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P. spinipollex (Pl. 11A).—One long note is repeated at intervals of 45 seconds to four minutes and has an average dominant frequency of 4300 cycles per second.
P. euthysanota (Pl. 11B).—One long note is repeated six to nine times at intervals of 2.7 to 3.4 seconds and has an average dominant frequency of 3070 cycles per second.
P. leonhardschultzei (Pl. 11C).—One long note is repeated once after 10 to 13 seconds and has an average dominant frequency of 2750 cycles per second.
P. schmidtorum (Pl. 11D).—The complete call consists of one short series of notes alternating with two long series. Numbers of notes per series in one individual having a typical call were 5-8-8-3-9-9. The average dominant frequency of notes in the short and long series alike is 3400 cycles per second.
P. ignicolor (Pl. 11E).—The complete call consists of a short series of notes alternating with a long series. In one complete recording the numbers of notes in these series were 4-13-3-11. The notes in the short series have an average dominant frequency of 2100 cycles per second, whereas the notes in the long series have an average dominant frequency of 3150 cycles per second. The four series of notes were given in one minute and 15 seconds.
The museum catalogue numbers of the specimens examined, together with the localities from which they came, are listed at the end of the account of each subspecies or monotypic species. The localities that are represented by symbols on the distribution map (Fig. 7) are in roman type; those that are not represented on the map, because overlapping of symbols would have occurred, are in italic type.
Diagnosis.—Small hylids having stream-adapted tadpoles and differing from other hylid genera in having large ventrolateral glands in breeding males.
Composition.—Five species, two of which are made up of two subspecies, arranged in two groups of species on the basis of morphological characters of adults and tadpoles and on the basis of breeding calls.
Distribution.—Moderate elevations from southern Guerrero and northern Oaxaca, México, to northern El Salvador and central Honduras.
| 1. | Lips greatly expanded forming a funnel-shaped mouth; tooth-rows 3⁄3P. schmidtorum group—2 |
| Lips folded laterally, not forming a funnel-shaped mouth; tooth-rows 4⁄6 or moreP. euthysanota group—4 | |
| 2. | Belly and mouth mottled; tail cream color heavily blotched with brown3 |
| Belly dark gray; tail cream color with dense brown flecking, giving brown appearanceP. schmidtorum chamulae | |
| 3. | Belly cream color with brown mottling; no large tubercle at each end of first lower tooth-rowP. schmidtorum schmidtorum |
| Belly grayish green with brown mottling; a large tubercle at each end of first lower tooth-rowP. ignicolor | |
| 4. | Tooth-rows 4⁄6; cream-colored crescent-shaped mark on posterior part of body bordered posteriorly by large brown mark5 |
| Tooth-rows usually 4⁄7 (sometimes 4⁄6); cream-colored crescent-shaped mark on posterior part of body usually indistinct, not bordered posteriorly by large brown markP. spinipollex | |
| 5. | Caudal musculature uniformly flecked with brown; lower tooth-rows 1-4 about equal in length to upper rowsP. euthysanota euthysanota |
| Caudal musculature having brown square blotches dorsally on anterior one-half of tail; lower tooth-rows 1-4 usually slightly shorter than upper rows6 | |
| 6. | Dorsal caudal blotches well defined and extending onto sides of tail; moderately large brown flecks on caudal fin; eye in life pale reddish brownP. leonhardschultzei |
| Dorsal caudal blotches faint, not extending onto sides of tail; small brown flecks on caudal fin; eye in life silvery bronzeP. euthysanota macrotympanum |
Three species in group; adults having moderate amount of webbing between fingers, and tarsal fold; breeding males having spinous, horny, nuptial tuberosities on pollex; mouths of tadpoles having lateral folds in lips and 4⁄6 or 4⁄7 tooth-rows; breeding call consisting of one long note.
Diagnosis.—Rostral keel absent; nuptial spines in males small; interorbital region much wider than eyelid.
Diagnosis.—Dorsum tan to reddish brown; venter white; rarely flecked with brown or black; a white stripe on upper lip, on flank, and usually above anus.
