Males usually call from secluded spots at the edge of water. All calling males that we observed were on the ground within a few centimeters of the water. The males usually are hidden beneath an overhanging leaf or some other cover; they definitely do not sit in the open like Smilisca baudini. Most calling males and clasping pairs have been found at the edges of small pools or shallow ditches, although occasional individuals are found at the edges of large ponds or streams.
The breeding call consists of one or two moderately short, low-pitched notes (duration 0.33 to 0.42 seconds), repeated at intervals of about 20 seconds to several minutes. Each note is a low, vibrant "wauk," having 100 to 130 pulses per second and a dominant frequency of 330 to 420 cycles per second (Pl. 10C).
The eggs are deposited in loose clumps amidst vegetation in the water. Hatchling tadpoles have total lengths of 8.7 to 10.6 mm., and body lengths of 4.1 to 4.5 mm. The external gills are long and filamentous, and the yolk sac is large. The head and caudal musculature are dark brownish black, and the caudal fins are gray. The oral discs are large and roughly circular. The growth and development of the tadpoles are summarized in table 11 and figure 16.
A typical tadpole in stage 30 of development (KU 68482 from the Río Chitaría, Cartago Province, Costa Rica) may be described as follows: body length 9.7 mm.; tail length 14.6 mm.; total length 24.3 mm.; body as wide as deep; snout rounded dorsally and laterally; eyes widely separated, directed dorsolaterally; nostril about midway between eye and tip of snout; mouth anteroventral; spiracle sinistral, about midway on length of body and slightly below midline; anal tube dextral; caudal musculature slender, curved upward distally; dorsal fin extending onto body; depth of dorsal fin slightly less than that of ventral fin at mid-length of tail; dorsal part of body pale brown; ventral surfaces transparent with scattered pigment; pale cream-colored, crescent-shaped mark on posterior edge of body; caudal musculature pale creamy tan with scattered pale brown spots; caudal fins transparent with scattered small brown blotches on dorsal and ventral fins; iris pale bronze in life (Fig. 13); mouth small; median part of upper lip bare; rest of mouth bordered by one row of pointed papillae; lateral fold present; tooth-rows 2/3, first upper row longest; second upper row slightly shorter, broadly interrupted medially; three lower rows complete, equal in length, slightly shorter than second upper row; upper beak moderately deep, forming broad arch with slender lateral processes; lower beak slender, broadly V-shaped; both beaks serrate (Fig. 15E).
In tadpoles having fully developed mouthparts the tooth-row formula of 2/3 is invariable. The pale crescent-shaped mark on the posterior part of the body curves anterodorsally on the dorsal surface of the body. These marks in dorsal view give the appearance of a pair of short, pale stripes on the posterior part of the body. Most specimens from Costa Rica have the pale coloration like that described above, but some individuals (notable KU 87683 from Guápiles, Costa Rica, KU 87707 from Finca Tepeyac, Nicaragua, and KU 87708 from Bonanza, Nicaragua) have much more pigment. In these specimens the same color pattern obtains as in the pallid individuals, but the pigmentation is dense. This is especially noticeable on the tail.
Recently metamorphosed young have snout-vent lengths of 12.7 to 16.7 mm. (average, 14.3 mm. in eleven specimens). Coloration of young in life (KU 68484 from Río Chitaría, Cartago Province, Costa Rica): "Dorsum pale tan; side of head and flanks darker brown, separated from tan dorsum by an indistinct cream stripe. Limbs pale yellow; thighs flecked with brown; shank and tarsus yellowish tan with indistinct brown bars. Soles of feet brown. Belly white; throat dusty cream flecked with silvery white. Upper lip silvery white. Iris bright gold with black flecks. Heels, tarsal and anal stripes white" (Duellman, field notes, May 23, 1961).
Remarks.—Peters (1863:463) named Hyla labialis from the "region of Bogotá, Colombia", but in 1873 regarded his new species as identical with Hyla phaeota Cope, 1862, from Turbo, Colombia. The name Hyla labialis has been used for frogs from the northern Andes in Colombia (see Dunn, 1944:72, and Stebbins and Hendrickson, 1959:522, for discussion of nomenclature). Rivero (1961:131) used the name Hyla vilsoniana Cope, 1899, for the frogs from the northern Andes previously referred to Hyla labialis. A review of the nomenclature and taxonomy of these frogs, which superficially resemble Smilisca but are unrelated, is beyond the scope of the present study.
Hyla baudini dolomedes Barbour, 1923, is based on a small Smilisca phaeota (MCZ 8539) having a snout-vent length of 45.5 mm. Dunn (1931a:413) placed dolomedes in the synonymy of Smilisca phaeota. We have examined the holotype of dolomedes and agree with Dunn's assignment.
Smith (1953:150) described Hyla phaeota cyanosticta from Guatemala. Our studies on the external morphology, coloration, and especially the cranial osteology provide evidence that cyanosticta is a species distinct from phaeota.
Distribution.—Smilisca phaeota inhabits humid tropical forests from northeastern Nicaragua southward on the Caribbean lowlands to elevations of about 1000 meters and on the Pacific lowlands of Costa Rica, exclusive of the arid regions of Guanacaste, throughout the lowlands of Panamá, exclusive of the savannas of the Pacific lowland and the Azuero Peninsula, and southward on the Pacific slopes of South America through Colombia to west-central Ecuador; also the valleys of the Río Cauca and Río Magdalena in Colombia (Fig. 2).