic variations and development sites of tadpoles. Specimens were collected in streamside ponds and streams of non-flooded forest during the rainy season. The tadpole of A. hahneli at stage 36 is characterized by: body elongate, depressed (lateral view), and oval (dorsal view); small size (mean 23.96 mm, range 21.7-26.2 mm); oral disc anteroventral; labial tooth row formulae 1/2; marginal papillae uniseriate, triangular, and distributed only on the lower labium. Like other tadpoles of the genus, the upper jaw sheath is W-shaped with a ventral notch and the lower jaw sheath is V-shaped, the spiracle is sinistral, and the vent tube is dextral. Ontogenetic variations were observed in body size, number of marginal papillae, lateral line system and ventral coloration. Total length increased gradually from the stage 25 (14.67 mm) to stage 37 (26.70 mm), the latter being the maximum total length observed. The combination of the morphological organization of its labial tooth row formulae and the presence of triangular marginal papillae only at the posterior labium allows the A. hahneli tadpoles to be easily distinguished from all the others species of the genus Ameerega.