19.8 mm., 54.1 per cent of snout-vent length; foot length 15.5 mm., 42.3
per cent of snout-vent length; head length 12.7 mm., 34.7 per cent of
snout-vent length; head width 13.3 mm., 36.8 per cent of snout-vent
length; snout short, in lateral profile truncate, only slightly rounded
above, in dorsal profile rounded; canthus rounded; loreal region
noticeably concave; lips thick, rounded, not flaring; nostrils not
protuberant, directed laterally; internarial distance 3.0 mm.;
internarial area flat; top of head flat; interorbital distance 3.5 mm.,
26.3 per cent of head width; diameter of eye 4.2 mm., thrice distance
(1.4 mm.) from tympanum to eye, and half again distance (2.8 mm.) from
orbit to nostril; pupil horizontally ovoid; width of eyelid 2.8 mm.,
21.1 per cent of head width; dermal fold from posterior corner of orbit
covering upper edge of tympanum to point above insertion of forelimb;
diameter of tympanum 2.3 mm., 54.7 per cent of diameter of eye; no
axillary membrane; arms moderately robust; weak fold on wrist; faintly
scalloped fold along ventrolateral margin of forearm; fingers short,
slender; fingers from shortest to longest, 1-2-4-3; vestige of web
between first and second fingers; others about two-fifths webbed; discs
moderate, diameter of that on third finger about one-third diameter of
eye; triangular outer palmar tubercle; elliptical inner palmar tubercle
on base of pollex; subarticular tubercles large, conical, none bifid;
supernumerary tubercles few, large, conical; brown nuptial excrescence
on prepollex; heels overlap by about one-fifth length of shank when hind
limbs adpressed; tibiotarsal articulation extending to nostril; tarsal
fold weak, extending nearly full length of tarsus; inner metatarsal
tubercle elliptical, flat; outer metatarsal tubercle absent; toes
moderately long; toes from shortest to longest, 1-2-3-5-4, third and
fifth about equal in length; discs about same size as those on fingers;
webbing extending to middle of penultimate phalanx on all toes, except
only to distal end of antepenultimate phalanx of fourth toe;
subarticular tubercles round; supernumerary tubercles large, round,
present only on proximal digits. Anal opening directed posteriorly at
level of upper edge of thighs; no noticeable anal sheath; flat tubercles
ventrolateral to anal opening large; skin of chest, belly, and posterior
surfaces of thighs granular; other surfaces smooth; tongue broadly
cordiform, shallowly notched posteriorly, and barely free behind;
vomerine teeth 4-4, situated on ventral surfaces of separated rounded
prominences between posterior margins of small, ovoid inner nares; vocal
slits long, each situated along inner margin of ramus; color (in
preservative) pinkish tan above with irregular olive-brown markings
forming interconnected spots on back; four bars on dorsal surface of
each thigh; five bars on shank, and three on tarsus; inguinal region
white with black mottling; posterior surfaces of thighs yellowish tan
proximally, dark brown distally; margins of lips grayish white with
brown markings; ventral surfaces of hands and feet grayish brown; belly
and posterior part of throat creamy white; anterior part of throat
brown.
_Description and variation._--Ten breeding males from Finca La
Sumbadora, Panama, have snout-vent lengths of 40.0 to 44.8 mm. (42.3
mm.). In these specimens the tibia/snout-vent length ratio is 0.50 to
0.57 (0.54), and the tympanum/eye ratio is 0.48 to 0.58 (0.53). There is
a geographic gradient in size; specimens from the western part of the
range (southern Costa Rica) are smaller than those from the eastern part
of the range (eastern Panama). Five males from the Pacific lowlands of
southern Costa Rica have snout-vent lengths of 31.6 to 38.2 mm. (34.7
mm.); ten males from El Volcan, Chiriqui, Panama, 32.6 to 37.9 mm. (36.4
mm.), and eight males from Barro Colorado Island, Canal Zone, 38.2 to
42.0 mm. (35.6 mm.). These are smaller than the males from Finca La
Sumbadora, which is east of the Canal Zone. Ten females from El Volcan
have snout-vent lengths of 44.2 to 55.6 mm. (49.2 mm.), as compared 56.1
to 62.2 mm. (58.2 mm.) in three females from Finca La Sumbadora.
Large females have scattered small tubercles on the head and back;
tubercles occur in males from Costa Rica and in some males from western
Panama. The truncate snout is characteristic of both sexes.
