Part 3

Hyla pellita new species

Plate 18

Holotype.--Adult male, KU 100970 from 33 kilometers north of San Gabriel Mixtepec, Oaxaca, Mexico, elevation 1675 meters; obtained on February 20, 1966, by William E. Duellman and Linda Trueb.

Paratypes.--KU 100971-2 collected with the holotype and KU 100974-5 from 30 kilometers north of San Gabriel Mixtepec, Oaxaca, Mexico, elevation 1530 meters; same date and collectors.

Diagnosis.--A small yellowish tan Hyla characterized by tympanum concealed, anal opening not bordered below by large tubercles, brown bands on shanks, and dark flecks on roof of mouth anteriorly.

Description of holotype.--Adult male having snout-vent length of 27.3 mm.; tibia length 13.7 mm., 50.2 per cent of snout-vent length; foot length (measured from proximal edge of inner metatarsal tubercle to tip of longest toe) 11.7 mm., 42.9 per cent of snout-vent length; head length 8.7 mm., 31.9 per cent of snout-vent length. Snout in lateral profile truncate, rounded above, in dorsal profile rounded; canthus angular; loreal region slightly concave; lips thin, flared. Snout moderately long, distance from anterior corner of eye to nostril slightly less than diameter of eye; nostrils slightly protuberant, directed anterolaterally; internarial area barely depressed; distance between nostrils 2.6 mm.; top of head flat; interorbital distance 3.2 mm., 34.4 per cent of width of head. Diameter of eye 2.7 mm.; thin dermal fold extending from posterior corner of eye to point above insertion of arm; tympanum absent, not visible through skin.

Axillary membrane absent; forearms moderately slender, having indistinct tuberculate fold on ventrolateral edge, lacking distinct transverse fold on wrist; fingers short; length of fingers from shortest to longest, 1-4-2-3, fourth nearly as long as second; discs small, about half again as wide as digits; subarticular tubercules large, round, flattened, distal ones on third and fourth fingers bifid; supernumerary tubercles large, round, present only on proximal segments; prepollex barely enlarged, lacking nuptial excrecence. Web lacking between first and second fingers, extending from base of penultimate phalanx of second to base of antepenultimate phalanx of third, from middle of antepenultimate phalanx of third to distal end of antepenultimate of fourth finger. Heels overlap by about one-fifth length of shank when hind limbs adpressed; tibiotarsal articulation extending to middle of eye, tarsal fold present, extending full length of tarsus; inner metatarsal tubercle flat, ovoid, partly visible from above; outer metatarsal tubercle absent; toes short; length of toes from shortest to longest, 1-2-3-5-4; discs small, about two-thirds width of those on fingers; subarticular tubercles small, round; supernumerary tubercles small, flattened, irregularly arranged on proximal segments. Toes three-fourth webbed; web extending from base of disc of first to middle of penultimate phalanx of second, from base of disc of second to middle of penultimate phalanx of third, from base of disc of third to base of penultimate phalanx of fourth and to base of disc of fifth toe.

Anal opening directed posteriorly at level of dorsal surfaces of thighs, bordered below by vertical dermal folds and few small tubercles; anal sheath absent. Skin heavily granular on throat, chest, belly and ventral surfaces of thighs, smooth elsewhere. Tongue cordiform, deeply notched posteriorly, barely free behind. Prevomerine teeth 3-4, situated on short elevations between small round choanae; vocal slits absent.

Color (in preservative): pale tan above with dark brown mark in occipital region and large irregular brown mark extending from scapular region to sacral region; anterior and posterior surfaces of thighs and flanks lacking pigment; dorsal surfaces of arms, shanks, and feet tan with brown transverse bars (two on each forearm, two on left shank, one on right shank, and one on each foot); entire dorsal surfaces, except hands and first four toes, peppered with black; venter creamy white; roof of mouth between, and anterior to, choanae speckled with minute black flecks.

Color (in life): yellowish tan above with reddish brown flecks (later changed to pale brown with dull olive-green interorbital bar, blotch on back, and flecks on dorsum); hands, feet, and anterior and posterior surfaces of thighs dull yellow; belly white; creamy white stripes on outer edge of forearm, foot, and above anus; iris pale silver-bronze.

Variation.--Three adult males (including holotype) have snout-vent lengths of 25.2-27.3 (mean 26.5) mm., and two females have 28.6 and 31.6 (mean 30.1) mm. One juvenile has a snout-vent length of 21.5 mm. No significant variation occurs in the proportions. Males have 6-8, and females have 8 and 9, prevomerine teeth. The tympanum is completely concealed in all specimens.

All specimens have distinct transverse bars on the limbs; the number of bars on the shank varies from one to four. Two individuals are dark brown dorsally; in these the small black flecks either are not visible or are absent; flecks are present on the dorsal surfaces of four specimens that are tan or pale brown above with darker brown irregular markings.

The coloration in life consisted of olive-green or olive-brown markings on the body and olive-green or brown bars on the limbs. The dorsal ground color was yellowish tan or pale brown in all individuals.

Comparisons.--Hyla pellita differs from all known Middle American Hyla, except mixe, mixomaculata, nubicola, and pinorum, by having a concealed tympanum. The first three of these differ from pellita in greater size and by having many bands on the hind limbs. Superficially H. pellita resembles Hyla pinorum, which likewise has a tan dorsum with irregular markings and limbs with transverse bars. Hyla pinorum differs from pellita by having a proportionately larger head, no transverse bands on the thighs, and large tubercles below the anus. Furthermore, in pinorum the quadratojugal articulates with the maxillary, whereas in pellita the quadratojugal is reduced to a small spur and does not articulate with the maxillary.

