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UNIVERSITY OF KANSAS PUBLICATIONS
MUSEUM OF NATURAL HISTORY
Volume 18, No. 6, pp. 505-545, 7 figs., 4 pls.
December 2, 1969
The Systematics of the Frogs of the
_Hyla rubra_ Group in Middle America
BY
JUAN R. LEON
University of Kansas
Lawrence
1969
UNIVERSITY OF KANSAS PUBLICATIONS, MUSEUM OF NATURAL HISTORY
Editors: Frank B. Cross, Philip S. Humphrey, Robert M. Mengel.
Volume 18, No. 6, pp. 505-545, 7 figs., 4 pls.
Published December 2, 1969
UNIVERSITY OF KANSAS
Lawrence, Kansas
PRINTED BY
ROBERT R. (BOB) SANDERS, STATE PRINTER
TOPEKA, KANSAS
1969
The Systematics of the Frogs of the _Hyla rubra_ Group in Middle
America
BY
JUAN R. LEON
CONTENTS
PAGE
INTRODUCTION 508
Acknowledgments 508
Materials and Methods 509
THE HYLA RUBRA GROUP 509
Key to Species and Subspecies 510
Key to Known Tadpoles 511
ACCOUNTS OF SPECIES AND SUBSPECIES 511
_Hyla boulengeri_ (Cope) 511
_Hyla foliamorta_ Fouquette 520
_Hyla rubra_ Laurenti 524
_Hyla elaeochroa_ Cope 525
_Hyla staufferi_ Cope 532
_Hyla staufferi staufferi_ Cope 537
_Hyla staufferi altae_ Dunn 540
EVOLUTIONARY HISTORY 540
LITERATURE CITED 543
INTRODUCTION
The tree frogs of the _Hyla rubra_ group are abundant and form a
conspicuous element of the Neotropical frog fauna. Representatives of
the group occur from lowland Mexico to Argentina; the greatest
diversity is reached in the lowlands of southeastern Brazil (Cochran,
1955). The group apparently originated in South America; the endemic
Central American species evolved from stocks that invaded Middle
America after the closure of the Colombian Portal in the late Pliocene.
Dunn (1933) partially defined the _rubra_ group as it occurs in Central
America. Cope (1865, 1876, 1887), Brocchi (1881), Boulenger (1882),
Guenther (1901), Noble (1918), Kellogg (1932), Dunn and Emlen (1932),
Stuart (1935), and Gaige (1936) dealt with the Middle American species
now considered to make up the _rubra_ group. More recently, Taylor
(1952, 1958), Fouquette (1958), Starrett (1960), and Duellman (1960,
1963, 1966a) studied aspects of the taxonomy and biology of the species
of this group. The five species of the _rubra_ group in Central America
have received ten different names. One species, _Hyla staufferi_, has
received five names (two subspecies are recognized herein). _Hyla
boulengeri_ was named in the genus _Scytopis_, but the type species of
_Scytopis_ is a member of the genus _Phrynohyas_ Fitzinger, 1843
(Duellman, 1956.)
Little has been published concerning the ecology, life history,
osteology, and mating calls of the Middle American species of this
group. The purpose of the present report is to describe the species
occurring in Middle America and to comment on their distributions,
ecology, cranial osteology, and mating calls, and in so doing provide
evidence for the evolutionary history of the species inhabiting Middle
America.
Acknowledgments
For permission to examine specimens in their care, I am grateful to
Drs. Richard G. Zweifel, American Museum of Natural History (AMNH);
Robert F. Inger, Field Museum of Natural History (FMNH); Ernest E.
Williams, Museum of Comparative Zoology (MCZ); Hobart M. Smith,
University of Illinois Museum of Natural History (UIMNH); Charles F.
Walker, University of Michigan Museum of Zoology (UMMZ); Jay M. Savage,
University of Southern California (USC); James A. Peters, United States
National Museum (USNM); Richard J. Baldauf, Texas Cooperative Wildlife
Collection (TCWC); and W. Frank Blair, Texas Natural History Collection
(TNHC). KU refers to specimens in the Museum of Natural History,
University of Kansas. For the loan of tape-recordings of mating calls I
thank Drs. W. Frank Blair, University of Texas, and Richard G. Zweifel,
American Museum of Natural History.
I am indebted to the Ford Foundation-Universidad de Oriente (Venezuela)
Science Project for a scholarship which enabled me to study for two
years at The University of Kansas, foster institution of the project. I
have benefited by being able to work in the Museum of Natural History
at The University of Kansas and I am grateful to Dr. E. Raymond Hall,
Director, for providing space and equipment.
I gratefully acknowledge the assistance and advice of Dr. William E.
Duellman, who suggested and directed this work, made available
specimens under his care and gave much of his time in reading the
manuscript and suggesting improvements. I am grateful to Dr. Frank B.
Cross who critically read the manuscript and made many editorial
suggestions. I am indebted to Linda Trueb for assistance with the
osteological aspects of this study; she helped to clarify many
confusing points. I am grateful to Charles W. Myers for making
available his field notes on these frogs in Panama, to Arthur C.
Echternacht for reading part of the manuscript, and to John D. Lynch
for many suggestions and helpful criticisms. The illustrations were
executed by David M. Dennis.
Materials and Methods
For the purposes of the present study I examined 1383 preserved
specimens, 50 skeletons, and 9 lots of tadpoles. External
characteristics used in the analysis of variation are those currently
employed in the study of anuran systematics. Twelve measurements
and six proportions were taken in the manner described by Duellman
(1956). Only the most important references are given in the synonymies,
except those of the two subspecies of _Hyla staufferi,_ which are
more nearly complete. The taxonomic history of each frog is discussed
under _Remarks_ in each account. The cranial osteology was studied
by using skeletons and cleared and stained specimens of all species.
Developmental stages of tadpoles were determined from Gosner's (1960)
table. Personal field work in Central America in the summer of 1966
provided an opportunity to make observations on the ecology, calling
sites, and color in life; these data were supplemented by field notes
from, and discussions with, Dr. William E. Duellman and Charles W.
Myers.