The coloration of _Smilisca sila_ consists of a gray, tan, or pale
reddish brown dorsal ground color and a creamy white venter. The dorsum
is marked by dark brown, olive-brown, or dark reddish brown spots or
blotches (Pl. 7B). Usually the blotches are discrete, but in some
individuals they are interconnected and form an irregular dark mark on
the dorsum. There is no tendency for the blotches to form transverse
bars as in _Smilisca sordida_. In one specimen (KU 80467) the blotches
are fused and form two wide irregular longitudinal stripes, as in
_Smilisca puma_. In some females the dorsal markings are reduced to a
few small spots or are nearly absent (KU 92332), whereas in other
females the dorsal markings are bold. In one female (KU 91894) the
dorsal markings are narrowly bordered by pale blue, and numerous pale
blue flecks are present on the pale brown dorsum. In many individuals of
both sexes small white flecks are present on the dorsal surfaces.
Usually the flanks and posterior surfaces of the thighs have black
mottling enclosing pale blue spots and flecks, respectively. The dorsal
surfaces of the limbs are marked by dark brown transverse bars; usually
three or four bars are present on each forearm, thigh, and shank. The
coloration of the flanks and limbs varies geographically. Specimens from
southern Costa Rica and western Panama have distinct bars on the limbs;
the posterior surfaces of the thighs have brown reticulations enclosing
small blue flecks in specimens from Costa Rica and bolder, black
reticulations enclosing large pale blue spots in specimens from western
Panama. In specimens from Costa Rica the flanks are brown with pale blue
flecks, whereas in those from Chiriqui, Panama, the flanks are pale blue
with dark brown mottling in the inguinal region. Frogs from El Valle and
Cerro la Campana usually have distinct bars on the limbs; the posterior
surfaces of the thighs are colored as in frogs from Chiriqui, and the
inguinal region is pale blue with coarse brown mottling. Specimens from
Barro Colorado Island are marked like those from El Valle and Cerro la
Campana, except that on the posterior surfaces of the thighs fine black
reticulations enclose many dark blue spots. In specimens from Darien and
from Panama Province east of the Canal Zone (Altos de Pacora, Cerro
Jefe, Finca La Sumbadora, and Rio Pacora), the markings on the dorsal
surfaces of the limbs are indistinct or absent in males, but distinct in
some females. Intense brown and black pigment forms fine reticulations
delimiting bold blue spots on the flanks; this coloration extends to the
axilla in many specimens. Fine black reticulations enclose many dark
blue spots on the posterior surfaces of the thighs.
In females, the throat is creamy white; in some specimens scattered
brown flecks are present on the chin and throat. In breeding males the
anterior part of the throat is dark gray or dark brown.
The coloration in life is as variable as it is in preservative. In life
the holotype had a tan dorsum with dark olive-green irregular markings
and small green flecks. The limbs were tan with dark brown transverse
bars. The flanks were grayish tan anteriorly; the inguinal region and
posterior surfaces of thighs were blue with black mottling. The belly
was creamy white, and the throat was brown with creamy yellow flecks.
The iris was a dull bronze color. Among the paratypes, some individuals
had green flecks, others did not. The inguinal region and posterior
surfaces of the thighs were pale blue, pale yellowish green, or grayish
tan with black mottling. The blue was most noticeable in females.
Colors of a male from Finca La Sumbadora, Panama, were described as
follows: "Dorsum olive-brown; irregular dark brown blotches, pale green
flecks, and raised creamy yellow spots on dorsal surfaces; belly creamy
white; throat grayish brown; undersides of limbs grayish tan; groin,
anterior and posterior surface of thigh, inner surface of shank,
anterior edge of tarsus, and proximal parts of third and fourth toes
pale blue marbled with dark brown and black; webbing brown; iris pale
bronze, finely reticulated with black." (Duellman, field notes, January
28, 1964.)
A female (now KU 91894) from Altos de Pacora, Panama, was described as
follows: "An irregular dark brown, green-bordered figure on head and
back; dark brown, green-bordered bands on limbs--all on a lighter brown
and heavily green-spotted background. These markings are more vivid at
night than during the day. Lower sides, from midbody onto front of
thighs and rear of thighs onto venter of shanks to heels and thence
dorsally onto basal portions of toes heavily blue spotted on a light
brown (front of thighs and venter of shanks) to blackish brown
background. Venter cream. Iris gray-brown, finely veined with dark
brown." (Charles W. Myers, field notes, December 14, 1964.) Note that in
the earlier discussion of coloration of preserved specimens, the green
spots and borders have changed to pale blue after six months in
alcohol.
