_Smilisca sordida_; left column females, right column males;
all from Costa Rica: (A) Camp Seattle, Rincon de Osa, Puntarenas
Prov. (UMMZ 123684); (B) Quebrada Agua Buena, 3 km. SW Rincon de
Osa, Puntarenas Prov. (USC 7236); (C) Rio Oro, 28.5 km. NW Villa
Neily, Puntarenas Prov. (KU 91742); (D) Rio Jorco, near
Desamparados, San Jose Prov. (KU 91765); (E-F) Bambu, Limon Prov.
(USC 7183). x3.]
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.
The series of dark dashes on the dorsal edge of the caudal musculature
is diagnostic of all stages studied. In life, tadpoles from 15 and 20
kilometers west-southwest of San Isidro el General, Costa Rica, had a
tan body, often with an olive-tan tinge; the caudal musculature was
tan; the flecks and dashes were dull red or reddish brown. Tadpoles from
6 kilometers east of Golfito, Costa Rica, had bodies with olive-green
flecks. The caudal musculature was brown with bluish green flecks; the
fins were transparent with reddish brown flecks. The belly was a silvery
golden color. Tadpoles from Bajos de Jorco, Costa Rica, had brown bodies
with bluish green flecks; the tail and fins had reddish brown flecks and
dashes. The iris was a bronze color in specimens from all three
localities, as well as in the young mentioned in the following
paragraph.
Nine recently metamorphosed young were found on vegetation at the edges
of streams in April. These specimens have snout-vent lengths of 13.1 to
15.7 mm. (14.9 mm.) and in life were pale greenish tan or olive-tan
above and white below. The hands, feet, and thighs were pale yellowish
tan.
_Remarks._--The foregoing synonymies indicate that confusion has existed
in the application of various names, to this species, as well as in use
of the names _sordida_ and _gabbi_ to include the species that we
describe and name _Smilisca sila_. Correct allocation of the names
involved was possible only after studying and comparing the type
specimens, for the descriptions given by the various authors are not
sufficiently explicit to determine the nature of many essential
features.
The presence of a rounded snout and a long white throat in males
distinguishes _S. sordida_ from _S. sila_, which has a high truncate
snout and short dark throat in males. The two syntypes of _Hyla sordida_
Peters, 1863, (ZMB 3141) are males having snout-vent lengths of 36.9 and
37.0 mm. The two syntypes of _Hyla gabbi_ Cope, 1876 (USNM 30658-9), are
females having snout-vent lengths of 52.8 and 53.7 mm., respectively.
Also included in the collections made by Gabb is eastern Costa Rica are
two males (USNM 30685-6), which Cope (1876) named and described as _Hyla
nigripes_. These specimens are soft and faded, but are recognizable as
the same as _Hyla sordida_ Peters; the syntypes of _Hyla nigripes_ have
snout-vent lengths of 37.6 and 37.7 mm. We have examined one of the
syntypes of _Hyla salvini_ Boulenger, 1882 (BMNH 1947.2.24.13), a female
having a snout-vent length of 54.6 mm. We are convinced that all of
these type specimens are representatives of one species, the earliest
name for which is _Hyla sordida_ Peters, 1863. The type localities for
three of the named species are in Costa Rica--_H. gabbi_ from Sipurio on
the Caribbean lowlands, _H. nigripes_ from the Caribbean slopes of Pico
Blanco, and _H. salvini_ from Cartago on the Meseta Central. The type
locality of _H. sordida_ was given as "Veraguas" by Peters (1863). At
that time Veraguas was often considered to be most of western Panama.
Though we have not seen Panamanian specimens other than the types of _S.
sordida_ and one specimen from the Pacific lowlands of western Panama,
the species probably occurs on the Caribbean slopes of western Panama.
The species has been taken on the Caribbean lowlands of Costa Rica
within a few kilometers of Panama; collecting on the Caribbean slopes in
the provinces of Bocas del Toro and Veraguas should reveal the presence
of _Smilisca sordida_ there.
_Distribution._--_Smilisca sordida_ is found along the Pacific slopes
and lowlands from Guanacaste, Costa Rica, southeastward to extreme
western Panama, to elevations of about 1200 meters on the Meseta Central
in Costa Rica, and on the Caribbean slopes and lowlands of Costa Rica
and probably adjacent Panama (Fig. 5). One specimen purportedly comes
from "Rio Grande, Nicaragua."