The mating calls of the frogs were recorded in the field on Magnemite
and Uher Tape Recorders by Dr. Duellman in the course of his work on
the hylid frogs of Middle America--supported by grants from the
National Science Foundation (G-9827 and GB-1441). These recordings,
plus those borrowed from other institutions, provided 50 tapes for
analysis of the mating calls. The calls were analyzed on a Vibralyzer
(Kay Electric Company).
THE HYLA RUBRA GROUP
_Definition._--The species forming the group are small to moderate-sized
tree frogs (maximum snout-vent length of males of various species 20-49
mm.), distinguished from other groups in the genus _Hyla_ as follows:
Brown, grayish brown, or yellowish tan above; thighs plain, marbled
with dark brown, or having vertical bands; vocal sac single, median,
subgular; snout flat, protruding, rounded or pointed; webbing between
fingers reduced or absent; web between first and second toes reduced to
fringe on second toe, rest of toes about half webbed; tarsal fold
reduced or absent; shanks robust; inner metatarsal tubercle larger than
outer; prevomerine teeth on transverse ridges between small to large
sized choanae; skull generally longer than wide; nasals large (length
more than 40 per cent total length of skull) and having pointed
maxillary processes; maxillary bearing small ventromedial palatine
process; quadratojugal slender, always joined to maxillary by bony
suture; auditory region of prooetic slender and short; delicate
spatulate columella ventral to crista parotica, broad basally,
compressed anterolaterally, slightly rounded distally; anterior arm of
squamosal extending about half distance to maxillary; sphenethmoid
wider than long; frontoparietal fontanelle present or absent;
prevomerine, premaxillary, and maxillary teeth present; prevomer with
two lateral processes forming incomplete bony margin to internal nares;
tadpoles having pointed xiphicercal tail, snout short, rounded; 2/3
tooth rows; dorsal fin deeper than ventral fin; sinistral spiracle;
short dextral anal tube not reaching edge of ventral fin; mating calls
consisting of single long note or series of short notes.
_Composition._--This group contains about 24 currently recognized
species, most of which occur in Brazil. Only five species--_boulengeri,_
_elaeochroa_, _foliamorta_, _rubra_, and _staufferi_ with two
subspecies--occur in Central America. _Hyla boulengeri_ and _rubra_ are
widespread in South America, and _foliamorta_ occurs in Colombia,
whereas the other species are known only from Middle America.
_Distribution._--The species of the _Hyla rubra_ group range from the
lowlands of northern Argentina and Bolivia to southern Tamaulipas and
Guerrero, Mexico.
_Comments._--In Central America two subgroups of species can be
recognized. _Hyla boulengeri_ and _H. foliamorta_ are distinctive in
the large size of adults (snout-vent lengths 41-49 mm.); both have
prominent bars on the thighs, a well-defined interorbital triangular
mark, blotches or spots dorsally, and large choanae. _Hyla elaeochroa,_
_H. rubra,_ and _H. staufferi_ are smaller (snout-vent lengths 29-40
mm.); they have the thighs weakly barred or vermiculate anteriorly and
posteriorly or unmarked, an ill-defined interorbital triangular mark,
linear markings dorsally, and small choanae.
Key to Species and Subspecies
1. Larger frogs (males to 49 mm. snout-vent length); thighs
strongly barred; supratympanic fold black; dorsum blotched or
spotted 2
Smaller frogs (males to 40 mm. snout-vent length); thighs weakly
barred or plain; supratympanic fold pale brown; dorsum usually
having linear pattern 3
2. Dorsum tuberculate; snout subacuminate; vocal sac flecked with
brown; tarsal fold rudimentary; web absent between fingers; black
spots absent in scapular region _H. boulengeri_
Dorsum smooth; snout pointed; vocal sac dark gray; tarsal fold
absent; trace of web between fingers; two or more elongate dark
spots in scapular region _H. foliamorta_
3. Snout-vent length more than 30 mm.; tympanum 2/3 to 3/4 diameter
of eye; prevomerine elevations about size of choanae 4
Snout-vent length less than 30 mm.; tympanum less than 1/2 diameter
of eye; prevomerine elevations smaller than choanae 5
4. Thighs mottled posteriorly; discs on fingers about 1/2 size of
tympanum; faint dark line from nostril to eye _H. rubra_
Thighs faintly barred or plain posteriorly; discs on fingers
about size of tympanum; distinct dark line from nostril to eye
_H. elaeochroa_
5. Dorsum brown with irregular dorsolateral stripes and
interrupted paravertebral stripes; two transverse bars on shanks;
interorbital bar present _H. staufferi staufferi_
Dorsum gray with complete dorsolateral and paravertebral stripes;
longitudinal stripe on shank; interorbital bar absent
_H. staufferi altae_
Key to Known Tadpoles
1. Entire lower beak black; beaks moderate-sized, serrate; dorsal
fin high, extending to middle of back 2
No more than half of lower beak black; beaks small, finely serrate;
dorsal fin lower, barely extending onto body 3
2. Papillae present only laterally _H. boulengeri_
Papillae present laterally and ventrally _H. foliamorta_
3. Distinct brown stripe from nostril to eye; two stripes below
eye, _H. elaeochroa_
Faint stripe from nostril to eye; no stripe below eye
_H. staufferi_
ACCOUNTS OF SPECIES AND SUBSPECIES
_Hyla boulengeri_ (Cope)
_Scytopis boulengeri_ Cope, Bull. U.S. Natl. Mus., 32:12, December
1, 1887 [Holotype.--USNM 13974, from "Nicaragua"; J. A. McNiel,
collector].
_Hyla boulengeri:_ Guenther, Biologia Centrali-Americana, Reptilia
and Batrachia, p. 267, June 1901. Noble, Bull. Amer. Mus. Nat.
Hist, 38:339, June 1918. Taylor, Univ. Kansas Sci. Bull., 35:856,
July 1, 1952.
_Diagnosis._--Size large (Male to 49 mm., Female to 53 mm.); skull as
long as wide; frontoparietal fontanelle present; snout subacuminate;
canthus not pronounced; choanae large; tongue cordiform, slightly
longer than broad; interorbital triangle tubercular; skin on dorsum
tuberculate; tarsal fold reduced or absent; thighs, shanks, and tarsi
boldly barred with dark brown and pale yellow-green in life.
