Descriptions of New Hylid Frogs From Mexico and Central America Part 1

Descriptions of New Hylid Frogs From Mexico and Central America.

by William E. Duellman.

Biological exploration of Mexico and Central America has revealed the presence of a diverse fauna, elements of which have undergone speciation in separate areas within the relatively small region. Some genera of amphibians, especially _Eleutherodactylus_ and _Hyla_, are represented by many species having small geographic ranges in Mexico and Central America. Most of the species of _Hyla_ inhabiting the lowlands have been known to science for many years, and most of the novelties today are found in the less accessible highlands. No fewer than 19 new species of hylid frogs have been discovered and named from Mexico and Central America in the past decade.

In the spring and summer of 1966 I studied hylid frogs in many parts of southern Mexico and Central America; the field work was designed to obtain specimens and data that would resolve certain systematic problems. To a certain extent the studies were successful, but in the course of the work five previously unknown hylids were discovered; these are named and described in this paper. The only species described herein that I do not know in life is one of _Plectrohyla_ that has been represented in museum collections for several years but was not obtained in my own field work.

In this paper I am presenting diagnoses, descriptions, and brief comments on the relationships of five new species and one subspecies.

More exhaustive accounts will be included in a monograph, now in preparation, on the Middle American hylids.

For use of comparative material used in the preparation of this paper, I am indebted to Richard J. Baldauf, Texas Cooperative Wildlife Collection (TCWC); Charles M. Bogert, American Museum of Natural History (AMNH); James A. Peters, United States National Museum (USNM); Hobart M. Smith, University of Illinois Museum of Natural History (UIMNH); Charles F.

Walker, University of Michigan Museum of Zoology (UMMZ); and Ernest E.

Williams, Museum of Comparative Zoology (MCZ). KU refers to the University of Kansas Museum of Natural History. I am especially grateful for help in obtaining specimens and data to Linda Trueb, who accompanied me throughout Mexico and Central America, where we were joined by John D. Lynch in Costa Rica and Charles W. Myers in Panama. Linda Trueb offered helpful suggestions in the course of preparing the ma.n.u.script, and David M. Dennis skillfully prepared the ill.u.s.trations which more accurately depict the frogs than my written descriptions; both of these persons have my thanks for their contributions.

Ratibor Hartmann of Finca Santa Clara, Chiriqui, Panama, made possible our travels to the Rio Changena on the Atlantic slopes of Bocas del Toro. Field work in Costa Rica was facilitated by the Organization of Tropical Studies through the courtesy of Stephen B. Preston and Norman Scott. Rodolfo Hernandez Corzo of the Direccion General de la Fauna Silvestre provided the necessary permits to collect in Mexico. I thank each of these persons for his helpfulness and cooperation.

Field work in Mexico and Central America and the a.s.sociated laboratory studies on Middle American hylid frogs are supported by grants from the National Science Foundation (GB-1441 and GB-5818). The field work in Panama was part of a survey of the herpetofauna of that country carried out in cooperation with the Gorgas Memorial Laboratory and supported by the National Inst.i.tutes of Health (GM-12020).

Hyla xanthosticta new species

Plate 17

_Holotype._--Adult female, KU 103772, from the south fork of the Rio Las Vueltas on the south slope of Volcan Barba, near the northwest base of Cerro Chompipe, Heredia Province, Costa Rica, elevation 2100 meters; obtained on June 26, 1966, by John D. Lynch.

_Diagnosis._--A member of the _Hyla pictipes_ group (Starrett, 1966), characterized by having dorsum uniform green, canthal stripe bronze-color, flanks and anterior and posterior surfaces of thighs dark brown with bright yellow spots, throat and belly yellow, and hands having only vestigial web.