[Illustration: FIG. 5. Map showing locality records for
_Smilisca sordida_.]
_Specimens examined._--412, as follows: NICARAGUA: "Rio Grande"
(? Depto. Zelaya), MCZ 2634.
COSTA RICA: =Alajuela=: Between Atena and Salto de San Mateo, USC 6185;
8 km. N Ciudad Quesada, USC 7155 (4); La Fortuna, USC 7153 (20); 3 km. E
La Fortuna, USC 7150; San Carlos, USNM 29969; Sarchi, KU 32990-9,
36792-3.
=Cartago=: Cartago, BMNH 1947.2.24.13; headwaters of Rio Pacuare, USC
119; Instituto Interamericano de Ciencias Agricolas, Turrialba, KU
37012, USC 420, 437; Rio Reventazon, Turrialba, MCZ 29268: 10 km. N Rio
Reventazon bridge, USC 7073; 5 km. SW Rio Reventazon bridge on
Paraiso-Orosi road, USC 669; Turrialba, UMMZ 118405, USC 455, USNM
29936-9.
=Heredia=: Puerto Viejo, KU 36791.
=Guanacaste=: Las Canas, USC 7164; Santa Cecilia, MCZ 7924-5; Tilaran,
USC 7161 (5).
=Limon=: Bambu, USC 7171 (2), 7183 (13); La Lola, USC 820 (6), 6083-94,
8064, 8071; Pandora, USC 7188 (7), 7189, 7190 (3), 7191 (5); Pico
Blanco, USNM 30685-6; Rio Lari, 14-16 km. SW Amubre, USC 7179, 7180
(10); Sipurio, USNM 30658-9; Suretka, KU 36764, 36765 (skeleton),
36766-78.
=Puntarenas=: 6 km. N Dominical, KU 91749-50, 91811 (young), 91812
(tadpoles); Esparta, MCZ 8028; 6 km. E Golfito, KU 91718-41, 91809
(young), 91810 (tadpoles), 91816-9 (skeletons), USC 7103 (23); Quebrada
Agua Buena, 3 km. SW Rincon de Osa, USC 7236 (6); Quebrada Boruca, 22
km. E Palmar Norte, KU 64264; Rincon de Osa, Camp Seattle, UMMZ
123680-5, S-2792 (skeleton), USC 705 (5), 6023, 7254; Rio Barranca, USC
7119 (2); Rio Ceiba, 6 km. NW Buenos Aires, KU 91747-8, USC 7112 (7);
Rio Ciruelitas, 16 km. NW Esparta, USC 7121 (3); Rio Claro, 14.2 km. NW
Villa Neily, USC 7110 (4); Rio Ferruviosa, 7 km. S Rincon de Osa, USC
7235 (4); Rio Lagarto at Pan-American Hwy. (Guanacaste Border), USC 7122
(4); Rio La Vieja, 30 km. E Palmar Norte, KU 87684 (tadpoles), 91743-6,
USC 7083 (2); Rio Oro, 28.5 km. NW Villa Neily, KU 91742; Rio Volcan, 10
km. W Buenos Aires, USC 7113; Rio Zapote, 7 km. E Palmar, USC 7100 (4);
3-5 km. W Palmar, USC 7101 (18); 7 km. SE Palmar, KU 64261-3; 1.2 km. NW
Villa Neily, USC 8032; 3 km. NW Villa Neily, USC 7109 (20); 5 km. NW
Villa Neily, USC 6176, 8035.
=San Jose=: Bajos de Jorco, KU 91813 (tadpoles); Escazu, KU 34863,
34869-75, USC 813; between Monrovia and La Hondura, +- 0.5 km. N Santa
Rosa, USC 302 (2); Paso Ancho, Rio Jorco, UMMZ 122649 (6), USC 530 (3);
Rio Jorco, near Desamparados, KU 91757-65, 91796-7, 91820-3 (skeletons),
USC 228, 513, 7117 (7); Rio Peje, 10 km. SSE San Isidro el General, USC
7115 (3); Rio Tirivi, MCZ 7972; San Isidro el General, CNHM 101096, KU
28201, 32989, UMMZ 72024; 15 km. WSW San Isidro el General, KU 64245-56,
68473 (tadpoles), 68474 (young), 68475 (tadpoles), 86516, 91754-6,
91793-5, USC 7097 (6); 17.1 km. WSW San Isidro el General, USC 6047; 18
km. WSW San Isidro el General, USC 689; 20 km. WSW San Isidro el
General, KU 64257-9, 64260 (skeleton), 68468 (young), 68469 (tadpoles),
68470 (young), 68471-2 (tadpoles), 68476 (young), 68633-4 (skeletons),
91751-3; San Jose, AMNH 7501-4, USC 298; Santa Rosa, Rio Virilla, USC
7145.
