Leptodactylus macrosternum Miranda-Ribeiro 1926

Leptodactylus macrosternum

External morphology. Description based on five tadpoles at Stage 37 (LCS 604). Total length 34.8 ± 1.5 mm (N = 5). Body elongate oval in dorsal view and globular in lateral view (Fig. 56A, B). Snout rounded in dorsal and lateral views. Eyes small, dorsally positioned and dorsolaterally directed. Nostrils small, oval, dorsally positioned near to snout, with opening anterolaterally directed, without a projection on the marginal rim. Oral disc (Fig. 56C) anteroventral, emarginate ventrolaterally; marginal papillae conical, uniseriate anterolateralmente and biseriate posteriorly, with a dorsal gap. Submarginal papillae absent. LTRF 2/3; A1 and A2 of the same length; P2 slightly longer than P1 and P3. Posterior jaw sheath wider than anterior jaw sheath, both finely serrated; anterior jaw sheath arch-shaped, posterior jaw sheath V-shaped. Spiracle single, sinistral, lateroventral, cylindric, 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 medial, fused to the ventral fin, with a medial opening. Caudal musculature of moderate width; in lateral view gradually tapering to a pointed tip. Dorsal fin of moderate height, originating at the tail-body junction, convex; ventral fin of moderate height, convex. Tail tip rounded.

Colour. In preservative body and caudal musculature light brown; dorsum and lateral regions of the body, caudal musculature and fins covered by many, homogeneously distributed small chromatophores; fins translucent. In life body transparent olive grey; caudal musculature transparent olive grey; fins transparent (as Leptodactylus ocellatus in Hero 1990).

Variation. LTRF 2/3 or 2/3(1) between Stages 36 and 39.

Metamorphs. Metamorphs light brown. One individual in Stage 42 presented faint, early developing dorsolateral glandular lines that are characteristic of the adults.

Natural history. Floating foam nests guarded by females in temporary ponds in open and disturbed areas. Tadpoles form schools in the water column. Eggs and tadpoles are prey to Typhlonectes compressicauda (Verdade et al. 2000).

Comments. Tadpoles of L. macrosternum described by Dixon & Staton (1976) from Venezuela differ from those herein characterized by presenting nostrils dorsally positioned, spiracle narrow and, P1 to P3 of same length. Tadpoles from Argentina characterized by Cei (1980) differ from those herein characterized only by dorsal fin originating on the end of the body. Tadpoles of L. macrosternum from Central Amazonia illustrated by Hero (1990) as Leptodactylus ocellatus differ from those herein characterized by presenting marginal papillae uniseriate anterolaterally, spiracle narrow, nostrils dorsally positioned, and tip tail rounded. The terminal position of the oral disc in tadpoles from Bolivia (Schulze et al. 2015) is the same we considered anteroventral herein. Moreover, tadpoles from Bolivia differ from those herein characterized by presenting oral disc not emarginate, marginal papillae triangular, nostrils rounded, and dorsal fin originating in the posterior third of the body (although in Fig. 36a it seems originating at the tail-body junction). Tadpoles from northeastern Brazil (Dubeux et al. 2020) differ from those characterized herein by the eyes relatively small and the spiracle positioned more anteriorly at the body.