In living individuals from Costa Rica and Panama west of the Canal Zone,
the blue coloration on the flanks and thighs is much less conspicuous
than in specimens from eastern Panama. The color of the iris is
variable, even in frogs from one locality. The coloration of the iris in
13 living frogs (now KU 92333-45) from Valle Hornito, Chiriqui, Panama,
was described as follows: "Iris variable--from pale to dark brown; in a
few the iris has a golden cast to the brown; in a few others the lower
half of the iris is pale gray with the upper half being light brown."
(Charles W. Myers, field notes, April 24, 1965).
_Natural history._--_Smilisca sila_ inhabits the Pacific slopes of lower
Central America where a pronounced dry season occurs. We have records of
males calling in December through May and also in August (latter date
from El Volcan, Chiriqui, Panama). The breeding season seems to be
correlated with the time of the year when the water is clear and at a
low level in the streams where these frogs breed.
Males call from the edges of small, shallow streams, from rocks in the
streams, or less frequently from vegetation overhanging the streams.
Females are most frequently found on the banks of streams, and clasping
pairs usually are in shallow pools in streams. One individual was found
in a bromeliad about three meters above the ground in the daytime.
The breeding call consists of a low squawk, usually followed by a series
of one or more rattling secondary notes (duration of primary notes, 0.06
to 0.28 seconds; of secondary notes, 0.14 to 0.48 seconds), repeated at
intervals of 4 to 20 seconds. The primary notes have 97 to 120 pulses
per second and major frequencies of about 900 to 2220 cycles per second
(Pl. 11B).
Eggs were obtained artificially in the field; the average length of ten
embryos in the neural groove stage is 2.4 mm., and the average diameter
of the outer envelope is 4.9 mm. Hatchlings have large, conical oral
discs, heavy gills, and a large amount of yolk; their average total
length is 6.3 mm.
Tadpoles have been found in pools in clear streams; some tadpoles have
been observed to cling by their mouths to rocks in the stream; others
were found on the bottom where they seek refuge among pebbles or under
rocks and leaves. A complete developmental series of tadpoles is not
available. Eleven tadpoles in stage 25 of development have body lengths
of 8.3 to 10.2 mm. (9.3 mm.), tail lengths of 17.3 to 21.0 mm. (18.8
mm.), and total lengths of 25.9 to 31.0 mm. (28.1 mm.). One tadpole in
stage 41 and one in stage 42 have body lengths of 11.5 and 12.5 mm.,
tail lengths of 27.2 and 29.5 mm., and total lengths of 38.7 and 42.0
mm., respectively. The snout-vent lengths of two specimens in stage 43
and one in stage 45 are 12.7, 13.0, and 13.6 mm., respectively.
A typical tadpole in stage 25 of development (KU 80620 from Finca La
Sumbadora, Panama) has a body length of 9.5 mm., tail length of 19.0
mm., and a total length of 28.5 mm.; body only slightly wider than deep,
nearly flat dorsally; snout broadly rounded in dorsal view, bluntly
rounded in lateral view; eyes widely separated, directed dorsolaterally;
nostril slightly closer to eye than to tip of snout; mouth ventral;
spiracle sinistral, located about two-thirds distance from snout to
posterior edge of body; anal tube dextral; caudal musculature moderately
heavy, straight; dorsal fin not extending onto body; fins deepest at
about two-fifths length of tail, where depth of caudal musculature about
equal to depth of dorsal and depth of ventral fin; musculature
extending nearly to tip of tail; body dark grayish brown above and pale
grayish tan below with small dark brown spots dorsally and white flecks
laterally; caudal musculature pale tan with dark brown flecks over
entire surface and dark brown streaks on posterior one-half of ventral
fin and on all of dorsal fin (Fig. 14B). Median one-third of upper lip
bare; rest of mouth bordered by a single row of conical papillae;
lateral fold present; tooth rows 2/3; upper rows cone-shaped, about
equal in length, broadly /\-shaped; second upper row narrowly
interrupted medially; lower rows complete, about equal in length, but
slightly shorter than upper rows; upper beak moderately massive, its
inner surface forming a continuous arch with short lateral processes;
lower beak broadly \/-shaped; both beaks finely serrate (Fig. 15D).
Tadpoles from El Volcan, Chiriqui (KU 91833), are more heavily pigmented
than those from Finca La Sombadora; the spots on the tail are larger. In
life these tadpoles had dark brownish black bodies with golden and green
lichenous flecks; the tail was tan with dark brown markings, and the
iris was a grayish bronze color. In life tadpoles from Finca La
Sumbadora were olive-tan above and dark gray with pale bluish gray
irridescent spots ventrally. The caudal musculature was creamy tan with
brown flecks and streaks, and the iris was pale bronze.
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 ([M] 45 mm., [F] 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.