Part 11

Metamorphosing young have been found on vegetation at the edge of streams and have been raised in the laboratory. Seven recently metamorphosed young have snout-vent lengths of 13.6 to 15.6 mm. (14.6 mm.). A living juvenile (KU 91913) raised in the laboratory from a tadpole obtained at Finca La Sumbadora had a brown dorsum with darker brown markings, a white spot below the eye, and a narrow white labial stripe. The belly was white; the flanks were brown with white spots, and the posterior surfaces of the thighs were yellowish tan. The iris was a golden bronze color with much black reticulation.

Remarks.--This species has been confused with Smilisca sordida; most authors have referred both species to Hyla (Smilisca) gabbi. Examination of the types of Hyla sordida, gabbi, salvini, and nigripes revealed that all of the names were referable to a single species (S. sordida), and that the small, blunt-snouted species in Panama and southern Costa Rica probably was without a name. Possibly Hyla molitor Schmidt (1857) is based on the species that we have named S. sila, but several discrepancies in his description, plus the unknown provenance of the type, have led us to discount the applicability of that name to the species under consideration.

Distribution.--Smilisca sila ranges along the Pacific slopes and lowlands of southern Costa Rica and Panama at elevations from sea level to about 1300 meters; in northern South America the species occurs in the Caribbean lowlands and in the valleys of the northward draining rivers of Colombia (Fig. 3).

Specimens examined, 234, as follows: COSTA RICA: =Puntarenas=: 6 km. E Golfito, KU 91717; Quebrada Boruca, 22 km. E Palmar Norte, KU 64265-6; Rio Zapote, 7 km. E Palmar Norte, USC 7100 (2). =San Jose=: San Isidro el General, KU 28200; 14 km. NW San Isidro el General, USC 7098 (2); 15 km. WSW San Isidro el General, USC 7097.

PANAMA: =Canal Zone=: Barro Colorado Island, AMNH 62320-3, CNHM 13324, 13326-8, 13330, 13338, 13359, 13423-5, KU 80460-6, 80619 (young), 80625 (skeleton), UMMZ 63542-6, USC 7051. =Chiriqui=: Boquete, AMNH 69815, UMMZ 58441-5; El Volcan, KU 77413, 91828-31 (skeletons), 91852-74, 91832 (eggs), 91833 (tadpoles); 6 km. S El Volcan, CNHM 60442; 16 km. NNW El Volcan, KU 91879-90; Finca Palosanto, 6 km. WNW El Volcan, KU 77406-12, 77692 (skeleton), 91875-7, 92330-1; Rio Colorado, 17 km. NNW El Volcan, KU 91878, 92332; Valle Hornito, 19 km. NE Gualaca, KU 92333-45. =Cocle=: El Valle, AMNH 55440-5 (13), 59607-14, CNHM 48140, 60349-2, 60387-92, 60401-4, 60443, 67842-5, KU 91834 (young), 91902-4, TNHC 23751-2, USNM 140653. =Colon=: Rio Candelaria, AMNH 53708-15, CNHM 67826-36. =Darien=: Camp Creek, Camp Townsend, AMNH 40756-7, 40936-9, 40992; Rio Chico, AMNH 39784, 40986-7; Rio Pita, CNHM 67823-5; Tacarcuna, USNM 141796-802; Three Falls Creek, AMNH 41684, 51788. =Los Santos=: Cerro Hoya, USNM 148213-4; Lajamina, Rio Puria, KU 67915. =Panama=: Altos de Pacora, KU 91894; Cerro Jefe, KU 91895-6; Cerro La Campana, CNHM 67846, KU 91897-900, USNM 139689; Finca La Sumbadora, KU 80467-81, 80620 (tadpoles), 91910 (eggs), 91911-2 (tadpoles), 91913 (young), 91908-9 (skeletons); Rio Calobra, USNM 53722, Rio Pacora, 9 km. NNE Pacora, KU 91901. =Veraguas=: Cerro Carbunco, USNM 129066; Cerro Tute, CNHM 67837-41; Isla Cebaco, Rio Platanal, KU 91891-3.

COLOMBIA: =Antioquia=: Uraba, Villa Arteaga, CNHM 63893 (Goin). =Atlantico=: Sabanalarga, Rio Causa, AMNH 14506.