_Description._--Head flattened, longer than wide; snout projecting
beyond lower lip; loreal region oblique; canthus not pronounced; length
of eye less than interorbital distance; tympanum large, about 70 per
cent of diameter of eye; interorbital triangle distinct; arms short;
fingers lacking web; palmar tubercle tripartite; subarticular tubercles
distinct; long tubercle on base of first finger; discs truncate; legs
long; tarsal fold reduced or absent; inner metatarsal tubercle rounded,
larger than outer, both elevated; subarticular tubercles distinct; one
phalanx free of web on second, third, and fifth toes, three free on
fourth toe (Fig. 1A and B); skin tuberculate on dorsum, less so on
flanks; skin of belly granular, that on chest and throat weakly
granular; tongue cordiform, longer than wide, free and notched behind;
vocal slits large, lateral to tongue.
[Illustration: Fig. 1. A and B.--Hand and foot of _Hyla boulengeri_
(KU 102173), x 3. C and D.--Hand and foot of _Hyla s. staufferi_x (KU
57790), x 6]
In life, dorsum tan or brown with dark spots on snout, head, and
scapular region; interorbital triangle and blotch posteriorly on dorsum
dark brown; flanks pale green; groin pale green or orange, mottled with
dark brown; thighs tan or brown above with dark transverse bars on
anterior and posterior surfaces; spaces between bars green or orange;
inner surfaces of shanks and outer surfaces of tarsi brown and orange;
foot brown above; forelimbs brown and pale green above, weakly barred;
belly creamy white with scattered brown spots; vocal sac creamy white
flecked with brown; lower jaw brown with white spots on lips (Pl. 1A).
In preservative, head and dorsum dark brown with triangular spot
between eyes; dark spots on head and scapular region and dark brown
blotch posteriorly on dorsum; flanks creamy white with brown spots;
groin creamy white mottled with dark brown; thighs brown above with
dark brown transverse bars on anterior and posterior surfaces; inner
surfaces of shanks and outer surfaces of tarsi barred with pale brown;
dorsal surface of foot mottled brown and creamy white; ventral surface
of foot and toes pale brown; forelimbs faintly barred with pale brown;
belly white with a few pale brown spots; vocal sac flecked with pale
brown; lower jaw marked with small white spots on lips.
_Variation._--Geographic variation is evident in the snout-vent length,
tibia length, and foot length, all in relation to snout-vent length,
and the relative size of the tympanum to the eye (Table 1). The largest
specimens are from the humid Pacific lowlands of Costa Rica;
individuals from the Caribbean lowlands of Costa Rica, Canal Zone, and
South America are smaller. A general trend for increase in size extends
from South America to the Pacific lowlands of Costa Rica.
Most variation in color does not seem to be correlated with geography;
color variation is nearly as great within a given population as between
separated populations. However, most specimens from Rincon de Osa,
Puntarenas Province, Costa Rica, are dusky brown, but a few are darker.
In comparison with specimens from the Caribbean lowlands of Central
America, specimens from the Pacific slopes in Costa Rica have a darker
interorbital triangle. In some specimens from the latter area
rugosities are present on the borders of the interorbital triangle, on
the snout, on the upper eyelid, and on the heel. Specimens from the
Caribbean lowlands are less tuberculate, and most individuals from
there lack rugosities on the tarsus. Living individuals from Puerto
Viejo, Heredia Province, Costa Rica, and from the Canal Zone, Panama,
are brown above with a metallic green tint. Rugosities are present on
the posterior edges of the forelimbs in some specimens from throughout
the range. In most respects, specimens from the Canal Zone resemble
those from the Caribbean lowlands of Costa Rica more than they resemble
those from the Pacific lowlands of Costa Rica, but some individuals
from the Canal Zone are less metallic above and have small white spots
dorsally on the body, head, and limbs.
A moderate amount of color change from night to day has been noted. At
night, a male from Puerto Viejo, Heredia Province, Costa Rica, was
grayish tan above with slightly darker markings; the flanks were pale
yellowish green. By day, the dorsum was brown with darker markings, and
the throat was pale gray with white flecks; the rest of the venter was
creamy white. The groin was pale green with black mottling; the
anterior and posterior surfaces of the thighs and inner edges of the
tarsi were greenish yellow with black bars.
TABLE 1.--Geographic Variation in Size and Proportions in Males of
_Hyla boulengeri_. (Means in parentheses below observed ranges.)
=========================================================================
| | Snout-vent| Tibia | |
| | length | length/ |Tympanum/|Foot length/
Locality | N | (mm.) | snout-vent| eye | snout-vent
--------------------+----+-----------+-----------+---------+-------------
Costa Rica: Tilaran | 23 | 37.4-48.7 | 0.52-0.58 |0.62-0.76| 0.39-0.45
| | (43.8) | (0.55) | (0.71) | (0.42)
| | | | |
Costa Rica: Rincon | 10 | 41.4-46.1 | 0.54-0.60 |0.68-0.80| 0.40-0.45
de Osa | | (44.0) | (0.57) | (0.74) | (0.43)
| | | | |
Costa Rica: Alajuela| 13 | 35.6-43.1 | 0.55-0.60 |0.63-0.78| 0.41-0.46
Province | | (39.8) | (0.57) | (0.69) | (0.44)
| | | | |
Costa Rica: Puerto | 25 | 37.5-42.9 | 0.51-0.62 |0.63-0.79| 0.38-0.46
Viejo | | (41.6) | (0.55) | (0.71) | (0.43)
| | | | |
Costa Rica: Suretka | 9 | 38.7-42.0 | 0.56-0.58 |0.53-0.72| 0.35-0.45
| | (41.0) | (0.56) | (0.62) | (0.42)
| | | | |
Panama: Canal Zone | 16 | 36.7-42.9 | 0.52-0.58 |0.70-0.78| 0.40-0.44
| | (39.0) | (0.54) | (0.74) | (0.42)
| | | | |
Venezuela: Santome | 4 | 35.5-40.9 | 0.45-0.48 |0.63-0.67| 0.36-0.40
| | (38.5) | (0.46) | (0.65) | (0.38)
TABLE 2.--Comparison of Mating Calls in the _Hyla rubra_ Group. (Means
in parentheses below observed ranges.)
