Physalalemus fuscomaculatus

Nomura, Fausto, Rossa-Feres, Denise De Cerqueira & Prado, Vitor Hugo Mendonça Do, 2003, The tadpole of Physalaemus fuscomaculatus (Anura: Leptodactylidae), with a description of internal oral morphology, Zootaxa 370, pp. 1-8 : 3-6

Description of the tadpole of Physalalemus fuscomaculatus

Measurements (mm). Mean and standard deviation (range) of 10 specimens at Gosner (1960) developmental stage 38: total length 23.32 1.37 (22.0–25.59); body length 11.36 0.66 (10.08–12.16); tail length 11.96 1.29 (10.58–13.61); maximum body height 4.73 0.28 (4.16–5.12); maximum body width 5.95 0.27 (5.44–6.40); eye diameter 1.42 0.034 (1.36–1.44); nostril diameter 0.44 0.076 (0.32–0.56); interorbital distance 1.27 0.096 (1.12–1.44); internarial distance 0.82 0.039 (0.80–0.88); nostril – snout distance 0.75 0.086 (0.64–0.88); eye–snout distance 1.76 0.18 (1.44–2.08); maximum dorsal fin height 2.14 0.23 (1.60–2.40); maximum ventral fin height 0.92 0.11 (0.80–1.09); maximum tail muscle width 1.80 0.038 (0.83–0.93); maximum tail muscle height 2.50 0.11 (2.40– 2.72).

External morphology. Body ovoid in dorsal view and globular/depressed in lateral view ( Fig. 1 A and 1B). Snout rounded in dorsal and lateral view. Eyes relatively small, dorsal, dorsolaterally directed. Nostrils large, rounded, with dorsally directed aperture. Spiracle sinistral, long and narrow with free distal edge. Centripetal wall of the spiracle tube fused to body wall, spiracular opening directed posterodorsally, on the middle third of the body. Vent tube long, medial, attached to the ventral fin, with dextrally directed opening.

Oral disc ventral ( Fig. 2 A), laterally emarginated. Marginal papillae in single row usually with a wide dorsal gap and two narrow ventral gaps. Ventral papillae number 8 to 18 (13.45 2.44, n = 33), and are in a single row (23.7%), alternate row (65.8%) or mixed of both (10.5%); only 10% of 43 analyzed tadpoles examined lacked ventral gaps in the marginal papillae; one to five submarginal papillae, larger than marginal papillae, in unequal number on each side of oral disc. Papillae long, conical, simple, with convex extremity. Tooth row formula 2(2)/2(1); A­1 and A­2 rows subequal in length, P­2 slightly shorter than P­1; A­2 and P­1 rows interrupted medially by a gap approximately three to four labial teeth wide; tooth density 52/mm in A­1 row. Labial teeth dark, curved slightly toward the oral opening, with five to seven cusps with slightly divergent tips ( Fig. 2 B and 2C). Jaw sheaths heavy, darkly pigmented; upper sheath M­shaped and the lower Vshaped; upper jaw sheath with 40 serrations/mm on the edge, individual serration triangular, broad­based with equal sides.

Caudal muscle heavy, higher than dorsal fin along the anterior third of the tail. Dorsal fin moderate, with the same height of caudal musculature at the plane of tail­body junction, weakly convex, originating on the posterior third of the body; ventral fin low, nearly parallel to tail muscle; tip narrowly rounded.

Coloration. In formalin, body brown, with dark spots forming a semicircular arch around the internal margins of nostrils. Ventrally transparent. Caudal muscle light brown, with dark brown dots with irregular distribution. A midlateral blood vessel, similar to a thin dark stripe, lying on proximal fifth of the tail. Fins transparent, with slight reticulation formed by blood vessels and with some dark brown marks, on dorsal and ventral fin edges. In life, coloration very similar to that of preserved tadpoles, with the body, tail, and sickleshaped marks near the nostrils darker brown.

