mm. Other characters are as follows: depth of tail equal to length of

body; body deeper than wide; distance between eye and nostril equal to distance between eye and spiracle; mouth anteroventral; median part of upper lip bare; rest of lip having one row of papillae; a few other rows of small papillae at corners of mouth; tooth rows 2/3; first upper row entire, second upper row interrupted medially, shorter than first; lower rows shorter than upper rows, third shortest; beak moderately robust; spiracle nearer eye than anus; anal tube short, aperture not extending to border of ventral fin; caudal musculature slender, extending to tip of pointed tail; dorsal fin extending onto body (Table 4).

TABLE 4.--Sizes of Tadpoles of _Hyla foliamorta_ in Relation to Developmental Stages. (Means in parentheses below observed ranges; measurements in mm.)

======================================================= Stage | N | Body length | Tail length | Total length --------+---+-------------+-------------+-------------- 25 | 2 | 5.0-5.2 | 8.0-8.5 | 13.0-13.7 | | (5.1) | (8.3) | (13.4) | | | | 26 | 3 | 7.0-7.5 | 12.0-12.4 | 17.0-19.5 | | (7.2) | (12.1) | (18.6) | | | | 28 | 2 | 6.5-7.0 | 18.0 | 25.0 | | (6.8) | | | | | | 35 | 1 | 9.5 | 25.0 | 34.5

In life, yellow above, white below; caudal fin greenish yellow with black or gray reticulations; dark line from snout to eye; dark spot behind eye; tail unpigmented except for fine dark reticulations. In preservative body creamy white, transparent below with dark pigment above in some specimens.

_Remarks._--_Hyla foliamorta_ can be confused only with _Hyla boulengeri_. The differences between adults of these species were discussed in _Remarks_ on _H. boulengeri_. The tadpoles of _foliamorta_ have labial papillae on the lower lip and a stripe between the eye and the tip of the snout. By comparison the tadpoles of _boulengeri_ have a bare lower lip and no stripe between the eye and the tip of the snout.

_Distribution._--_Hyla foliamorta_ inhabits the subhumid Pacific lowlands (elevations of less than 100 meters) of Central Panamá and Caribbean lowlands of northern Colombia (Fig. 4).

_Specimens Examined._--Panamá: _Panamá_: 3 km WSW Chepo, KU 77164-9, 101573-5, 104243-4 (tadpoles); 6 km WSW Chepo, KU 77170, 101576-8; 1.5 km SW Naranjal, KU 77171, 77687 (skeleton); 2 km N Tocumen, KU 101579-83, 104349 (skeleton); 8 km NE Tocumen, KU 101584-92.

No specific locality: TNHC 24401.

_Hyla rubra_ Laurenti

_Hyla rubra_ Laurenti, Synopsis Reptilium Emendatum, p. 35, 1768. Daudin, Hist. Nat. Rainettes Grenouilles Crapauds, II:26, 1802. Daudin, Hist. Nat. Particuliere Reptiles, 8:53, 1803. Günther, Catalogue Batrachia Salientia Brit. Mus., p. 110, 1859. Boulenger, Catalogue Batrachia Salientia s. Ecaudata, p. 403, February 1, 1882. Dunn, Occas. Papers, Boston Soc. Nat. Hist., 5:413, October 10, 1931.

_Hyla elaeochroa_ (part): Dunn and Emlen, Proc. Acad. Nat. Sci. Philadelphia, 84:25, March 22, 1932.

_Diagnosis._--Size medium; skull longer than wide; frontoparietal fontanelle absent in adults; snout subovoid; choanae rounded; dorsal stripes present; black vermiculations on posterior surfaces of thighs.

_Description._--Head flat, longer than wide; snout long, subovoid, slightly protruding beyond lower lip; loreal oblique, concave; canthus rounded, indistinct; diameter of eye about equal to interorbital space; tympanum large, about three fifths diameter of eye, smaller than internarial distance; supratympanic fold indistinct; arms short; fingers free of webs; subarticular tubercles distinct; median palmar tubercle large, bifid; inner palmar tubercle on base of first finger flat, elongate; disc of third finger about one half diameter of tympanum; legs moderately long; tarsal fold absent; inner metatarsal tubercle distinct, oval; toes about half webbed; web on fourth toe extending to disc; discs of toes about size of those on fingers; skin smooth above with small granules on head and in scapular region in some specimens; skin on flanks, throat, belly, and lower surfaces of thighs granular; tongue oval, longer than wide, not free behind; choanae small, oval; vocal slits long, lateral to tongue.

In preservative, dorsum pale brown with darker dorsolateral stripes; narrow dark brown line from nostril to eye; groin, anterior surface of thighs, and posteroventral surfaces of shanks creamy tan with dark brown vermiculations; white spots present on thighs in some specimens; throat flecked with brown; belly creamy white or gray.

_Remarks._--The taxonomic history of _Hyla rubra_ Laurenti is confused. Seba (1734:70) illustrated and diagnosed a frog for which he used the name _Ranula, Americana, Rubra_. Linnaeus (1758:213) considered Seba's frog to be a variety of _Hyla arborea_. Laurenti (1768:35) apparently examined the same individual that Seba called _Ranula, Americana, Rubra_. For this specimen, Laurenti used the binominal _Hyla rubra_ and provided a brief diagnosis. The type locality was given as America.

