NATURAL HISTORY.
SURVEY

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[fj FIELDIANA . ZOOLOGY

Published by
CHICAGO NATURAL HISTORY MUSEUM

Volume 39 October 27, 1961 No. 55

Status of the Frog Hyla albomarginata
in Central America

M. J. Fouquette, Jr.1
Department of Biology, University of Florida, Gainesville

One of the common treefrogs of the Caribbean drainage of isth-
mian Panama is a moderate-sized green Hyla with bright red-orange
webs. This form has been referred to Hyla albomarginata by Cope
(1886) in Nicaragua, by Taylor (1952) and others in Costa Rica, and
by Dunn (1931a, b) in Panama. Dunn (1931a) and Wettstein (1934)
pointed out differences which they believed might indicate racial dis-
tinction, and Taylor (1952) also suggested that this Central American
form might not be identical with the South American species origi-
nally described by Spix (1824) as Hyla albomarginata (type locality,
"Bahia")- I have compared a series of specimens from Panama and
Nicaragua with material from Brazil which conforms to published
descriptions of Brazilian albomarginata. The Central American frogs
differ in several respects, and probably represent a form specifically
distinct from H. albomarginata. There seems no prior name avail-
able, so I propose to call this species

Hyla rufitela,2 new species. Figure 108.

Holotype. — Chicago Natural History Museum no. 13453, adult
male. Collected by K. P. Schmidt on Barro Colorado Island, Canal
Zone, December 24, 1928.

Paraiypes.— CNHM 13052, 13054, 13425, 13429-30, and TNHC
24089 (topotypes). TNHC 26700: Near the mouth of the Chagres
River, Canal Zone. AMNH 7362-63: Maselina Creek, Nicaragua
(tributary feeding the Machuco area of Rio San Juan).

1 Present address: Department of Biology, University of Southwestern Louisi-
ana, Lafayette, Louisiana.

1 In reference to the reddish webbing between the digits.
Library of Congress Catalog Card Number: 61-17978
No. 934 595

1

NATURAL

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596

FIELDIANA: ZOOLOGY, VOLUME 39

Fig. 108. Hyla rufitela, new sp., CNHM 13453, holotype.

Diagnosis. — A medium-sized Hyla, green above, with profuse,
tiny, dark punctations and usually scattered dark spots; webs bright
red-orange; concealed areas of axilla, groin and thigh bluish or blue-
green, sometimes with red also; iris golden yellow. A distinct pollex
rudiment, bearing a spine in males. Fingers about one-half webbed,
toes three-fourths webbed (fig. 109).

Description of holotype. — Greatest width of head slightly more
than length (measured directly from tip of snout to posterior edge
of tympanum); snout rounded with truncate tip, nostrils supero-
lateral, slightly raised. Canthus distinct, loreal region somewhat
concave and sloping obliquely. Eyes large and protruding, horizon-
tal diameter about equal to their distance from the nostril. Inter-
orbital distance equal to about one and one-half times width of upper

• .-* *?

<no S 5" FOUQUETTE: STATUS OF HYLA ALBOMARGINATA 597

eyelip, or about diameter of eye. Internarial distance about three-
fourths of distance from nostril to eye, or about equal to width of
eyelid. Tympanum distinct, round, but upper edge hidden under a
fold of skin from posterior border of eye. Horizontal diameter of
tympanum about one-half that of eye, separated from eye by about
one-half the diameter of tympanum. Top of head relatively flattened
(actually slightly concave). Vomerine teeth in two large oblique

Fig. 109. Ventral aspects of hand (left) and foot (right) of Hyla rufitela (not
to scale). The drawings indicate the relative positions of the subarticular tubercles
and the extent of the webbing. The dotted lines indicate the extent of webbing in
Hyla dlbomarginata, for comparison.

rows, only slightly separated medially, each row posteromedial to
the choana of that side, and parallel to the long axis of that choana.
Tongue broad, only slightly longer than wide, with an indistinct
notch on posterior free edge. A pair of elongate vocal slits parallel
and adjacent to mandible, extending along posterior half of jaw.

Skin relatively smooth above, finely granular. Glandular fold
from posterior border of eye across upper edge of tympanum, pass-
ing down obliquely behind tympanum to a point immediately behind
angle of jaw; here a vague connection over the axilla with a rather
distinct ventrolateral fold. A weak dorsolateral fold from above
axilla to sacrum. A transverse fold above vent. Arm of moderate
length, wrist reaching to about end of snout. Lower arm stout.