Description.—The following description is based on KU 58008 from Finca La Paz, Depto. San Marcos, Guatemala (Pl. 12). Adult male having a snout-vent length of 35.0 mm.; tibia length, 16.5 mm.; tibia length/snout-vent length, 47.1 per cent; foot length, 14.2 mm.; head length, 11.0 mm.; head length/snout-vent length, 31.4 per cent; head width, 10.7 mm.; head width/snout-vent length, 30.6 per cent; diameter of eye, 3.3 mm.; diameter of tympanum, 1.8 mm.; tympanum/eye, 54.5 per cent. Snout in lateral profile nearly square, slightly rounded above, and in dorsal profile bluntly rounded; canthus pronounced; loreal region moderately concave; lips thick, rounded, and slightly flaring; nostrils protuberant; internarial distance, 3.0 mm.; top of head flat; interorbital distance, 4.1 mm., and approximately a third broader than width of eyelid, 2.9 mm. Moderately heavy dermal fold from posterior corner of eye above tympanum to point above insertion of forelimb, covering upper edge of tympanum; tympanum round, its diameter slightly more than its distance from eye. Forearm moderately robust, having distinct dermal fold on wrist; dermal fold, but no row of tubercles along ventrolateral surface of forearm; pollex only slightly enlarged, bearing triangular shaped patch of small horn-covered spines (128 on right, 134 on left); second and fourth fingers equal in length; subarticular tubercles round, distal one on fourth finger bifid; discs moderate in size, that of third finger equal to diameter of tympanum; no web between first and second fingers; other fingers one-third webbed. Heels broadly overlap when hind limbs adpressed; tibiotarsal articulation reaches to middle of eye; low rounded tarsal fold; inner metatarsal tubercle large, elliptical, and flat; outer metatarsal tubercle small and round; low dermal fold from heel to disc of fifth toe; 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 proximal end of penultimate phalanx; thin dermal fold from inner metatarsal tubercle to disc of first toe; disc smaller than on fingers. Anal opening at the level of the upper edge of thighs; anal flap short; anal opening bordered above by thin transverse dermal fold and laterally by heavy dermal fold. Skin of dorsum and ventral surfaces of forelimbs and shanks smooth; that of throat, belly, and ventral surfaces of thighs granular. Ventrolateral glands moderately developed, not reaching axilla or groin and broadly separated midventrally. Tongue ovoid, emarginate, and only slightly free posteriorly; vomerine teeth 2-2, situated on small triangular elevations between ovoid inner nares; openings to vocal sac large, one situated along inner posterior edge of each mandibular ramus.
Dorsal ground-color of head, body, and limbs dull reddish brown with irregular dark brown reticulations on head and body and dark brown transverse bands on limbs; dorsal surfaces of first and second fingers and webbing on hand cream color; dorsal surfaces of third and fourth fingers dull brown; anterior surfaces of thighs dull creamy yellow; posterior surfaces of thighs dull brown; tarsi and toes tan with brown flecks; webbing of feet brown; faint creamy white stripe along lateral edges of tarsi and forearms; thin white line along edge of upper lip; distinct white stripe above and beside anal opening; axilla white; throat, chest, belly, and ventral surfaces of forelimbs creamy white; flanks white, separated from pale venter by a row of partly connected dark brown spots; ventral surfaces of thighs dull creamy yellow; feet grayish brown; ventrolateral glands pale grayish brown; small brown flecks on periphery of chin.
In life the dorsal ground-color was pale reddish brown (Orange-Cinnamon); dorsal reticulations dark brown (Chocolate); dorsal surfaces of first and second fingers and webbing on hands creamy tan (Light Pinkish Cinnamon); posterior surfaces of thighs reddish brown (Vinaceous-Tawny); webbing of feet gray (Deep Mouse Gray); throat and belly grayish white (Pale Gull Gray); ventral surfaces of hind limbs creamy white (Marguerite Yellow); spots on flanks dark brown (Warm Sepia); iris reddish bronze (Apricot Orange).
