A Review of the Middle American Tree Frogs of the Genus Ptychohyla

by William Edward Duellman

Table 2.—Comparison of Certain Larval Characters in the Species of Ptychohyla. (Means Are in Parentheses Below the Ranges.)

Species Number of specimens Maximum length Head length Total length Tooth-rows P. euthysanota euthysanota 23 40.8 30.9-37.3 (33.5) 4⁄6 P. euthysanota macrotympanum 13 43.3 30.6-33.4 (32.7) 4⁄6 P. leonhardschultzei 7 47.5 29.2-32.7 (31.1) 4⁄6 P. spinipollex 32 45.0 30.2-35.9 (33.0) 4⁄7 P. schmidtorum schmidtorum 14 42.5 28.9-31.2 (29.9) 3⁄3 P. schmidtorum chamulae 4 45.0 26.9-29.3 (27.8) 3⁄3 P. ignicolor 2 39.6 29.6-29.8 (29.7) 3⁄3

Evidence on the pattern of development of tooth-rows indicates that the inner rows develop first. A small tadpole of P. euthysanota euthysanota has six lower rows and three fully developed upper rows and only the beginning of the first (outer) upper row. A small tadpole of P. euthysanota macrotympanum has four upper rows and five lower rows. In a small tadpole of P. leonhardschultzei the three upper and four lower tooth-rows are well developed; the first upper and fifth lower rows are beginning to develop, and the sixth lower row is absent. 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. For example, four individuals of P. spinipollex were recorded, but only one recording was sufficiently free of background noise to be analyzed.

Analysis of breeding calls supports the division of the genus Ptychohyla into two groups of species. The call of each member of the Ptychohyla euthysanota group consists of a single long note, whereas the call of species in the Ptychohyla schmidtorum group consists of a series of short notes. Since no differences were found between the calls of subspecies of any given species, the following discussion of breeding calls pertains to species. These calls are described briefly below and at greater length in the systematic accounts farther on. Audiospectrographs of the breeding calls are shown in [Plate 11], and comparisons of the characteristics of the calls are given in [Table 3].

Table 3.—Comparison of the Breeding Calls of Ptychohyla

Species Number Notes per call group Duration of note (seconds) Pulses per second Frequency range (cps) Dominant frequency (cps) P. spinipollex 1 1 46 147 3000-5100 4300 P. euthysanota 7 1 62 (.60-.65) 95.3 (91-102) 1800-4200 3070 (3000-3200) P. leonhardschultzei 2 1 79 (.62-.95) 77 (76-78) 1500-3500 2750 (2700-2800) P. schmidtorum 6 8.5[A] (8-9) .064 (.054-.070) 110 (96-121) 1400-5800 (3350-3450) 3400. P. ignicolor 2 12[A] (11-13) .079 (.078-.080) 126 (123-129) 1000-5000 3150 (3100-3200)

[A] Only an analysis of the long series of calls is given here; see text for explanation.