Scinax sp. 3

External morphology. Description based on five tadpoles at Stages 35 and 37 (LCS 583, 598/1). Total length 26.6 ± 0.8 mm (N = 5). Body ovoid in dorsal view and triangular/depressed in lateral view (Fig. 45A, B). Snout rounded in dorsal and lateral views. Eyes medium-sized, positioned and directed laterally. Nostrils small, circular, laterally positioned, near to eyes, with opening anterolaterally directed, without a projection on the marginal rim. Oral disc (Fig. 45C) anteroventral, ventrolaterally emarginate; marginal papillae conical, uniseriate, with a wide dorsal gap. Submarginal papillae present laterally. LTRF 2(1,2)/3; A2 sligthly longer than A1; P2 slightly longer than P1; P3 about a third of P2 length. Jaw sheaths wide, finely serrated; anterior jaw sheath arch-shaped, posterior jaw sheath V-shaped. Spiracle single, sinistral, conical, short and wide, posterodorsally directed, opening in the medial third of the body, with the centripetal wall fused to the body wall and longer than the external wall. Vent tube dextral, fused to the ventral fin, with a dextral opening. Caudal musculature of moderate width; in lateral view gradually tapering to a pointed tip. Dorsal fin of moderate height, originating on the medial third of the body, convex; ventral fin of moderate height and convex. Tail tip pointed.

Colour. In preservative body and caudal musculature light brown with numerous melanophores; fins translucent with very light and fine reticulation.

Natural history. Eggs were not observed. Tadpoles are found in várzea floodplains.

Genus Sphaenorhynchus. Tadpoles of genus Sphaenorhynchus found in the Central Amazonia share the following combination of morphological characteristics: small to moderate size; body oval elongate or ovoid in dorsal view and globular or globular/depressed in lateral view; spiracle sinistral; vent tube medial with medial opening; oral disc anteroventral, non-emarginate or ventrally emarginate; marginal papillae uniseriate with a dorsal gap; submarginal papillae absent; LTRF 1/2(1) or 2(2)/3(1).