598 FIELDIANA: ZOOLOGY, VOLUME 39

Fingers about one-half webbed, but webbing reduced between the
first two fingers (fig. 109); webs thickened. Finger 4 distinctly-
longer than 2, and nearly as long as 3. A well-developed pollex
rudiment bearing a small spine. Discs of fingers 2, 3, and 4 large,
each about twice the size of that of finger 1, and nearly as extensive
as tympanum. Subarticular tubercles 2, 2, 3, 3, on fingers 1 through
4 respectively; distal tubercle of each digit slightly developed; prox-
imal tubercle of fingers 3 and 4 very small and indistinct; other sub-
articular tubercles distinct. A faint glandular ridge along outer edge
of arm and finger, passing around elbow. Legs moderately long, heel
reaching tip of snout. Heels overlap slightly when legs are placed
at right angles to body, and knee and elbow overlap slightly when
leg is placed alongside body. Toes three-fourths webbed (fig. 109),
the webbing thick. Toes 3 and 5 about equal in length. Discs well
developed, but the largest slightly smaller than the largest finger disc;
disc of toe 1 about one-half the size of the others. Subarticular
tubercles 2, 2, 3, 4, 3 on toes 1 through 5 respectively; distal tuber-
cle of each digit slightly developed; proximal tubercle of toes 3, 4,
and 5 very small and indistinct; other subarticular tubercles quite
distinct. A rather long, flat, inner metatarsal tubercle medial to
inner toe, suggesting a rudimentary digit. A faint, outer tarsal fold,
continued along outer edge of toe 5, and a poorly developed dermal
pad on heel. Venter coarsely granular, throat skin smoother and
more finely granular. An internal vocal sac.

Faded in preservative to a light yellowish color. Dorsal surfaces
covered with profuse, tiny, dark brown punctations, which under
magnification appear to be melanophores, imparting a finely speckled
appearance. Some groups of these coalesced to form large spots
scattered over upper surfaces of head, body, and limbs. A dark
stripe marking canthus from eye to nostril, bordered below by an
indistinct white line. The speckling occurs on nearly all normally
exposed surfaces, including entire lip, tympanum, and upper surface
of digits and discs. No pigment flecks laterally, venirally, or on
concealed surfaces of limbs, axilla, and groin, or on webs. Outer
arm ridge, tarsal ridge, and anal fold white.

Measurements (mm.): snout-urostyle, 43.7; head length, 15.2;
head width, 15.8; tibia, 23.7; heel to tip of longest toe, 32.0; eye, 5.5;
tympanum, 2.7.

Variation in paratypes. — The number of large dorsal spots varies,
some specimens showing more than the holotype, and some lacking
them. The canthus may be more or less distinctly marked than in

FOUQUETTE: STATUS OF HYLA ALBOMARGINATA 599

the holotype. In one specimen the dorsolateral line is faintly marked
with white. Five specimens exhibit some scattered, white dorsal
spots. The cutaneous body folds are seldom more distinct than in
the type, though often less so, and never so well defined as those of
H. albomarginata (particularly the dorsolateral fold). The dorso-
lateral fold sometimes appears connected with the supratympanic
fold. A distinct fold of skin may cross the chest, especially in males
collected during the breeding season so that the throat skin is
stretched from calling. The pollex rudiment is reduced in females;
these also lack the spine. Variation in snout-urostyle of adults:
males, 39.0 to 43.8; females, 46.3 to 47.6.

Color in life. — The following is based on color notes made on speci-
mens I collected in the field (TNHC 24089, 26700). Dorsally a
medium to light yellowish-green (darker at night when active in the
field), with a profusion of tiny blackish flecks and a few larger scat-
tered black or dark gray-green spots. Concealed surfaces of axilla,
groin, and thigh bluish or bluish-green. Side yellow to yellow-green.
Webs of fingers and toes a vivid red-orange. In one example the
dorsolateral fold distinctly marked with cream, a distinct cream-
white line from eye to nostril, and traces of reddish above eyes,
along dorsolateral fold, and on concealed surfaces of thighs. In the
other example the cream markings not visible, nor any red except
in webs. Greenish-white below. Iris golden yellow.

Mating call. — A rather loud "cluck" or "quack" of medium-low
pitch, occasionally accompanied by a guttural trill (the latter prob-
ably a "warm up" call). Audiospectrographic analysis (by Kay
Electric Co. Sonagraph) of calls recorded from a single individual
(TNHC 24089) indicates that the typical call is a single short note
(mean duration about 0.06 second) (fig. 110). This note is well-
tuned, with a fundamental frequency averaging about 400 cycles per
second (actually rising from about 375 to about 425 during its dura-
tion). The fourth harmonic (considering the fundamental as the
first) is dominant (midpoint about 1600 cps), but the third and fifth
are also rather strongly resonated. The notes are repeated rather
regularly at a rate of 43.1 per minute (based on a recorded series of
14 notes).

