protruding beyond mouth; canthus indistinct; length of eye equal to
interorbital distance; loreal region not pronounced; tympanum distinct
and about two-fifths diameter of eye; interorbital triangle present or
absent; arms short; trace of web between fingers, extending as fringe
along sides of fingers; first finger very short with small disc; other
discs about size of those on toes; discs on third finger and fourth
toe as large as tympanum; outer palmar tubercle moderate in size,
partly bifid; inner palmar tubercle large, elongate, flat;
subarticular tubercles distinct; legs moderately long; tarsal fold
absent; inner metatarsal tubercle flat; outer metatarsal tubercle
smaller, indistinct; subarticular tubercles moderate in size; fringe
on toes to tip of disc of second toe; rest of toes about two-thirds
webbed; foot length about two fifths snout-vent length; tibia length
about one half snout-vent length; skin above smooth or with minute
pustules; belly finely granular; ventral surfaces of thighs and areas
below anus granular; skin on ventral surfaces of limbs smooth; tongue
relatively large, longer than wide, barely notched behind; vocal slits
elongate, lateral to tongue; choanae medium in size. In life, dorsum
yellowish brown, olive green, or grayish brown with dark brown spots
on snout, dark brown stripe from nostril to eye, dark yellow-brown
interorbital triangle, and dark supratympanic region; generally five
interrupted longitudinal dark brown stripes on dorsum (one on each
flank, pair of paravertebral and one vertebral); flanks pale yellow;
groin yellowish brown; thighs marked with one or two transverse
yellow-brown blotches; shanks with two or three yellow-brown blotches
above; spaces between blotches on thighs, shanks, tarsi, and feet
yellow; brown spots on tarsi and in some specimens on feet; arm pale
yellow with pale brown spots; belly creamy white having slight
blue-green tint; vocal sac and chin yellow; axillary region yellow,
blue-green in some specimens (Pl. 2A).
In preservative, head and dorsum yellowish brown; dark brown stripe
from nostril to eye; dark brown spots on snout; a dark brown
interorbital triangle with apex directed backward; dark brown
supratympanic region; dorsal stripes same as in living individuals;
flanks pale yellow with brown spots in some specimens; groin creamy
white; thighs and shanks having or lacking transverse dark brown
blotches; spaces between blotches creamy white or yellow-brown; arms
pale yellowish brown; belly and vocal sac creamy white.
_Variation._--Geographic variation in size and some proportions, such
as the ratio of tibia length to snout-vent length and the ratio of the
diameter of the tympanum to that of the eye, have been observed in
this species. The largest individuals are from the Golfo Dulce region
(samples from Piedras Blancas and Rincon de Osa), Puntarenas Province,
Costa Rica. The smallest individuals are from El Recreo, Zelaya
Province, Nicaragua, and from the Caribbean lowlands of Costa Rica.
The diameter of the tympanum is proportionately larger (relative to
the size of the eye) in males from Tilaran, Guanacaste Province; the
tympanum is nearly as large in males from Piedras Blancas, Puntarenas
Province, and Puerto Viejo, Heredia Province, Costa Rica. The lowest
ratios occur in individuals from Almirante, Bocas del Toro, Panama, in
specimens from the Caribbean lowlands of Costa Rica (except Puerto
Viejo), and in those from El Recreo, Zelaya Province, Nicaragua. In
general, the tympanum is proportionately larger in females than in
males; the tympanum is largest in females from the Pacific lowlands
of Costa Rica (Table 5).
Color variation has been observed in individuals from the same
population, as well as in individuals from different localities,
between males and females, and from night to day. In life, most
individuals from the Pacific lowlands of Costa Rica are dark tan to
greenish gray above with dark brown longitudinal stripes that are
entire or broken, but some specimens (mostly males) are dusky brown
and lack longitudinal stripes or an interorbital triangle; females
usually have the dark interorbital triangle and the stripes on the
dorsum. Individuals from Turrialba, Cartago Province, Costa Rica, are
pale olive-tan with olive-brown markings. Individuals from Puerto
Viejo, Heredia Province, Costa Rica, are uniformly yellowish brown
with or without dark longitudinal stripes. Specimens from El Recreo,
Zelaya Province, Nicaragua, are like those from Puerto Viejo. Males
from Almirante, Bocas del Toro, Panama, are pale brown with dark brown
longitudinal stripes and an indistinct interorbital triangle. Females
have a distinct interorbital triangle and dark brown blotches on the
thighs and shanks.