============================================================================
| |Notes| | | | Major frequencies
| | per |Duration| Pulses|Fundamental| (cps)
| |call | of note| per | frequency |---------------------
Species | N |group| (sec.) | second| (cps) | Lower | Upper
---------------+---+----+---------+-------+-----------+---------+-----------
H. boulengeri | 8 | 1 | 0.24- | 80-120| 70-74 |1400-1820|2520-3182
| | | 0.47 | (101)| (71) | (1611) | (2840)
| | | (0.35) | | | |
| | | | | | |
H. foliamorta | 7 | 1 | 0.23- | 50-60 | 52-61 | 912-1026|2736-3477
| | | 1.86 | (51) | (56) | (918) | (3055)
| | | (0.69) | | | |
| | | | | | |
H. elaeochroa |15 | 2-95| 0.12- | 40-50 | 48-65 |1254-1586|2562-3477
| | (19)| 0.24 | (42) | (57) | (1499) | (2911)
| | | (0.17) | | | |
| | | | | | |
H. s. staufferi|18 | 2-77| 0.13- |100-130| 96-130 |1582-1872|1962-3744
| | (23)| 0.23 | (120) | (106) | (1743) | (3056)
| | | (0.18) | | | |
| | | | | | |
H. s. altae | 7 | 2-22| 0.14- |110-130| 104-117 |1853-2106|3379-4056
| | (11)| 0.18 | (120) | (112) | (2008) | (3775)
| | | (0.15) | | | |
_Cranial Osteology._--The skull of _Hyla boulengeri_ is as long as it
is wide, and is flat; the premaxillary is small and bears 13 to 17
teeth (mean for 6 specimens, 14.9). The alary processes of the
premaxillaries are widely separated, concave posteriorly, and vertical.
Ventrally, the premaxillary is connected to the prevomer by bony
tissues. The maxillary is slender and bears 70 to 91 teeth (mean for 6
specimens 78.1). The pars facialis of the maxillary is laterally convex
and about four times as high as the pars dentalis.
The nasal is large (its length about 40 per cent of total length of
skull), and pointed anteriorly and posteriorly in dorsal view. The
nasals are separated anteromedially by the cartilaginous septum nasi.
One or two protuberances are present on the midlateral concavity of the
nasal. Posteriorly, the nasal overlaps the sphenethmoid and articulates
with the palatine. Dorsally the sphenethmoid is large, pentagonal, and
completely ossified. The frontoparietal is elongate, smooth, and bears
a small supraorbital process on the anterior edge of the orbit. A
keyhole-shaped frontoparietal fontanelle is present; the fontanelle is
narrow anteriorly and wide posteriorly.
The bony part of the prooetic is separated dorsally from the squamosal
by the cartilaginous crista parotica. The squamosal is small, its
anterior arm slender and pointed. The posterior arm of the squamosal is
pointed terminally and articulates with the prooetic medially.
The prevomer is large and elongate. Anteriorly the prevomer is
connected to the maxillary-premaxillary articulation; posteriorly, the
prevomer is separated from the sphenethmoid by cartilage. Each prevomer
bears six to nine teeth. The palatine is present and edentate. The
anterior end of the parasphenoid is broad (less pointed than in _Hyla
foliamorta_). The pterygoid is slender and well developed.
_Natural History._--_Hyla boulengeri_ inhabits humid lowland tropical
forests and breeds in temporary ponds. Clasping pairs and gravid
females were observed at Puerto Viejo, Heredia Province, Costa Rica, on
June 21, 1966. Males were calling from depressions in decaying logs and
stumps, in forked stems, and from leaves of broad-leafed plants near
the pond. Males were observed in late July and early August calling
from _Calathea_ and _Heliconia_ leaves at the edge of a pond in the wet
forest of the Osa Peninsula. William E. Duellman informed me that he
collected calling males in January at El Real, Darien, and in March at
Almirante, Bocas del Toro, Panama. Taylor (1952) found calling males in
June at Turrialba, Cartago Province, Costa Rica, and Dunn (1931a)
observed males calling in July, November, and December in Panama.
Gravid females have been found from April to August. Breeding
activities of _Hyla boulengeri_ always seem to be associated with
temporary ponds; in Central America breeding apparently takes place
throughout most of the year.
The mating call of _Hyla boulengeri_ consists of one short, moderately
low-pitched note. Each note has a duration of 0.24 to 0.47 second and
is repeated at intervals of one second to several minutes. The notes
have 80 to 120 pulses per second, a fundamental frequency of about 70
cycles per second, and a dominant frequency of 2,840 cycles per second
(Table 2, Pl. 3A).
The eggs are deposited in a mass in the water. No information is
available concerning early development. Tadpoles in advanced stages of
development were found in a temporary pond at Rincon de Osa, Puntarenas
Province, Costa Rica. The pond was about 10 cm. deep, had a muddy
bottom and lacked vegetation. Three recently metamorphosed young were
found in mid-August, 1966, on grass at the edge of another temporary
pond in the forest.
_Tadpoles_--Twelve tadpoles are available. These were collected at
Rincon de Osa, Puntarenas Province, Costa Rica. The maximum size
represented is 34.0 mm., total length (stage 42 of development).
A typical tadpole in stage 36 of development (KU 104295) has a body
length of 12.0 mm., tail length of 20.0 mm., and total length of 32.0
mm. Other characters are as follows: depth of tail equal to length of
body; body deeper than wide; distance between eye and nostril equal to
that between nostril and tip of snout; mouth anteroventral, upper and
lower lips bare; papillae present laterally; tooth rows 2/3; upper rows
about equal in length; first upper row slightly, and second upper row
widely, interrupted medially; lower rows about equal in length, shorter
than upper rows; third lower row containing 5-10 large teeth; beak
strong, serrate; spiracle nearer anus than eye; anal aperture not
extending to border of ventral fin; caudal musculature slender
posteriorly, extending to tip of pointed tail; dorsal fin extending to
middle of body, slightly deeper than ventral fin; posterior three
fourths of tail spotted; rest of tail and body gray-brown or
transparent; hindlimbs flecked or spotted with brown (Table 3, Fig. 2A
and 3A).