Relationships. — Hyla rufitela appears to be very closely related to
H. albomarginata. It is distinguished from albomarginata by reduced
skin pigmentation, iris color (silver in albomarginata), smaller size, a
more pronounced pollex rudiment, and less distinct cutaneous folds
of limbs and body. In addition, the webbing is generally somewhat

600 FIELDIANA: ZOOLOGY, VOLUME 39

less extensive, especially between the toes (fig. 109). There are no
available recordings of the call of Brazilian H. albomarginata; how-
ever, Cochran's (1955) characterization of this call does not seem
to me an apt description of the call of H. rufitela. Because of the
demonstrated significance of the mating call as an isolating mech-
anism and consequently as a taxonomic character in anurans, it
would be highly desirable to analyze the call of the Brazilian form

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Fig. 110. Audiospectrograph (sonagram) of the mating call of Hyla rufitela.
The second note is followed by a "warm-up" trill. The frog was calling from a
leaf of a "pita" plant (Ananas magdalenae). Recorded at Barro Colorado Island,
Canal Zone, August 21, 1956.

for comparison. Such analysis should provide more critical evidence
for evaluating the relationship of these two frogs.

Remarks. — Ecologically H. rufitela is an inhabitant of lowland
rain forest, at least in Panama. Its apparent restriction to the
Caribbean forests indicates a hygric affinity, as this coast receives
considerably more rainfall than the Pacific side.

Hyla rufitela is presently known from Nicaragua, Costa Rica, and
Panama, and all localities which can be located are in the Caribbean
drainage, at low elevation. I examined three of the four specimens
reported from Colombia by Cochran (1955) as H. albomarginata,
and these small, poorly preserved specimens may be related to albo-
marginata and rufitela, but are not conspecific with either. Specimens
represented by USNM 65438 and 65439 appear to be identical and
differ from rufitela in having a more rugose, coarsely granular skin
dorsally, no indication of speckling, toes only about one-third webbed,
pollex rudiment much reduced, and no supratympanic fold or any
other cutaneous folds except a ventrolateral one. USNM 107639

FOUQUETTE: STATUS OF HYLA ALBOMARGINATA 601

differs from rufitela chiefly in having the vomerine teeth arranged
in transverse rows, reduced finger webbing, and tympanum not so
distinct. This specimen is from the mountains north of Cali. The
fourth Colombian specimen (Musee Royale d'Histoire Naturelle
[Brussels] No. 12175) was not examined. However, it, too, was
collected in the mountains; thus it is ecologically improbable that it
is rufitela. The specimens reported by Cochran (1955) from Ecuador
were not examined, but on a geographic basis it is unlikely that these
are either rufitela or albomarginata. I know of no specimens of rufi-
tela from Panama south (east) of the Canal Zone. Coleman J. Goin,
who is intensively studying the treefrogs of Colombia, informs me
that he knows of no Colombian specimens which can be allocated to
rufitela or albomarginata, so it is doubtful that the present ranges of
these two forms overlap.

ACKNOWLEDGMENTS

Coleman Goin called my attention to this problem, provided
comparative material, and offered valuable advice. The following
individuals and institutions kindly lent specimens: Robert F. Inger,
Chicago Natural History Museum (CNHM); Charles M. Bogert,
American Museum of Natural History (AMNH); and W. Frank
Blair, University of Texas Natural History Collection (TNHC);
U. S. National Museum (USNM). The drawing of the holotype is
by Miss Esther Coogle.

REFERENCES
Cochran, D.

1955. Frogs of southeastern Brazil. Bull. U. S. Nat. Mus., 206: xvi+423 pp.

Cope, E. D.

1886. Thirteenth contribution to the herpetology of tropical America. Proc.
Amer. Phil. Soc, 23: 271-287.

Dunn, E. R.

1931a. New frogs from Panama and Costa Rica. Occ. Pap. Boston Soc. Nat.

Hist., 5: 385-401.
1931b. The amphibians of Barro Colorado Island. Op. cit., 5: 403-421.

Spix, J. B. VON

1824. Animalia nova, sive species novae Testudinum et Ranarum, quas in iti-
nere per Brasiliam, annis 1817-20 jessu et auspiciis Maximiliani Josephi I.
Monachii.

Taylor, E. H.

1952. The frogs and toads of Costa Rica. Univ. Kansas Sci. Bull., 35: 577-942.

Wettstein, O.

1934. Ergebnisse der osterreichischen biologischen Costa Rica-Expedition 1930.
Die Amphibien und Reptilien. Sitzber. Akad. Wiss. Wien, Math.-naturw.,
Abt. 1, 143: 1-39.