By night, the dorsum usually is pale yellow, and the belly is creamy
white. By day, the dorsum is dark tan; the stripes and spots are
darker, and the belly is yellowish white. Taylor (1952) noticed that
considerable variation in color pattern occurred from night to day in
individuals from Turrialba, Cartago Province, Costa Rica. At night
some individuals lacked a dorsal pattern, but by day many of these
individuals developed dorsal stripes.
_Cranial Osteology._--The skull of _Hyla elaeochroa_ is slightly wider
than it is long, and flat. The premaxillary is small and bears 10 to
15 teeth (mean for 9 specimens, 12.3). The alary process of the
premaxillary is small, vertical, and slightly concave posteriorly.
Ventrally, the premaxillary is partially united to the prevomer by
ossification. The maxillary is slender and bears 70 to 82 teeth (mean
for 9 specimens, 74.3). The pars facialis of the maxillary is
laterally convex and is about twice as high as the pars dentalis.
The nasal is large, robust, anteriorly truncate, but pointed
posteriorly in dorsal view. The nasal comprises about 45 per cent of
the total length of the skull. There is an anterior cartilaginous
septum nasi separating the two nasals; the latter overlap the
sphenethmoid posteriorly. Each nasal bears a shallow concavity in the
midlateral side and lacks a maxillary process. Dorsally, the
sphenethmoid is wider than long, roughly pentagonal in shape; the
frontoparietal is elongate, smooth, and bears a small anterior
supraorbital process. The sphenethmoid and frontoparietal form the
anterior margin of the frontoparietal fontanelle; the fontanelle is
narrow anteriorly and wider posteriorly (Fig. 5B).
The entire distal surface of the prooetic is in contact with the
posterior arm of the squamosal. A narrow cartilaginous crista parotica
is visible dorsally in some specimens. The squamosal is broad
posteriorly but its anterior arm is slender and not in contact with
the maxillary.
TABLE 5.--Geographic Variation in Size and Proportions in Males of
_Hyla elaeochroa_. (Means in parentheses below observed ranges.)
==========================================================================
| |Snout-vent| Tibia | |
| | length | length/ |Tympanum/|Foot length/
Locality | N | (mm.) | snout-vent | eye | snout-vent
---------------------+----+----------+------------+---------+-------------
Nicaragua: El Recreo | 9 | 28.0-30.3| 0.51-0.57 |0.47-0.59| 0.39-0.54
| | (29.3) | (0.55) | (0.51) | (0.41)
| | | | |
Costa Rica: Tilaran | 21 | 28.8-33.6| 0.47-0.57 |0.48-0.65| 0.40-0.46
| | (30.6) | (0.52) | (0.59) | (0.41)
| | | | |
Costa Rica: Puerto | 22 | 26.3-32.4| 0.49-0.54 |0.48-0.65| 0.38-0.45
Viejo | | (29.7) | (0.52) | (0.57) | (0.42)
| | | | |
Costa Rica: Turrialba| 95 | 28.1-35.0| 0.47-0.56 |0.47-0.68| 0.37-0.46
| | (30.6) | (0.51) | (0.56) | (0.41)
| | | | |
Costa Rica: Bataan, | 26 | 26.3-32.7| 0.47-0.54 |0.45-0.66| 0.36-0.44
Limon, and Suretka | | (30.0) | (0.51) | (0.50) | (0.41)
| | | | |
Costa Rica: Piedras | 21 | 33.3-37.7| 0.50-0.54 |0.48-0.64| 0.40-0.46
Blancas | | (35.2) | (0.51) | (0.57) | (0.43)
| | | | |
Costa Rica: Rincon de| 24 | 31.4-35.9| 0.50-0.56 |0.45-0.61| 0.40-0.46
Osa | | (34.1) | (0.53) | (0.54) | (0.43)
| | | | |
Panama: Bocas del | 6 | 31.0-33.5| 0.49-0.54 |0.47-0.50| 0.41-0.43
Toro | | (32.1) | (0.51) | (0.48) | (0.42)
[Illustration: PLATE 1
Living _Hyla_: (A) _H. boulengeri_ (KU 86322) and (B) _H.
foliamorta_ (KU 101576), x 2.]
