Most of the species of amphibians and reptiles found in southern El Peten are found in humid tropical forests from the Isthmus of Tehuantepec southeastward on the Atlantic lowlands well into Central America.
ACCOUNTS OF SPECIES
In the following pages various aspects of the occurrence, life histories, ecology, and variation of the species of amphibians and reptiles known from southern El Peten are discussed. Only _Cochranella fleischmanni_ reported by Stuart (1937) from Rio Subin at Santa Teresa was not collected by us and is excluded. Because more worthwhile information was gathered for some species than others, the length and completeness of the accounts vary. All specimens listed are in the Museum of Natural History at the University of Kansas, to which inst.i.tution all catalog numbers refer. Preceding the discussion of each species is an alphabetical list of localities from which specimens were obtained; numbers after a locality indicate the number of specimens obtained at each locality.
=Bolitoglossa dofleini= (Werner)
Chinaja, 1.
An adult female having minute ovarian eggs has a snout-vent length of 81 mm., a tail length of 59 mm., 13 costal grooves, two intercostal s.p.a.ces between adpressed toes, 38-35 vomerine teeth in irregular rows forming a broad arch from a point posterolaterad to the internal nares to a point near the anterior edge of the parasphenoid teeth, and 43-44 maxilliary-premaxillary teeth. In life the dorsum was rusty brown with irregular black and orange spots and streaks. The flanks were bluish gray with black in the costal grooves and creamy tan flecks along the ventral edge of the flank. The belly and underside of the tail were yellowish tan with dark brown spots laterally. The limbs were orange proximally and black distally; the pads of the feet were bluish black.
The dorsal and lateral surfaces of the tail were yellowish orange with black spots. The iris was grayish yellow.
Stuart (1943:17) reported this species from Finca Volcan, Alta Verapaz.
He diagnosed his specimens as having 13 costal grooves and two or three intercostal s.p.a.ces between adpressed toes. He stated that the vomerine teeth were about 12 in number and that in life the dorsum was mottled gray and black, the sides gray and brown, and the undersurfaces uniformly dark gray. These specimens differ noticeably from the individual from Chinaja in the number of vomerine teeth and in coloration.
In August, 1961, I obtained a specimen of _Bolitoglossa dofleini_ at Finca Los Alpes, Alta Verapaz, approximately 13 kilometers airline south-southwest of Finca Volcan and at approximately the same elevation.
Although the salamander was dead when found, it obviously was more heavily pigmented than the individual from Chinaja. The belly was bluish gray with black spots laterally; the dorsum was dull brownish gray with some brownish red streaks. The specimen is a female having small ovarian eggs, a snout-vent length of 90 mm., 13 costal grooves, and two intercostal s.p.a.ces between adpressed limbs. There are 28-29 vomerine teeth, more than twice as many as in specimens from Finca Volcan (Stuart, 1943:17), but noticeably fewer than in the specimen from Chinaja.
The presence of this species at Chinaja lends support to the idea that the specimen from the Rio de la Pasion listed by Brocchi (1882:116) also is _Bolitoglossa dofleini_. Furthermore, the confirmed presence of this species in the lowlands of El Peten suggests that there may be genetic connection between _B. dofleini_ in the Alta Verapaz and _B.
yucatana_ in the Yucatan Peninsula. _Bolitoglossa yucatana_ differs from _B. dofleini_ in having five intercostal s.p.a.ces between adpressed toes and in having a different color pattern. Both are robust species having no close relationships to other species of _Bolitoglossa_ in northern Central America.
The specimen from Chinaja was found in water in the axil of a large elephant-ear plant (_Xanthosoma_) by day in March. Its stomach contained fragments of beetles and a large roach. The natives did not know salamanders and had no name for them.
=Bolitoglossa moreleti mulleri= (Brocchi)
Chinaja, 2; Rio San Roman, 1.
One specimen is a female having a snout-vent length of 80 mm., a tail length of 82 mm., and a total length of 162 mm. It contains 63 large eggs, the largest of which has a diameter of about three millimeters.
This specimen has 13 costal grooves, four intercostal s.p.a.ces between adpressed toes, and 12-13 vomerine teeth. A juvenile having a snout-vent length of 39 mm. and a tail length of 33 mm. has 12 costal grooves, three intercostal s.p.a.ces between adpressed toes, and 8-8 vomerine teeth.
In life these salamanders were uniformly dull brownish black above with a dull creamy yellow irregular dorsal stripe beginning on the occiput and continuing onto the tail. There are no yellow or orange streaks or flecks on the head or limbs. The specimen from the Rio San Roman was taken from the stomach of a _Pliocercus euryzonus aequalis_ and has not been studied in detail, because of its poor condition.
The present specimens show no tendency for the development of a broad irregular dorsal band that encloses black spots or forms irregular dorsolateral stripes, as is characteristic of _B. moreleti mexica.n.u.s_, a subspecies that has been reported from La Libertad (Stuart, 1935:35) and Piedras Negras (Taylor and Smith, 1945:545) in El Peten, and from Xunantunich, British Honduras (Neill and Allen, 1959:20).
Schmidt (1936:151) and Stuart (1943:13) found _B. moreleti mulleri_ in bromeliads at Finca Samac, Alta Verapaz. Taylor and Smith"s (1945:545) and Neill and Allen"s (1959:20) specimens of _B. moreleti mexica.n.u.s_ were obtained from bromeliads, but Neill and Allen (_loc. cit._) stated that the natives in British Honduras said that they had found salamanders beneath rubbish on the forest floor. My specimens were obtained from beneath logs on the forest floor in the rainy season.
