Phyllomedusa azurea

Santos, Danusy Lopes, de Morais, Alessandro Ribeiro, Signorelli, Luciana, Bastos, Rogério Pereira, Feio, Renato & Nomura, Fausto, 2018, Description of the Tadpole of Phŋllomedusa azurea from the Brazilian Cerrado, with a Description of the Internal Oral Morphology of Phŋllomedusa oreades, Herpetologica 74 (1), pp. 50-57 : 52-54

Phyllomedusa azurea

External morphology ( Table 1). —The body shape is elliptical ( Fig. 2 ), elongated in dorsal view and compressed in lateral view (BW/BH ¼ 0.98). Snout truncated in lateral and rounded in dorsal view. Eyes moderately sized (ED/BH ¼ 0.29), laterally positioned and directed. Nostrils small (ND/ BH ¼ 0.05), ovoid, anterolaterally positioned, and located near the snout tip. Spiracle ventral, directed posteriorly, with opening at the middle third of the body. The centripetal wall of the spiracle is totally fused to the body wall, and the external wall has a free distal margin that overlays the spiracle opening. Vent tube short, fused to the ventral fin and opening dextrally. Dorsal fin low, parallel to the caudal musculature, originating in the body–tail junction. Ventral fin wide, arch shaped, and higher than the dorsal fin. The tail tip is acute. Lateral line evident. The oral disc is anteroventral, with a uniseriate row of marginal papillae. The marginal papillae are longer than wide and with alternate disposition. A few rounded submarginal papillae are scattered throughout lateral portions of the oral disc, and these papillae are smaller than marginal papillae. Tooth row formula 2(2)/3(1), A1 slightly smaller than A2, P1 ¼ P2, and P3 smaller than P1 and P2. The upper jaw sheath is wider than the lower jaw sheath. The upper jaw sheath is M shaped and the lower jaw sheath V shaped. The caudal musculature is robust and gradually tapered.

Internal oral morphology. —Buccal floor diamond shaped ( Fig. 3A ), longer than wide; oral aperture about 20% of buccal floor width; two large and strong conical infralabial papillae. Two large lingual papillae, longer than wide and with smooth apices. Buccal floor arena round with three to five conical papillae on each side, with smooth apices; numerous pustulations randomly distributed within buccal floor arena; anterior to the buccal pocket region, there are no papillae and few pustulations (zero to three); buccal pocket perforated, wider than long, transversely oriented on the middle region of the buccal floor; free velar surface, with distinct glandular zone, with pustulations at the bottom of the velum and pustulations on the region anterior to the glottis, which is notched, distinct, open, and fully exposed.

Buccal roof rounded ( Fig. 3B ), with the prenarial arena possessing two broad pustulations anteriorly, parallel to the buccal opening, and three small ones posteriorly, forming a row. Nares elliptical, oriented parallel to the buccal opening and positioned on the anterior third of the buccal roof; internarial distance smaller than nare opening; narial valve distinct with anterior and posterior wall pustulate and flaplike; postnarial arena rectangular with four fringed papillae with the anteromedial pair triangular and larger than the posterolateral pair; the posterolateral papillae are broader than the anteromedial pair; no pustulations visible in the postnarial arena; median ridge triangular, wider than long. Buccal roof arena round in shape with one to five small papillae on each side; pustulations extensively distributed throughout the buccal roof arena; glandular zone conspicuous; dorsal velum uniform in width, with pustulated margins, except at the midline, which has smooth margins.

Morphological variation ( Fig. 4A,B ). —Most of the variation that we observed in P. azurea tadpoles was related to the oral disc and spiracle, and this variation was observed in all studied populations. Eleven out of 25 tadpoles presented a narrow ventral gap, while two presented lateroventral emargination on the oral disc. Also, one tadpole had the marginal papillae biseriate laterally, and three tadpoles presented a wider upper jaw compared to the remaining individuals. The external wall of the spiracle did not have a free distal margin overlapping the spiracle opening in 10 tadpoles ( Fig. 4C,D ). Four tadpoles presented rounded snouts.

We observed variation in the density of pustulations scattered throughout the buccal floor arena, with at least one individual having many pustulations in front of the buccal pockets, but few in the buccal floor arena. In one individual from Jataí, the papillae of the buccal floor arena were fused, forming large ones ( Fig. 5A ). Another individual from Mineiros had 29 papillae scattered throughout the buccal floor and less than 40 pustulations, grouped mainly in front of the buccal pockets, and a large infralabial papillae ( Fig. 5B ). In one individual from Barro Alto, the lingual papillae were fused together. The buccal roof was more consistent as we noted variation in only the number of papillae in the buccal roof arena, with at least two individuals from Mineiros not presenting papillae in the buccal roof arena ( Fig. 5C ).

Color of fixed specimens. —Body silver-whitish with brown spots scattered on dorsal and lateral surfaces, and on tail musculature; some individuals showed few or no spots in these body regions. Venter creamy and dorsal and ventral fins transparent with brown spots.

Figures

FIG. 2.—Larva of Phŋllomedusa azurea, Stage 35, from Barro Alto (ZUFG 819), state of Goiás, Brazil: (A) lateral and (B) dorsal views (scale ¼ 10 mm); (C) oral disc of specimen from Cocalzinho (ZUFG 2351; scale ¼ 2 mm). A color version of this figure is available online.

FIG. 3.—Internal oral features of the Phŋllomedusa azurea larva, Stage 37 (ZUFG 838): (A) buccal floor, (B) buccal roof.

FIG. 4.—Tadpoles of Phŋllomedusa azurea showing variation in snout shape in lateral views (A, B), spiracle (C, D), and details for the position of the spiracle in P. oreades (E). Scale in all images ¼ 10 mm. A color version of this figure is available online.

FIG. 5.—Morphological variation in the buccal roof of larval Phŋllomedusa azurea specimens from the state of Goiás, Brazil: (A) Jataí, (B) Mineiros, and