[Illustration: PLATE 2
Living _Hyla:_ (A) _H. elaeochroa_ (KU 91688), (B) _H. staufferi
staufferi_ (KU 57791), and (C) _H. staufferi altae_ (KU 101688), x
2.]
[Illustration: PLATE 3
Audiospectrograms and sections of mating calls of (A) _Hyla
boulengeri_ (KU Tape No. 511) and (B) _H. foliamorta_ (KU Tape No.
511) and (B) _H. foliamorta_ (KU Tape No. 288).]
[Illustration: PLATE 4
Audiospectrograms and sections of mating calls of (A) _Hyla
elaeochroa_ (KU Tape No. 97), (B) _H. s. staufferi_ (KU Tape No.
93), and (C) _H. staufferi altae_ (KU Tape No. 502).]
The prevomer is short, and broadest anteriorly. The prevomer is joined
to the premaxillary by ossification. The posterior margin of the
prevomer bears a narrow cartilaginous articulation with the
sphenethmoid. The anterolateral and posterolateral processes of the
prevomer form an incomplete bony margin to the small choanae; each
prevomer bears four to seven teeth. The palatine is small, curved
anteriorly and edentate. The anterior part of the parasphenoid is
robust and ends in a point. The pterygoid is slender and weakly
developed.
_Natural History._--_Hyla elaeochroa_ inhabits humid lowland tropical
forests in lower Central America and breeds in temporary ponds.
Clasping pairs, gravid females, and calling males have been found
mostly in June, July, and August. William E. Duellman informed me that
he also found males calling in mid-February, late April, and May.
Duellman (1967) reported detailed observations of the social
organization in the mating call of _Hyla elaeochroa_. The choruses in
this species are initially organized, but when many individuals call,
the chorus loses organization. I observed this species breeding in a
temporary pond at Puerto Viejo, Heredia Province, Cost Rica, in late
June. Calling males and clasping pairs were extremely abundant within a
few hours after a heavy rain. Males were mostly found calling from low
emergent herbs in the pond and less commonly from bushes and trees to
heights of six meters above the water. Calling males were also observed
at Ricon de Osa, Puntarenas Province, Costa Rica, in late July. These
breeding individuals were found in a shallow pond at the edge of a wet
forest. Calling stations were less than two meters in height. John D.
Lynch informed me that after a heavy rain in early August, he found
several hundred individuals congregated in a small grassy pond less
than a foot deep, at Rincon de Osa. Males were calling from sites on
grass stems a few centimeters above the water.
The mating call of _Hyla elaeochroa_ consists of short notes, repeated
at intervals of about 0.40 second. Each note has a duration of 0.12 to
0.24 second. The fundamental frequency varies from 48 to 65 cycles per
second, and the notes have 40-50 pulses per second; the dominant
frequency is at about 2,900 cycles per second (Table 2, Pl. 4A).
The eggs are deposited in a mass in the water near floating vegetation.
William E. Duellman informed me that he observed hatchlings oriented
vertically with the tip of the mouth at the surface of the water. They
gradually sank to bottom, but swam back to surface again. No additional
information is available concerning early development. Tadpoles have
been found in shallow grassy ponds in clearings and in temporary
woodland ponds.
_Tadpoles._--Three hundred and thirty-one tadpoles in various stages of
development are available. Thirty-five tadpoles in stage 35 have a mean
body length of 8.1 mm. (8.0-9.0 mm.), tail length of 17.7 mm.
(15.0-19.5 mm.), and total length of 25.9 mm. (23.0-27.5 mm.). The
largest tadpole examined is in stage 40 and has a total length of 34.5
mm. (Table 6).
A typical tadpole, stage 35 of development (KU 104134, from Puerto
Viejo, Heredia Province, Costa Rica), has a body length of 9.1 mm.,
tail length of 17.7 mm., and a total length of 26.8 mm. Other
characters are as follows: body depressed anteriorly; body length
greater than depth of tail; internarial space as broad as interorbital
distance; nostril equidistant between eye and tip of snout; eyes
moderately large; mouth anteroventral and triangular; median fourth of
upper lip bare; rest of lip bordered by one row of papillae; clumps of
small papillae at corners of mouth; tooth rows 2/3; upper rows equal in
length; second row interrupted medially; lower rows shorter than upper
rows, diminishing in length; beak rather weak with small serrations;
spiracle short and nearer eyes than anus; anal opening not reaching
edge of ventral fin; caudal musculature attenuated distally (Figs. 2B
and 3B).