Internal oral features. Buccal floor triangular ( Fig. 3 A), about 20% wider than long; oral aperture about 20% of buccal floor width; four infralabial papillae, the lateral pair large, and the medial ones small, all papillae with pustulated margins. Two simple, conical, lingual papillae, with rounded apices; buccal floor arena triangular, with four to six papillae on each side, majority conical, with acute apices or with a slight projections; a bifurcate papilla, with acute apices, lateral to each buccal pocket and 30 to 40 pustulations randomly distributed within buccal floor arena; two to three short, conical papillae and three to five prepocket pustulations; buccal pockets perforated, wider than long, tranversely oriented on middle region of buccal floor; free velar surface, about 20% of buccal floor length, with three pustulations on each side. Glottis distinct, open, fully exposed.

Buccal roof triangular ( Fig. 3 B), same shape as floor, broad posteriorly; prenarial arena with two semicircular arches of pustulations separated by a moderate notch, arranged in a V­shaped pattern, with vertex oriented posteriorly; nares elliptical, positioned at about 25% of the distance from oral disc to esophagus, in 25° orientation from transverse plane; internarial distance about 50% of long axis of naris; narial­valve projection indistinct; anterior narial wall pustulate; posterior narial wall flap­like and twice as wide as high; postnarial arena triangular and narrow with four papillae, one anteromedial pair tall and conical, with pustulate anterior margin and the posterolateral pair short and conical; median ridge semicircular, with pustulate free surface; lateral­ridge papillae clawshaped, with pustulate anterior margins; buccal roof arena narrow elongate rectangle; bounded by three or four papillae on each side, all papillae conical, with truncate or acute apices, distributed parallel to longitudinal plane; about 50–60 pustulations randomly distributed; glandular zone conspicuous; dorsal velum long, interrupted on midline with smooth free margin.

Habitat. In the northwestern region of São Paulo State, Brazil, males of Physalaemus fuscomaculatus were observed calling during the early rainy season (October to December), in temporary, rain­filled ponds in pasture areas. In this region, males were not detected every year, but are very abundant in those years they appear ( Rossa­Feres, 1997). Tadpoles were found along unshaded shallow (13.7 10.9 cm deep, n = 16) pond edges, mostly in areas without vegetation.

These tadpoles are preponderantly nocturnal, benthonic, and have cryptic coloration. They do not constitute aggregates and react quickly to predators, swimming a short distance and then stopping (personal observation). This set of characteristics is found in tadpoles of other Physalaemus Fitzinger, 1826 species (e.g. P. pustulosus, Heyer et al. 1975 ; P. nattereri , personal observation). The swimming behavior by rapid bursts is an efficient means of avoiding invertebrate predators ( Hoff et al. 1999; Azevedo­Ramos et al. 1992; Heyer et al. 1975), which are abundant in temporary ponds ( Buskirk, 1988; Pearman, 1995). Foam nests of Physalaemus fuscomaculatus were observed inside the ponds on the water surface, anchored on emergent vegetation in the shallows; the foam nests had a mean diameter of 10.56 cm 2.56 SD (range = 7–14, n = 18 clutches) and 2036.67 479.62 eggs (range = 1740–2590, n = 3 clutches), with a mean diameter of 1.5 mm 0.12 SD (range = 1.32–1.82, n = 14 eggs).

Figures

FIGURE 1. Physalaemus fuscumaculatus tadpole at stage 35 (Gosner, 1960), (A) Dorsal view, (B) Lateral view (scale = 10 mm).

FIGURE 2. Physalaemus fuscumaculatus tadpole (A) Oral disc (scale = 1 mm), (B) Lateral view of a tooth of the A­ 2 row (scale = 100 m), (C) Ventral view of apical region of a tooth (scale = 20 m).

FIGURE 3. Physalaemus fuscomaculatus tadpole (A) floor and (B) roof of buccopharyngeal cavity (scale = 1 mm).