_Description of holotype._--Female having a snout-vent length of 29.3 mm.; tibia length 16.2 mm., 55.3 per cent of snout-vent length; foot length (measured from proximal edge of inner metatarsal tubercle to tip of longest toe) 14.1 mm., 48.1 per cent of snout-vent length; head length 10.0 mm., 34.1 per cent of snout-vent length; head width 10.3 mm., 35.2 per cent of snout-vent length. Snout in lateral profile truncate, slightly inclined posteroventrally, in dorsal profile narrow but truncate; canthus angular; loreal region barely concave; lips thick, barely flared. Snout long; distance from anterior corner of eye to nostril equal to diameter of eye; nostrils slightly protuberant, directed laterally; internarial distance, 2.6 mm.; internarial area slightly depressed; top of head slightly convex; interorbital distance 3.2 mm., 31.1 per cent of width of head; width at eyelid 2.6 mm.; 24.3 per cent of width of head. Diameter of eye 3.0 mm.; thin dermal fold extending posteriorly from posterior corner of eye, above tympanum, to point above insertion of arm. Tympanum distinct, its diameter half that of eye.

Axillary membrane absent; arms slender; thin scalloped dermal fold on ventrolateral edge of forearm; thin dermal fold on wrist; fingers long, tapering; length of fingers from shortest to longest, 1-2-4-3; discs small, only slightly wider than digits; subarticular tubercles large; distal tubercle on third finger broad, flat; distal tubercle on fourth finger strongly bifid; supernumerary tubercles large, round, closely s.p.a.ced irregularly on proximal segments of digits; prepollex moderately enlarged. Web lacking between first and second fingers, vestigial between second and third fingers, extending from middle of antepenultimate phalanx of third to base of penultimate phalanx of fourth. Heels overlap by about one-third length of shank when hind limbs adpressed; tibiotarsal articulation extends to anterior edge of eye; thin transverse dermal fold on heel; scalloped dermal fold along outer edge of tarsus; inner metatarsal tubercle large, flat, elliptical, visible from above; toes long, slender; length of toes from longest to shortest, 1-2-5-3-4; discs small, barely wider than digits; subarticular tubercles large, round, subconical; supernumerary tubercles few, scattered on proximal segments of digits; toes about two-thirds webbed; webbing extending from middle of penultimate phalanx of first toe to middle of penultimate phalanx of second, from distal end of penultimate phalanx of second to base of penultimate of third, from distal end of penultimate phalanx of third to middle of antepenultimate of fourth to middle of penultimate of fifth toe.

a.n.a.l opening directed posteroventrally at level of mid-thigh, bordered below by large tubercles; a.n.a.l sheath lacking. Skin smooth on dorsum except for small scattered tubercles, granular on belly and posteroventral surfaces of thighs. Tongue round, emarginate, barely free behind. Prevomerine teeth 5-5, on large ovoid elevations at level of posterior edges of small round choanae.

Color (in preservative): dark purplish brown above, brown on limbs; first three fingers and first three toes creamy yellow; other digits brown; flanks dark brown with white spots; anterior and posterior surfaces of thighs and inner surfaces of shanks brown with cream-colored spots. White stripes on edge of upper lip, ventrolateral edge of forearm, outer edge of tarsus, and above a.n.u.s. Chin and throat white; belly and ventral surfaces of limbs cream-color.

Color (in life): dorsum green, palest on sides of head; dorsal surfaces of thighs tan; canthal stripe bronze-tan (reddish copper at night); flanks, anterior and posterior surfaces of thighs, and inner surfaces of tarsi brown with bright yellow spots. Throat and belly pale yellow; ventral surfaces of limbs dull, dark yellow; large, bright yellow spot on anteroventral surface of thigh; bright yellow tubercles on median part of ventral surface of thigh. a.n.a.l area dark brown with white stripe above and yellow stripe below; white stripe on outer edge of forearm, outer edge of tarsus, and edge of upper lip. Iris gold-color with fine black reticulations and faint reddish suffusion medially; palpebral membrane clear.