PANAMA: =Chiriqui=: Rio Jacu, 5.8 km. ESE Paso Canoas, KU 91905.
"Veraguas," ZMB 3141 (2).
ANALYSIS OF MORPHOLOGICAL CHARACTERS
Osteology
In attempting to assay the taxonomic significance of skeletal
differences we are faced with a dearth of data on the skeletons of frogs
in general and hylids in particular. Recent reviews by Brattstrom (1957)
and Hecht (1962, 1963) have been concerned with general salientian
classification and phylogeny, principally at the family level. Savage
and Carvalho (1953), Griffiths (1959), and Baldauf (1959) used
osteological characters in determining the taxonomic status of the
families Pseudidae, Brachycephalidae, and Bufonidae, respectively.
Carvalho (1954) presented osteological evidence for the generic
separation of New World microhylids. Zweifel (1956) and Tihen (1962)
used osteological characters at the levels of the species-group and
species in their respective studies on _Scaphiopus_ and _Bufo_. Little
has been recorded about the skeletons of the hylids. Goin (1961)
mentioned dentigerous elements and cranial co-ossification in his
synopsis of the genera of hylids. Copland (1957) in his review of
the _Hyla_ of Australia, Funkhouser (1957) in her revision of
_Phyllomedusa_, and Zweifel (1958) in his review of _Nyctimystes_ did
not consider skeletal characters.
Some osteological studies on hylids have yielded worthwhile information.
Mittleman and List (1953) used osteological characters in defining the
genus _Limnaoedus_: Starrett (1960) used cranial characters in
combination with jaw musculature in defining the genus _Smilisca_, and
Duellman (1964) used cranial characters in delimiting the _Hyla
bistincta_ group. Brief descriptions of cranial structure were given for
_Phrynohyas_ (Duellman, 1956) and _Ptychohyla_ (Duellman, 1963a);
specific and sexual differences in the skulls of _Hyla chaneque_ and
_Hyla taeniopus_ were pointed out by Duellman (1965). Stokely and List
(1954) described early cranial development in the hylid _Pseudacris
triseriata triseriata_.
Because our knowledge of the skeleton in hylids is so incomplete, we are
not attempting to place _Smilisca_ in the general scheme of hylid
phylogeny on the basis of skeletal characters. Instead, our purposes are
to describe the skeleton and its ontogenetic development in one member
of the genus (_S. baudini_), and to make comparisons that show taxonomic
differences in osteological characters among species of _Smilisca_.
The study of 68 dried skeletons and 25 cleared and stained preparations,
including an ontogenetic series of _S. baudini_, has resulted in an
understanding of the progressive development of skeletal elements and a
knowledge of interspecific and intraspecific variation in these
elements. Furthermore, investigations of the osteology have provided
correlations between some cranial characters and certain aspects of
external morphology.
_Descriptive Osteology of Smilisca baudini_
The following description is based primarily on an adult female (KU
68184):
_Skull._--The skull is large, solid, and broader than long; the greatest
width is between the sutures of quadratojugal and maxillary on either
side of the skull (Pls. 2-3). The maxillaries bear well-developed dorsal
flanges, curve gently, join the moderately convex premaxillaries
anteriorly and form a slightly truncate snout. The combined premaxillary
width is about one-fourth the width of the skull. The premaxillaries are
separated medially, and laterally from the maxillaries by sutures. Each
premaxillary bears a dorsomedial alary process, which is anteriorly
convex and four times as high as the depth of the lateral wing of
premaxillary; each premaxillary also has a ventromedial palatine process
that projects dorsally from the lingual edge of the premaxillary. The
septomaxillaries are closely associated dorsally with the premaxillaries
immediately lateral to the prenasal processes.