TABLE 6.--Sizes of Tadpoles of _Hyla elaeochroa_ in Relation to
Developmental Stages. (Means in parentheses below observed ranges;
measurements in mm.)
------+---+-------------+-------------+--------------
Stage | N | Body length | Tail length | Total length
------+---+-------------+-------------+--------------
24 | 2 | 4.0-4.0 | 8.5-9.0 | 12.5-13.0
| | (4.0) | (8.8) | (12.8)
| | | |
25 |64 | 5.0-6.5 | 8.5-15.0 | 13.5-21.5
| | (5.7) | (11.8) | (17.6)
| | | |
27 |30 | 7.0-7.5 | 13.0-16.0 | 20.0-23.0
| | (7.1) | (14.2) | (21.3)
| | | |
30 |15 | 7.0-8.0 | 13.0-16.5 | 20.0-24.0
| | (7.3) | (15.0) | (22.4)
| | | |
32 |30 | 7.5-8.5 | 15.0-17.0 | 22.5-25.0
| | (7.8) | (16.1) | (23.8)
| | | |
35 |35 | 8.0-9.0 | 15.0-19.5 | 23.0-27.5
| | (8.1) | (17.7) | (25.9)
| | | |
37 |22 | 8.5-9.5 | 16.0-22.0 | 25.0-31.0
| | (9.0) | (18.8) | (27.8)
| | | |
39 |14 | 9.5-10.5 | 19.0-24.9 | 28.5-33.5
| | (9.9) | (21.1) | (31.0)
| | | |
40 |27 | 7.0-11.5 | 15.0-23.0 | 23.0-34.5
| | (9.1) | (22.0) | (31.2)
| | | |
43 |10 | 8.0-12.0 | 11.0-17.0 | 20.0-26.0
| | (10.2) | (13.5) | (23.7)
| | | |
45 |16 | 10.0-12.0 | 1.0-7.0 | 12.0-17.0
| | (11.2) | (3.4) | (14.6)
| | | |
46 |45 | 11.0-13.0 | |
| | (11.8) | |
In life, dorsum yellowish tan with gray-brown mottling; belly and
ventrolateral surfaces silvery-gold or white; black stripe from tip of
snout to eye; two black blotches below eye, another blotch extending
from eye to base of caudal musculature; caudal musculature and fins
gray-brown. In preservative, yellowish tan and silvery-gold colors
lost; black reticulations present on tail.
_Remarks._--Cope (1876:105) described _Hyla elaeochroa_ from Sipurio,
Limon Province, Costa Rica. He based his description on a small
specimen, 26.0 mm. in snout-vent length, having a dorsum uniformly
colored and lacking an interorbital triangle and blotches on the
thighs. Cope (1887) described pigmented specimens from Nicaragua as
_Hyla quinquevittata_, which he diagnosed as having dark brown bars on
the hind limbs and five dark brown longitudinal stripes on the dorsum,
the median one of which was expanded anteriorly so as to form a large
triangular spot between the eyes. He thought this species was related
to _Hyla eximia_ Baird and noted that "the hinder legs are much larger;
the muzzle is more acuminate and the color bands are much wider" than
in _eximia_. Cope did not compare _quinquevittata_ with _elaeochroa_,
which he had described ten years before. Guenther (1901:268), Noble
(1918:340), and Nieden (1923:251) regarded both _elaeochroa_ and
_quinquevittata_ as valid species. Dunn and Emlen (1932:25) regarded
both as synonyms of _Hyla rubra_, but they made no qualifying
statements. Taylor (1952:859) placed _quinquevittata_ as a synonym of
_elaeochroa_ and indicated that _rubra_ was another species.
Taylor (1958:37) described _Hyla dulcensis_ from the humid tropical
forests of Golfo Dulce, Puntarenas Province, Costa Rica. He thought
this species was "related to _H. elaeochroa_ but differs in its
somewhat larger size, smaller finger and toe discs, the obsolete
canthus rostralis; the loreal region concave and the choanae larger."
