Neotropical Hylid Frogs, Genus Smilisca Part 5

_Distribution._--_Smilisca cyanosticta_ inhabits wet forests on the Atlantic slope of southern Mexico and northern Central America from northern Oaxaca and southern Veracruz through northern Chiapas in Mexico and into El Peten and northern Alta Verapaz in Guatemala (Fig. 2).

Apparently the range is discontinuous, for in southern Mexico the species is found in cloud forest at elevations of 830 to 900 meters on the northern slopes of the Sierra de Juarez. In the Sierra de Los Tuxtlas in southern Veracruz the species is found in wet forest at elevations of 300 to 1200 meters, but is absent in the intervening lowlands characterized by drier forest. In the west forests of northern Alta Verapaz and El Peten, Guatemala, the species is found at low elevations.

_Specimens examined._--78, as follows: MEXICO: =Chiapas=: Monte Libano, MCZ 28271-9; 8 km. N San Fernando, 24 km. NE Tuxtla Gutierrez, UIMNH 41588. =Oaxaca=: 11 km. N Vista Hermosa, KU 84918-20 (skeletons), 87198-212, 87647 (eggs), 87648-52 (tadpoles), 87653 (young), UIMNH 57199-201; 8 km. S Yetla, KU 87213, UMMZ 124838 (8). =Veracruz=: Coyame, UMMZ 111459-60; between Coyame and Tebanco, UMMZ 121198; Dos Amates, UMMZ 121297; between Laguna de Catemaco and Volcan San Martin, UMMZ 121200; Volcan San Martin, UIMNH 35403-4, 35408-12, UMMZ 118163; SE slope Volcan San Martin, UMMZ 121199, 121295 (2), 121296, 121298.

GUATEMALA: =Alta Verapaz=: Chinaja, KU 55935-7, 55938 (skeleton). =El=

=Peten=: 10 km. NNW Chinaja (Alta Verapaz), KU 55934; Piedras Negras, CNHM 99006-7, 99227, UIMNH 28853, USNM 111139-41, 111143-7; 8 km. S Piedras Negras, CNHM 99008; Semicoch, USNM 35907.

[Ill.u.s.tration: FIG. 2. Map showing locality records for _Smilisca cyanosticta_ (triangles) and _Smilisca phaeota_ (circles).]

=Smilisca phaeota= (Cope)

_Hyla phaeota_ Cope, Proc. Acad. Nat. Sci. Philadelphia, 14 (9):358, 1862 [Holotype.--USNM 4347 from Turbo, Colombia; J. Ca.s.sin collector]. Boulenger, Catalogue Batrachia Salientia in British Museum, p. 402, Feb. 1, 1882. Werner, Sitzungsb. Akad. Wiss.

Munchen, 27:215, 1897. Gunther, Biologia Centrali-Americana: Reptilia and Batrachia, p. 269, Sept. 1901. Nieden, Das Tierreich, Amphibia, Anura I, p. 261, June 1923. Dunn, Occas. Papers Boston Soc. Nat. Hist., 5:413, Oct. 10, 1931. Gaige, Hartweg, and Stuart, Occas. Papers Mus. Zool. Univ. Michigan, 357:4, Oct. 26, 1937.

Cooper, Copeia, 2:122, June 30, 1944. Breder, Bull. Amer. Mus. Nat.

Hist., 86(6):416, Aug. 26, 1946. Smith and Taylor, Bull. U. S. Natl.

Mus., 194:88, June 17, 1948; Univ. Kansas Sci. Bull, 33:364, March 20, 1950. Taylor, Univ. Kansas Sci. Bull., 35(1):837, July 1, 1952.

Brattstrom and Howell, Herpetologica, 10:117, Aug. 1, 1954. Goin, Herpetologica, 14:120, July 23, 1958. Cochran, Bull. U. S. Natl.

Mus., 220:57, 1961.

_Hyla l.a.b.i.alis_ Peters, Monats. Konigl. Akad. Wissen. Berlin, p.

463, 1863 [Holotype.--ZMB 4913 from "region of Bogota," Colombia]; Monats. Konigl. Akad. Wissen. Berlin, p. 618, Oct. 16, 1873.

Boulenger, Catalogue Batrachia and Salientia in British Museum, p.

397, Feb. 1, 1882.

_Hyla baudini dolomedes_ Barbour, Occas. Papers Mus. Zool. Univ.

Michigan, 129:11, Jan. 25, 1923 [Holotype.--MCZ 8539 from Rio Esnape, Sambu Valley, Darien, Panama; Barbour and Brooks collectors]. Barbour and Loveridge, Bull. Mus. Comp. Zool. Harvard, 69:278, June, 1929.

_Hyla phaeota phaeota_, Smith, Herpetologica, 8:152, Jan. 30, 1953.

Minton and Smith, Herpetologica, 16:103, June 17, 1960.

