Boana boans (Linnaeus, 1758)

Schiesari, Luis, Rossa-Feres, Denise De Cerqueira, Menin, Marcelo & Hödl, Walter, 2022, Tadpoles of Central Amazonia (Amphibia: Anura), Zootaxa 5223 (1), pp. 1-149 : 39

Boana boans

External morphology. Description based on three tadpoles at Stages 33, 36 and 39 (LCS 600, 652, 653). Total length ranging from 33.4 mm (Stage 36) to 33.8 mm (Stage 39). Body ovoid in dorsal view and globular/depressed in lateral view ( Fig. 15A, B ). Snout rounded in dorsal view and rounded in lateral view. Eyes small, dorsally positioned and dorsolaterally directed. Nostrils small, reniform, dorsally positioned, near to eyes, with opening anterolaterally directed, with a small projection on the marginal rim. Oral disc ( Fig. 15C ) anteroventral, ventrolaterally emarginate; marginal papillae conical, biseriate, with a narrow dorsal gap. Submarginal papillae laterally. LTRF 2(2)/4(1); A1 shorter than A2; P1, P2 and P3 similar in length; P4 shorter. Jaw sheaths moderate, 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 not fused to body wall and longer than the external wall. Vent tube medial, fused to the ventral fin, with a dextral opening. Caudal musculature of moderate width; in lateral view gradually tapering to a pointed tip. Dorsal fin of moderate height and convex, originating at the tail-body junction; ventral fin shallow, parallel to the ventral margin of caudal musculature. Tail tip pointed.

Colour. In preservative dorsum and sides from grayish to light brown with a few scattered melanophores to marbled of brown, cream and pigmentless with scattered dark brown spots; venter transparent without pigmentation except for small scattered leucophores; tail fins translucent cream with diffuse melanophores. Aggregation of melanophores in the dorsal portion of the tail musculature often gives the impression that the tail musculature has transversal bars in dorsal view. In life tadpole brown, with a combination of light brown and dark brown spots over the dorsal portions of body and tail; tail fin transparent; aggregation of melanophores in the dorsal portion of the tail musculature gives the impression that the tail musculature has transversal bars in dorsal view.

Variation. LTRF 2(2)/3, 2(2)/4 or 2(2)/4(1) between Stages 25 and 30.

Metamorphs. Dorsum yellowish brown, venter from light beige to cream; black dots on dorsum and head.

Natural history. Eggs are deposited as a gelatinous film on the surface of water-filled basins constructed by the males, or natural depressions, at the margin of streams in terra-firme forest, forest edge and deforested land ( Magnusson et al. 1999; Lima et al. 2012; this study). Clutches contain from 1,300 to 3,000 pigmented eggs ( Lima et al. 2012). Larvae are found in most months of the year. Larvae are benthic and camouflaged against the substrate; when disturbed swim fast and stop suddenly, behavior which probably reinforces the effectiveness of camouflage (this study). In experiment eggs were found to be avoided by fish but consumed by dytiscid beetles, dragonflies and oophagous tadpoles; B. boans tadpoles are themselves moderately oophagous ( Hero 1991; Magnusson & Hero 1991).

Comments. Tadpoles were described by Duellman (1970, 1978, 2005) from Colombia, Ecuador and Peru, respectively, and by Lynch (2006) from Colombia. Tadpoles from Colombia, characterized by Duellman (1970) and those from Ecuador differ from those herein characterized by presenting oral disc ventral, laterally emarginate, a uniseriate row of marginal papillae, LTRF 2(2)/4, spiracle opening just below the midline of the body, and dextral vent tube. Tadpoles from Peru differ from those herein characterized by presenting dorsal fin originating on the tail, vent tube dextral, and tail tip acutely rounded, oral disc laterally emarginate, uniseriate row of marginal papillae except on the lateral side of oral disc where it is biseriate, submarginal papillae absent and LTRF 2(2)/4 [the specimen depicted by Duellman shows LTRF 2(1,2)/4(1) and submarginal papillae present laterally and much larger than the marginal papillae]. Duellman (2005) also commented about a variation in LTRF, since P2 may be interrupted, and P4 may be fragmented. Tadpoles from Central Amazonia illustrated by Hero (1990) present LTRF 2(2)/3-4(1). No morphological differences were found between tadpoles herein characterized and those from Colombia described by Lynch (2006) and illustrated by Lynch & Suárez-Mayorga (2011).

Figures

FIGURE 15. Tadpole of Boana boans (LCS 659) at Stage 36: (A) lateral view, (B) dorsal view (scale = 10 mm), and (C) oral disc (scale = 1 mm).