Scinax ruber (Laurenti, 1768)

Schiesari, Luis, Rossa-Feres, Denise De Cerqueira, Menin, Marcelo & Hödl, Walter, 2022, Tadpoles of Central Amazonia (Amphibia: Anura), Zootaxa 5223 (1), pp. 1-149 : 72

Scinax ruber

External morphology. Description based on three tadpoles at Stages 35 and 37 (LCS 574/4, 574/5, 574/6). Total length 28.4 ± 1.1 mm (N = 3). Body ovoid in dorsal view and triangular in lateral view ( Fig. 42A, B ). Snout rounded in dorsal and lateral views. Eyes medium-sized, positioned and directed laterally. Nostrils small, circular, dorsolaterally positioned, near to eyes, with opening anterolaterally directed, without a projection on the marginal rim. Oral disc ( Fig. 42C ) anteroventral, ventrolaterally emarginate; marginal papillae conical, uniseriate, dorsally and ventrally and with multiple rows laterally, with a dorsal gap. Submarginal papillae present lateroventrally. LTRF 2(1,2)/3(1); A1 and A2 of the same length; P2 slightly longer than P1 and P3. 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 posterior 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 that does not reach the margin of the lower fin. Caudal musculature of moderate width; in lateral view gradually tapering to a pointed tip. Dorsal fin high, originating on the posterior third of the body, convex; ventral fin high and convex. Tail tip pointed.

Colour. In preservative body and caudal musculature greenish yellow; venter translucent with digestive tract dark gray; fins translucent; dorsum, caudal musculature and fins with numerous melanophores. In life dorsum and anterior dorsal part of the caudal musculature light brown; venter silver; fins translucent; a black stripe from the snout to the base of caudal musculature; iris silver.

Variation. LTRF 2(2)/3 or 2(2)/3(1) at Stages 25, 26, 33, 36, and 37.

Metamorphs. Metamorph green with coppery dorsum; dark dorsolateral stripe between snout and eye; iris copper ( Fig. 42D ).

Natural history. Gravid females of S. ruber from Ecuador contain from 591 to 1,117 ovarian eggs ( Crump 1974) and those from Peru contain from 745 to 1,890 eggs ( Aichinger 1992). Eggs are pigmented. Tadpoles are found in temporary and permanent ponds in terra-firme forests, forest edge and deforested land all the way to the margins of large rivers. Tadpoles are found during the rainy season. In experiment tadpoles were found to be preyed upon by dragonfly larvae ( Azevedo-Ramos et al. 1992).

Comments. Tadpoles of S. ruber were described by Kenny (1969) from Trinidad, by Duellman (1978) from Ecuador, by Hero (1990) from Central Amazonia, Brazil, by Lynch (2006) and Lynch & Suárez-Mayorga (2011) from Colombia, and by Schulze et al. (2015) from lowland Bolivia. Tadpoles described by Kenny (1969), Duellman (1978), Duellman (2005) and Hero (1990) are similar to those herein characterized. Tadpoles characterized by Lynch (2006) and by Lynch & Suárez-Mayorga (2011) differ from those herein characterized by presenting a single row of marginal papillae and by seeming to present higher body and fins in lateral view. The LTRF varies among these descriptions, but all fall within the range herein presented.

Figures

FIGURE 42. Tadpole of Scinax ruber (LCS 534) at Stage 36: (A) lateral view, (B) dorsal view (scale = 10 mm), and (C) oral disc (scale = 1 mm). (D) Dorsolateral view of newly metamorphosed froglet.