Daudin (1802:26) redescribed the same specimen(s?) treated by Seba and Laurenti and provided a fairly good description and figures. Daudin restricted the type locality to Surinam and indicated that Marin de Baize was the probable collector. Daudin (1802:26 and 1803:53) neglected to consider Laurenti's work, but he applied the same name used by Laurenti. Most authors have credited _Hyla rubra_ to Daudin, but Rivero (1961:120) noted that _Hyla rubra_ Laurenti, 1768, has priority over _Hyla rubra_ Daudin, 1802. Since both Laurenti and Daudin worked on Seba's material, it is reasonable to assume that Daudin redescribed the same frog that was named by Laurenti; this was not an uncommon practice in the early nineteenth century. Thus I conclude that _Hyla rubra_ Daudin, 1802, is a junior synonym of _Hyla rubra_ Laurenti, 1768.

Dunn (1931a:413) first reported _Hyla rubra_ from Central America; he recorded the species from the Canal Zone and San Pablo, Panamá. I have examined the material of _Hyla rubra_ from Panamá deposited in various museums. Most of the specimens are faded, discolored, and do not have distinct brown vermiculations on the thighs. The specimens seem to be more like _Hyla rubra_ than any of the other species in the _rubra_ group. The presence of oval choanae and a tympanum larger than the largest finger disc separate these specimens from _Hyla elaeochroa_, a species with which _rubra_ has been confused. _Hyla elaeochroa_ does not occur in the Canal Zone or eastern Panamá. All museum specimens from Nicaragua, Costa Rica, and western Panamá that have been called _Hyla rubra_, plus those mentioned by Dunn and Emlen (1932:25) and Dunn (1933:61) are _Hyla elaeochroa_.

The taxonomic status of the many South American populations referred to _Hyla rubra_ and of other populations now recognized as different species is not clear at the present time. Considerable variation in external characters and in cranial features has been observed in South American _rubra_. A review of the taxonomy of these populations is beyond the scope of this paper. Possibly the Central American specimens herein referred to _rubra_ will ultimately be found to be specifically distinct from those in Surinam. Since I have no osteological material from Central America, I have been unable to describe the cranium in this account. Furthermore, I have no data on the ecology and life history of _rubra_ in Central America.

_Distribution._--_Hyla rubra_ inhabits lowland tropical forests from central-eastern Panamá to northern South America and thence through lowlands east of the Andes to northern Argentina (Fig. 6).

_Specimens Examined._--Panamá: _Canal Zone_: Gatun, UMMZ 52720 (2); Madden Dam, FMNH 67820; no specific locality, UMMZ 56517 (3), USNM 37863. _Colón_: Cerro Bruja, MCZ 13248. _Darién_: El Real, USNM 140569-70, 140573. _Panamá_: Juan Díaz, MCZ 17973; Las Sabanas, MCZ 17581; Río Trinidad, UMMZ 64003; San Pablo, MCZ 1398-9.

_Hyla elaeochroa_ Cope

_Hyla elaeochroa_ Cope, Jour. Acad. Nat. Sci. Philadelphia, 8:105, 1876 [Holotype.--USNM 30689, Sipurio, Limón Province, Costa Rica; William M. Gabb collector]. Günther, Biologia Centrali-Americana, Reptilia and Batrachia, p. 265, June 1901. Taylor, Univ. Kansas Sci. Bull., 35:859, July 1, 1952. Duellman, Univ. Kansas Publ., Mus. Nat. Hist., 17:270, June 17, 1966.

_Hyla quinquevittata_ Cope, Proc. Amer. Philos. Soc., 23:273, April 1887 [Holotype.--USNM 14187, Nicaragua; J. F. Bransford collector]. Günther, Biologia Centrali-Americana, Reptilia and Batrachia, p. 268, June 1901. Noble, Bull. Amer. Mus. Nat. Hist., 38:340, June 1918.

_Hyla rubra_ (part): Dunn and Emlen, Proc. Acad. Nat. Sci. Philadelphia, 84:25, March 22, 1932.

_Hyla dulcensis_ Taylor, Univ. Kansas Sci. Bull., 39:37, November 18, 1958 [Holotype.--KU 32168, Golfito, Puntarenas Province, Costa Rica; Edward H. Taylor collector].

_Diagnosis._--Size medium (Male to 38 mm., Female to 40 mm.); skull wider than long; nasals truncate anteriorly; frontoparietal fontanelle moderate in size; snout slightly protruding; tympanum about size of largest discs on fingers; dorsum marked by longitudinal stripes; dark stripe between eye and nostril; in life tan to olive-green with or without dark mark between eyes; bones greenish blue.