The nasals are large, widest anteriorly and narrowing posteriorly,
parallel to maxillaries, and not separated from the ethmoid by
cartilage. The nasals bear long, delicate maxillary processes extending
nearly to the maxillaries. Anteriorly, the nasals are widely separated
by the partially ossified internasal septum, which is in contact with
the premaxillaries between the prenasal processes; the anterior points
of the nasals lie approximately one-half the distance between the
anterior ends of the ethmoid and the premaxillaries. The ethmoid is
large and completely ossified; the margins are smooth. The trunate
anterior edge lies between the nasals and is in contact with the
internasal septum. The frontoparietals are large, smooth-margined, and
bear large supraorbital flanges curving posterolaterally at the rear of
the orbit. A small, oval foramen involves the posterior part of the
ethmoid and anterior portion of frontoparietals; continued ossification
in older specimens fills in the foramen, thereby resulting in a solidly
roofed cranium. The auditory regions are relatively massive and bear
narrow tegmen tympani; the distal ends of the tegmen tympani are medial
to the lateral edge of the pterygoids in dorsal view. The squamosals are
large; the long anterior arm is separated from the maxillary by a
suture. The delicate, spindle-shaped columellae lie ventral to the
tegmen tympani and squamosals, are spatulate distally, and have a broad
basal attachment to the auditory region.
The vomers are moderately large and are in contact anteriorly with the
premaxillaries and posteriorly with the ethmoid. Each vomer has two wide
serrated flanges laterally. The tooth-bearing parts of the vomers are
widely separated and at a slight angle to one another; the vomers
terminate medially in two pointed processes on the ethmoid. The
palatines are edentate, but bear strong ridges throughout their lengths.
They are broadly in contact with the maxillary, are narrow medially, and
are attached by pointed processes to the medial part of the ethmoid.
The pterygoids are large, attached to the maxillaries immediately
anterior and medial to the squamosal-maxillary connection, bear
well-developed pedicles, which are broadly attached to the prooetic, and
a wide wing is in contact posteriorly with the distal two-thirds of the
quadrate.
The angular makes up most of the lower jaw, bears a broad articular
surface posteriorly, and has a small coronoid process on the lingual
edge; anteriorly the angular is separated from the dentary and
mentomecklian by Meckel's cartilage. The dentary lies external to the
angular and extends from the mentomecklian to approximately the
mid-length of the angular. The mentomecklians are ossified, but
separated by cartilage medially.
_Hyoid._--The hyoid plate is curved, thin, and mostly cartilaginous, but
calcined posteriorly (Fig. 6). The anterior cornua are slender,
cartilaginous, and curve anteromedially from the hyoid plate and thence
laterally and posteriorly, to attach to the posterior surface of the
prooetics. The lateral cornua are broad, flat, cartilaginous lateral
extensions from the bases of the anterior cornua. The posterior cornua
are bony, except distally.
[Illustration: FIG. 6. Ventral view of hyoid apparatus of an adult
male _Smilisca baudini_ showing areas of muscle attachment: _Gen.
L._, attachment of geniohyoideus lateralis; _Gen. M._, attachment
of geniohyoideus medialis; _Hyo._, attachment of hyoglossus; _Omo._,
attachment of omohyoideus; _Pet._, petrohyoideus; _St._, attachment
of sternohyoideus. KU 64220, x5.]
_Vertebral Column._--The atlas lacks transverse processes and a neural
crest, whereas transverse processes are present on the other seven
presacral vertebrae, and knoblike neural crests are present on the
second, third, and fourth vertebrae; a faint neural ridge is visible on
the fifth vertebra. The transverse processes are directed laterally on
the second and sixth vertebrae, ventrolaterally on the third,
posterolaterally on the fourth and fifth, and anterolaterally on the
seventh and eighth. The processes are slightly expanded on the fourth,
and more so on the fifth, vertebra. The sacral diapophyses are expanded
and have a border of calcified cartilage laterally. There are two sacral
condyles. The slender coccyx has a thin dorsal ridge on the anterior
three-fourths of its length.
_Pectoral Girdle._--The omosternum is large, ovoid, and cartilaginous;
the sternum is a thin cartilaginous sheet deeply notched posteriorly and
is not differentiated into episternal and xiphisternal elements. The
coracoids are robust, twice as stout as the clavicles. The epicoracoidal
cartilages overlap in the usual arciferal manner, except that they are
fused anteriorly between the slender clavicles. The clavicles are
strongly arched. The clavicle, coracoid, and scapula on each side form a
bony articulation at the glenoid fossa. A bifurcation of the ventral end
of the scapula results in a large glenoid foramen. The scapula is flat
and expanded dorsally; the suprascapula is broad, flat, and calcified in
large adults. In young specimens no distinct ossification of the
cleithrum or ossification of endochondral centers are evident.