William Edward Duellman

“ At no locality were Ptychohyla and associated species of hylids found so abundantly as were species of pond-breeding hylids in the lowlands. Apparently reproductive activity is not concentrated in a short breeding season, and it is highly doubtful if the populations of these frogs are as large as those of the lowland pond-breeders. The continual humid conditions and abundance of insect food throughout the year in the cloud forest are perhaps indicative of little interspecific competition among adults of Ptychohyla and other sympatric hylids. ”

“ Some species have a complete quadratojugal-maxillary arch; others do not. Assuming that the parental stock that gave rise both to the Hyla uranochroa group and to Ptychohyla was widespread in Central America at a time of cooler, more humid conditions, it is possible that with subsequent warming temperatures and seasonal rainfall in the lowlands the parental stock was restricted to the Costa Rican highlands, where the Hyla uranochroa group developed, and to the Chiapas-Guatemala highlands, where Ptychohyla evolved. ”

“ As I have mentioned previously, ecological segregation and [Pg 348] interspecific competition probably is highly developed in the tadpoles of Ptychohyla. If this ecological segregation resulted from intraspecific competition in a stock of Ptychohyla, possibly P. euthysanota and P. schmidtorum differentiated sympatrically in this way. Specific identity is maintained, at least in part, by different breeding calls in males.
Ptychohyla spinipollex and P. leonhardschultzei seem to be more closely related to one another than either is to P. euthysanota. ”

“ All small hylids that are sympatric with Ptychohyla leonhardschultzei are either yellow (Hyla dendroscarta and H. melanomma) or green (Hyla erythromma, which has a red eye, Hyla hazelae, which has a black line on the canthus, and Ptychohyla ignicolor, which has red flash colors on the thighs) .
Life History.—This frog has been found along streams in cloud forests and in pine-oak forest. Males call from vegetation along the stream or from rocks in and at the edge of the stream. ”

“ The tongue always is notched posteriorly; in some individuals the notch is shallow; in others it is deep.
Some specimens are paler and less boldly marked than the specimen described above. All specimens from Agua del Obispo and some specimens from the northern slopes of the Sierra Madre Oriental in Oaxaca have a pale tan dorsum with brown markings. In most individuals the white color in the axilla extends onto the posterior edge of the upper arm. The creamy white color of the flanks is constant and usually extends slightly dorsad in the inguinal region. ”

“ The distribution of species of Ptychohyla reflects the distribution of cloud forest in southern México and northern Central America. The frogs are restricted to mountainous areas, usually at elevations higher than 1000 meters above sea level. Ptychohyla does not range to great heights in the mountains, where west of the Isthmus of Tehuantepec the mountain streams are inhabited by frogs of the Hyla bistincta group, and in Chiapas and Guatemala by species of Plectrohyla. ”

“ Ptychohyla euthysanota and P. schmidtorum have white stripes on the upper lips and on the flanks. All species have some form of a pale stripe above the anus and usually rather distinct white or pale stripes along the ventrolateral edges of the tarsi and forearms. There are no bright or boldly marked flash-colors (colors that are revealed only when the hind limbs are extended) , except in P. ignicolor, which has bright red flash-colors in the groin and on the thighs. In life the iris varies from several different shades of bronze color to deep red in P. schmidtorum schmidtorum. ”

“ Variation.—The distal subarticular tubercle beneath the fourth finger is bifid in about two-thirds of the specimens; in the rest it is round. The posterior edge of the tongue varies from being emarginate to shallowly notched. In most specimens the row of tubercles along the outer edge of the tarsus is made up of discrete tubercles, but in some individuals the tubercles form a nearly continuous dermal fold. ”

“ My own field work was made more enjoyable and profitable through the assistance of Dale L. Hoyt, Craig E. Nelson, Jerome B. Tulecke, and John Wellman, all of whom spent many hours in often unsuccessful attempts to collect specimens and record breeding calls of Ptychohyla. I am indebted to many residents of México, Guatemala, and El Salvador for permission to work on their land and for providing shelter, food, and guides. I am especially grateful to Mr. and Mrs. Horatio Kelly of "Colegio Linda Vista" at Pueblo Nuevo Solistahuacán, Chiapas, for a pleasant stay at their school ”

