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A Review of the Middle American Tree Frogs of the Genus Ptychohyla · William Edward Duellman — chapter 8 of 16 · ~1,941 words · public domain

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Hyla spinipollex Schmidt, Proc. Biol. Soc. Washington, 49:45-46, May 1, 1936 [Holotype.--MCZ 21300 from the mountains behind Ceiba, Depto. Atlantidad, Honduras; Raymond E. Stadelman collector]. Stuart, Misc. Publ. Mus. Zool. Univ. Michigan, 69:32-34, figs. 5-6, June 12, 1948; Contr. Lab. Vert. Biol. Univ. Michigan, 45:22, 52, 54, 57, May, 1950; Proc. Biol. Soc. Washington, 67:169, August 5, 1954.

Ptychohyla spinipollex, Stuart, Contr. Lab. Vert. Biol. Univ. Michigan, 68:48, November, 1954. Duellman, Univ. Kansas Publ. Mus. Nat. Hist., 13:351, April 27, 1961.

Diagnosis.--Rostral keel present; snout in lateral profile rounded above; eyelid nearly as wide as interorbital region; flanks white with brown spots; belly spotted; nuptial spines pointed and moderate in size.

Description.--The following description is based on KU 58054 from Finca Los Alpes, Depto. Alta Verapaz, Guatemala (Pl. 15). Adult male having a snout-vent length of 37.7 mm.; tibia length, 18.2 mm.; tibia length/snout-vent length, 48.2 per cent; foot length, 15.8 mm.; head length, 11.7 mm.; head length/snout-vent length, 31.0 per cent; head width, 11.7 mm.; head width/snout-vent length, 31.0 per cent; diameter of eye, 3.6 mm.; diameter of tympanum, 1.9 mm.; tympanum/eye, 52.7 per cent. Snout in lateral profile nearly square, slightly rounded above, and in dorsal profile rounded with a pointed tip resulting from vertical rostral keel; canthus pronounced; loreal region barely concave; lips thick, rounded, and barely flaring; nostrils protuberant; internarial distance, 3.0 mm.; top of head flat; interorbital distance, 3.7 mm., about equal to width of eyelid, 3.6 mm. A heavy dermal fold from posterior corner of eye above tympanum to point above insertion of forearm, covering upper edge of tympanum; tympanum round, its diameter equal to its distance from eye. Forearm moderately robust, having faint dermal fold on wrist; row of low, rounded tubercles along ventrolateral edge of forearm; pollex only slightly enlarged, bearing triangular patch of moderate-sized, pointed, horn-covered spines (38 on right, 43 on left); second finger noticeably shorter than fourth; subarticular tubercles round, distal one on fourth finger bifid; discs of fingers of moderate size, that of third finger slightly smaller than diameter of tympanum; vestigial web between first and second fingers; other fingers one-third webbed. Heels broadly overlapping when hind limbs adpressed; tibiotarsal articulation reaches to middle of eye; distinct, but low, tarsal fold extending length of tarsus; inner metatarsal tubercle elevated, flat, and elliptical; outer metatarsal tubercle small and round, near base of fourth toe; row of low indistinct tubercles from heel to base of fifth toe; subarticular tubercles round; length of toes from shortest to longest 1-2-3-5-4, the third and fifth being about equal in length; third and fifth toes webbed to base of disc; fourth toe webbed to base of penultimate phalanx; discs of toes slightly smaller than those on fingers. Anal opening near upper edge of thighs; opening bordered laterally by moderately heavy dermal folds and ventrolaterally by tubercles. Skin of dorsum and ventral surfaces of forelimbs and shanks smooth; that of throat, belly, and ventral surfaces of thighs granular. Ventrolateral glands barely evident. Tongue ovoid, barely notched behind and slightly free posteriorly; vomerine teeth 2-3, situated on V-shaped elevations between round 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 grayish tan with dark brown reticulations on head and body and dark brown transverse bars or spots on limbs; first and second fingers cream color; third and fourth fingers and webbing on hands pale grayish brown; anterior surfaces of thighs reddish tan; posterior surfaces of thighs yellowish tan; tarsi and toes pale grayish tan with brown flecks; webbing on foot pale brown; faint white stripe along ventrolateral edges of tarsi and forearms; narrow white line above and beside anal opening; no white stripe on edge of upper lip; axilla pale flesh-color; throat, chest, and ventral surfaces of limbs pale creamy gray; belly white with scattered brown flecks; flanks grayish white with dark brown flecks; ventral surfaces of tarsi dark brown; ventrolateral glands grayish tan.