TABLE 3.--Sizes of Tadpoles of _Hyla boulengeri_ in Relation to
Developmental Stages. (Means in parentheses below observed ranges;
measurements in mm.)
=======================================================
Stage | N | Body length | Tail length | Total length
--------+---+-------------+-------------+--------------
30 | 1 | 11.0 | 22.2 | 33.2
| | | |
35 | 1 | 11.0 | 12.0 | 23.0
| | | |
36 | 3 | 9.5-12.0 | 20.0-21.5 | 31.0-32.0
| | (11.2) | (20.5) | (31.7)
| | | |
38 | 2 | 11.5 | 22.0 | 33.5
| | | |
42 | 2 | 10.5-13.0 | 21.0-22.0 | 32.5-34.0
| | (11.8) | (21.5) | (33.3)
| | | |
44 | 2 | 14.0-15.0 | 8.0-15.0 | 22.0-30.0
| | (14.5) | (12.5) | (26.0)
| | | |
46 | 1 | 15.0 | 15.0 |
A recently metamorphosed young has a snout-vent length of 15 mm.; the
head is as long as wide, the eyes are prominent; the limbs are weakly
barred; the skin is rugose above and granular below. The venter is
immaculate; the dorsum and limbs are gray-brown in preservative (pale
green in life). The interorbital space, supratympanic fold, and
scapular region are darker than the rest of the body; the fingers lack
webbing; the webbing on the foot is the same as in adults; small
metatarsal tubercles are present, but the tarsal fold is absent.
[Illustration: Fig. 2. Tadpoles of (A) _Hyla boulengeri_ (KU 104295)
and (B) _Hyla elaeochroa_ (KU 104134), x 3.]
[Illustration: Fig. 3. Mouthparts of tadpoles of (A) _Hyla
boulengeri_ (KU 104295) and (B) _Hyla elaeochroa_ (KU 104134), x 25.]
_Remarks._--Cope (1887:12) described _Scytopis boulengeri_ from
Nicaragua. Guenther (1901:267) placed _boulengeri_ in the genus _Hyla_,
and stated that Cope possibly placed _boulengeri_ in the genus
_Scytopis_ on the supposition that it had an accumulation of
"sebaceous glands" above the tympanum. Noble (1918:339) redescribed
_Hyla boulengeri_ on the basis of three specimens from Zelaya
Province, Nicaragua, and noted that the glands were not prominent in
any of the specimens. Duellman (1956:8) showed that _Scytopis hebes_
(generotype of _Scytopis_ by monotypy) is a Phrynohyas, and thus
placed _Scytopis_ Cope, 1862, in the synonymy of _Phrynohyas_
Fitzinger, 1843.
Dunn and Emlen (1932:25) placed _Hyla lancasteri_ Barbour in the
synonymy of _Hyla boulengeri_; the former was known solely from one
juvenile. They made no qualifying statements, but probably they were
impressed by the strongly barred thighs, a coloration known among
Central American hylids at that time only in _Hyla boulengeri_
(Duellman, 1966a:271). Taylor (1952:856) followed Dunn and Emlen with
reservation and noted some differences. Duellman (1966a:271) showed
that the holotype of _lancasteri_ was a juvenile of a species
subsequently named as _Hyla moraviaensis_ by Taylor (1952:865).
In Central America, _Hyla boulengeri_ can be confused only with _Hyla
foliamorta;_ the latter is restricted to central and eastern Panama
and northern Colombia. The snout of _foliamorta_ is more pointed and
protruding, and the vocal sac is darker than in _boulengeri_; the
groin of _foliamorta_ usually is creamy white, whereas _boulengeri_
usually has a dark spot. The skulls differ in that _boulengeri_ has a
frontoparietal fontanelle, the prevomer is larger and elongate,
anteriorly connected to the premaxillary, and posteriorly separated
from the sphenethmoid by cartilage; _foliamorta_ lacks a fontanelle,
the prevomer is smaller, anteriorly separated from the premaxillary by
cartilage, but connected by a bony suture to the sphenethmoid. The
mating call of _boulengeri_ differs by having shorter notes, twice as
many pulses per second, a higher fundamental frequency, and more
closely approximated major frequencies than does that of _foliamorta_.
_Hyla boulengeri_ need not be compared in detail with the other Central
American members of the _Hyla rubra_ group, because all of them are
smaller and have shorter snouts, smoother skin, and dissimilar color
patterns.
_Distribution._--In Central America _Hyla boulengeri_ inhabits the
forested lowlands in locally humid areas in Guanacaste Province, Costa
Rica, and in the humid Golfo Dulce region of Costa Rica; it occurs on
the Carribbean lowlands from central Nicaragua to South America, where
it ranges to Guyana and Ecuador. The highest elevations where _H.
boulengeri_ has been found are 620 meters at Turrialba, Cartago
Province, and 700 meters at Tilaran, Guanacaste Province, Costa Rica
(Fig. 4).
_Specimens Examined._--Costa Rica: _Alajuela_: 9 km N Ciudad Quesada,
near La Florencia, USC 8059 (4); 18 km N Florencia, USC 2624; Laguna
Monte Alegre, KU 64334; Las Playuelas, 11 km S Los Chiles, USC 7216,
7217 (2), 7219; 3 km NE Muelle del Arenal, USC 2644 (5). _Cartago_:
Turrialba, KU 24741. _Guanacaste_: 7 km N Liberia, USC 8096 (2), 8138
(6); 13.6 km N Liberia, USC 8151, 8171 (2); 20.5 km S Liberia, USC
8205; Taboga, 20 km SE Las Canas, KU 102170, USC 7166; 4 km NE Tilaran,
USC 8023; 6 km NE Tilaran, USC 523 (3), 6262, 7019. _Heredia_: Puerto
Viejo, KU 64323-7 (skeletons), 104351-3 (skeletons), 64330-3,
103592-620; 1 km NE Puerto Viejo, UMMZ 126042; 1 km S Puerto Viejo, KU
84983-4 (skeletons), 86317-22, 87774 (skeleton); 4.2 km W Puerto Viejo,
KU 64329, 64328 (skeleton). _Limon_: Mountain Cow Creek, near Banano,
KU 37031, 41067 (skeleton); 3 km S Rio Tortuguero, AMNH 69057; Suretka,
KU 36482-8, 36699. _Puntarenas_: 4.8 km S Bahia Rincon on NW side Rio
Rincon, USC 705; Parrita, USC 6163; 4.5 km W Rincon de Osa, KU
102177-9, 104295-6 (tadpoles); 6 km SW Rincon de Osa, KU 102171-6; 4.4
km NW Villa Neilly, USC 8003; 10.5 km WNW Villa Neilly, KU 64321. _San
Jose_: 21 km WSW San Isidro el General, KU 34104-6.