Variation.—No geographic variation in structural characters is discernible; variation in size and proportions is given in Table 1. Of 32 adults examined, seven have the tongue shallowly notched posteriorly; in the others the tongue is emarginate. Twenty specimens have a bifid subarticular tubercle beneath the fourth finger; in the others there are no bifid tubercles.
The coloration described above is typical of the 16 specimens available from Finca La Paz. The living coloration at night, when the frogs were collected, was somewhat darker than the living colors described above, which were recorded for the frogs the morning after collection, at which time one individual had a pale reddish brown dorsum (Orange-Cinnamon) with dull olive green (Deep Grape Green) reticulations on the back and transverse bands on the limbs; the dorsal surfaces of the first and second fingers and the discs on the third and fourth fingers were orange (Mikado Orange).
More than half of the specimens from Finca La Paz agree in all essential characters with the description given above. The distinctness of the white stripe on the upper lip is variable; in two individuals the stripe is barely discernible. Likewise, in some individuals the white stripe on the flanks is not distinct, either because there are few or no brown spots separating the stripe from the pale venter, or because the ventrolateral gland has diffused the pale color on the flanks. There is some noticeable variation in dorsal coloration, either through a greater or lesser development of dark pigment. One specimen (KU 58007) is grayish tan above with dark brown markings; the posterior surfaces of the thighs are dull grayish yellow; the first and second fingers and the webbing on the hands are pale yellowish gray; the belly and throat are dusty white; the flecks on the throat are gray; the ventral surfaces of the feet are grayish brown. Dark individuals, such as KU 58009 have a uniform dark brownish black dorsum; the belly is cream; the first and second fingers and the webbing on the hands are dull creamy tan; the dorsal and ventral surfaces of the feet are dark brown. In KU 58013 there is a heavy suffusion of brown on the throat and flanks. Two specimens have scattered white flecks on the dorsum.
The reddish brown dorsal ground-color with dark brown reticulations on the head and body and dark brown transverse bands on the limbs seems to be rather constant throughout the range of the subspecies. Likewise, the presence of the white stripe on the upper lip and the white stripe around the anal opening are present on most specimens. In breeding males having well-developed ventrolateral glands the lateral white stripe often is obliterated.
Description of Tadpole.—The following description is based on KU 60042 from Finca La Paz, Depto. San Marcos, Guatemala (Figs. 4A and 6A). No limb buds; total length, 35.8 mm.; body length, 11.2 mm.; body length/total length, 31.3 per cent. Body moderately depressed, slightly wider than deep, ovoid in dorsal profile; mouth directed ventrally; eyes small, directed dorsolaterally; nostrils slightly protuberant and directed anteriorly, closer to eye than snout; spiracle sinistral and posteroventrad to eye; anal tube dextral. Caudal fin low, rounded posteriorly; depth of caudal musculature about one-half greatest depth of caudal fin; musculature extends nearly to tip of tail.
Mouth large; lips having deep lateral folds; two complete rows of papillae on lips; five to six rows of papillae laterally. Beaks moderately developed, bearing peglike serrations; slender lateral projections on upper beak; tooth-rows 4⁄6; upper rows subequal in length, second longest; fourth row interrupted medially; lower rows complete; lower rows 1-4 equal in length to upper rows; fifth lower row somewhat shorter; sixth lower row short.
Body brown above; tip of snout cream color; grayish cream color below; caudal musculature creamy tan; caudal fin transparent; cream-colored crescent-shaped mark on posterior edge of body and anterior part of caudal musculature, bordered posteriorly by dark brown blotch; scattered brown flecks on caudal musculature and posterior part of caudal fin. Eye bronze color in life.
Variation.—The variation in size and proportions is given in Table 2. In some specimens the first upper tooth-row is irregular, sometimes broken, and often shorter than other upper tooth-rows. Usually the fourth upper and first lower, and sometimes the sixth lower, tooth-rows are interrupted medially. One specimen has a short, irregular, seventh lower tooth-row; all others have six.
