Amphibians and Reptiles of the Rainforests of Southern El Peten, Guatemala Part 3

=Leptodactylus melanonotus= (Hallowell)

Sayaxche, 1.

One individual was found beneath a rock beside a stream in the forest.

The local name is _ranita_, meaning little frog.

=Syrrhophus leprus= Cope

Chinaja, 2; 15 km NW of Chinaja, 1.

An adult female having a snout-vent length of 27.5 mm. was found on the forest floor by day. Two juveniles having snout-vent lengths of 15.5 and 19.0 mm. were beneath rocks on the forest floor. The specimens are typical of the species as defined by Duellman (1958:8).

=Hyla ebraccata= Cope

Toocog, 66.

This small tree frog congregated in large numbers at a forest pond at Toocog. Between June 30 and July 2 we collected specimens and observed the breeding habits of this and other species at the pond. Calling males were distributed around the pond, where they called from low herbaceous vegetation at the edge of the pond or from plants rising above the water. Calling commenced at dusk and continued at least into the early hours of the morning. On one occasion a female was observed at a distance of about 50 centimeters away from a calling male sitting on a blade of gra.s.s. The female climbed another blade of gra.s.s until she was about eight centimeters away from the male, at which time he saw her, stopped calling, jumped to the blade of gra.s.s on which she was sitting and clasped her. Clasping pairs were observed on blades of gra.s.s and leaves of plants above the water; most pairs were less than 50 centimeters above the surface of the pond.

The eggs are deposited on the dorsal surfaces of leaves above the water.

All eggs are in one plane (a single layer) on the leaf. External membranes are barely visible, as the eggs consist of a single coherent ma.s.s. Eggs in the yolk plug stage have diameters of 1.2 to 1.4 mm.

Seventeen eggs ma.s.ses were found; these contained from 24 to 76 (average 44) eggs. The jelly is extremely viscous and tacky to the touch. At time of hatching the jelly becomes less viscous; the tadpoles wriggle until they reach the edge of the leaf and drop into the water.

Eleven tadpoles were preserved as they hatched; these have total lengths of 4.5 to 5.0 (average 4.77) mm. Hatchling tadpoles are active swimmers and have only a small amount of yolk. The largest tadpoles preserved have total lengths of 13.0 and 13.5 mm. At this size distinctive sword-tail and bright coloration have developed.

[Ill.u.s.tration: FIG. 2. Tadpole of _Hyla ebraccata_ (KU 59986) from Toocog, El Peten, Guatemala. 6.]

Description of fully developed tadpole (KU 59986): Total length, 13.5 mm.; tail-length, 8.4 mm., 62 per cent of total length. Snout, in dorsal view, bluntly rounded; in lateral view less bluntly rounded; body depressed; head flattened; mouth terminal; eye large, its diameter 25 per cent of length of body; nostrils near tip of snout and directed anteriorly; spiracle sinistral and situated postero-ventrad to eye; cloaca median. Tail-fin thrice depth of tail-musculature, which extends beyond posterior end of tail-fin giving sword-tail appearance (Fig. 2).

In life, black stripe on each side of body and on top of head; black band on anterior part of tail and another on the posterior part; body and anterior part of tail creamy yellow; dark red band between black bands on tail. Mouth terminal, small, its width about one-fifth width of body; fleshy ridge dorsally and ventrally; row of small papillae on ventral lip; no lateral indentations of lips; upper beak ma.s.sive, convex, and finely serrate; lower beak small and mostly concealed behind upper; no teeth (Fig. 3).

[Ill.u.s.tration: FIG. 3. Mouthparts of larval _Hyla ebraccata_ (KU 59986) from Toocog, El Peten, Guatemala. 100.]

=Hyla loquax= Gaige and Stuart

Toocog, 14.

These specimens were found at night when they were calling from low vegetation in a forest pond. Most of the frogs were several meters away from the edge of the pond. Although two clasping pairs were found, we obtained no eggs or tadpoles referable to this species.

=Hyla microcephala martini= Smith

Chinaja, 1; Toocog, 21.

The specimen from Chinaja was calling from a small bush at the edge of a temporary gra.s.sy pond in a clearing in the forest. At Toocog this species was closely a.s.sociated with _Hyla ebraccata_; males were calling from herbaceous vegetation in and around the forest pond. These frogs were not so abundant in the forest at Toocog as they were around ponds on the savanna at La Libertad.

=Hyla picta= (Gunther)

Toocog, 8.

This small tree frog was calling from herbs in a pond in the forest on June 30 and July 2. The voice is weak; probably greater numbers of males were present than are indicated by the few specimens collected, for the din from the more vociferous species made it impossible to hear _Hyla picta_ unless one was calling close by.

=Hyla staufferi= Cope

Chinaja, 1.

This individual was calling from a low bush in the clearing at Chinaja.

None was found in the pond in the forest at Toocog. Stuart (1935:38) and Duellman (1960:63) noted that _Hyla staufferi_ breeds early in the rainy season. Nevertheless, I think early breeding habits do not account for the near absence of this species in our collections from southern El Peten. In early July, 1960, a few individuals were heard at a pond on the savanna at La Libertad. In mid-July of the same year they were calling sporadically from temporary ponds in the lower Motagua Valley.

