Rhinella merianae (Gallardo, 1965)

Schiesari, Luis, Rossa-Feres, Denise De Cerqueira, Menin, Marcelo & Hödl, Walter, 2022, Tadpoles of Central Amazonia (Amphibia: Anura), Zootaxa 5223 (1), pp. 1-149 : 32

Rhinella merianae

External morphology. Description based on four tadpoles at Stages 37 and 38 (LCS 527). Total length 19.0 ± 0.9 mm (N = 4). Body oval in dorsal view and globular in lateral view ( Fig. 10A, B ). Snout rounded in both dorsal and lateral views. Eyes medium-sized, dorsally positioned and laterally directed. Nostrils medium-sized, rounded, dorsally positioned closer to eyes than to snout, with opening anterodorsally directed, without a projection on the marginal rim. Oral disc ( Fig. 10C ) anteroventral, laterally emarginate; marginal papillae conical, uniseriate, with wide dorsal and ventral gaps. Submarginal papillae absent. LTRF 2(2)/3; A1 and A2 of the same length; P1 slightly longer than P2, P3 distinctly shorter. Jaw sheaths narrow, 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 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 high, convex, originating at the tail-body junction; ventral fin of moderate height and parallel to the ventral margin of caudal musculature. Tail tip rounded.

Colour. In preservative, body greyish-brown; venter and sides of body transparent; caudal musculature light gray, upper half of caudal musculature grey, lower half unpigmented; fins transparent. In life, body and caudal musculature light brown (sand-coloured), lateroventral portion of caudal musculature without pigmentation, laterodorsal portion with melanophores giving a weak black colouration; in the dorsal portion there are wide spots formed by accumulation of golden chromatophores that give the impression of transversal stripes in dorsal view; tail fins transparent.

Metamorphs. Dorsum dirty brown, venter translucid creamy-brown, limbs light brown, legs with discrete light transversal stripes.

Natural history. Pigmented eggs are laid in shallow water as two gelatinous strings. One clutch contained 1,557 eggs. A dissected female contained 3,142 ovarian eggs. Tadpoles are found in small (<26 m 2) and shallow (<10 cm) temporary ponds and puddles with clayish or sandy bottom, with or without leaf-litter, twigs and branches ( Silva et al. 2017). In Central Amazonia the species is found during the rainy season in terra-firme forest edge and deforested land. In the igapó flooded forests of eastern Amazonia R. merianae is found to breed frequently in lakes and rivers ( Magnusson & Windle 1988; Azevedo-Ramos et al. 1999).

Comments. Tadpoles from Central Amazonia previously described by Silva et al. (2017) had no noticeable morphological variation relative to the ones herein characterized. Hero (1990) illustrated these tadpoles as Bufo granulosus (Plate 1) from the same region, and they differ from those herein characterized and from those described by Silva et al. (2017) by the larger spiracle and the wider tail tip.

Figures

FIGURE 10. Tadpole of Rhinella merianae (LCS 527) at Stage 37: (A) lateral view, (B) dorsal view (scale = 10 mm), and (C) oral disc (scale = 1 mm).