=Smilisca sordida= (Peters), new combination

Hyla sordida Peters, Monatsb. Konigl. Akad. Wissen. Berlin., p. 460, 1863 [Syntypes.--ZMB 3141 (two specimens) from "Veragua," Panama; J. von Warszewicz collector]. Brocchi, Mission scientifique au Mexique ..., pt. 3, sec. 2, Etudes sur les batrachiens, p. 42, 1881. Boulenger, Catalogue Batrachia Salientia in British Museum, p. 393, Feb. 1, 1882. Guenther, Biologia Centrali-Americana: Reptilia and Batrachia, p. 273, Sept. 1901. Nieden, Das Tierreich, Amphibia, Anura, I, p. 258, June, 1923.

Hyla gabbi Cope, Jour. Acad. Nat. Sci. Philadelphia, new ser., 8, pt. 2:103, 1876 [Syntypes.--USNM 30658-9 from near Sipurio, Limon, Costa Rica; William M. Gabb collector]. Brocchi, Mission scientifique au Mexique ..., pt. 3, sec. 2, Etudes sur les batrachiens, p. 37, 1881. Boulenger, Catalogue Batrachia Salientia in British Museum, p. 372, Feb. 1, 1882. Cope, Bull. U. S. Natl. Mus., 32:32, 1887. Guenther, Biologia Centrali-Americana: Reptilia and Batrachia, p. 274, Sept. 1901. Werner, Abhand. Konigl. Akad. Wissen. Muenchen., 22:351, 1903. Nieden, Das Tierreich, Amphibia, Anura I, p. 252, June, 1923. Taylor, Univ. Kansas Sci. Bull., 35(1):840, July 1, 1952. Cochran, Bull. U. S. Natl. Mus., 220:54, 1961.

Hyla nigripes Cope, Jour. Acad. Nat. Sci. Philadelphia, new ser., 8, pt. 2:104, 1876 [Syntypes.--USNM 30685-6, from Pico Blanco, Costa Rica; William M. Gabb collector]. Brocchi, Mission scientifique au Mexique ..., pt. 3, sec. 2, Etudes sur les Batrachiens, p. 38, 1881. Boulenger, Catalogue Batrachia Salientia in British Museum, p. 394, Feb. 1, 1882. Cope, Bull. U. S. Natl. Mus., 32:32, 1887. Guenther, Biologia Centrali-Americana: Reptilia and Batrachia, p. 278, Sept., 1901. Nieden, Das Tierreich, Amphibia, Anura I, p. 253, June, 1923. James, Copeia, 3:147, Sept. 30, 1944. Taylor, Univ. Kansas Sci. Bull, 35(1):853, July 1, 1952. Cochran, Bull. U. S. Natl. Mus., 220:56, 1961.

Hyla salvini Boulenger, Catalogue Batrachia Salientia in British Museum, p. 372, Feb. 1, 1882 [Syntypes.--BMNH 1947.2.24.13-14 from Cartago, Costa Rica; Osbert Salvin collector]. Guenther, Biologia Centrali-Americana: Reptilia and Batrachia, pl. 71, Fig. B., Sept., 1901. Werner, Abhand. Zool.-Bot. Gesell. Wien, 46:8, Sept. 30, 1896.

Smilisca gabbi, Starrett, Copeia, 4:303, Dec. 30, 1960.

Diagnosis.--Size moderate ( 45 mm., 64 mm.); skull slightly wider than long, having large and elongate frontoparietal fontanelle; supraorbital flanges absent; squamosal small, not contacting maxillary; bony section of ethmoid terminating just anterior to anterior edge of orbit; tarsal fold weak, full length of tarsus; inner metatarsal tubercle long, low, flat, elliptical; lips thin and flaring; fingers one-half webbed; toes four-fifths webbed; diameter of tympanum about one-half that of eye; no white labial stripe; dorsal dark markings irregular, sometimes forming broad transverse bars; pale flecks on flanks and usually on posterior surfaces of thighs; vocal sacs in breeding males white. (Foregoing combination of characters distinguishing S. sordida from any other species in genus.)

