Descriptions of Two Species of Frogs,

Genus Ptychohyla

Studies of American Hylid Frogs, V

Holotype.—University of Michigan Museum of Zoology No. 119603, from
a stream 6 kilometers south of Vista Hermosa, Oaxaca, México (1865 meters);
obtained on March 31, 1959, by Thomas E. Moore. Original Number WED
14159.

Paratype.—UMMZ 119602 from Vista Hermosa, Oaxaca (1500 meters);
obtained on March 30, 1959, by William E. Duellman.

Diagnosis.—A species of the schmidtorum-group of Ptychohyla differing
from other known members of the group in having the diameter of the tympanum
less than one-half the diameter of the eye, no white spot below the
eye, no lateral light stripe, bright green dorsum in life and red flash-colors on
groin and thighs.

Description of Holotype.—Adult male having a snout-vent length of 30.0
mm.; tibia length, 14.6 mm.; tibia length/snout-vent length, 48.7 per cent; foot
length (measured from proximal edge of inner metatarsal tubercle to tip of
longest toe), 12.3 mm.; head length, 9.2 mm.; head length/snout-vent length,
32.3 per cent; head width, 9.3 mm.; head width/snout-vent length, 31.0 per cent;
diameter of eye, 3.2 mm.; diameter of tympanum, 1.3 mm.; tympanum/eye,
40.6 per cent. Snout in lateral profile square, in dorsal profile obtusely rounded;
canthus pronounced; loreal region slightly concave; lips moderately flaring; top
of head flat; nostrils protuberant; internarial distance, 2.8 mm.; interorbital
distance, 3.3 mm., much broader than width of eyelid, 2.8 mm. A heavy
dermal fold from posterior corner of eye above tympanum to insertion of forelimb,
covering upper edge of tympanum; tympanum elliptical, its greatest
diameter equal to its distance from eye. Forearm robust with a distinct fold
on wrist; pollex moderately enlarged without nuptial spines; second and fourth
fingers equal in length; subarticular tubercles round; none is bifid; disc of third
finger slightly larger than tympanum; no web between first and second fingers;
vestige of web between other fingers. Heels overlap when hind limbs
adpressed; tibiotarsal articulation extends to anterior corner of eye; no tarsal
fold; inner metatarsal tubercle large, flat, and elliptical; outer metatarsal tubercle
near inner one and triangular; subarticular tubercles round; length of digits from
shortest to longest 1-2-5-3-4; toes about one-half webbed; discs smaller on toes
than on fingers. Anal opening directed posteriorly at upper level of thighs;
no anal flap; pair of large tubercles below anal opening; small tubercles ventral
and lateral to these. Skin of dorsum and ventral surfaces of limbs smooth,
that of throat and belly granular. Ventrolateral glands noticeably thickened,
extending from axilla nearly to groin and only narrowly separated medially on
chest. Skin of anterior part of chin thickened and glandular. Tongue cordiform,
shallowly notched behind and only slightly free posteriorly; vomerine
teeth 0-3, situated on rounded elevations between somewhat larger, round
inner nares; openings to vocal sac large, one situated along posterior margin
of each mandibular ramus.

Color (in alcohol) dull brown above with irregular dark brown blotches;
dorsal surfaces of limbs brown with narrow darker brown transverse bars;
posterior surfaces of thighs cream-color with brown spots and mottling; groin
and dorsal surfaces of first and second toes white; belly cream-colored; glandular
areas orange-brown; chest and chin having black spots. Ventral surfaces
of hind limbs and first toes cream-colored; undersides of other toes and soles
of feet brown.

Color (in life) uniform bright green above; venter pale creamy yellow;
anterior and posterior surfaces of thighs, ventral surfaces of shanks, anterior
surfaces of tarsi and upper proximal surfaces of first three toes red; iris pale
golden color.

The paratype is an adult male, having a snout-vent length of 26.3 mm., and
agrees with the holotype in proportions. The ventrolateral glands are less
extensive and the chin less spotted than in the holotype.

Comparisons: Both Ptychohyla schmidtorum and the species described below
differ from P. ignicolor in lacking red flash-colors and in having a white spot
below the eye. Ptychohyla ignicolor also differs in having a small tympanum.
As stated above, these species can be distinguished from the rest of the genus
by the absence of a tarsal fold and absence of horny nuptial spines in breeding
males.