_Description._--Head flat, longer than wide; snout long, rounded, protruding beyond mouth; canthus indistinct; length of eye equal to interorbital distance; loreal region not pronounced; tympanum distinct and about two-fifths diameter of eye; interorbital triangle present or absent; arms short; trace of web between fingers, extending as fringe along sides of fingers; first finger very short with small disc; other discs about size of those on toes; discs on third finger and fourth toe as large as tympanum; outer palmar tubercle moderate in size, partly bifid; inner palmar tubercle large, elongate, flat; subarticular tubercles distinct; legs moderately long; tarsal fold absent; inner metatarsal tubercle flat; outer metatarsal tubercle smaller, indistinct; subarticular tubercles moderate in size; fringe on toes to tip of disc of second toe; rest of toes about two-thirds webbed; foot length about two fifths snout-vent length; tibia length about one half snout-vent length; skin above smooth or with minute pustules; belly finely granular; ventral surfaces of thighs and areas below anus granular; skin on ventral surfaces of limbs smooth; tongue relatively large, longer than wide, barely notched behind; vocal slits elongate, lateral to tongue; choanae medium in size. In life, dorsum yellowish brown, olive green, or grayish brown with dark brown spots on snout, dark brown stripe from nostril to eye, dark yellow-brown interorbital triangle, and dark supratympanic region; generally five interrupted longitudinal dark brown stripes on dorsum (one on each flank, pair of paravertebral and one vertebral); flanks pale yellow; groin yellowish brown; thighs marked with one or two transverse yellow-brown blotches; shanks with two or three yellow-brown blotches above; spaces between blotches on thighs, shanks, tarsi, and feet yellow; brown spots on tarsi and in some specimens on feet; arm pale yellow with pale brown spots; belly creamy white having slight blue-green tint; vocal sac and chin yellow; axillary region yellow, blue-green in some specimens (Pl. 2A).

In preservative, head and dorsum yellowish brown; dark brown stripe from nostril to eye; dark brown spots on snout; a dark brown interorbital triangle with apex directed backward; dark brown supratympanic region; dorsal stripes same as in living individuals; flanks pale yellow with brown spots in some specimens; groin creamy white; thighs and shanks having or lacking transverse dark brown blotches; spaces between blotches creamy white or yellow-brown; arms pale yellowish brown; belly and vocal sac creamy white.

_Variation._--Geographic variation in size and some proportions, such as the ratio of tibia length to snout-vent length and the ratio of the diameter of the tympanum to that of the eye, have been observed in this species. The largest individuals are from the Golfo Dulce region (samples from Piedras Blancas and Rincón de Osa), Puntarenas Province, Costa Rica. The smallest individuals are from El Recreo, Zelaya Province, Nicaragua, and from the Caribbean lowlands of Costa Rica.

The diameter of the tympanum is proportionately larger (relative to the size of the eye) in males from Tilarán, Guanacaste Province; the tympanum is nearly as large in males from Piedras Blancas, Puntarenas Province, and Puerto Viejo, Heredia Province, Costa Rica. The lowest ratios occur in individuals from Almirante, Bocas del Toro, Panamá, in specimens from the Caribbean lowlands of Costa Rica (except Puerto Viejo), and in those from El Recreo, Zelaya Province, Nicaragua. In general, the tympanum is proportionately larger in females than in males; the tympanum is largest in females from the Pacific lowlands of Costa Rica (Table 5).

Color variation has been observed in individuals from the same population, as well as in individuals from different localities, between males and females, and from night to day. In life, most individuals from the Pacific lowlands of Costa Rica are dark tan to greenish gray above with dark brown longitudinal stripes that are entire or broken, but some specimens (mostly males) are dusky brown and lack longitudinal stripes or an interorbital triangle; females usually have the dark interorbital triangle and the stripes on the dorsum. Individuals from Turrialba, Cartago Province, Costa Rica, are pale olive-tan with olive-brown markings. Individuals from Puerto Viejo, Heredia Province, Costa Rica, are uniformly yellowish brown with or without dark longitudinal stripes. Specimens from El Recreo, Zelaya Province, Nicaragua, are like those from Puerto Viejo. Males from Almirante, Bocas del Toro, Panamá, are pale brown with dark brown longitudinal stripes and an indistinct interorbital triangle. Females have a distinct interorbital triangle and dark brown blotches on the thighs and shanks.

By night, the dorsum usually is pale yellow, and the belly is creamy white. By day, the dorsum is dark tan; the stripes and spots are darker, and the belly is yellowish white. Taylor (1952) noticed that considerable variation in color pattern occurred from night to day in individuals from Turrialba, Cartago Province, Costa Rica. At night some individuals lacked a dorsal pattern, but by day many of these individuals developed dorsal stripes.

_Cranial Osteology._--The skull of _Hyla elaeochroa_ is slightly wider than it is long, and flat. The premaxillary is small and bears 10 to 15 teeth (mean for 9 specimens, 12.3). The alary process of the premaxillary is small, vertical, and slightly concave posteriorly. Ventrally, the premaxillary is partially united to the prevomer by ossification. The maxillary is slender and bears 70 to 82 teeth (mean for 9 specimens, 74.3). The pars facialis of the maxillary is laterally convex and is about twice as high as the pars dentalis.

The nasal is large, robust, anteriorly truncate, but pointed posteriorly in dorsal view. The nasal comprises about 45 per cent of the total length of the skull. There is an anterior cartilaginous septum nasi separating the two nasals; the latter overlap the sphenethmoid posteriorly. Each nasal bears a shallow concavity in the midlateral side and lacks a maxillary process. Dorsally, the sphenethmoid is wider than long, roughly pentagonal in shape; the frontoparietal is elongate, smooth, and bears a small anterior supraorbital process. The sphenethmoid and frontoparietal form the anterior margin of the frontoparietal fontanelle; the fontanelle is narrow anteriorly and wider posteriorly (Fig. 5B).