The cream-colored crescent-shaped mark usually is distinct. The brown blotch posterior to this mark is variously shaped ranging from a narrow vertical bar to a triangular blotch. Brown flecks seldom are present on the anterior part of the ventral caudal fin.
Comparisons.—Aside from the characters given in the diagnosis, P. euthysanota euthysanota can be distinguished from both P. spinipollex and P. leonhardschultzei by the absence of bold black and white marbling on the flanks; furthermore, from the former it can be distinguished by having more and smaller horny nuptial spines and from the latter by having the snout, in lateral profile, rounded above and not acutely angulate. Ptychohyla euthysanota euthysanota differs from P. euthysanota macrotympanum by normally having a darker dorsal color, broader stripe on upper lip, and a distinct lateral stripe.
Occurring sympatrically with Ptychohyla euthysanota euthysanota are several species of Plectrohyla, all of which differ in having a bony prepollex, rather rugose skin on the dorsum, and more squat bodies. Other sympatric species are Ptychohyla schmidtorum schmidtorum, which lacks a tarsal fold and nuptial spines and has a red eye in life, Hyla salvadorensis, which has a green dorsum and lacks spinous nuptial tuberosities, and Hyla sumichrasti, a small yellow frog usually lacking vomerine teeth.
Life History.—This subspecies breeds in clear, swift mountain streams. Males call from stems and leaves of plants at the edge of, or overhanging, the streams. The breeding call consists of a soft "wraack," repeated at intervals of three to four seconds. Each note has a duration of 0.60 to 0.65 seconds and has 91 to 102 pulses per second; the dominant frequency falls between 3000 and 3200 cycles per second.
Tadpoles in various stages of development were found at Finca La Paz, Guatemala, in late July. This indicates that there is either extreme differential growth, or, more probably, an extended breeding season. A tadpole having a body length of 6.8 mm. and a total length of 19.1 mm. has a short median first upper tooth-row; lower tooth-rows 3-6 are only two-thirds as long as lower rows 1 and 2. Two recently metamorphosed young have snout-vent lengths of 14.2 and 14.8 mm.; they are colored like the adults.
Remarks.—The type specimen of Hyla euthysanota Kellogg (1928:123) is a female; therefore, when Taylor (1944) proposed the name Ptychohyla for hylids having ventrolateral glands in breeding males, he was unaware that Hyla euthysanota was a member of this group. In his description of Hyla rozellae, Taylor (1942) did not compare his specimens with Hyla euthysanota, but instead placed H. rozellae with H. loquax and H. rickardsi. The type series of H. rozellae consists of one large adult female and several metamorphosing young. Taylor (1949:16) based the description of Ptychohyla bogerti on two males and compared these specimens with P. adipoventris Taylor [= P. leonhardschultzei (Ahl)]. Thus, in a period of 22 years the females of this species were given two names and the male another. Stuart (1954:169) suggested that Hyla euthysanota and Hyla rozellae were Ptychohyla. Now that sufficient specimens are available from throughout the range it is possible to determine that the various named populations are conspecific.
Distribution.—This subspecies inhabits cloud forests at elevations of 660 to 2200 meters on the Pacific slopes of the Sierra Madre from extreme eastern Oaxaca and western Chiapas, México, through Guatemala to northern El Salvador; probably it occurs also in southwestern Honduras. Aside from the specimens listed below, three in the Frankfurt Museum from Depto. Santa Ana, El Salvador (44571, Hacienda San José; 43040, Hacienda Los Planes; 65119, Miramundo) are listed by Mertens (1952:29).
Specimens examined.—Mexico: Chiapas: Cascarada, 30 km. W of Cíltapec, UMMZ 87851-2; Cerro Ovando, UMMZ 87853-4; Chicomuselo, UMMZ 94439-40; Finca Juárez, 28 km. N of Escuintla, USNM 115052-5; Las Nubes, Cerro Ovando, USNM 115030-8; Salto de Agua, USNM 115039-51. Oaxaca: Cerro Pecho Blanco, UIMNH 40963; between La Gloria and Cerro Azul, UIMNH 40976-7; Río Grande, AMNH 51847-8; Santo Tomás Tecpan, UIMNH 41071.