_Comparisons._--_Hyla xanthosticta_ is a member of the _Hyla pictipes_ group that contains _debilis_, _pictipes_, _rivularis_, and _tica_. From all of these, _xanthosticta_ differs by having large yellow spots on the flanks and thighs, a white l.a.b.i.al stripe, and a large yellow spot on the proximal ventral surface of each thigh. Females of _Hyla pictipes_ have small creamy yellow spots on the flanks and thighs but have dark spots on the venter; furthermore, _pictipes_ lacks white stripes on the upper lip and above the a.n.u.s, lacks a canthal stripe, and has larger discs and less webbing on the hand. _Hyla tica_ differs from _xanthosticta_ by having white mottling on the flanks, dark transverse bands on the limbs, and larger discs, and lacks yellow spots on the thighs, and white stripes on the upper lip, limbs, and above the a.n.u.s. _Hyla rivularis_ is notably different in having a tan dorsum and creamy yellow venter with black flecks; moreover, _rivularis_ lacks spots on the flanks and thighs and white stripes on the upper lip, limbs, and above the a.n.u.s. Of all of the species in the _pictipes_ group, _xanthosticta_ most closely resembles _debilis_. This species has a dull green dorsum, usually flecked with brown or black, and a creamy white venter. The flanks of _debilis_ are creamy white with small brown flecks, and the anterior and posterior surfaces of the thighs are bright yellow. _Hyla debilis_ has a dull tan canthal stripe and white spots on the upper lip; the webbing on the hand is slightly more extensive, and the discs are slightly larger, in _debilis_ than in _xanthosticta_.

The presence of the large yellow spots on the flanks and thighs in combination with the uniformly green dorsum and yellow venter immediately distinguishes _Hyla xanthosticta_ from all other known species of Middle American hylids.

_Remarks._--The only known specimen of _Hyla xanthosticta_ was perched at night on a leaf about one meter above the ground. The frog was found in humid upper montane forest characterized by large oaks supporting many bromeliads and heavy growths of mosses. Two other members of the _Hyla pictipes_ group--_pictipes_ and _rivularis_--were abundant along a stream in the oak forest.

The specific name is derived from the Greek _xanthos_ meaning yellow and the Greek _stiktos_ meaning spotted, and alludes to the diagnostic yellow spots on the flanks and thighs.

Hyla pseudopuma infucata new subspecies

Plate 17

_Holotype._--Adult male, KU 101770 from the Rio Changena, Bocas del Toro Province, Panama, elevation 830 meters; obtained May 18, 1966, by William E. Duellman.

_Paratypes._--KU 101771-80; MCZ 55251-2, and UMMZ 126811-12, same locality; collected May 18-22, 1966, by William E. Duellman.

_Diagnosis._--A subspecies of _Hyla pseudopuma_ characterized by having dark red, instead of yellow, in groin and on anterior and posterior surfaces of thighs; white stripe above a.n.a.l opening; and blunt snout.

_Description of holotype._--Adult male having a snout-vent length of 37.8 mm.; tibia length 20.6 mm., 54.4 per cent of snout-vent length; foot length (measured from proximal edge of inner metatarsal tubercle) 18.6 mm., 49.2 per cent of snout-vent length; head length 11.9 mm., 31.4 per cent of snout-vent length; head width 11.4 mm., 30.1 per cent of snout-vent length. Snout in lateral profile bluntly rounded, in dorsal profile truncate; canthus rounded; loreal region barely concave; lips thick, moderately flared. Snout short, distance from anterior corner of eye to nostril equal to about three-fourths diameter of eye; nostrils slightly protuberant, directed dorsolaterally; internarial distance 2.6 mm.; internarial area not depressed; top of head flat; interorbital distance 3.8 mm., 33.3 per cent of width of head; width of eyelid 3.2 mm., 28.2 per cent of width of head. Eye large, protuberant, diameter 4.3 mm.; thin dermal fold extending posteriorly from posterior corner of eye, obscuring upper edge of tympanum, curving downward to point above insertion of arm. Tympanum distinct except dorsally, its diameter 51.1 per cent that of eye, separated from eye by distance equal to diameter of tympanum.

Axillary membrane absent; arms moderately robust; dermal fold on outer edge of forearm indistinct, interrupted; transverse fold on wrist weak; fingers short, stocky; length of fingers from shortest to longest, 1-2-4-3; discs large, width of that on third finger 2.6 mm., larger than tympanum; subarticular tubercles moderately small, flat, none distinctly bifid; supernumerary tubercles conical, present on proximal segments; prepollex enlarged, bearing nuptial excrescence composed of many minute h.o.r.n.y spinules; webbing absent between first and second fingers, extending from middle of antepenultimate phalanx of second to base of antepenultimate phalanx of third and beyond to base of penultimate phalanx of fourth finger. Heels overlap by about one-third length of tarsus when hind limbs adpressed; tibiotarsal articulation extends to anterior corner of eye; transverse dermal fold on heel; tarsal fold absent; inner metatarsal tubercle long, elliptical, flat, barely visible from above; outer metatarsal tubercle small, conical; toes moderately long, stout; length of toes from shortest to longest, 1-2-3-5-4; discs nearly as large as those on fingers; subarticular tubercles small, flat; supernumerary tubercles large, conical, pigmented, in single row on proximal segments of each toe; toes about two-thirds webbed; webbing extending from distal end of penultimate phalanx of first toe to base of penultimate phalanx of second, from distal end of penultimate phalanx of second to middle of antepenultimate of third, from distal end of penultimate phalanx of third to base of penultimate of fourth to distal end of penultimate of fifth toe.

