Osteocephalus sp.

Schiesari, Luis, Rossa-Feres, Denise De Cerqueira, Menin, Marcelo & Hödl, Walter, 2022, Tadpoles of Central Amazonia (Amphibia: Anura), Zootaxa 5223 (1), pp. 1-149 : 65-66

Osteocephalus sp.

External morphology. Description based on six tadpoles between Stages 35 and 37 (CZPB-LA 205/466, 214/495, 233/537). Total length 35.6 ± 2.2 mm (N = 6). Body elongate oval in dorsal view and globular in lateral view ( Fig. 36A, B ). Snout rounded in dorsal and lateral views. Eyes medium-sized, positioned and directed laterally. Nostrils small, oval, dorsolaterally positioned, near to eyes, with opening anterolaterally directed, without a projection on the marginal rim. Oral disc ( Fig. 36C ) anteroventral, ventrolaterally emarginate; marginal papillae conical, uniseriate, with a dorsal gap. Submarginal papillae present laterally. LTRF 2(2)/6(1); A1 and A2 of the same length; P2 slightly longer than P1; length gradually diminishing from P3 to P6. Anterior jaw sheath moderately wide, posterior jaw sheath narrow, both finely serrated; anterior jaw sheath arch-shaped, posterior jaw sheath V-shaped. Spiracle single, sinistral, conical, long 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 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 of moderate height, convex. Tail tip pointed. Lateral lines visible.

Colour. In preservative anterior part of the body creamy white with dark brown marks under the eyes, on the interorbital region and on the internarial region; posterior part of the body dark brown; caudal musculature creamy white; fins translucent. In life anterior part of the body light orange with dark grey marks under the eyes, on the interorbital region and on the internarial region; posterior part of the body dark grey; caudal musculature light orange; fins translucent.

Natural history. Eggs not observed; tadpoles in streamside ponds in terra-firme forest.

In ReBio Uatum„, where these tadpoles were collected, there are four species of Osteocephalus ( O. cabrerai , O. leprieurii , O. oophagus and O. taurinus ). Collected tadpoles are morphologically distinctive from O. cabrerai , O. oophagus and O. taurinus . Therefore O. sp is possibly O. leprieurii , but we will leave this tadpole species unnamed because we were unable to rear them to metamorphosis to confirm species identification.

Comments. Tadpoles of Osteocephalus sp. differ from all those of other Osteocephalus species herein characterized. Tadpoles of O. cabrerai differ from those herein characterized by presenting body globular/depressed, eyes dorsally positioned; oral disc without emargination, P1–P6 of the same length, spiracle ventrolateral and short, vent tube dextral, tail tip rounded. Tadpoles of O. oophagus differ from those herein characterized by presenting body ovoid in dorsal view, snout truncate in dorsal view, eyes small and dorsally positioned, nostrils circular, marginal papillae uniseriate on anterior labium and biseriate on posterior labium, LTRF 2(2)/3, jaw sheaths moderately wide, without serrations, spiracle ventrolateral, cylindrical, and short, dorsal fin shallow, and tail tip rounded. Tadpoles of O. taurinus differ from those herein characterized by presenting body ovoid in dorsal, snout truncate in dorsal view, eyes dorsally positioned, oral disc anteroventral, ventrolaterally emarginate, LTRF 2(2)/7(1), P1 shorter than P2; P3 to P6 similar in length and smaller than P2 and P7 shorter than others, spiracle short, and dorsal and ventral fins shallow.

Genus Pseudis . Only one species of Pseudis is found in the Central Amazon.

Figures

FIGURE 36. Tadpole of Osteocephalus sp. (CZPB 233/537) at Stage 37: (A) lateral view, (B) dorsal view (scale = 10 mm), and (C) oral disc (scale = 1 mm).