Guatemala: San Marcos: Finca La Paz, 2 km. W of La Reforma, KU 58001-14, 59937 (skeleton), 60042-3 (tadpoles), 60044 (4 young), MCZ 34997, UMMZ 107739, 123151-7 (tadpoles); Finca Pirineos, Río Samalá, CNHM 35066. Santa Rosa: Finca La Gloria, UMMZ 123148 (tadpoles), 123150 (tadpoles). Sololá: Finca Santo Tomás, UMMZ 123149 (tadpoles); Olas de Mocá, near Mocá, CNHM 20208.
El Salvador: Chalatenango: Los Esemiles, USNM 73296. Santa Ana: Miramundo, CNHM 65120.
Diagnosis.—Dorsum usually pale tan; venter white with scattered brown or black flecks; a thin white stripe on upper lip and another above anal opening; no distinct white stripe on flanks.
Description.—The following description is based on KU 58049 from Linda Vista, Chiapas, México (Pl. 13). Adult male having a snout-vent length of 38.0 mm.; tibia length, 19.5 mm.; tibia length/snout-vent length, 51.3 per cent; foot length, 15.7 mm.; head length, 11.8 mm.; head length/snout-vent length, 31.1 per cent; head width, 11.7 mm.; head width/snout-vent length, 30.8 per cent; diameter of eye, 3.8 mm.; diameter of tympanum, 2.1 mm.; tympanum/eye, 55.2 per cent. Snout in lateral profile nearly square, slightly rounded above, and in dorsal profile bluntly rounded; canthus pronounced; loreal region concave; lips thick, rounded, and slightly flaring; nostrils protuberant; internarial distance, 3.1 mm.; top of head flat; interorbital distance, 3.8 mm., and approximately a fourth broader than width of eyelid, 3.1 mm. A moderately heavy dermal fold from posterior corner of eye above tympanum to point above insertion of forelimb, covering upper edge of tympanum; tympanum round, its diameter equal to its distance from eye. Forearm moderately robust, having a distinct dermal fold on wrist; dermal fold, but no row of tubercles along ventrolateral surface of forearm; pollex only slightly enlarged, bearing triangular patch of small horn covered spines (94 on right, 100 on left); fourth finger slightly longer than second; subarticular tubercles round, none bifid; discs moderate in size, that of third finger equal to diameter of tympanum; vestige of web between first and second fingers; other fingers one-third webbed. Heels broadly overlap when hind limbs adpressed; tibiotarsal articulation reaches to middle of eye; weak tarsal fold on distal two-thirds of tarsus; inner metatarsal tubercle large, elliptical, and flat; outer metatarsal tubercle small and round; no dermal fold from heel to disc of fifth toe; subarticular tubercles round; length of digits from shortest to longest 1-2-5-3-4; third toe webbed to base of disc; fifth toe webbed to middle of penultimate phalanx; fourth toe webbed to proximal end of penultimate phalanx; no fold of skin from inner metatarsal tubercle to base of disc on first toe; discs much smaller than on fingers. Anal opening near upper edge of thighs; short anal flap bordered above by thin dermal fold; small tubercles and heavy dermal fold lateral to anal opening. Skin of dorsum and ventral surfaces of fore limbs and shanks smooth; that of throat, belly, and ventral surfaces of thighs granular. Ventrolateral glands weakly developed, not reaching axilla or groin and broadly separated midventrally. Tongue ovoid, shallowly notched posteriorly, and barely free behind; vomerine teeth 2-2, situated on small triangular elevations between ovoid inner nares; openings to vocal sac large, one situated along inner posterior edge of each mandibular ramus.