a.n.a.l opening directed posteriorly at level of upper surfaces of thighs, bordered below by vertical flesh folds; a.n.a.l sheath absent. Skin of belly, ventral surfaces of arms, and proximal posteroventral surfaces of thighs granular, elsewhere smooth. Tongue ovoid, about twice as long as wide, shallowly notched posteriorly, barely free behind. Prevomerine teeth 5-6, situated on transverse ridges between posterior borders of small round choanae. Vocal slit extending from midlateral edge of tongue to angle of jaw.

Color (in preservative): dorsum grayish tan with large brown blotch extending from eyelids to middle of back, limbs marked with brown transverse bars, 2 on each forearm, 3 on each thigh, shank, and foot.

Flanks dark gray with white spots; groin, anterior and posterior surfaces of thighs, ventral surfaces of shanks, and inner edges of feet orange-tan; a.n.a.l region dark brown, bordered above by white stripe; belly and chin creamy white, latter with grayish brown flecks.

Color (in life): dorsum yellowish tan with olive-brown markings by night and uniform pale yellowish tan by day; axilla, inner surface of elbow, groin, anterior and posterior surfaces of thighs, ventral surfaces of thighs and shanks, inner surfaces of feet, and dorsal surfaces of first three toes tomato red; flanks dark blue with yellow spots and reticulations. Throat, chest, and anterior part of belly creamy white; posterior part of belly orange, becoming red in extreme posterior region; throat flecked with brown; iris pale bronze with black reticulations; palpebral membrane clear above, yellowish tan below; nuptial excrescenses dark brown.

_Variation._--The discussion of variation is based on the type series plus 31 specimens (KU 101781-811) from the Rio Claro near its junction with the Rio Changena, at an elevation of 910 meters. Females are slightly larger than males, but do not differ significantly in proportions (Table 1). All specimens have the diagnostic red legs and blue flanks with yellow spots or mottling, but the dorsal pattern is highly variable. In most individuals the dark markings on the dorsum are a solid color, but in some the borders of the marks are dark, and the interior of each mark is nearly the same color as the rest of the dorsum. A triangular dark mark with the anterolateral corners on the eyelids is present in all specimens. In some individuals the posteriorly directed apex of this triangular mark is connected to the apex of another triangular mark on the back; in other individuals the marks are narrowly separated, whereas in a few specimens the marks are broadly connected. A dark blotch usually is present on the posterior end of the body. One specimen (KU 101771) has many small white spots on the dorsum.

The white stripe above the a.n.u.s is invariably present, and the transverse bars on the limbs are present in all specimens, although they are indistinct in some individuals. The pattern on the flanks varies from three or four large spots to many (30-44) small spots. All males have dark flecks or reticulations on the throat; in some individuals the chest and belly are heavily flecked. Although the amount of flecking is much less in most females, one individual is as heavily flecked on the throat and belly as any male.

The change in coloration in this frog is noteworthy. The following description of metachrosis in seven specimens from the Rio Claro ill.u.s.trates the change. At night the frogs were yellowish tan above with slightly darker dorsal markings. The axilla, groin, anterior and posterior surfaces of the thighs, ventral surfaces of the hind limbs, and webbing on the hands and feet were tomato red. By day, some individuals became creamy yellow, others ashy white, and others grayish tan. The flanks were dark blue with yellow spots.

_Comparisons._--The population of frogs described here closely resembles _Hyla pseudopuma_ Gunther in the highlands of Costa Rica. Both have the same kind of, and variation in, dorsal markings; conical, pigmented supernumerary tubercles on the toes; bilobate vocal sac; and large prepollex bearing h.o.r.n.y nuptial spinules. Although at present no evidence for intergradation exists, the population described here is considered to be a subspecies of _Hyla pseudopuma_.

