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.
Along two cascading mountain streams in cloud forest on the northern slopes of the Mesa Central in central Chiapas numerous specimens of a distinctive species of Ptychohyla were found in association with two species of Hyla and two of Plectrohyla. The first specimen of this new species of Ptychohyla was discovered by Dale L. Hoyt, who found the frog on a rock at midday. At night on August 5, 1960, numerous individuals were found calling from leaves of plants growing on the slopes of the ravine by the streams. None was more than two meters above the ground. Tadpoles were found in the fast-flowing stream, where they were holding onto rocks with their mouths. Little is known of the herpetofauna of these mountains that are the home of the Chamula Indians. Since the little frog described here comes from the land of the Chamulas, I propose that it be named:
Ptychohyla chamulae new species
(Plate 25, [Fig. 2])
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.