Rhinella arenarum (Hensel)

Oliveira, Marianna Isabella Rosa Rodrigues De, Weber, Luiz Norberto & Napoli, Marcelo Felgueiras, 2013, Internal oral morphology in larvae of the genus Rhinella Fitzinger, 1826 (Amphibia, Anura, Bufonidae), Zootaxa 3745 (5), pp. 501-523 : 503

Rhinella arenarum (Hensel)

Material: one specimen (stage 37), two specimens (stage 39).

Buccal floor ( Fig. 1C ): Ovoid buccal floor, wider than long. One pair of large infralabial papillae, concave on the anterior surface, apex with small projections and occupying a large part of the oral cavity entrance. There are three small infrarrostral projections on each side. Four lingual papillae, digitiform, in equivalent size, rounded apex and arranged on the same transversal plane. The BFA is delimited by nearly 45 digitiform papillae, in different size, tapered apex and nearly 120 pustules distributed between the papillae. There are no structures in the anterior region of the BFA. The buccal pockets are transversely oriented. The ventral velum is long and U-shaped; undulated and tumid margin, with glandular appearance, constituted by secretory pits ( Fig.5B ) and nearly 11 globular projections in the middle portion. Buccal roof ( Fig. 1D ): Ovoid buccal roof, longer than wide. Prenarial arena has a transversal ridge and irregular apex. Laterally to the prenarial ridge there are three pustules. Large choanae, elliptical, almost transversely arranged on the buccal roof; the posterior valve is high and the anterior has two prenarial papillae on the inner edge. The distance between the choanae is almost equivalent to median ridge width. The postnarial arena has three conical papillae on each side, in different size, smooth surface, tapered apex and arranged forming an inverted " V " design. Before these papillae there are about six pustules. Median ridge is trapezoid-shaped; flattened and anterior margin irregular. The lateral ridge papillae have the base as wide as the apex, flattened, apex with three triangular secondary branches in different sizes and anterior margin of the branches with slight irregularities. The BRA is delimited by five digitiform papillae on each side, elongated, the most anterior pair is conical, tapered apex and arranged on the BRA lower side. There are nearly 75 pustules evenly distributed in the middle region of the BRA. Conspicuous glandular zone, thickened in the middle portion. The dorsal velum is short; undulated margin, with the lateral fold showing a glandular appearance and irregular margin in the middle region, without projections.

Figures

FIGURE 1. Scanning electron micrographs of the internal oral morphology. R. abei (A) floor and (B) roof, stage 36, DZSJRP 908.1; R. arenarum (C) floor and (D) roof, stage 38, MNRJ 44936; R. crucifer (E) floor and (F) roof, stage 35, UFBA 0107. IP, infralabial papillae; LP, lingual papillae; BP, buccal pocket; BFA, buccal floor arena; BFAP, buccal floor arena papillae; VV, ventral velum; PRA, prenarial arena; CH, choanae; POA, postnarial arena; LRP, lateral ridge papillae; MR, median ridge; BRA, buccal roof arena; BRAP, buccal roof arena papillae; GZ, glandular zone; DV, dorsal velum.

FIGURE 5. Scanning electron micrographs of the glandular regions on internal oral surface in tadpoles of Rhinella. (A) Velar margin tumid and showing the concentration of secretory pits in R. schneideri; (B) Detail of secretory pits in the margin of the ventral velum of R. arenarum; (C) Concentration of secretory pits on the glandular zone (GZ) and surface of the dorsal velum with glandular appearance (GDV) of R. schneideri.