The entire distal surface of the proötic is in contact with the posterior arm of the squamosal. A narrow cartilaginous crista parotica is visible dorsally in some specimens. The squamosal is broad posteriorly but its anterior arm is slender and not in contact with the maxillary.

TABLE 5.--Geographic Variation in Size and Proportions in Males of _Hyla elaeochroa_. (Means in parentheses below observed ranges.)

========================================================================== | |Snout-vent| Tibia | | | | length | length/ |Tympanum/|Foot length/ Locality | N | (mm.) | snout-vent | eye | snout-vent ---------------------+----+----------+------------+---------+------------- Nicaragua: El Recreo | 9 | 28.0-30.3| 0.51-0.57 |0.47-0.59| 0.39-0.54 | | (29.3) | (0.55) | (0.51) | (0.41) | | | | | Costa Rica: Tilarán | 21 | 28.8-33.6| 0.47-0.57 |0.48-0.65| 0.40-0.46 | | (30.6) | (0.52) | (0.59) | (0.41) | | | | | Costa Rica: Puerto | 22 | 26.3-32.4| 0.49-0.54 |0.48-0.65| 0.38-0.45 Viejo | | (29.7) | (0.52) | (0.57) | (0.42) | | | | | Costa Rica: Turrialba| 95 | 28.1-35.0| 0.47-0.56 |0.47-0.68| 0.37-0.46 | | (30.6) | (0.51) | (0.56) | (0.41) | | | | | Costa Rica: Bataán, | 26 | 26.3-32.7| 0.47-0.54 |0.45-0.66| 0.36-0.44 Limón, and Suretka | | (30.0) | (0.51) | (0.50) | (0.41) | | | | | Costa Rica: Piedras | 21 | 33.3-37.7| 0.50-0.54 |0.48-0.64| 0.40-0.46 Blancas | | (35.2) | (0.51) | (0.57) | (0.43) | | | | | Costa Rica: Rincón de| 24 | 31.4-35.9| 0.50-0.56 |0.45-0.61| 0.40-0.46 Osa | | (34.1) | (0.53) | (0.54) | (0.43) | | | | | Panamá: Bocas del | 6 | 31.0-33.5| 0.49-0.54 |0.47-0.50| 0.41-0.43 Toro | | (32.1) | (0.51) | (0.48) | (0.42)

The prevomer is short, and broadest anteriorly. The prevomer is joined to the premaxillary by ossification. The posterior margin of the prevomer bears a narrow cartilaginous articulation with the sphenethmoid. The anterolateral and posterolateral processes of the prevomer form an incomplete bony margin to the small choanae; each prevomer bears four to seven teeth. The palatine is small, curved anteriorly and edentate. The anterior part of the parasphenoid is robust and ends in a point. The pterygoid is slender and weakly developed.

_Natural History._--_Hyla elaeochroa_ inhabits humid lowland tropical forests in lower Central America and breeds in temporary ponds. Clasping pairs, gravid females, and calling males have been found mostly in June, July, and August. William E. Duellman informed me that he also found males calling in mid-February, late April, and May. Duellman (1967) reported detailed observations of the social organization in the mating call of _Hyla elaeochroa_. The choruses in this species are initially organized, but when many individuals call, the chorus loses organization. I observed this species breeding in a temporary pond at Puerto Viejo, Heredia Province, Cost Rica, in late June. Calling males and clasping pairs were extremely abundant within a few hours after a heavy rain. Males were mostly found calling from low emergent herbs in the pond and less commonly from bushes and trees to heights of six meters above the water. Calling males were also observed at Ricón de Osa, Puntarenas Province, Costa Rica, in late July. These breeding individuals were found in a shallow pond at the edge of a wet forest. Calling stations were less than two meters in height. John D. Lynch informed me that after a heavy rain in early August, he found several hundred individuals congregated in a small grassy pond less than a foot deep, at Rincón de Osa. Males were calling from sites on grass stems a few centimeters above the water.

The mating call of _Hyla elaeochroa_ consists of short notes, repeated at intervals of about 0.40 second. Each note has a duration of 0.12 to 0.24 second. The fundamental frequency varies from 48 to 65 cycles per second, and the notes have 40-50 pulses per second; the dominant frequency is at about 2,900 cycles per second (Table 2, Pl. 4A).

The eggs are deposited in a mass in the water near floating vegetation. William E. Duellman informed me that he observed hatchlings oriented vertically with the tip of the mouth at the surface of the water. They gradually sank to bottom, but swam back to surface again. No additional information is available concerning early development. Tadpoles have been found in shallow grassy ponds in clearings and in temporary woodland ponds.

_Tadpoles._--Three hundred and thirty-one tadpoles in various stages of development are available. Thirty-five tadpoles in stage 35 have a mean body length of 8.1 mm. (8.0-9.0 mm.), tail length of 17.7 mm. (15.0-19.5 mm.), and total length of 25.9 mm. (23.0-27.5 mm.). The largest tadpole examined is in stage 40 and has a total length of 34.5 mm. (Table 6).