In life the dorsal ground-color of the head, body, fore limbs, and thighs was yellowish tan (Pinkish Buff); dorsal surfaces of shanks and tarsi pale yellowish tan (Pale Pinkish Buff); markings on head and back brown (Snuff Brown) to dark brown (Chocolate); dark bands on limbs brown (Tawny-Olive); first and second fingers creamy tan (Light Pinkish Cinnamon); posterior surfaces of thighs creamy tan (Light Pinkish Cinnamon); third and fourth fingers and webbing on hand grayish brown (Avellaneous); webbing on feet dark brown (Olive Brown); axilla pale pink (Hydrangea Pink); flanks buff (Cream-Buff) becoming yellow (Lemon Chrome) in groin; spots on flanks dark brown (Clove Brown); iris dull grayish bronze (Orange-Citrine).

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. Most specimens have the vomerine teeth situated on V-shaped elevations, but in some individuals the elevations are more nearly transversely situated between the inner nares.

All 42 specimens from Finca Los Alpes, Guatemala, have dark brown spots and flecks on the venter. Some individuals have only a few flecks on the throat and a few large spots on the flanks, as does KU 64125. Other specimens, such as KU 64132, have dense spotting over the entire venter. The color of the dorsum varies from pale tan to dark brown with darker brown markings; the white line above the anus is present in all specimens, but in some it is indistinct. KU 58053 and 64127 have a dark brown dorsum with large pale tan, square blotches; in life the blotches were pale tan (Pinkish Buff); the rest of the dorsum was dark brown (Sayal Brown). KU 58052 is dark brown with many small white flecks on the dorsum; in life the dorsum was deep olive brown (Dark Olive).

Aside from the differences mentioned above, all specimens from Guatemala are similar in coloration. Three specimens from Honduras (MCZ 21300 and UMMZ 113102-3) have unspotted white venters. MCZ 21300, the holotype of P. spinipollex, lacks a white stripe above the anal opening, whereas the stripe is indistinct in UMMZ 113102-3.

Description of tadpole.--The following description is based on KU 60053 from Fina Los Alpes, Depto. Alta Verapaz, Guatemala (Figs. 4D and 6D). No limb buds; total length, 37.2 mm.; body length, 12.2 mm.; body length/total length, 32.8 per cent. Body rounded, not depressed, as wide as deep, ovoid in dorsal profile; mouth directed ventrally; eyes small, directed dorsolaterally; nostrils barely protuberant and directed anterolaterally, somewhat closer to eye than snout; spiracle sinistral and posteroventrad to eye; anal tube dextral. Caudal fin low, bluntly rounded posteriorly; greatest depth of caudal musculature about one-half 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; six or seven rows of papillae laterally; beaks moderately developed, bearing fine blunt serrations; slender lateral projections on upper beak; tooth-rows 4/7; upper rows subequal in length; fourth row interrupted medially; lower rows 1-4 equal in length to upper rows; lower rows 5-7 decreasing in length; first lower row interrupted medially.

Top of head and tip of snout brown; venter creamy gray; caudal musculature tan; caudal fin transparent; faint cream-colored, narrow, crescent-shaped mark on posterior edge of body, not bordered posteriorly by dark brown mark; brown flecks scattered on caudal musculature and caudal fin; only a few flecks on anterior half of ventral caudal fin; eye bronze-color in life.

Variation.--The variation in size and proportions as compared with tadpoles of other species is given in Table 2. Of the 57 tadpoles of this species that I have examined, 21 have only six lower tooth-rows, although in some of these specimens a faint ridge for a seventh row is present. In those specimens having seven lower rows, the seventh often is broken.