Remarks: The holotype was found on a moss-covered log over a stream in
dense cloud forest by day. The paratype was calling at night from a low herb
at the edge of a small stream in the cloud forest. Nearby a Ptychohyla leonhard-schultzei
was calling.

Holotype.—University of Kansas Museum of Natural History No. 58063,
from a stream above (6.2 kilometers by road south) Rayón Mescalapa, Chiapas,
México (1690 meters); one of a series collected on August 5, 1960, by William
E. Duellman, Dale L. Hoyt, and John Wellman. Original No. WED 17327.

Paratypes.—KU Nos. 58064-58073 collected with the holotype.

Diagnosis.—A species of the schmidtorum-group of Ptychohyla differing from
other known members of the group in having the following combination of
characters: diameter of tympanum not noticeably less than half that of eye;
white spot below eye; white lateral stripe on body anteriorly; dorsum bright
green in life; thighs yellowish brown.

Description of Holotype.—Adult male having snout-vent length of 27.3 mm.;
tibia length, 12.8 mm.; tibia length/snout-vent length, 48.7 per cent; foot length
(measured from proximal edge of inner metatarsal tubercle to tip of longest
toe), 10.8 mm.; head length, 9.2 mm.; head length/snout-vent length, 33.7
per cent; head width, 9.0 mm.; head width/snout-vent length, 30.9 per cent;
diameter of eye, 2.8 mm.; diameter of tympanum, 1.4 mm.; tympanum/eye, 50.0
per cent. Snout in lateral profile nearly square, slightly rounded above; in dorsal
profile bluntly squared; canthus pronounced; loreal region concave; lips
thick, rounded, and flaring; nostrils protuberant; internarial distance, 2.3 mm.;
top of head flat; interorbital distance, 3.3 mm.; much broader than width of
eyelid, 2.4 mm. A thin dermal fold from posterior corner of eye above tympanum
to insertion of forelimb, covering upper edge of tympanum; tympanum
nearly round, its diameter equal to its distance from eye. Forearm slender
lacking distinct fold on wrist; a row of low, rounded tubercles on ventrolateral
surface of forearm; pollex moderately enlarged without nuptial spines; second
and fourth fingers equal in length; subarticular tubercles round, none bifid;
discs small, that of third finger noticeably smaller than tympanum; no web
between first and second fingers; vestige of web between other fingers. Heels
overlap when hind limbs adpressed; tibiotarsal articulation reaches to middle
of eye; no tarsal fold; inner metatarsal tubercle large, flat, and elliptical; outer
metatarsal tubercle slightly more distal than inner, small, and elliptical; subarticular
tubercles round; length of digits from shortest to longest 1-2-5-3-4;
third and fifth toes webbed to base of disc; fourth toe webbed to base of
penultimate phalanx; discs smaller on toes than on fingers. Anal opening
directed posteriorly at upper level of thighs; no anal flap; pair of large tubercles
below anal opening and a slightly smaller pair farther below. Skin of dorsum
and ventral surfaces of forelimbs and shanks smooth; that of throat, belly, and
ventral surfaces of thighs granular. Ventrolateral glands well developed, not
reaching axilla or groin and broadly separated midventrally. Skin of anterior
part of chin glandular. Tongue cordiform, shallowly notched behind and only
slightly free posteriorly; vomerine teeth 2-2, situated on small triangular elevations
between large, ovoid inner nares; openings to vocal sac large, one
situated along inner posterior edge of each mandibular ramus.

Color (in alcohol) dark purplish brown on dorsal surfaces of head, body,
and shanks; thighs brown above and yellowish tan posteriorly; white stripe extending
from below eye above forearm to mid-flank. Ventral surfaces creamy[Pg 355]
white; ventrolateral glands orange-tan flecked with dark brown; edge of lower
lip with dark brown spots; narrow white line on upper lip; palms white and
soles brown.

Color (in life) uniform dark bright green above with creamy white bar
below eye; lateral stripe silvery white; ventral surfaces deep yellow; posterior
surfaces of thighs yellow brown; iris reddish bronze.

Variation.—Sixteen adult males are available; these have snout-vent lengths
of 26.3 to 28.5 mm. (average, 27.6 mm.). The tympanum/eye ratio is 48.2 to
58.6 per cent (average, 53.2 per cent). The number of vomerine teeth varies
from four to six. The extent of the ventrolateral glands is variable. In five
specimens the glands nearly meet midventrally; in two others the glands include
the axillary region; in none do the glands extend into the groin. In other
structural details there is no noticeable variation.