Dorsal ground-color of head, body, and limbs pale pinkish tan with the greatest part of head and body covered by large gray interconnected blotches; black flecks over most of dorsum; grayish brown transverse bands on shanks; dorsal surfaces of first and second fingers pale grayish yellow; dorsal surfaces of third and fourth fingers and webbing on hand pale grayish tan; anterior surfaces of thighs pale flesh-color; posterior surfaces of thighs pale grayish yellow; dorsal surfaces of tarsi and toes pale grayish tan with black flecks; webbing of feet pale gray; faint creamy white stripes along ventrolateral edges of tarsi and forearms; a very thin white line along edge of upper lip; a narrow grayish white stripe above anal opening; axilla gray; throat, chest, belly, and ventral surfaces of forelimbs pale grayish white; ventral surfaces of hind limbs cream color; flanks gray flecked with brown; ventral surfaces of feet grayish tan; ventrolateral glands pinkish tan; anterior one-half of chin flecked with brown.
In life the dorsum was pale tan (Pinkish Buff); the dark markings on dorsum dull brown (Tawny-Olive); tarsi pale tan (Pale Pinkish Buff); flanks pinkish tan (Pale Cinnamon-Pink); iris coppery bronze (Capucine Orange).
Variation.—The few specimens from a limited geographic region preclude any analysis of geographic variation. All specimens, except the one described above, have the fifth toe webbed to the base of the disc. Many individuals have a bifid subarticular tubercle beneath the fourth finger. The shape of the posterior edge of the tongue varies from nearly straight and shallowly notched to bluntly rounded and emarginate. Two females (KU 58050-1) have more pointed snouts in dorsal profile than do males.
Some specimens, such as KU 58048, are notably darker than the specimen described above; in dark specimens the dorsum is brown with dark brown markings; all fingers and the webbing on the hand are brown. The tarsi and feet are like those in the specimen described above, but the posterior surfaces of the thighs are yellowish tan heavily suffused with brown; the venter is cream color. In life KU 58048 had a brown (Verona Brown) dorsum with dark brown (Chocolate) markings. KU 58047 is slightly darker than KU 58048 and has scattered small white flecks on the dorsum. All specimens have the thin white line on the upper lip, but in some individuals it is indistinct. The grayish white line above the anus is present in all specimens.
Description of Tadpole.—The following description is based on KU 60049 from Río Hondo, 9.5 kilometers south of Pueblo Nuevo Solistahuacán, Chiapas, México (Figs. 4B and 6B). No limb buds; total length, 36.2 mm.; body length, 11.1 mm.; body length/total length, 30.6 per cent. Body moderately depressed, slightly wider than deep, ovoid in dorsal profile; mouth directed ventrally; eyes small, directed dorsolaterally; nostrils slightly protuberant and directed anteriorly, somewhat closer to eye than snout; spiracle sinistral and posteroventrad to eye; anal tube dextral. Caudal fin low, acutely rounded posteriorly; depth of caudal musculature slightly more than one-half greatest depth of caudal fin; caudal musculature extending nearly to tip of tail.
Mouth large; lips having deep lateral folds; two complete rows of papillae on lips; five or six rows of papillae laterally. Beaks moderately developed, bearing small peglike serrations; moderately wide lateral projections on upper beak; tooth-rows 4⁄6; upper rows subequal in length; fourth row interrupted medially; length of lower rows 1-4 subequal to upper rows; fifth and sixth lower rows decreasing in length; first lower row interrupted medially.
Body brown above; tip of snout cream color; venter creamy white; caudal musculature creamy tan; caudal fin transparent; cream-colored crescent-shaped mark on posterior edge of body and anterior part of caudal musculature, bordered posterodorsally by dark brown blotch; four dark brown blotches on dorsum of anterior part of caudal musculature; scattered brown flecks on caudal musculature and fin; eye silvery bronze in life.
Variation.—The variation in size and proportions is given in Table 2. All specimens have 4⁄6 tooth-rows; in some the first lower row is interrupted medially. Specimens from Jacaltenango and two kilometers west of San Pedro Necta, Depto. Huehuetenango, Guatemala, have weakly developed sixth lower tooth-rows.
The cream-colored crescent-shaped mark is distinct in all specimens; the dorsal blotches on the anterior part of the caudal musculature are narrow and do not extend far onto the sides of the tail. The blotches are most distinct in small tadpoles and sometimes indistinct in large ones.