Description and variation.--Ten breeding males from 15 to 20 kilometers west-southwest of San Isidro el General, San Jose, Costa Rica, have snout-vent lengths of 38.1 to 42.6 mm. (40.5 mm.). In these specimens, the tibia/snout-vent length ratio is 0.50 to 0.54 (0.52), and the tympanum/eye ratio is 0.45 to 0.57 (0.49). Specimens from the Pacific slopes of Costa Rica are larger than those from the Meseta Central and the Caribbean lowlands. Ten males from 6 kilometers east of Golfito, Puntarenas, have snout-vent lengths of 38.4 to 44.6 mm. (41.8 mm.), and five males from Rincon, Peninsula de Osa, have snout-vent lengths of 38.8 to 41.6 mm. (40.3 mm.). Snout-vent lengths of ten males from La Fortuna, Alajuela, are 31.9 to 36.0 mm. (34.4 mm.), of ten males from Pandora, Limon, 33.8 to 37.6 mm. (35.9 mm.), and of ten males from Escazu and Rio Jorco on the Meseta Central, 34.3 to 37.6 mm. (36.0 mm.). Eight females from the Rio Jorco on the Meseta Central have snout-vent lengths of 48.8 to 53.8 mm. (50.4 mm.), and six females from various localities on the Pacific slopes of Costa Rica have snout-vent lengths of 56.5 to 64.0 mm. (59.8 mm.). The only noticeable differences in proportions between males and females is in the tympanum/eye ratio; for example, this ratio is 0.47 to 0.53 (0.49) and 0.54 to 0.68 (0.61) in ten males and eight females, respectively, from the Meseta Central.

The shape of the snout and the associated cranial elements of S. sordida vary geographically and ontogenetically. Specimens from the Caribbean lowlands have blunt snouts in lateral view; those from the Pacific lowlands have longer, more slender snouts that are pointed in lateral view, and those from the Meseta Central are intermediate in snout shape between the two lowland populations (Fig. 4). These differences in shape of the snout are dependent on the nature of the underlying cranial bones, principally the maxillaries and nasals. In specimens from the Caribbean lowlands the nasals are long, wide, and narrowly separated from the ethmoid; the anterior edge is just posterior to the nostril. The maxillary flanges are nearly vertical. In specimens from the Pacific lowlands the nasals are relatively shorter, narrower, and rather widely separated from the ethmoid; the anterior edges of the nasals do not extend so far forward as in specimens from the Caribbean lowlands. The maxillary flanges slant medially. In these cranial characters, specimens from the Meseta Central are intermediate between the two lowland populations.

Superimposed on this geographic variation are ontogenetic changes, which are most noticeable in males. In smaller, and presumably younger, specimens the snouts are more pointed than in larger specimens; consequently some small males from the Caribbean lowlands resemble larger males from the Pacific lowlands, since the nasals and maxillaries of the former are not fully ossified. In addition, in small breeding males the ethmoid is only about one-half ossified, a large frontoparietal foramen is present, the anterior arm of the squamosal extends only about one-fourth the distance to the maxillary (two-thirds the distance in larger specimens), and the tegmen tympani are short, as compared with the long, thin elements in larger specimens.

The dorsal ground-color of Smilisca sordida is gray to pale tan or reddish brown; the venter is white. The dorsum is variously marked with dark gray, dark brown, reddish brown, or olive-green spots or blotches (Pl. 7C). A dark interorbital bar usually is present. The dorsal markings on the body usually consist of a blotch, or two or more spots, on the occiput, in the scapular region, and in the sacral region. In many specimens, especially females, these markings are in the form of broad transverse bars. A female (USC 7164) from Las Canas, Guanacaste, Costa Rica, has a tan dorsum with many black flecks and round brown spots bordered by darker brown. One female (KU 91763) from the Rio Jorco, San Jose, Costa Rica, has a unicolor tan dorsum. Some individuals have scattered, small white spots on the dorsum; these are most evident in a male (USC 7153) from La Fortuna, Alajuela. White labial stripes and anal stripes are absent in all specimens.

The limbs are marked by dark brown transverse bars; these are indistinct in some specimens from the Meseta Central and Caribbean lowlands, whereas they are distinct in all specimens from the Pacific lowlands. Specimens from the Caribbean lowlands have two to six bars on each shank, whereas specimens from the Pacific slopes have four to six bars on each shank, and specimens from the Meseta Central have as many as eight bars on each shank. A narrow, sometimes broken white line is present on the ventrolateral edge of the forearm. The webbing on the hand is tan or pale gray, and the ventral surfaces of the tarsi and the webbing on the feet are dark gray or brown. Breeding males have dark brown nuptial excrescences on the prepollex.

The flanks and posterior surfaces of the thighs usually are marked by bluish white and creamy tan flecks, respectively, but vary considerably. In specimens from the Caribbean lowlands a small amount of flecking is present in the inguinal region, and on the posterior surfaces of the thighs flecks are few or absent. In specimens from the Meseta Central, numerous large flecks or small, round spots (pale bluish white in life) are on the posterior half of the flanks; small flecks are on the posterior surfaces of the thighs. Specimens from the Pacific slopes and lowlands of southern Costa Rica (Puntarenas and San Jose Provinces) have bold mottling of black and bluish white on the flanks and many bluish white flecks on the posterior surfaces of the thighs. The flanks are reticulated from the axilla to the groin in two females (UMMZ 123684 and USC 7236) from Rincon, Peninsula de Osa. In specimens from the Pacific slopes of Guanacaste in northwestern Costa Rica, flecks are present in the inguinal region; indistinct flecks are on the posterior surfaces of the thighs.