Remarks.--All individuals were found on low vegetation along streams in cloud forest at night. No specimens were found when the type locality was revisited in August, 1966.

Duellman (1960) placed Hyla pinorum Taylor in the synonymy of Ptychohyla leonhardschultzei Ahl. At that time only the holotype, a female, of H. pinorum was known. In 1964 Kraig Adler and I independently collected frogs and associated tadpoles in Guerrero that subsequently proved to be Hyla pinorum and provided evidence that Hyla pinorum is not conspecific with Ptychohyla leonhardschultzei.

The specific name pellita is Latin, meaning covered with skin, and is here used in reference to the complete concealment of the tympanum beneath the skin.

Hyla siopela new species

Plate 18

Holotype.--Adult male, KU 100981, from a small stream on the west slope of Cofre de Perote, Veracruz, Mexico, elevation 2500-2550 meters; obtained on July 30, 1966, by William E. Duellman.

Paratypes.--KU 100976-80, 100982-5, same locality, date, and collector; KU 105628-9, same locality, obtained on June 18, 1966, by Howard L. Freeman; UIMNH 57687-57701, same locality, obtained on July 30-31, 1964, by Macreay J. Landy and John D. Lynch.

Diagnosis.--A member of the Hyla bistincta group characterized by truncate snout with short rostral keel; fingers having little webbing and bearing large discs; axillary membrane absent; thoracic fold weak; prepollex large, flat, bearing small nuptial spines; vocal slits absent; dorsum green or tan with small irregular dark spots; flanks mottled.

Description of holotype.--Adult male having a snout-vent length of 44.3 mm.; tibia length 21.1 mm., 47.6 per cent of snout-vent length; foot length (measured from proximal edge of inner metatarsal tubercle to tip of longest toe) 20.4 mm., 47.2 per cent of snout-vent length; head length 13.4 mm., 30.2 per cent of snout-vent length; head width 13.7 mm., 30.9 per cent of snout-vent length. Snout in lateral profile truncate, in dorsal profile truncate with weak vertical rostral keel; canthus angular; loreal region slightly concave; lips thick, not flaring; snout short; nostrils barely protuberant, directed dorsolaterally, situated about four-fifths distance from anterior corner of eye to tip of snout; internarial distance 3.6 mm.; internarial area not depressed; top of head slightly convex; interorbital distance 4.9 mm., 35.8 per cent of width of head; width of eyelid 3.5 mm., 26.0 per cent of width of head. Diameter of eye 4.7 mm.; heavy dermal fold curving posteroventrally from posterior corner of eye, covering upper one-third of tympanum, to insertion of arm; tympanum barely distinct, its diameter 2.2 mm., 46.8 per cent that of eye, separated from eye by distance equal to half again diameter of tympanum.

Axillary membrane absent; thoracic fold weak; arms moderately robust; fold on wrist heavy; fingers long, slender; length of fingers from shortest to longest, 1-2-4-3; discs large, that on third finger as large as tympanum; subarticular tubercles moderately small, round, none bifid; supernumerary tubercles small, some barely distinguishable, in single row on proximal segment of each digit; prepollex greatly enlarged, flat ventrally, bearing nuptial excrescence composed of minute horny spinules; webbing between first two fingers vestigial; web connecting other fingers at bases of penultimate phalanges of second and fourth, and base of antepenultimate phalanx of third fingers. Heels overlap by about one-third length of shank when hind limbs adpressed; tibiotarsal articulation extends to posterior edge of orbit; transverse dermal fold on heel; tarsal fold thin, distinct, extending length of tarsus; inner metatarsal tubercle large, elongate, flat, visible from above; outer metatarsal tubercle absent; toes moderately long, slender; length of toes from shortest to longest, 1-2-3-5-4; discs slightly smaller than those on fingers; subarticular tubercles moderately small, round; supernumerary tubercles small, in single row on proximal segment of each digit; toes about two-thirds webbed; webbing extends from middle of penultimate phalanx of first toe to base of penultimate phalanx of second, from middle of penultimate of second to middle of antepenultimate of third, from middle of penultimate of third to middle of antepenultimate of fourth to middle of penultimate phalanx of fifth toe.

Anal opening directed posteriorly at level of mid-thigh; anal sheath short. Skin granular on chin, belly, and posteroventral surfaces of thighs, smooth elsewhere. Tongue broadly cordiform, notched posteriorly, barely free behind. Prevomerine teeth 4-4, situated on posteromedially inclined elevations between small ovoid choanae. Vocal slits absent.

Color (in preservative): dull grayish brown above with small, irregularly-shaped black spots on head, back, and limbs; flanks gray mottled with creamy tan; anterior and posterior surfaces of thighs tan; belly dull creamy tan; throat marked with gray blotches; anal region and posterodorsal surfaces of thighs marked with small white spots.

Color (in life): dorsum pale green with black spots and reticulations; flanks mottled dark brown and creamy white; outer edges of feet silvery white with brown spots; anterior and posterior surfaces of thighs dull brown; webbing and first three toes dull yellowish tan; belly creamy gray; throat silvery white, mottled with gray; iris dull bronze-color with black reticulations; palpebral membrane clear.

Variation.--The snout-vent length in seven adult males is 47.2-50.0 mm., and in five females, 45.1-52.5 mm. In neither sex do the average proportions differ noticeably from those of the holotype, except that the tympanum is relatively larger in females. The ratio of the diameter of the tympanum to that of the eye is 0.363-0.468 (mean 0.438) in males and 0.500-0.545 (mean 0.516) in females. The average number of prevomerine teeth in males is 7.9, in females 8.4.