[Illustration: Fig. 4. Map showing locality records for _Hyla
boulengeri_ (circles) and _H. foliamorta_ (dots).]
Panama: _Bocas del Toro_: 3.2 km W Almirante, KU 95978. _Canal Zone_:
Barro Colorado Island, FMNH 13379; near Clayton Reservation, UIMNH
42000; 2.6 km SW Fort Kobbe, KU 95977; Miraflores Locks, AMNH 69764-5;
Summit, AMNH 73445, KU 97777, 101540-9, 104350 (skeleton). _Colon_: Rio
Gatuncillo, near Nuevo San Juan, KU 95976. _Darien_: El Real, KU
80451-3.
_Hyla foliamorta_ Fouquette
_Hyla foliamorta_ Fouquette, Herpetologica, 14:125, April 25,
1958 [Holotype.--TNHC 23109, 11 km. NW Miraflores Locks, Canal
Zone, Panama; M. J. Fouquette, Jr. collector].
_Diagnosis._--Size medium (Male to 43 mm., Female to 41 mm.); skull
longer than wide; frontoparietal fontanelle absent; snout acuminate,
projecting; interorbital triangle bordered by white lines; scapular
region having two or more elongate spots; dorsum smooth; vocal sac
dark gray; groin creamy white; traces of web between fingers.
_Description._--Head flattened, longer than wide; snout flat, pointed,
protruding beyond lower lip; loreal region slightly concave; canthus
moderately prominent; eyes smaller than interorbital space; tympanum
distinct, 55 to 75 per cent of diameter of eye, smaller than
internarial space; arms short; fingers having rudimentary webs; median
palmar tubercle tripartite; inner palmar tubercle on base of first
finger flat; subarticular tubercles distinct; discs of fingers smaller
than diameter of tympanum; legs long; tarsal fold lacking; inner
metatarsal tubercle larger than outer; one phalanx free on second,
third, and fifth toes, two and one half phalanges free on fourth toe;
narrow fringe continuing from web to discs of toes; discs of toes
about the size of those on fingers; skin smooth on dorsum and flanks,
that on belly and posterior part of thighs granular; tongue oval,
longer than wide; vocal slits oblique, about one half length of
tongue.
In life, dorsum pale tan to pale reddish brown with irregular reddish
brown markings; small dark spots on head; distinct dark brown
triangular mark between eyes, bordered by thin white lines; apex of
triangle always directed backward; supratympanic fold with black edge;
scapular region having two to five small, elongate black spots; belly
creamy tan with small brown spots; vocal sac uniformly dark brown with
scattered creamy tan flecks; upper jaw dark brown; limbs creamy white
below with scattered brown spots; groin marked with small brown spots
in some specimens; anterior and posterior surfaces of thighs
yellow-orange with three distinct black blotches; two dark bands on
upper surface of shanks; webbing of feet yellowish tan with brown
mottlings (Pl. 1B).
In preservative, dorsum brown or gray with darker markings; interorbital
triangle distinct, bordered by white lines; supratympanic fold with
black edge; two or more small elongate black spots in scapular region;
belly white with numerous brown flecks; edge of upper lip dark brown;
vocal sac dark gray; undersides of limbs creamy white; groin creamy
white with or without brown spots; anterior and posterior surfaces of
thighs having three black blotches separated by creamy white spaces;
shanks having two brown bands; webbing of feet mottled with brown.
_Variation._--Twenty-eight breeding males from the area between Chepo
and Tocumen, Panama, have snout-vent lengths of 39.0 mm. to 46.0 mm.
(mean 42.5 mm.). In these specimens, the ratio of the tibia length
to the snout-vent length is 0.54 to 0.61 (mean, 0.57); the ratio
of the diameter of the tympanum to that of the eye is 0.55 to 0.75
(mean, 0.67). One female has a snout-vent length of 41.0 mm.,
tibia/snout-vent length ratio of 0.57, and tympanum/eye ratio of 0.76.
Two to five (usually three) elongate black spots are present in the
scapular region in different individuals. The flanks in some are
spotted with brown; in others they are creamy white. A small black
spot is present in the groin of some specimens. Usually two to four
blotches are present on the anterior and posterior surfaces of the
thighs; in some specimens the blotches are reduced to small spots. One
or two brown spots are present proximally on the shanks in most
specimens. In some individuals tuberculations are scattered on the
head and in the tympanic and scapular regions, but the dorsum is
smooth in most specimens; the belly is creamy white flecked with
brown.
_Cranial Osteology._--The skull of _Hyla foliamorta_ is flat and
longer than it is wide. The premaxillary is small and bears 13 to 16
teeth (mean for 2 specimens, 14.8). The alary process of the
premaxillary is vertical and concave posteriorly. Ventrally, the
premaxillary is completely separated from the prevomer by cartilage.
The maxillary is slender; each bears 77 to 84 teeth (mean for 2
specimens, 81). The pars facialis of the maxillary is laterally convex
and less than three times the height of the pars dentalis.
The nasal is large and pointed anteriorly and posteriorly in dorsal
view. The length of the nasal comprises about 40 per cent of the total
length of the skull. The nasals are separated anteromedially by the
cartilaginous septum nasi. One protuberance is present on the
midlateral concavity of the nasal. Posteriorly, the nasal overlaps the
sphenethmoid; posterolaterally the nasal articulates with the
palatine. The sphenethmoid is completely ossified and pentagonal in
dorsal view. The frontoparietal is elongate, without a pronounced
anterior supraorbital process. The frontoparientals are sutured
medially throughout their lengths; the frontoparietal fontanelle is
absent.