The greatest variation in color pattern is found in the lateral stripe. The
pale spot or bar below the eye is present in all specimens; in one individual
there is no lateral stripe; in three the stripe extends posteriorly only to above
the forearm, in two to the mid-flank, and in the others to the groin.

Although all of the males were bright uniform green above when collected
at night as they were calling, some changed color later. In these individuals the
dorsum became a somewhat paler green with faint irregular yellowish tan
blotches.

The one available female (UMMZ 121399) has a snout-vent length of 30.3
mm. and a tympanum/eye ratio of 52.8 per cent, and is colored like the males.
The tubercles by the anal opening are placed irregularly and do not consist
of two pairs below the opening. There are no ventrolateral glands, glandular
area on the chin, or enlarged prepollex.

Comparisons.—Ptychohyla chamulae resembles P. schmidtorum in color pattern
and body proportions, but the ground color of schmidtorum is chocolate
brown and not green as in chamulae. Also, in schmidtorum the webbing and
posterior surfaces of the thighs are pale cream-color in preserved specimens
as contrasted with tan in chamulae. In living schmidtorum the iris is bright
red, not reddish bronze as in chamulae. The ventrolateral glands in schmidtorum
more closely approximate one another midventrally than in chamulae.
It is conceivable that these populations are subspecifically related; schmidtorum
occurs in the same kind of habitat as does chamulae, but is known only from
the Pacific slopes of southeastern Chiapas and southwestern Guatemala, whereas
chamulae is known only from the Atlantic slopes of the Mesa Central in north-central
Chiapas. Both of these species differ from Ptychohyla ignicolor in having
a relatively larger tympanum, more webbing on the foot, different arrangement
of anal tubercles, and different coloration.

Description of Tadpole.—Six tadpoles having fully developed mouth parts
have body lengths of 5.5 to 11.9 mm. and total lengths of 17.3 to 44.0 mm. The
following description is based on a tadpole (KU 58199) having small hind
limbs, a body length of 10.5 mm., and a total length of 39.0 mm. Body ovoid,
only slightly flattened dorsally and ventrally (Fig. 1); body only slightly deeper
than wide; eyes directed dorsolaterally and slightly protuberant; nostrils small.
Tail long and slender; greatest depth of tail-musculature two-thirds greatest
depth of tail-fin; tail-musculature extending nearly to tip of tail-fin.

Mouth directed anteroventrally; thin fleshy lips greatly expanded and forming[Pg 356]
large suckerlike disc; width of mouth greater than width of snout and
nearly as wide as body. Outer edge of lips having small papillae; inner surface
of mouth smooth; scattered large papillae, seemingly in rows, around teeth
and beak (Fig. 2). Tooth rows 3/3; the upper rows subequal in length; upper
rows one and three interrupted medially; lower rows one and two about equal
in length to upper rows; third lower row short. Upper beak heavy and horn-covered.

Color (in alcohol) dark brown over entire body and tail-musculature; a
white area near base of tail, and a dark streak on anterior one-fourth of tail;
tail-fin transparent having brown blotches.

Remarks.—Five metamorphosing tadpoles and juveniles (KU 58074,
58234-8) were found at night on vegetation by streams. Of two completely
metamorphosed young each has a snout-vent length of 15.7 mm. Another
having a snout-vent length of 16.2 mm. has a tail stub 2 mm. long and a completely
metamorphosed mouth. Two others have snout-vent lengths of 13.6
and 14.1 mm. and tail lengths of 11.5 and 8.1 mm. respectively; in these the
mouth parts are incompletely metamorphosed. The single female available
(UMMZ 121399) contains approximately 60 ovarian eggs, the largest of which
are about 2.5 mm. in diameter.[Pg 357]

Referred Specimens.—Chiapas: 6.2 km. S of Rayón Mescalapa, KU 58063-74,
58199 (1 tadpole), 58234-8; 5.6 km. S of Rayón Mescalapa, KU 58062, 58200
(5 tadpoles); 11.4 mi. N of Pueblo Nuevo Solistahuacán, UMMZ 121395-9. The
specimens listed last were collected along a stream between Pueblo Nuevo
Solistahuacán and Rayón Mescalapa, which, according to Floyd L. Downs, is
probably the same stream listed above as 5.6 km. S of Rayón Mescalapa.