A typical tadpole, stage 35 of development (KU 104134, from Puerto Viejo, Heredia Province, Costa Rica), has a body length of 9.1 mm., tail length of 17.7 mm., and a total length of 26.8 mm. Other characters are as follows: body depressed anteriorly; body length greater than depth of tail; internarial space as broad as interorbital distance; nostril equidistant between eye and tip of snout; eyes moderately large; mouth anteroventral and triangular; median fourth of upper lip bare; rest of lip bordered by one row of papillae; clumps of small papillae at corners of mouth; tooth rows 2/3; upper rows equal in length; second row interrupted medially; lower rows shorter than upper rows, diminishing in length; beak rather weak with small serrations; spiracle short and nearer eyes than anus; anal opening not reaching edge of ventral fin; caudal musculature attenuated distally (Figs. 2B and 3B).

TABLE 6.--Sizes of Tadpoles of _Hyla elaeochroa_ in Relation to Developmental Stages. (Means in parentheses below observed ranges; measurements in mm.)

------+---+-------------+-------------+-------------- Stage | N | Body length | Tail length | Total length ------+---+-------------+-------------+-------------- 24 | 2 | 4.0-4.0 | 8.5-9.0 | 12.5-13.0 | | (4.0) | (8.8) | (12.8) | | | | 25 |64 | 5.0-6.5 | 8.5-15.0 | 13.5-21.5 | | (5.7) | (11.8) | (17.6) | | | | 27 |30 | 7.0-7.5 | 13.0-16.0 | 20.0-23.0 | | (7.1) | (14.2) | (21.3) | | | | 30 |15 | 7.0-8.0 | 13.0-16.5 | 20.0-24.0 | | (7.3) | (15.0) | (22.4) | | | | 32 |30 | 7.5-8.5 | 15.0-17.0 | 22.5-25.0 | | (7.8) | (16.1) | (23.8) | | | | 35 |35 | 8.0-9.0 | 15.0-19.5 | 23.0-27.5 | | (8.1) | (17.7) | (25.9) | | | | 37 |22 | 8.5-9.5 | 16.0-22.0 | 25.0-31.0 | | (9.0) | (18.8) | (27.8) | | | | 39 |14 | 9.5-10.5 | 19.0-24.9 | 28.5-33.5 | | (9.9) | (21.1) | (31.0) | | | | 40 |27 | 7.0-11.5 | 15.0-23.0 | 23.0-34.5 | | (9.1) | (22.0) | (31.2) | | | | 43 |10 | 8.0-12.0 | 11.0-17.0 | 20.0-26.0 | | (10.2) | (13.5) | (23.7) | | | | 45 |16 | 10.0-12.0 | 1.0-7.0 | 12.0-17.0 | | (11.2) | (3.4) | (14.6) | | | | 46 |45 | 11.0-13.0 | | | | (11.8) | |

In life, dorsum yellowish tan with gray-brown mottling; belly and ventrolateral surfaces silvery-gold or white; black stripe from tip of snout to eye; two black blotches below eye, another blotch extending from eye to base of caudal musculature; caudal musculature and fins gray-brown. In preservative, yellowish tan and silvery-gold colors lost; black reticulations present on tail.

_Remarks._--Cope (1876:105) described _Hyla elaeochroa_ from Sipurio, Limón Province, Costa Rica. He based his description on a small specimen, 26.0 mm. in snout-vent length, having a dorsum uniformly colored and lacking an interorbital triangle and blotches on the thighs. Cope (1887) described pigmented specimens from Nicaragua as _Hyla quinquevittata_, which he diagnosed as having dark brown bars on the hind limbs and five dark brown longitudinal stripes on the dorsum, the median one of which was expanded anteriorly so as to form a large triangular spot between the eyes. He thought this species was related to _Hyla eximia_ Baird and noted that "the hinder legs are much larger; the muzzle is more acuminate and the color bands are much wider" than in _eximia_. Cope did not compare _quinquevittata_ with _elaeochroa_, which he had described ten years before. Günther (1901:268), Noble (1918:340), and Nieden (1923:251) regarded both _elaeochroa_ and _quinquevittata_ as valid species. Dunn and Emlen (1932:25) regarded both as synonyms of _Hyla rubra_, but they made no qualifying statements. Taylor (1952:859) placed _quinquevittata_ as a synonym of _elaeochroa_ and indicated that _rubra_ was another species.

Taylor (1958:37) described _Hyla dulcensis_ from the humid tropical forests of Golfo Dulce, Puntarenas Province, Costa Rica. He thought this species was "related to _H. elaeochroa_ but differs in its somewhat larger size, smaller finger and toe discs, the obsolete canthus rostralis; the loreal region concave and the choanae larger." Duellman (1966a:270) compared adults, tadpoles, and mating calls of _dulcensis_ and _elaeochroa_ and concluded that a single species was involved.

_Hyla elaeochroa_ can be easily confused with the closely related _Hyla staufferi_. Although the durations of the calls are similar, the call of _elaeochroa_ has only about one third the number of pulses per second, a much lower fundamental frequency, and a lower dominant frequency than that of _staufferi_. _Hyla elaeochroa_ is larger and has a less pointed snout than does _staufferi_. Although the skulls of the two species are similar, that of _elaeochroa_ differs in having broad palatines and comparatively larger nasals that are truncate anteriorly. In _staufferi_ the nasal is rounded anteriorly and the palatine is absent.

_Distribution._--_Hyla elaeochroa_ occurs on the Caribbean lowlands from western Panamá through Costa Rica to eastern Nicaragua, and on the Pacific lowlands of southeastern Costa Rica and extreme western Panamá. Most localities where it has been collected are below 800 meters, but the species has been found at two localities above 1000 meters (El Silencio and Pacuare, Cartago Province) on the Caribbean slopes of the Cordillera de Talamanca, Costa Rica (Fig. 6).