The bony part of the prooetic is narrowly separated dorsolaterally from
the squamosal by the cartilaginous crista parotica. The squamosal is
large; the anterior arm is pointed. The posterior arm of the squamosal
is broad, rounded terminally, and articulates with the prooetic
medially.
The prevomer is short and separated anteriorly from the premaxillary
and maxillary by cartilage. The posterior margin of the prevomer has a
bony articulation with the sphenethmoid. Each prevomer bears five to
seven teeth. The palatine is small and edentate. The anterior end of
the parasphenoid is narrow (more pointed than in _Hyla boulengeri_).
The pterygoid is slender and well developed (Fig. 5A).
[Illustration: Fig. 5. Dorsal views of the skulls of (A) _Hyla
foliamorta_ (KU 77687) and (B) _H. elaeochroa_ (KU 68289), x 3.]
_Natural History._--_Hyla foliamorta_ inhabits lowland forests in
eastern Panama and breeds in temporary ponds. Males have been observed
calling from grasses, bushes, and emergent vegetation near temporary
ponds and ditches along roads. William E. Duellman informed me that he
found a breeding congregation of this species in June near Chepo,
Panama, where males were calling from spiny palms at the edge of a
woodland pond. Fouquette (1958) found calling males in May, August,
and September near Miraflores Locks, Canal Zone. Calling stations vary
from one to two meters above ground. No clasping pairs have been
found; only one female is known (KU 101589, from 8 km NE Tocumen,
Panama); this gravid individual was collected in early June.
The mating call of _Hyla foliamorta_ consists of one pulsed,
low-pitched, moderate trill of about O.5 second duration. Each note is
repeated at intervals of 5 seconds to a few minutes. The notes have
about 50 pulses per second, a fundamental frequency of 56 cycles per
second and a dominant frequency of about 3000 cycles per second (Table
2, Pl. 3B).
Egg deposition sites are unknown. No information is available
concerning early development, and little is known about the breeding
season of _Hyla foliamorta_. Probably its breeding activities are
restricted to the rainy months.
_Tadpoles._--Eight tadpoles were collected from a weedy temporary pond
near Chepo, Panama, in early June.
A typical tadpole in stage 35 of development (KU 104244) has a body
length of 9.5 mm., tail length of 25.0 mm., and a total length of 34.5
mm. Other characters are as follows: depth of tail equal to length of
body; body deeper than wide; distance between eye and nostril equal to
distance between eye and spiracle; mouth anteroventral; median part of
upper lip bare; rest of lip having one row of papillae; a few other
rows of small papillae at corners of mouth; tooth rows 2/3; first
upper row entire, second upper row interrupted medially, shorter than
first; lower rows shorter than upper rows, third shortest; beak
moderately robust; spiracle nearer eye than anus; anal tube short,
aperture not extending to border of ventral fin; caudal musculature
slender, extending to tip of pointed tail; dorsal fin extending onto
body (Table 4).
TABLE 4.--Sizes of Tadpoles of _Hyla foliamorta_ in Relation to
Developmental Stages. (Means in parentheses below observed ranges;
measurements in mm.)
=======================================================
Stage | N | Body length | Tail length | Total length
--------+---+-------------+-------------+--------------
25 | 2 | 5.0-5.2 | 8.0-8.5 | 13.0-13.7
| | (5.1) | (8.3) | (13.4)
| | | |
26 | 3 | 7.0-7.5 | 12.0-12.4 | 17.0-19.5
| | (7.2) | (12.1) | (18.6)
| | | |
28 | 2 | 6.5-7.0 | 18.0 | 25.0
| | (6.8) | |
| | | |
35 | 1 | 9.5 | 25.0 | 34.5
In life, yellow above, white below; caudal fin greenish yellow with
black or gray reticulations; dark line from snout to eye; dark spot
behind eye; tail unpigmented except for fine dark reticulations. In
preservative body creamy white, transparent below with dark pigment
above in some specimens.
_Remarks._--_Hyla foliamorta_ can be confused only with _Hyla
boulengeri_. The differences between adults of these species were
discussed in _Remarks_ on _H. boulengeri_. The tadpoles of
_foliamorta_ have labial papillae on the lower lip and a stripe
between the eye and the tip of the snout. By comparison the tadpoles
of _boulengeri_ have a bare lower lip and no stripe between the eye
and the tip of the snout.
_Distribution._--_Hyla foliamorta_ inhabits the subhumid Pacific
lowlands (elevations of less than 100 meters) of Central Panama and
Caribbean lowlands of northern Colombia (Fig. 4).
_Specimens Examined._--Panama: _Panama_: 3 km WSW Chepo, KU 77164-9,
101573-5, 104243-4 (tadpoles); 6 km WSW Chepo, KU 77170, 101576-8; 1.5
km SW Naranjal, KU 77171, 77687 (skeleton); 2 km N Tocumen, KU
101579-83, 104349 (skeleton); 8 km NE Tocumen, KU 101584-92.
No specific locality: TNHC 24401.
_Hyla rubra_ Laurenti
_Hyla rubra_ Laurenti, Synopsis Reptilium Emendatum, p. 35, 1768.
Daudin, Hist. Nat. Rainettes Grenouilles Crapauds, II:26, 1802.
Daudin, Hist. Nat. Particuliere Reptiles, 8:53, 1803. Guenther,
Catalogue Batrachia Salientia Brit. Mus., p. 110, 1859. Boulenger,
Catalogue Batrachia Salientia s. Ecaudata, p. 403, February 1,
1882. Dunn, Occas. Papers, Boston Soc. Nat. Hist., 5:413, October
10, 1931.
_Hyla elaeochroa_ (part): Dunn and Emlen, Proc. Acad. Nat. Sci.
Philadelphia, 84:25, March 22, 1932.
_Diagnosis._--Size medium; skull longer than wide; frontoparietal
fontanelle absent in adults; snout subovoid; choanae rounded; dorsal
stripes present; black vermiculations on posterior surfaces of thighs.