Duellman (1966a:270) compared adults, tadpoles, and mating calls of
_dulcensis_ and _elaeochroa_ and concluded that a single species was
involved.
_Hyla elaeochroa_ can be easily confused with the closely related _Hyla
staufferi_. Although the durations of the calls are similar, the call
of _elaeochroa_ has only about one third the number of pulses per
second, a much lower fundamental frequency, and a lower dominant
frequency than that of _staufferi_. _Hyla elaeochroa_ is larger and has
a less pointed snout than does _staufferi_. Although the skulls of the
two species are similar, that of _elaeochroa_ differs in having broad
palatines and comparatively larger nasals that are truncate anteriorly.
In _staufferi_ the nasal is rounded anteriorly and the palatine is
absent.
_Distribution._--_Hyla elaeochroa_ occurs on the Caribbean lowlands
from western Panama through Costa Rica to eastern Nicaragua, and on the
Pacific lowlands of southeastern Costa Rica and extreme western Panama.
Most localities where it has been collected are below 800 meters, but
the species has been found at two localities above 1000 meters (El
Silencio and Pacuare, Cartago Province) on the Caribbean slopes of the
Cordillera de Talamanca, Costa Rica (Fig. 6).
_Specimens Examined._--Nicaragua: _Zelaya_: El Recreo, UMMZ 79721 (9).
Costa Rica: _Alajuela_: Laguna Monte Alegre, KU 64499. _Cartago_: 2 km E
Chitaria, KU 107058; El Silencio, 14.4 km NE Turrialba, KU 107059-60;
4.6 km ENE Pacuare, KU 64451-75, 64628-37; 4 km S Pavones, KU 64500;
Turrialba (Instituto Interamericano de Ciencias Agricolas), KU 30305-26,
24616-57, 30337-54, 31776-91, 31803, 31807-15, 64413-50, 68283-87
(skeletons), 68390-1 (young), 35042 (eggs), 25207-8 (skeletons), 25221
(skeleton), 41073-83 (skeletons). _Guanacaste_: 2 km E Tilaran, KU
86356-77, 87667-8 (young). _Heredia_: Puerto Viejo, KU 36696, 46466,
64501-17, 68288-91, 68387, 68388-9 (young), 91803 (young), 91688-9,
104134 (tadpoles), 104135 (young), 104354-6 (skeletons); 1.5 km N Puerto
Viejo, KU 64518-23, 68386 (tadpoles); 1 km S Puerto Viejo, KU 84985-6
(skeletons), 87669 (young), 87772-3 (skeletons). _Limon_: Bataan, KU
30327-36; La Lola, KU 64478-98, 68281-2 (skeletons); Los Diamantes, KU
31800-02, 64476-7; Peralta, KU 31816-21; Puerto Limon, KU 31792-99;
Suretka, KU 36467-79, 36697, 41084. _Puntarenas_: 5 km NW Buenos Aires,
KU 107057; 10 km E Esparta, KU 87666 (tadpoles); Golfito, KU 32166-8; 8
km E Palmer Norte KU 93939; 10.7 km SE Palmar Sur, KU 93938 (skeleton),
93940-51, 93952 (eggs), 93953-6 (tadpoles); Piedras Blancas, KU
103646-59; 4.5 km W Rincon de Osa, KU 102208-41, 104298 (tadpoles).
[Illustration: Fig. 6. Map showing locality records for _Hyla
elaeochroa_ (circles) and _H. rubra_ (dots).]
Panama: _Bocas del Toro_: Almirante, KU 80079; Isla Bastimentos, KU
96008-11; Rio Cricamola, 3.7 km from coast, KU 96012. _Chiriqui_: Rio
Gariche, 8.3 km ESE Paso de Canoas, KU 101571-2.
_Hyla staufferi_ Cope
_Hyla staufferi_ Cope, Proc. Acad. Nat. Sci. Philadelphia, 17:165,
October 1, 1865 [Holotype.--USNM 15317, Orizaba, Veracruz, Mexico;
Francis Sumichrast collector].