_Specimens Examined._--Nicaragua: _Zelaya_: El Recreo, UMMZ 79721 (9).

Costa Rica: _Alajuela_: Laguna Monte Alegre, KU 64499. _Cartago_: 2 km E Chitaría, KU 107058; El Silencio, 14.4 km NE Turrialba, KU 107059-60; 4.6 km ENE Pacuare, KU 64451-75, 64628-37; 4 km S Pavones, KU 64500; Turrialba (Instituto Interamericano de Ciéncias Agrícolas), KU 30305-26, 24616-57, 30337-54, 31776-91, 31803, 31807-15, 64413-50, 68283-87 (skeletons), 68390-1 (young), 35042 (eggs), 25207-8 (skeletons), 25221 (skeleton), 41073-83 (skeletons). _Guanacaste_: 2 km E Tilarán, KU 86356-77, 87667-8 (young). _Heredia_: Puerto Viejo, KU 36696, 46466, 64501-17, 68288-91, 68387, 68388-9 (young), 91803 (young), 91688-9, 104134 (tadpoles), 104135 (young), 104354-6 (skeletons); 1.5 km N Puerto Viejo, KU 64518-23, 68386 (tadpoles); 1 km S Puerto Viejo, KU 84985-6 (skeletons), 87669 (young), 87772-3 (skeletons). _Limón_: Bataán, KU 30327-36; La Lola, KU 64478-98, 68281-2 (skeletons); Los Diamantes, KU 31800-02, 64476-7; Peralta, KU 31816-21; Puerto Limón, KU 31792-99; Suretka, KU 36467-79, 36697, 41084. _Puntarenas_: 5 km NW Buenos Aires, KU 107057; 10 km E Esparta, KU 87666 (tadpoles); Golfito, KU 32166-8; 8 km E Palmer Norte KU 93939; 10.7 km SE Palmar Sur, KU 93938 (skeleton), 93940-51, 93952 (eggs), 93953-6 (tadpoles); Piedras Blancas, KU 103646-59; 4.5 km W Rincón de Osa, KU 102208-41, 104298 (tadpoles).

Panamá: _Bocas del Toro_: Almirante, KU 80079; Isla Bastimentos, KU 96008-11; Río Cricamola, 3.7 km from coast, KU 96012. _Chiriquí_: Río Gariché, 8.3 km ESE Paso de Canoas, KU 101571-2.

_Hyla staufferi_ Cope

_Hyla staufferi_ Cope, Proc. Acad. Nat. Sci. Philadelphia, 17:165, October 1, 1865 [Holotype.--USNM 15317, Orizaba, Veracruz, México; Francis Sumichrast collector].

_Diagnosis._--Small frogs (Male to 29 mm., Female to 31.6 mm.); skull longer than wide; palatine absent; large cartilaginous crista parotica present; snout flat, elongate and protruding; dark interorbital bar and dorsal stripes usually present.

_Description._--Head flat, especially in females, longer than wide; snout long, protruding beyond mouth; loreal region concave; canthus ill-defined; length of eye greater than internarial distance or width of eyelid; length of eye less than interorbital space; tympanum distinct; interorbital spot irregular; supratympanic fold faint; arms short; fingers free of webs; discs on third and fourth fingers equal to diameter of tympanum; inner metatarsal tubercle on base of first finger distinct; first finger shorter than second; palmar tubercle distinct (Fig. 1C); legs short (usually less than 50 per cent of snout-vent length); tarsal fold absent; metatarsal tubercles small, outer tubercle smaller than inner; subarticular tubercles small, simple, distinct; toes less than half webbed (Fig. 1D); skin smooth above with a few small pustules on head, scapular region, flanks, and supratympanic region; arms and legs smooth; skin of belly coarsely granular; posteroventral surfaces of thighs finely granular; tongue small, rounded, longer than wide, slightly free and notched posteriorly; vocal slits small, lateral to tongue; choanae moderate in size.

_Variation._--The largest males of _Hyla staufferi_ are from Jalapa, Guatemala, and from San Salvador, El Salvador. In these samples the average snout-vent length is 27 mm. In Panamanian specimens the average snout-vent length is 23.6 mm. Slight variation in the ratio of tibia length to snout-vent length exists throughout the range; more variation exists in the ratio of the diameter of the tympanum to that of the eye; the tympanum is proportionately larger in northern populations (Table 7). The primary differences between Panamanian and more northern populations are in size, color pattern on the dorsum and shanks, amount of webbing between the toes, and duration of notes in the mating call (Table 2, Pl. 4).

The color in Panamanian _staufferi_ is gray or gray-brown with a pair of distinct, complete, dark brown dorsolateral stripes, a pair of entire paravertebral stripes, and in some specimens a vertebral stripe. About five per cent of the individuals have interrupted stripes on the dorsum, whereas in the more northern populations complete paravertebral stripes are present in less ten per cent of the specimens; when complete stripes are present, they are irregular. The dorsal ground color in non-Panamanian specimens is brown, olive-brown, or dark brown.