There is considerable variation in coloration. None has a distinct cream-colored, crescent-shaped mark bordered posteriorly by a dark brown bar or triangle, as in the other species in the Ptychohyla euthysanota group. Most specimens have a rather indistinct crescent; some have no crescent. In a few specimens there is a weakly outlined dark mark posterior to the crescent. Some specimens in a series of tadpoles from 32 kilometers north of Morazan, Baja Verapaz, Guatemala, have faint dorsal blotches on the dorsal musculature, much like those in tadpoles of Ptychohyla leonhardschultzei.

Comparisons.--Ptychohyla spinipollex differs from all other species in the genus by having moderate-sized, instead of small, pointed nuptial spines; also it has fewer spines than the other species (see discussion of this character in Analysis of Data). The nearly equal interorbital breadth and width of the upper eyelid also is diagnostic of this species.

Other hylids sympatric with Ptychohyla spinipollex include three species of Plectrohyla, each of which has a bony prepollex, heavy body, and rugose skin on the dorsum. The only other sympatric hylid that could be confused with Ptychohyla spinipollex is Hyla bromeliacea, which has a round snout and yellowish tan dorsum not marked with dark brown.

Life History.--At Finca Los Alpes, Guatemala, in July, 1960, and in August, 1961, calling males were found on bushes and trees along cascading mountain streams. The breeding call consists of a soft "wraack," repeated at intervals of 45 seconds to four minutes. Each note has a duration of about .46 of a second and a rate of 147 pulses per second. The dominant frequency is 4300 cycles per second (Pl. 11A).

Tadpoles have been found in cascading mountain streams. Two metamorphosed young have snout-vent lengths of 15.0 and 15.5 mm.

Remarks.--There is little doubt that all of the specimens herein referred to Ptychohyla spinipollex are conspecific. However, the three specimens from Honduras, including the type of Ptychohyla spinipollex, differ from Guatemalan specimens in lacking all dark spotting on the venter. Additional specimens from Honduras and eastern Guatemala may show that two subspecies are recognizable, in which case the nominal subspecies will be the population in Honduras.

Distribution.--This species lives in cloud forests at elevations of 800 to 1700 meters on the Atlantic side of the Guatemalan Highlands from the Sierra de Cuchumatanes in western Guatemala eastward to central Honduras.

Specimens examined.--GUATEMALA: Alta Verapaz: Finca Chichen, UMMZ 90876 (tadpoles); Finca Los Alpes, KU 58052-60, 59939 (skeleton), 60053 (tadpoles), 64122-41, 68562, 68563 (tadpoles), 68631-2 (skeletons), MCZ 35000-1, UMMZ 90873, 90874 (3), 90875 (tadpoles); La Primavera, UMMZ 90877 (tadpoles); Panzamala, UMMZ 90878 (tadpoles). Baja Verapaz: 32 km. N of Morazan, KU 68564 (tadpoles); Santa Elena, UMMZ 98119, 98120 (2). Huehuetenango: 1 km. E of Barillas, UMMZ 123136-7 (tadpoles). Progreso: Finca Bucaral, UMMZ 106783 (3), 123138 (tadpoles), S-1292 (skeleton).

HONDURAS: Atlantidad: Mountains behind Ceiba, MCZ 21300. Morazan: Cerro Uyuca, UMMZ 123102-3.

The Ptychohyla schmidtorum Group

Two species in group; adults having only vestige of web between fingers and lacking tarsal fold; pollex of breeding males lacking spinous, horny, nuptial tuberosities; mouth of tadpole greatly expanded, funnel-shaped, lacking lateral folds, and having 3/3 tooth-rows; breeding call consisting of series of short notes.

=Ptychohyla schmidtorum=

Diagnosis.--Diameter of tympanum more than half of diameter of eye; internarial region depressed; toes three-fourths webbed; no red flash-colors on thighs.

=Ptychohyla schmidtorum schmidtorum= Stuart

Ptychohyla schmidtorum Stuart, Proc. Biol. Soc. Washington, 67:169-172, August 5, 1954 [Holotype.--CNHM 27055 from El Porvenir (17 kilometers air-line west of San Marcos), Depto. San Marcos, Guatemala; Karl P. Schmidt collector]. Duellman, Univ. Kansas Publ. Mus. Nat. Hist., 13:351, 355, April 27, 1961.

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