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 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.