Transverse bars are present on the shanks in _Hyla staufferi_ from Costa Rica northward to México, whereas in Panamá all the individuals have a longitudinal stripe on the shank (Table 7, Pl. 2). The interorbital spot or bar is more noticeable in northern populations than in specimens from Panamá. Frogs from Costa Rica and northward have the toes about three fourths webbed, whereas in Panamá the toes are about two fifths webbed. The mating calls of the northern and Panamanian populations are similar, but the notes have a longer duration in the northern populations and a higher dominant frequency in Panamanian populations.

_Hyla staufferi_ is the most variable member of the _Hyla rubra_ group in Central America. The Panamanian populations are geographically separated from the Costa Rican and more northern populations by an area of tropical rainforest in the Golfo Dulce region in southeastern Costa Rica and adjacent Panamá. _Hyla staufferi_ does not occur on the Caribbean versant of Costa Rica and Panamá. The Golfo Dulce region and the Caribbean versant are humid and inhabited by _Hyla elaeochroa_. _Hyla staufferi_ is an inhabitant of subhumid and xeric areas.

On the basis of the discontinuous variation in several characters which correlate with the disjunct distribution of the two populations, two subspecies of _Hyla staufferi_ are recognized. The accounts that follow apply equally to each.

_Cranial Osteology._--The skull of _Hyla staufferi_ is flat and longer than wide. The premaxillary is small and bears 9 to 13 teeth (mean for 5 specimens, 11.3). The alary process of the premaxillary is small, concave posteriorly and vertical. Ventrally, the premaxillary is united to the prevomers by partially ossified cartilage. The maxillary is slender and usually bears 49 to 70 teeth (mean for 5 specimens, 60.7). The pars facialis of the maxillary is convex and less than twice the height of the pars dentalis.

The nasal is large, rounded anteriorly, and pointed posteriorly in dorsal view. The nasal comprises about 40 per cent of the total length of the skull. Anteromedially the two nasals converge; posteriorly they overlap the sphenethmoid. The nasals lack a concavity in the midlateral surface. Dorsally, the sphenethmoid is wider than long, roughly pentagonal in shape; the frontoparietal is elongate, narrow, and smooth, with a small supraorbital process anteriorly. The frontoparietal fontanelle is narrow anteriorly and wide posteriorly.

TABLE 7.--Geographic Variation in Size and Color in Males of _Hyla staufferi_. (Means in parentheses below observed ranges.)

================================================================= | | |Complete dorsal| | |Snout-vent | stripes |Barred shanks Locality | N |length (mm.)| (per cent) | (per cent) ---------------+-----+------------+---------------+-------------- Veracruz | 47 | 23.0-27.3 | 0.0 | 100 | | (25.4) | | | | | | Campeche | 20 | 24.6-27.5 | 0.0 | 100 | | (25.5) | | | | | | Oaxaca | 75 | 24.0-28.7 | 9.3 | 100 | | (26.4) | | | | | | Chiapas | 20 | 23.2-27.8 | 10.0 | 100 | | (25.5) | | | | | | Guatemala | 22 | 25.0-29.0 | 10.9 | 100 | | (26.9) | | | | | | El Salvador | 21 | 24.7-28.6 | 0.0 | 100 | | (27.0) | | | | | | Honduras | 34 | 20.6-27.0 | 3.3 | 100 | | (24.9) | | | | | | Nicaragua | 67 | 21.5-26.8 | 3.0 | 92.7 | | (24.9) | | | | | | Costa Rica | 54 | 20.7-26.6 | 5.5 | 98.1 | | (24.2) | | | | | | Total | 360 | 20.7-29.0 | 5.4 | 98.3 Non-Panamanian | | (25.9) | | | | | | Panamá | 72 | 21.7-26.0 | 94.5 | 0.0 | | (23.6) | |

Only a narrow connection exists between the posterior, pointed arm of the squamosal and the lateral edge of the proötic. The crista parotica is visible dorsally along the lateral edge of the bony proötic. The squamosal is narrow anteriorly and posteriorly.

The prevomers are short and separated anteriorly by partly ossified cartilage of the overlying solum nasi. The prevomer is joined to the premaxillary by cartilage. The posterior margin of the prevomer articulates directly with the sphenethmoid. The anterolateral and posterolateral processes of the prevomers form the incomplete bony internal margin of the choanae. Each prevomer bears three to six teeth. The palatine is absent. The anterior part of the parasphenoid is narrow and ends in a point. The pterygoid is slender and weakly developed.

_Natural History._--Throughout its range _Hyla staufferi_ occurs in subhumid forests and savannas; consequently, the breeding activities are limited by the seasonal occurrence of rainfall, which accumulates in temporary ponds where this species breeds. Clasping pairs and gravid females have been found mostly from June to August throughout its range. This species was observed calling at Finca Taboga, Guanacaste Province, Costa Rica, in mid-July. The males were calling from temporary grassy and weedy ponds in which _Hyla microcephala_ also was calling, but the two species had different calling sites. _Hyla staufferi_ called at stations at heights of five to 80 cm. near the edge of the pond, whereas _Hyla microcephala_ called from emergent vegetation in the middle of the pond. Charles W. Myers informed me that at Penonomé, Coclé, Panamá, he found _staufferi_ calling from grass in puddles where _microcephala_ was absent, and at El Caño, Coclé, Panamá, _staufferi_ was calling from higher sites ("several inches to a few feet above water") than _microcephala_.