Possibly the individual collected at Chinaja was accidentally transported there in cargo from Toocog, from which camp at the edge of the savanna planes fly to Chinaja weekly. My observations on this species throughout its range in Mexico and Central America indicate that it inhabits savannas and semi-arid forests and usually is absent from heavy rainforest. Stuart (1948:34) obtained this species at Cubilquitz in the lowlands of Alta Verapaz.

=Phyllomedusa callidryas taylori= Funkhouser

Toocog, 25.

Between June 30 and July 2 this species was abundant at a pond in the forest at Toocog. Calling males were as high as five meters in bushes and trees around the pond. At dusk males were observed descending a vine-covered tree at the edge of the pond; this strongly suggests that the frogs retreat to this tree and others like it for diurnal seclusion.

Clasping pairs were found on branches and leaves above the water. The eggs are deposited in clumps usually on vertical leaves, but sometimes on horizontal leaves or on branches, vines, and aerial roots above the water. Twenty-six clutches of eggs contained from 14 to 44 (average 29) eggs. In a clutch in which the eggs are in yolk plug stage the average diameter of the embryos is 2.3 mm. and that of the vitelline membranes, 3.4 mm. Most of the eggs are in the external part of the gelatinous ma.s.s; the jelly is clear. The yolk is pale green, and the animal pole is brown. As development ensues, the yolk becomes yellow and the embryo first dark brown and then pale grayish tan. Upon hatching the tadpoles wriggle free of the jelly and drop into the water. One clutch of 19 eggs was observed to hatch in three minutes. Apparently, on dropping into the water the hatchling tadpoles go to the bottom of the pond, for one or two minutes pa.s.s from the time they enter the water until they reappear near the surface. The average total length of seven hatchling tadpoles is 7.4 mm. There is a moderate amount of yolk, but this does not form a large ventral bulge. Large tadpoles congregate in the sunny parts of the pond, where they were observed just beneath the surface. Many had their mouths at the surface. Except for constant fluttering of the tip of the tail, they lie quietly with the axis of the body at an angle of about 45 degrees with the surface of the water.

Description of tadpole (KU 60006): total length, 24.5 mm.; tail-length, 15.4 mm.; body broader than deep; head moderately flattened; snout viewed from above blunt; nostrils close to snout and directed dorsally; eyes of moderate size and directed laterally; mouth directed anteroventrally; a.n.u.s median; spiracle ventral, its opening just to left of midline slightly more than one-half distance from tip of snout to vent. Tail-fin slightly more than twice as deep as tail musculature, which curves upward posteriorly; tail-fin narrowly extending to tip of tail (Fig. 4). Color in life pale gray; in preservative white with scattered melanoph.o.r.es; tail-fin transparent.

[Ill.u.s.tration: FIG. 4. Tadpole of _Phyllomedusa callidryas taylori_ (KU 60006) from Toocog, El Peten, Guatemala. 4.]

Upper lip having single row of papillae laterally, but none medially; lower lip having single row of papillae; no lateral indentation of lips; two or more rows of papillae at lateral corners of lips; tooth-rows 2/3; second upper tooth row as long as first, interrupted medially; inner lower tooth-row as long as upper rows, interrupted medially; second and third lower rows decreasingly shorter; upper beak moderate in size and having long lateral projections; lower beak moderate in size; both beaks finely serrate (Fig. 5).

[Ill.u.s.tration: FIG. 5. Mouthparts of larval _Phyllomedusa callidryas taylori_ (KU 60006) from Toocog, El Peten, Guatemala. 30.]

=Smilisca baudini= (Dumeril and Bibron)

Chinaja, 9; 20 km. NNW of Chinaja, 42; Rio de la Pasion, 1; Rio San Roman, 5; Sayaxche; Toocog, 2.

Individuals of this species were found at night sitting on bushes and small trees in the forest in February and March and again in June and July. One was in the axil of a leaf of a _Xanthosoma_. In June and July males were heard nearly every night. The series of specimens from 20 kilometers north-northwest of Chinaja was taken from a breeding congregation in a shallow muddy pool in the forest. Tadpoles of this species were in small, often muddy pools in the forest. To my knowledge _Smilisca baudini_ is the only hylid to breed in these pools at Chinaja, although perhaps _Smilisca phaeota_ also utilizes them. The only other amphibian at Chinaja known to breed in the pools is _Bufo valliceps valliceps_. Although two specimens were on bushes at night at Toocog, _Smilisca baudini_ was not present at the pond where five other species of hylids were breeding. Nevertheless, _Smilisca baudini_ was calling from two ponds on the savannas near La Libertad. All of the specimens from southern El Peten have yellow or yellowish white flanks and ventrolateral surfaces.

=Smilisca phaeota cyanosticta= (Smith)

Chinaja, 4; 10 km. NNW of Chinaja, 1.

All specimens were found in February and March. Those from Chinaja were obtained from _Xanthosoma_ and bromeliads; the individual from 10 kilometers north-northwest of Chinaja is an adult male that was calling from a puddle in a fallen tree on March 13. A juvenile having a snout-vent length of 34.7 mm. lacks the pale blue spots on the thighs; instead, the anterior and posterior surfaces of the thighs are bright red.

=Hypopachus cuneus nigroreticulatus= Taylor

Toocog, 1.