Leptodactylus riveroi

Schiesari, Luis, Rossa-Feres, Denise De Cerqueira, Menin, Marcelo & Hödl, Walter, 2022, Tadpoles of Central Amazonia (Amphibia: Anura), Zootaxa 5223 (1), pp. 1-149 : 95-96

Leptodactylus riveroi

External morphology. Description based on one tadpole at Stage 36 (INPA-H 1530). Total length 33.6 mm. Body elongate oval in dorsal view and globular/depressed in lateral view ( Fig. 61A, B ). Snout rounded in dorsal and lateral views. Eyes small, dorsally positioned and dorsolaterally directed. Nostrils small, reniform, dorsally positioned and laterally directed in an intermediate distance between the eyes and the snout, with opening anterolaterally directed, with a small projection on the marginal rim. Oral disc ( Fig. 61C ) anteroventral, with subtle emarginations ventrolaterally; marginal papillae conical, biseriate, with a dorsal gap. Submarginal papillae present laterally. LTRF 2(2)/3; A1 and A2 of the same length; P1, P2 and P3 nearly the same length. Jaw sheaths moderately 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 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 pointed. Lateral lines visible.

Colour. In preservative body and caudal musculature dark brown; fins opaque brown. In life body and tail black; internal organs are not visible through the body wall ( Lima 1992); body dark grey, tail lighter than body, fins translucent.

Variation. Prior to Stage 37, body black but the internal organs are visible; fins transparent ( Lima 1992).

Natural history: Foam nests are deposited in the margins of streamside ponds in terra-firme forest; tadpoles move to the ponds through tunnels excavated by their parents ( Lima et al. 2012). Tadpoles are benthic and remain hidden in particulate matter in the substrate. Clutches contain about 1,000 eggs ( Lima et al. 2012).

Comments. Tadpoles of L. riveroi from Central Amazonia were described by Lima (1992), and they differ from those herein characterized by presenting body ovoid in dorsal view (although Fig. 1 shows an elongate oval body), and dorsal and ventral fins narrow .

MICROHYLIDAE . Tadpoles of the Microhylidae occurring in Central Amazonia belong to four genera and are characterized by the following characteristics: small size; nostrils absent; absence of oral keratinized parts (LTRF 0/0); spiracle positioned ventrally; free-swimming tadpoles (except Synapturanus ).

Genus Chiasmocleis . Tadpoles of genus Chiasmocleis found in the Central Amazonia share the following combination of morphological characteristics: body ovoid in dorsal view and triangular/depressed in lateral view; tail fins of moderate height; vent tube dextral; mouth terminal with fleshy lips covering the oral opening.

Figures

FIGURE 1. Larval amphibian habitat in Central Amazonia. (A) isolated forest pond, (B) streamside pond, (C) forest floor, (D) bromeliad, (E) treehole (with male Trachycephalus cunauaru), (F) stream, (G) river (blackwater), (H) várzea floodplain lake with floating meadows, and (I) igapó floodplain lake. Pictures by Marcelo Gordo (A, B, D, E, F, G, H) and LS (C, I).

FIGURE 61. Tadpole of Leptodactylus riveroi (INPA-H 1530) at Stage 36: (A) lateral view, (B) dorsal view (scale = 10 mm), and (C) oral disc (scale = 1 mm).