_Smilisca phaeota_, Starrett, Copeia, 4:303, Dec. 30, 1960.

_Diagnosis._--Size large ([M] 65 mm., [F] 78 mm.); skull as long as wide, lacking frontoparietal fontanelle; large supraorbital f.l.a.n.g.es having straight edges and extending posterolaterally; large squamosal not in contact with maxillary; tarsal fold moderately wide, full length of tarsus; inner metatarsal tubercle moderately large, low, flat, elliptical; hind limbs relatively long, tibia averaging more than 53 per cent of snout-vent length; l.a.b.i.al stripe silvery white; lips lacking vertical bars; loreal region pale green; dark brown or black tympanic mark dispersing into brown venated pattern on flanks; posterior surfaces of thighs pale brown, with or without darker flecks or small cream-colored flecks. (Foregoing combination of characters distinguis.h.i.+ng _S. phaeota_ from any other species in genus.)

Table 2.--Geographic Variation in Size and Proportions in Males of Smilisca phaeota. (Means in Parentheses Below Observed Ranges; Data Based on Ten Specimens From Each Locality.)

================================================================== |Snout-vent |Head width/|Interorbital Locality |length |snout-vent |distance/ | |length |head width -----------------------------+-----------+-----------+------------ Bonanza, Nicaragua | 40.8-47.7 | 34.1-38.0 | 31.0-36.1 | (43.7) | (36.3) | (35.4) -----------------------------+-----------+-----------+------------ Heredia Prov., Costa Rica | 46.3-59.0 | 32.5-36.0 | 30.5-39.6 | (51.7) | (35.0) | (34.7) -----------------------------+-----------+-----------+------------ Puntarenas Prov., Costa Rica | 53.6-64.9 | 32.6-36.1 | 31.0-38.0 | (61.4) | (34.5) | (34.4) -----------------------------+-----------+-----------+------------ Ca.n.a.l Zone, Panama | 52.4-65.5 | 33.5-37.6 | 31.3-37.2 | (56.5) | (35.6) | (34.7) -----------------------------+-----------+-----------+------------ Rio Quesada, Colombia | 52.6-61.0 | 33.1-37.1 | 30.1-33.9 | (56.0) | (35.0) | (32.1) ------------------------------------------------------------------

_Description and Variation._--For the purposes of a.n.a.lyzing geographic variation in size and proportions, measurements were taken on ten adult males from each of five samples throughout the range of the species.

Aside from the data summarized in Table 2, the average ratio of tibia length to snout-vent length is noticeably less in Colombian specimens (53.4 per cent, as compared with 54.8 to 57.8 per cent in the other samples) and the ratio of head length to snout-vent length is noticeably less in Costa Rican specimens (33.5 per cent as compared with 34.9 to 35.1 per cent in the other samples). Also, specimens from Heredia Province, Costa Rica, have a relatively smaller tympanum (62.7 to 80.4 [mean 68.4] per cent of the diameter of the eye, as compared with means of 74.0 to 77.9 per cent in the other samples).

Two populations are distinctive as regards the size of adult males.

Specimens from the northern Caribbean lowlands of Nicaragua (Bonanza, the northernmost locality for the species) are remarkably small. Males having snout-vent lengths of between 40 and 43 mm. were breeding; the largest male found had a snout-vent length of 47.7 mm. The other extreme in size is attained in specimens from the Pacific lowlands of eastern Costa Rica and western Panama, where most breeding males have snout-vent lengths of more than 55 mm.; the largest male had a snout-vent length of 64.9 mm.

The rather striking differences in size among certain samples and the minor differences in proportions among other samples show no geographic trends. Instead, the variations apparently are random among the samples.

The data presented here possibly are the results of inadequate sampling, but more likely reflect actual differences in the populations.

The dorsal ground color of _Smilisca phaeota_ is pale green to tan; the venter is creamy white. The dorsum is variously marked with dark olive-green or dark brown spots or blotches (Pl. 6C). A dark interorbital bar is usually present. Usually a large dark dorsal mark extends from the occiput to the sacral region, but in many individuals this blotch is replaced by two or three dark marks. The dorsal markings are irregular in shape and do not tend to form transverse bands or longitudinal bars. The hind limbs are marked by dark transverse bands, usually four or five on the thigh, five or six on the shank, and four on the tarsus. Two or three narrow bands are usually present on the proximal part of the fourth toe. The webbing on the feet is brown. The loreal region is pale green, bordered above by a narrow dark brown canthal stripe extending from the nostril to the orbit. The upper lip is silvery white. A broad dark brown or black mark extends posteriorly from the orbit, encompa.s.sing the tympanum, to a point above the insertion of the forelimb. The flanks are pale green or pale tan and marked with a fine dark brown or black venation. The anterior surfaces of the thighs usually are pale brown or grayish tan, sometimes having small, indistinct darker flecks. The posterior surfaces of the thighs are similarly colored, but in most specimens small but distinct dark flecks are present; in some specimens small cream-colored spots are also present on the posterior surfaces of the thighs. A distinct, narrow creamy white a.n.a.l stripe usually is present. A distinct white stripe is present on the outer edge of the tarsus and fifth toe; on the tarsus the white stripe is bordered below by dark brown. A white stripe also is present on the outer edge of the forearm and fourth finger. In breeding males the throat is dark gray.