Possibly in drier environments the species characteristically inhabits bromeliads, at least in the dry season.
=Bufo marinus= (Linnaeus)
Chinaja, 3; 10 km. NNW of Chinaja, 1; 11 km. NNW of Chinaja, 1.
During both visits to Chinaja this large toad was breeding in a small permanent pond in the camp. During the day the toads took refuge in crevices beneath the buildings or beneath large boulders by the pond. At dusk from four to ten males congregated at the pond and called. Tadpoles of this species were in the pond in March and in July. One juvenile was found beneath a rock in the forest, and another was on the forest floor by day.
The natives" name for this species and the following one is _sapo_.
=Bufo valliceps valliceps= Wiegmann
Chinaja, 52; Rio San Roman, 8; Sayaxche, 2; Toocog, 1.
This is one of the most abundant, or at least conspicuous, amphibians inhabiting the forest. Breeding congregations were found on February 24, March 2, March 11, and June 27. At these times the toads were congregated at temporary ponds in the forest or along small sluggish streams. Throughout the duration of both visits to Chinaja individual males called almost nightly at the permanent pond at the camp.
The variation in snout-vent length of 20 males selected at random is 56.7 to 72.5 mm. (average, 64.8 mm.). Two adult females have snout-vent lengths of 80.4 and 87.6 mm. In all specimens the parotid glands are somewhat elongated and not rounded as in _Bufo valliceps wilsoni_ (see Baylor and Stuart, 1961:199). My observations on the condition of the cranial crests of the toads in El Peten agree with the findings of Baylor and Stuart (_op. cit._:198) in that hypertrophied crests are usual in large females. In the shape of the parotids and nature of the cranial crests the specimens from El Peten are like those from the Isthmus of Tehuantepec in Mexico. As I pointed out (1960:53), the validity of the subspecies _Bufo valliceps macrocristatus_, described from northern Chiapas by Firschein and Smith (1957:219) and supposedly characterized by hypertrophied cranial crests, is highly doubtful.
In the toads from El Peten the greatest variation is in coloration. The dorsal ground-color varies from orange and rusty tan to brown, yellowish tan, and pale gray. In some individuals the flanks and dorsum are one continuous color, whereas in others a distinct dorsolateral pale colored band separates the dorsal color from dark brown flanks. In some individuals the venter is uniform cream color, in others it bears a few scattered black spots, and in still others there are many spots, some of which are fused to form a black blotch on the chest. In breeding males the vocal sac is orange tan. All specimens have a coppery red iris.
Aside from the breeding congregations, active toads were found on the forest floor at night; a few were there by day. Some individuals were beneath logs during the day.
=Eleutherodactylus rostralis= (Werner)
Chinaja, 10.
Because of the multiplicity of names and the variation in coloration, the small terrestrial _Eleutherodactylus_ in southern Mexico and northern Central America are in a state of taxonomic confusion. Stuart (1934:7, 1935:37, and 1958:17) referred specimens from El Peten to _Eleutherodactylus rhodopis_ (Cope). Stuart (1941b:197) described _Eleutherodactylus anzuetoi_ from Alta Verapaz and El Quiche, Guatemala, suggested that the new species was an upland relative of _Eleutherodactylus rostralis_ (Werner), and used that name for the frogs that he earlier had referred to _Eleutherodactylus rhodopis_. Dunn and Emlen (1932:24) placed _E. rostralis_ in the synonymy of _E. gollmeri_ (Peters). Examination of series of these frogs from southern Mexico, Guatemala, and Costa Rica causes me to think that there are four species; these can be distinguished as follows:
_E. rhodopis._--No web between toes; one tarsal tubercle; tibiotarsal articulation reaches to nostril; iris bronze in life.
_E. anzuetoi._--No web between toes; a row of tarsal tubercles; tibiotarsal articulation reaches to tip of snout; color of iris unknown.
_E. rostralis._--A vestige of web between toes; no tarsal tubercles; tibiotarsal articulation reaches snout or slightly beyond; iris coppery red in life.
_E. gollmeri._--A vestige of web between toes; no tarsal tubercles; tibiotarsal articulation reaches well beyond snout; iris coppery red in life.
The presence of webbing between the toes, the absence of tarsal tubercles, and the coppery red iris distinguish _E. rostralis_ and _E.
gollmeri_ from the other species. Probably _E. rostralis_ and _E.
gollmeri_ are conspecific, but additional specimens are needed from Nicaragua and Honduras to prove conspecificity. On the other hand, the characters of the frogs from Chinaja clearly show that they are related to _E. gollmeri_ to the south and not to _E. rhodopis_ to the north in Mexico.
At Chinaja, _Eleutherodactylus rostralis_ was more abundant than the few specimens indicate, for upon being approached the frogs moved quickly and erratically, soon disappearing in the leaf litter on the forest floor. Most of the specimens were seen actively moving on the forest floor in the daytime; one was found beneath a rock, and one was on the forest floor at night.
=Eleutherodactylus rugulosus rugulosus= (Cope)
Chinaja, 2; 15 km. NW of Chinaja, 4.
These frogs were found on the forest floor by day. With the exception of one female having a snout-vent length of 69.5 mm., all are juveniles.
The apparent rarity of this species at Chinaja may be due to the absence of rocky streams, a favorite habitat of this frog. The local name for this frog is _sapito_, meaning little toad.
=Leptodactylus l.a.b.i.alis= (Cope)
Toocog, 1.
One juvenile having a snout-vent length of 16.4 mm. was found at night beside a pond in the forest. The scarcity of the species of _Leptodactylus_ in the southern part of El Peten probably is due to the lack of permanent marshy ponds.