The throat is immaculate in specimens from the Caribbean lowlands in Limon Province; the throats are dusky laterally in most other specimens except some from the Meseta Central, in which the throats are heavily flecked with black. This variation occurs in males and females.

The color and pattern in life are highly variable. A composite description of living individuals (now KU 91718-41) from 6 kilometers east of Golfito, Puntarenas, Costa Rica, illustrates the variability: "Dorsum pale olive-green, fading to tan posteriorly, or tan all over with dark olive-green or dark brown spots on back and bars on limbs. Flanks dark brown with cream, greenish gray, or bluish gray mottling. Posterior surfaces of thighs dark brown with pale blue, pale green, or tan flecks. Iris creamy silver. Throats white with some brown flecks peripherally." (Duellman, Field notes, February 15, 1965.) A male from the Rio Jorco, San Jose, Costa Rica, was dull olive-tan above with olive-green marks; the flanks were brown with pale tan flecks, and the posterior surfaces of the thighs were pale brown with cream-colored flecks. Six females from the same locality were reddish brown above with olive-brown or dark brown markings; one was uniform orange-tan, and another was dull olive-green with darker markings.

The color of the iris in living frogs varies from creamy silver to grayish yellow or bronze with a variable amount of black reticulation.

Natural History.--Smilisca sordida is not associated with any one type of vegetation; instead it lives in the vicinity of rocky streams having low gradients. Breeding takes place primarily in the dry season, when the water in the streams is clear and at a low level. Through most of the range of S. sordida showers, or even short heavy rains, occur in the dry season. After such rains the breeding activity is maximal. Breeding congregations have been found from December through April, but a few calling males and gravid females have been taken in June, July, and August. In the rainy season non-breeding individuals are found sitting on bushes near streams at night. Taylor (1952:843) found specimens in bromeliads by day.

Males usually call from rocks or gravel bars in, or at the edge of, streams. Some individuals perch in low bushes overhanging the streams, and some sit in shallows in the streams. Clasping pairs have been found on the banks of streams and in shallow water in streams.

The breeding call consists of one to six moderately short, rather high-pitched notes (duration 0.18 to 0.45 seconds) repeated at intervals of 12 seconds to several minutes. Each note is a vibrant rattle having 78 to 135 pulses per second and major frequences of about 1200 to 2600 cycles per second (Pl. 11C).

The tadpoles live in shallow parts of the streams, where they cling to the surfaces of small rocks and hide beneath leaves and rocks. A complete developmental series of tadpoles is not available; measurements of those stages examined are summarized in Table 12.

A typical tadpole in stage 36 of development (KU 68475 from 15 km. WSW of San Isidro el General, Costa Rica) has a body length of 11.7 mm., tail length of 22.8 mm., and a total length of 34.5 mm.; body about three-fourths as deep as wide; snout broadly rounded in dorsal view, sloping and rounded in lateral view; eyes widely separated, directed dorsolaterally; nostril slightly closer to eye than to tip of snout; mouth ventral; spiracle sinistral, about two-thirds distance from snout to posterior end of body and slightly below midline; anal tube dextral; caudal musculature heavy, straight; dorsal fin not extending onto body; fins deepest at about mid-length of tail; there depth of caudal musculature equal to depth of dorsal fin and half again as deep as ventral fin; musculature extending nearly to tip of tail; body reddish brown above and pale grayish brown with white flecks below; caudal musculature pale tan with brown flecks; a series of reddish brown dashes at base of caudal fin separated from others in series and from dashes on other side by creamy white; fins transparent with reddish brown flecks on posterior one-half of ventral fin and on all of dorsal fin (Fig. 14C). Mouth bordered by two rows of short, pointed papillae; lateral fold present; tooth-rows 2/3; upper rows equal in length; second upper row narrowly interrupted medially; three lower rows complete, nearly as long as upper rows, deeply indented medially; upper beak robust, inner surface not forming continuous arch with short lateral processes; lower beak deep, V-shaped; both beaks bearing short serrations (Fig. 15F).

Little variation occurs in structure. In some specimens the second upper tooth-row is complete; no individuals were found to have the row broadly interrupted medially.