“ The range of P. euthysanota euthysanota is along the Pacific slopes of the Sierra Madre in Chiapas, Guatemala, and El Salvador, whereas that of P. euthysanota macrotympanum is along the southern interior slopes of the Central Highlands of Chiapas and the Sierra de Cuchumatanes in Guatemala. Ptychohyla [Pg 341] spinipollex occurs on the wet Atlantic slopes of the Guatemalan and Honduranean Highlands; the range of the species in Honduras is poorly known. ”

“ From two to six completely metamorphosed young are available for each of the species, except for P. ignicolor of which none is available. The smallest young frog is a P. euthysanota having a snout-vent length of 14.2 mm.; the largest young frog is a P. schmidtorum schmidtorum having a snout-vent length of 17.0 mm. ”

“ Also living with Ptychohyla chamulae are Hyla chaneque, a large species having a tuberculate dorsum and webbed fingers, and Hyla bivocata, a small yellow species having a broad, flat head, small indistinct tympanum, and an axillary membrane.
Life History.—Calling males were found on leaves of herbs and bushes by cascading streams in cloud forest. The call consists of series of short notes, three to nine notes per series, sounding like "raa-raa-raa." The duration of each note is .054 to .070 of a second, and has a rate of 96 to 110 pulses per second. ”

“ Reproduction and Development
Since the cloud forests inhabited by Ptychohyla are daily bathed in clouds and have a fairly evenly distributed rainfall throughout the year, the frogs living in these forests are active throughout the year. At least some of the species evidently have a long breeding season, for I found calling males of P. leonhardschultzei in February, March, and August, and found tadpoles in February, March, June, and August. Tadpoles of the various species have been obtained throughout much of the year, as follows: P. euthysanota euthysanota, February, March, May, and July ”

“ Thin dermal fold, from posterior corner of eye above tympanum to insertion of fore limb, covering upper edge of tympanum; tympanum nearly round, its diameter equal to its distance from eye. Forearm slender, lacking distinct fold on wrist; row of low, rounded tubercles on ventrolateral surface of forearm; pollex slightly enlarged, without nuptial spines; second and fourth fingers equal in length; subarticular tubercles round, that under fourth finger bifid; discs small, that of third finger noticeably smaller than tympanum; no web between first and second fingers ”

“ Some individuals when active at night had a pale brown (Ochraceous-Tawny) dorsum with dull olive green (Dark Olive Buff) markings. Otherwise there was no noticeable variation in color.
Description of tadpole.—The following description is based on KU 60051 from Finca La Paz, Depto. San Marcos, Guatemala (Figs. 5A and 6E) . Small hind limbs; total length, 37.9 mm.; body length, 11.6 mm.; body length/total length, 30.6 per cent. Body only slightly depressed, nearly as deep as wide, in dorsal profile ovoid, widest just posterior to eyes; in lateral profile snout rounded ”

“ In small tadpoles of P. spinipollex, the sixth lower row is poorly developed, and the seventh row is absent; large individuals normally have seven lower rows. A small tadpole of P. schmidtorum chamulae has 3⁄2 tooth-rows.
Breeding Call
Breeding calls of all species and subspecies of Ptychohyla were recorded in the field. Obtaining series of calls of Ptychohyla is difficult because these frogs call mostly from vegetation along roaring mountain streams and only by locating a calling frog some distance from the water or along a quiet stretch of the stream can good recordings be obtained. ”

“ Skin of dorsum and ventral surfaces of forelimbs and shanks smooth; that of belly and ventral surfaces of thighs granular. Ventrolateral glands well developed, reaching axilla and groin and narrowly separated on chest. Tongue ovoid, emarginate posteriorly, and only slightly free behind; vomerine teeth 3-3, situated on small triangular elevations between ovid inner nares; openings to vocal sac large, one situated along inner posterior edge of each mandibular ramus. ”

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