Scarthyla goinorum (Bokermann, 1962)

Schiesari, Luis, Rossa-Feres, Denise De Cerqueira, Menin, Marcelo & Hödl, Walter, 2022, Tadpoles of Central Amazonia (Amphibia: Anura), Zootaxa 5223 (1), pp. 1-149 : 67-69

Scarthyla goinorum

External morphology. Description based on one tadpole at Stage 33 (CZPB-LA 243/555). Total length 27.1 mm. Body ovoid in dorsal view and triangular in lateral view ( Fig. 38A, B ). Snout truncate in dorsal and lateral views. Eyes medium-sized, positioned and directed laterally. Nostrils small, circular, dorsally positioned in an intermediate distance between the eyes and the snout, with opening dorsolaterally directed, without a projection on the marginal rim. Oral disc ( Fig. 38C ) anterior, ventrolaterally emarginate; marginal papillae conical, uniseriate, with dorsal and ventral gaps. Submarginal papillae absent. LTRF 2(2)/3(1); A1 and A2 of the same length; P2 slightly longer than P1; P3 of about half the length of P2. Anterior jaw sheath wide, posterior jaw sheath moderate, both finely serrated; anterior jaw sheath arch-shaped, posterior jaw sheath V-shaped. Spiracle single, sinistral, lateroventral, 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 dextral, 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 shallow, originating on the posterior third of the body, parallel to longitudinal axis of tail; ventral fin of moderate height and convex. Tail tip pointed.

Colour. In preservative body and caudal musculature creamy white; dorsum with large blotches; fins translucent with large blotches. In life not observed in Central Amazonia, but tadpoles of S. goinorum from Peru have body with dorsum and sides pale yellowish green; venter silvery white; caudal musculature and fins pale green with brown blotches; iris reddish copper ( Duellman 2005).

Natural history. Eggs not observed. Gravid females of S. goinorum from Peru contain from 130 to 202 pigmented ovarian eggs ( Duellman 2005). In Central Amazonia tadpoles of S. goinorum are found in the root zone of floating meadows in várzea floodplain lakes.

Comments. Tadpoles of S. goinorum from Peru were described by Duellman (2005). They differ from those herein characterized by presenting ventral fin shallow, snout bluntly rounded in dorsal view and acutely rounded in lateral view, caudal musculature robust, dorsal fin originating on caudal musculature well posterior to the terminus of the body, tail tip acutely rounded ( Fig. 13.6E ; Duellman 2005), oral disc laterally emarginate and the anteriormost three or four papillae much larger than the others. LTRF is 2(1)/2 or 2(1,2)/2(1), but the author mentions that in a few specimens, there are a few teeth forming an incomplete row on the margin of the posterior labium ( Fig. 13.14F ; Duellman 2005). The only morphological difference between tadpoles from Colombia illustrated by Lynch & Suárez-Mayorga (2011) is the dorsal fin originating at the tail.

Genus Scinax . Tadpoles of genus Scinax found in the Central Amazonia share the following combination of morphological characteristics: small size; body ovoid in dorsal view and triangular or triangular/depressed in lateral view; spiracle sinistral; vent tube dextral with a dextral opening; dorsal fin of moderate height or high; oral disc anteroventral, ventrolaterally emarginate; submarginal papillae present laterally; LTRF in variations from 2/3.

Figures

FIGURE 13. Tadpole of Ceratophrys cornuta (MNRJ s/n) at Stage 38: (A) lateral view, (B) dorsal view (scale = 10 mm), and (C) oral disc (scale = 1 mm).

FIGURE 38. Tadpole of Scarthyla goinorum (CZPB 243/555) at Stage 33: (A) lateral view, (B) dorsal view (scale = 10 mm), and (C) oral disc (scale = 1 mm).