_Description._--Head flat, longer than wide; snout long, subovoid,
slightly protruding beyond lower lip; loreal oblique, concave; canthus
rounded, indistinct; diameter of eye about equal to interorbital
space; tympanum large, about three fifths diameter of eye, smaller
than internarial distance; supratympanic fold indistinct; arms short;
fingers free of webs; subarticular tubercles distinct; median palmar
tubercle large, bifid; inner palmar tubercle on base of first finger
flat, elongate; disc of third finger about one half diameter of
tympanum; legs moderately long; tarsal fold absent; inner metatarsal
tubercle distinct, oval; toes about half webbed; web on fourth toe
extending to disc; discs of toes about size of those on fingers; skin
smooth above with small granules on head and in scapular region in
some specimens; skin on flanks, throat, belly, and lower surfaces of
thighs granular; tongue oval, longer than wide, not free behind;
choanae small, oval; vocal slits long, lateral to tongue.
In preservative, dorsum pale brown with darker dorsolateral stripes;
narrow dark brown line from nostril to eye; groin, anterior surface of
thighs, and posteroventral surfaces of shanks creamy tan with dark
brown vermiculations; white spots present on thighs in some specimens;
throat flecked with brown; belly creamy white or gray.
_Remarks._--The taxonomic history of _Hyla rubra_ Laurenti is
confused. Seba (1734:70) illustrated and diagnosed a frog for which
he used the name _Ranula, Americana, Rubra_. Linnaeus (1758:213)
considered Seba's frog to be a variety of _Hyla arborea_. Laurenti
(1768:35) apparently examined the same individual that Seba called
_Ranula, Americana, Rubra_. For this specimen, Laurenti used the
binominal _Hyla rubra_ and provided a brief diagnosis. The type
locality was given as America.
Daudin (1802:26) redescribed the same specimen(s?) treated by Seba and
Laurenti and provided a fairly good description and figures. Daudin
restricted the type locality to Surinam and indicated that Marin de
Baize was the probable collector. Daudin (1802:26 and 1803:53)
neglected to consider Laurenti's work, but he applied the same name
used by Laurenti. Most authors have credited _Hyla rubra_ to Daudin,
but Rivero (1961:120) noted that _Hyla rubra_ Laurenti, 1768, has
priority over _Hyla rubra_ Daudin, 1802. Since both Laurenti and
Daudin worked on Seba's material, it is reasonable to assume that
Daudin redescribed the same frog that was named by Laurenti; this was
not an uncommon practice in the early nineteenth century. Thus I
conclude that _Hyla rubra_ Daudin, 1802, is a junior synonym of _Hyla
rubra_ Laurenti, 1768.
Dunn (1931a:413) first reported _Hyla rubra_ from Central America; he
recorded the species from the Canal Zone and San Pablo, Panama. I have
examined the material of _Hyla rubra_ from Panama deposited in various
museums. Most of the specimens are faded, discolored, and do not have
distinct brown vermiculations on the thighs. The specimens seem to be
more like _Hyla rubra_ than any of the other species in the _rubra_
group. The presence of oval choanae and a tympanum larger than the
largest finger disc separate these specimens from _Hyla elaeochroa_, a
species with which _rubra_ has been confused. _Hyla elaeochroa_ does
not occur in the Canal Zone or eastern Panama. All museum specimens
from Nicaragua, Costa Rica, and western Panama that have been called
_Hyla rubra_, plus those mentioned by Dunn and Emlen (1932:25) and
Dunn (1933:61) are _Hyla elaeochroa_.
The taxonomic status of the many South American populations referred
to _Hyla rubra_ and of other populations now recognized as different
species is not clear at the present time. Considerable variation in
external characters and in cranial features has been observed in South
American _rubra_. A review of the taxonomy of these populations is
beyond the scope of this paper. Possibly the Central American
specimens herein referred to _rubra_ will ultimately be found to be
specifically distinct from those in Surinam. Since I have no
osteological material from Central America, I have been unable to
describe the cranium in this account. Furthermore, I have no data on
the ecology and life history of _rubra_ in Central America.
_Distribution._--_Hyla rubra_ inhabits lowland tropical forests from
central-eastern Panama to northern South America and thence through
lowlands east of the Andes to northern Argentina (Fig. 6).
_Specimens Examined._--Panama: _Canal Zone_: Gatun, UMMZ 52720 (2);
Madden Dam, FMNH 67820; no specific locality, UMMZ 56517 (3), USNM
37863. _Colon_: Cerro Bruja, MCZ 13248. _Darien_: El Real, USNM
140569-70, 140573. _Panama_: Juan Diaz, MCZ 17973; Las Sabanas, MCZ
17581; Rio Trinidad, UMMZ 64003; San Pablo, MCZ 1398-9.
_Hyla elaeochroa_ Cope
_Hyla elaeochroa_ Cope, Jour. Acad. Nat. Sci. Philadelphia, 8:105,
1876 [Holotype.--USNM 30689, Sipurio, Limon Province, Costa Rica;
William M. Gabb collector]. Guenther, Biologia Centrali-Americana,
Reptilia and Batrachia, p. 265, June 1901. Taylor, Univ. Kansas
Sci. Bull., 35:859, July 1, 1952. Duellman, Univ. Kansas Publ.,
Mus. Nat. Hist., 17:270, June 17, 1966.
_Hyla quinquevittata_ Cope, Proc. Amer. Philos. Soc., 23:273,
April 1887 [Holotype.--USNM 14187, Nicaragua; J. F. Bransford
collector]. Guenther, Biologia Centrali-Americana, Reptilia and
Batrachia, p. 268, June 1901. Noble, Bull. Amer. Mus. Nat. Hist.,
38:340, June 1918.
_Hyla rubra_ (part): Dunn and Emlen, Proc. Acad. Nat. Sci.
Philadelphia, 84:25, March 22, 1932.
_Hyla dulcensis_ Taylor, Univ. Kansas Sci. Bull., 39:37, November
18, 1958 [Holotype.--KU 32168, Golfito, Puntarenas Province, Costa
Rica; Edward H. Taylor collector].
_Diagnosis._--Size medium (Male to 38 mm., Female to 40 mm.); skull
wider than long; nasals truncate anteriorly; frontoparietal fontanelle
moderate in size; snout slightly protruding; tympanum about size of
largest discs on fingers; dorsum marked by longitudinal stripes; dark
stripe between eye and nostril; in life tan to olive-green with or
without dark mark between eyes; bones greenish blue.