The two subspecies exhibit few differences in size and proportions, except that the tympanum is larger in _pseudopuma_ (Table 1). _Hyla p.

pseudopuma_ has dark brown or yellowish tan thighs and brown flanks with a few creamy white spots; the groin in some specimens is pale blue. The red color on the limbs characteristic of _infucata_ is lacking in _pseudopuma_, which also lacks the white stripe above the a.n.u.s characteristic of _infucata_. The only noticeable morphological difference between the subspecies, except in the size of the tympanum, is the shape of the snout. In _infucata_ the snout is bluntly rounded in lateral profile and truncate in dorsal profile, whereas in _pseudopuma_ the snout is more acutely rounded in lateral profile and ac.u.minate in dorsal profile (Fig. 1). This external difference is correlated with the nature of the underlying premaxillaries. In _infucata_ the premaxillaries lie in a transverse plane and have short, nearly vertical alary processes, whereas in _pseudopuma_ the premaxillaries lie at a slight angle and have longer alary processes that are inclined posteriorly.

TABLE 1.--Variation in Certain Measurements and Proportions in the Subspecies of Hyla pseudopuma. (Means Are Given in Parentheses Below the Observed Range.)

==================+========+==+==========+==========+==========+========== | | |Snout-vent| Tibia | Foot | Tympanum/ SUBSPECIES | s.e.x | N| length | length/ | length/ | eye | | | | S-V L | S-V L | ------------------+--------+--+----------+----------+----------+---------- _H. p. pseudopuma_|[Male] |31| 37.6-41.4| 48.5-55.0| 44.7-52.9| 47.6-66.7 |[symbol]| | (39.7) | (51.5) | (48.2) | (57.6) | | | | | | _H. p. infucata_ |[Male] |31| 37.6-42.9| 50.7-56.9| 43.3-49.5| 41.8-55.3 |[symbol]| | (39.5) | (53.4) | (47.4) | (49.2) | | | | | | _H. p. pseudopuma_|[Female]|11| 41.6-47.6| 49.1-53.8| 45.4-49.5| 57.9-71.4 |[symbol]| | (44.3) | (51.7) | (47.6) | (60.2) | | | | | | _H. p. infucata_ |[Female]|11| 41.1-45.6| 50.0-55.4| 43.5-47.4| 47.6-56.1 |[symbol]| | (42.6) | (52.6) | (45.8) | (50.1) ------------------+--------+--+----------+----------+----------+----------

[Ill.u.s.tration: FIG. 1. Lateral views of the heads of _Hyla pseudopuma pseudopuma_ (left, KU 64884) and _H. p. infucata_ (right, KU 101784).

4.]

The only other frog in Central America having red webs and anterior and posterior surfaces of the thighs is _Hyla loquax_, which has a broad head, extensive axillary membrane, single median vocal sac, and uniformly creamy yellow flanks; furthermore, _loquax_ lacks conical, pigmented supernumerary tubercles on the toes and a large prepollex with h.o.r.n.y nuptial spinules. _Hyla rufitela_ has red webbing, but in no other diagnostic feature resembles _infucata_, for _rufitela_ is green above, white below, and has angular prevomerine dentigerous ridges.

_Remarks._--Most specimens of _Hyla pseudopuma infucata_ were found on bushes and low trees at night. Three males and one clasping pair were on the ground. The habitat is humid lower montane forest where the amount of rainfall is high. Although no breeding was observed nor calls heard, it is presumed that this subspecies breeds in shallow, temporary pools, like those utilized by the nominate subspecies.

The two localities where _Hyla pseudopuma infucata_ is known are in the maze of ridges north of Cerro Pando on the Panamanian-Costa Rican border. The Rio Claro is a tributary of the Rio Changena, in turn a tributary of the Rio Changuinola, which receives many streams and rivers draining the northern slopes of the highlands in Bocas del Toro Province before flowing into the Caribbean. We reached the Rio Claro and Rio Changena by walking from Finca Santa Clara on the Pacific slopes, over the continental divide, and down the north slope of Cerro Pando.

The subspecific name is derived from the Latin _infucatus_, meaning painted, in allusion to the red colors on the limbs and webs.

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.