Comparisons.—Ptychohyla euthysanota macrotympanum can be distinguished from both P. spinipollex and P. leonhardschultzei by the absence of bold black and white marbling on the flanks, as well as by the characters given in the diagnosis; furthermore, from the former it differs in having more and smaller horny nuptial tuberosities and from the latter by having the snout, in lateral profile, rounded above instead of angulate. Ptychohyla euthysanota macrotympanum differs from P. e. euthysanota by normally having a paler dorsum, narrower stripe on upper lip, and no distinct lateral stripe.
Ptychohyla euthysanota macrotympanum occurs sympatrically with Plectrohyla guatemalensis and P. matudai matudai. Each of the last two has a bony prepollex, rather rugose skin on the dorsum, and more squat body. Other sympatric species are Hyla walkeri, which has a green dorsum with brown markings and a rather pointed snout, and Hyla sumichrasti, a small yellow frog usually lacking vomerine teeth.
Life History.—This species breeds in clear mountain streams in mixed pine and broad-leafed forest. Males call from trees and bushes along the streams. The breeding call consists of a soft "wraack," repeated three to nine times with intervals of 2.7 to 3.4 seconds between notes. Each note has a duration of 0.60 to 0.65 second, and a rate of 92 to 100 pulses per second; the dominant frequency falls between 3000 and 3200 cycles per second (Pl. 11B). The call is indistinguishable from that of P. e. euthysanota.
Tadpoles in various stages of development were found in the Río Hondo, Chiapas, on June 16, 1960. The smallest tadpole has a total length of 24.1 mm.; in this individual the sixth lower tooth row has barely started to develop. A metamorphosing frog taken at the same time has a snout-vent length of 19.8 mm., a short remnant of the tail, and the mouth and tongue developed, whereas another individual having a snout-vent length of 17.8 mm. and a tail 31.0 mm. in length still has larval teeth. Three completely metamorphosed juveniles collected by L. C. Stuart at Jacaltenango, Guatemala, on June 6 and 7, 1955, have snout-vent lengths of 16.0, 16.0, and 16.1 mm.
Remarks.—Tanner (1957:52) based the description of Hyla macrotympanum on a single female, which, of course, lacked the characters diagnostic of Ptychohyla. On the basis of general external characters Tanner suggested that Hyla macrotympanum was related to H. miotympanum, from which it differed in having a larger tympanum and a bifid subarticular tubercle beneath the fourth finger. The collection of additional females, together with males of the species, has shown that Hyla macrotympanum is a Ptychohyla.
Intergradation between Ptychohyla euthysanota and P. macrotympanum has not been demonstrated. Currently their ranges are separated by the dry valleys of the Río Grijalva and Río Cuilco. The similarity in structure of the adults and tadpoles and the indistinguishable breeding calls are the basis for considering the two populations subspecies.
Distribution.—This species occurs in mixed pine and broad-leafed forests at elevations of 700 to 1700 meters on the southern slopes of the Chiapan Highlands and Sierra de Cuchumatanes, in Guatemala. These forests are on the south facing slopes north of the valleys of the Río Grijalva and Río Cuilco.
Specimens examined.—Mexico: Chiapas: 6 km. NE of Chiapa de Corzo, TCWC 16183; 16 km. E of Chiapa de Corzo, AMNH 62141; Linda Vista, 2 km. NW of Pueblo Nuevo Solistahuacán, KU 58049-51, 59939 (skeleton); Río Hondo, 9.5 km. S of Pueblo Nuevo Solistahuacán, KU 58047-8, 60046-7, 60048-9 (tadpoles); San Fernando, MZTG 15, 17; Tonina (ruins), KU 41592.
Guatemala: Huehuetenango: Jacaltenango, UMMZ 123139 (tadpoles); 0.5 km. E of Jacaltenango, UMMZ 123142-3; 2 km. S of Jacaltenango, UMMZ 123141; 2 km. W of San Pedro Necta, UMMZ 123140 (tadpoles).