_Diagnosis._--Small frogs (Male to 29 mm., Female to 31.6 mm.); skull
longer than wide; palatine absent; large cartilaginous crista parotica
present; snout flat, elongate and protruding; dark interorbital bar and
dorsal stripes usually present.
_Description._--Head flat, especially in females, longer than wide;
snout long, protruding beyond mouth; loreal region concave; canthus
ill-defined; length of eye greater than internarial distance or width
of eyelid; length of eye less than interorbital space; tympanum
distinct; interorbital spot irregular; supratympanic fold faint; arms
short; fingers free of webs; discs on third and fourth fingers equal to
diameter of tympanum; inner metatarsal tubercle on base of first finger
distinct; first finger shorter than second; palmar tubercle distinct
(Fig. 1C); legs short (usually less than 50 per cent of snout-vent
length); tarsal fold absent; metatarsal tubercles small, outer tubercle
smaller than inner; subarticular tubercles small, simple, distinct;
toes less than half webbed (Fig. 1D); skin smooth above with a few
small pustules on head, scapular region, flanks, and supratympanic
region; arms and legs smooth; skin of belly coarsely granular;
posteroventral surfaces of thighs finely granular; tongue small,
rounded, longer than wide, slightly free and notched posteriorly; vocal
slits small, lateral to tongue; choanae moderate in size.
_Variation._--The largest males of _Hyla staufferi_ are from Jalapa,
Guatemala, and from San Salvador, El Salvador. In these samples the
average snout-vent length is 27 mm. In Panamanian specimens the average
snout-vent length is 23.6 mm. Slight variation in the ratio of tibia
length to snout-vent length exists throughout the range; more variation
exists in the ratio of the diameter of the tympanum to that of the eye;
the tympanum is proportionately larger in northern populations (Table
7). The primary differences between Panamanian and more northern
populations are in size, color pattern on the dorsum and shanks, amount
of webbing between the toes, and duration of notes in the mating call
(Table 2, Pl. 4).
The color in Panamanian _staufferi_ is gray or gray-brown with a pair
of distinct, complete, dark brown dorsolateral stripes, a pair of
entire paravertebral stripes, and in some specimens a vertebral stripe.
About five per cent of the individuals have interrupted stripes on the
dorsum, whereas in the more northern populations complete paravertebral
stripes are present in less ten per cent of the specimens; when
complete stripes are present, they are irregular. The dorsal ground
color in non-Panamanian specimens is brown, olive-brown, or dark brown.
Transverse bars are present on the shanks in _Hyla staufferi_ from
Costa Rica northward to Mexico, whereas in Panama all the individuals
have a longitudinal stripe on the shank (Table 7, Pl. 2). The
interorbital spot or bar is more noticeable in northern populations
than in specimens from Panama. Frogs from Costa Rica and northward have
the toes about three fourths webbed, whereas in Panama the toes are
about two fifths webbed. The mating calls of the northern and
Panamanian populations are similar, but the notes have a longer
duration in the northern populations and a higher dominant frequency in
Panamanian populations.
_Hyla staufferi_ is the most variable member of the _Hyla rubra_ group
in Central America. The Panamanian populations are geographically
separated from the Costa Rican and more northern populations by an area
of tropical rainforest in the Golfo Dulce region in southeastern Costa
Rica and adjacent Panama. _Hyla staufferi_ does not occur on the
Caribbean versant of Costa Rica and Panama. The Golfo Dulce region and
the Caribbean versant are humid and inhabited by _Hyla elaeochroa_.
_Hyla staufferi_ is an inhabitant of subhumid and xeric areas.
On the basis of the discontinuous variation in several characters which
correlate with the disjunct distribution of the two populations, two
subspecies of _Hyla staufferi_ are recognized. The accounts that follow
apply equally to each.
_Cranial Osteology._--The skull of _Hyla staufferi_ is flat and longer
than wide. The premaxillary is small and bears 9 to 13 teeth (mean for
5 specimens, 11.3). The alary process of the premaxillary is small,
concave posteriorly and vertical. Ventrally, the premaxillary is united
to the prevomers by partially ossified cartilage. The maxillary is
slender and usually bears 49 to 70 teeth (mean for 5 specimens, 60.7).
The pars facialis of the maxillary is convex and less than twice the
height of the pars dentalis.