Little geographic variation in color or pattern is evident. Few, if any, specimens from the Pacific lowlands of South America are green in life.

(We have seen no living individuals from South America.) Some living individuals from Costa Rica and all those seen alive from Nicaragua have a tint of pale blue on the flanks. In some specimens the dorsal pattern is so faint as to be barely discernible, whereas in most specimens the pattern is bold.

The coloration in the living frogs is highly variable due to extreme metachrosis. Individuals of this species are capable of changing the dorsal coloration from green to brown in a short period of time. Both green and brown individuals have been found active at night. Usually those individuals found hiding by day are brown. One individual from Finca La Sumbadora, Panama (now KU 91914), was kept alive in the laboratory for nearly one month. This individual usually was pale green with tan dorsal markings at night and tan with pale green markings by day. On occasion the pale green dorsal markings were boldly outlined by bright dark green.

In living individuals from throughout the range of the species the iris is a bronze color, darkest medially with fine black reticulations.

_Natural History._--_Smilisca phaeota_ inhabits humid lowland tropical forest and seldom ascends the foothills to more than 1,000 meters. The rather equable climatic conditions, especially more or less evenly distributed rainfall throughout the year, permit this frog to be active most of the year. Dunn (1931:413) reported males calling on Barro Colorado Island, Panama, in February and in July, and Breder (1946:416) noted calling individuals in the Chucanaque drainage of Darien, Panama in January, March, July, August and October and in Costa Rica in April through August inclusively. Calling males were found at Bonanza, Nicaragua in March and in July.

At all times of year the usual daytime retreats for these frogs are near water; the frogs have been found in elephant ear plants (_Xanthosoma_) and in bromeliads; occasional individuals have been found sitting on shaded branches of bushes and trees. None has been observed on the ground or beneath ground-cover by day.

The length of the breeding season cannot be determined definitely. The earliest date on which eggs have been found is May 23; Gaige, Hartweg, and Stuart (1937:5) reported a gravid female taken at El Recreo, Nicaragua, in September, and we have a gravid female taken at Almirante, Panama, in March.

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 Rio Chitaria, 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; a.n.a.l 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 Guapiles, 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 Rio Chitaria, 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 a.n.a.l stripes white" (Duellman, field notes, May 23, 1961).

_Remarks._--Peters (1863:463) named _Hyla l.a.b.i.alis_ from the "region of Bogota, Colombia", but in 1873 regarded his new species as identical with _Hyla phaeota_ Cope, 1862, from Turbo, Colombia. The name _Hyla l.a.b.i.alis_ 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 l.a.b.i.alis_. 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 a.s.signment.

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 Panama, 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 Rio Cauca and Rio Magdalena in Colombia (Fig. 2).

_Specimens examined._--528, as follows: NICARAGUA: =Matagalpa=: Finca Tepeyac, 10 km. N, 9 km. E Matagalpa, KU 85439, 87707 (tadpoles); Matagalpa, MCZ 3546-7, UMMZ 92367; 19 km. N Matagalpa, UMMZ 116495-6.

Zelaya: Bonanza, KU 84854-62, 84950-2 (skeletons), 85440-50, 87708-9 (tadpoles); Cukra, AMNH 80618; Rio Mico, 16 km. E Recreo, UMMZ 79711 (6), 79712 (4); junction Rio Mico and Rio Siguia, UMMZ 79713 (10); Rio Siguia, 11 km. NW Rama, UMMZ 79714 (14), 79715 (11), 79716 (21), 79717, 79718 (3).

COSTA RICA: =Alajuela=: Cinchona, KU 32255, 64286-8; 5 km. S Ciudad Quesada, USC 8077; Laguna Monte Alegre, KU 64289-90; Las Playuelas, 11 km. S Los Chiles, USC 7216; San Carlos, USNM 29961.

=Cartago=: Moravia de Turrialba, KU 32212-47, 37133-5, 41093 (skeleton), 64280-1, USC 7243 (3); Peralta, KU 32271-2; Rio Chitaria, 3 km. NNE Pavones, KU 64273-9, 68477 (eggs), 68478-83 (tadpoles), 68484 (young); Rio Reventazon, MCZ 29196-203, UMMZ 117677 (9); Turrialba, KU 25720-2, 32209-11, 32266-8, 32273-4, 37136-67, 41090-2 (skeletons), 64270-2, MCZ 29221, 29222 (tadpoles), 29269-70, USNM 29934.