Stuart (1948:34) reported breeding individuals from La Libertad, Guatemala, after rainfall in late May, and Schmidt and Stuart (1941:239) reported _staufferi_ breeding in July in the Salamá basin, Alta Verapaz, Guatemala. Stuart (1935:38) and Duellman (1960:63 and 1963:226) agreed that this species breeds early in the rainy season. However, Rand (1957:519) stated that in El Salvador "these frogs did not begin to call until almost a month and a half after the beginning of the rains." Blair (1960:133) reported that males call in June and July in Chiapas, Oaxaca, Veracruz, and Tamaulipas, México.

The mating call of this species is a series of closely spaced notes having a fundamental frequency of about 100 cycles per second. Each note has a duration of 0.13 to 0.23 second, repeated at intervals that are longer than the duration of the call. The notes are moderately low-pitched and have a dominant frequency of more than 3,000 cycles per second and about 120 pulses per second (Table 2).

_Tadpoles._--Measurements of the 33 tadpoles that are available are given in Table 8. The largest tadpole examined is in stage 38 and has a total length of 29.5 mm.

A typical tadpole in stage 38 of development (KU 104162, 5 km ESE Córdoba, Veracruz, México) has a body length of 10 mm., tail length of 19.5 mm., and a total length of 29.5 mm. Other characters are as follows: body as deep as wide, depressed anteriorly; body as long as depth of tail; interorbital space greater than distance between eye and snout but equal to internarial space; nostril equidistant between eye and tip of snout; distance between spiracle and eye less than distance between eye and snout; eyes large, situated dorsolaterally; mouth anteroventral, approximately triangular in outline; one row of papillae covering lower lip and all except median fourth of upper lip; scattered papillae at corners of mouth; tooth rows 2/3; first upper row entire, second row interrupted medially, shorter than first; lower rows shorter than upper rows; beak weak; spiracle short and nearer eyes than anus; anal opening not reaching edge of ventral fin; dorsal fin barely extending onto body; caudal musculature pointed distally.

TABLE 8.--Sizes of Tadpoles of _Hyla s. staufferi_ in Relation to Developmental Stages. (Means in parentheses below observed ranges; measurements in mm.)

====================================================== Stage | N | Body length| Tail length | Total length --------+---+------------+-------------+-------------- 25 | 3 | 6.0-7.0 | 12.0-13.0 | 18.0-20.0 | | (6.7) | (12.5) | (19.2) | | | | 26 | 2 | 7.0-7.5 | 14.0-15.0 | 21.5-22.0 | | (7.3) | (14.5) | (21.8) | | | | 27 | 9 | 7.0-8.0 | 13.0-17.0 | 21.0-25.0 | | (7.6) | (14.5) | (22.0) | | | | 32 | 1 | 8.5 | 15.5 | 24.0 | | | | 36 | 2 | 8.0-10.0 | 16.5-17.0 | 25.0-26.5 | | (9.0) | (16.8) | (25.8) | | | | 38 | 6 | 9.0-10.0 | 19.0-20.5 | 28.0-29.5 | | (9.6) | (19.5) | (29.1) | | | | 41 | 1 | 10.0 | 14.0 | 24.0 | | | | 42 | 6 | 11.0-14.0 | 10.0-13.0 | 20.0-29.0 | | (11.8) | (11.9) | (24.8) | | | | 45 | 1 | 12.5 | 0.5 | 13.0 | | | | 46 | 1 | 13.0 | -- | --

In life, body pale olive-tan, belly silvery white with pinkish-orange reticulations in some specimens; tail creamy white with silvery flecks and black or brown reticulations. In preservative, tan and pinkish-orange coloration lost; body transparent, reticulations on tail present.

_Remarks._--_Hyla staufferi_ was described by Cope (1865:195) on the basis of specimens from Orizaba, Veracruz, México. He described the color pattern as "color above dark olive, with a short black bar over each scapula, and one from eye to eye, with a trace along the coccyx." Cope (1887:14) placed _staufferi_ as a subspecies of _Hyla eximia_, but he did not justify his action. Günther (1901:262) also considered _staufferi_ to be conspecific with _eximia_ without making any qualifying statement. Dunn and Emlen (1932:24) named _Hyla culex_ from Tela, Honduras, on the basis of a male (MCZ 16098) having a snout-vent length of 25.1 mm., and a female (USNM 20267) from Patuca, Honduras. They diagnosed the species as having "discs larger than tympanum ... black interorbital triangle, traces of black dorsal marking; three black bars on anterior and posterior face of thighs, two black bars on tibia, on tarsus and on forearm." The holotype now is faded but has some of the pattern described. Dunn and Emlen did not compare _culex_ with _staufferi_ but did compare it with _boulengeri_ and _rubra_.

Dunn (1933:61) named _Hyla altae_ from Summit, Canal Zone. His description was based on a male (MCZ 17972) having a snout-vent length of 25.1 mm., the color pattern was described as "gray with four darker dorsal stripes ... a faint trace of mid-dorsal striping...." Dunn defined the _Hyla rubra_ group and recognized _boulengeri_, _altae_, _culex_, and _rubra_ as members. _Hyla elaeochroa_ and _staufferi_ were omitted from his key to the group in Central America.

Kellogg (1932:174) compared _staufferi_ with _eximia_ and concluded that the two were probably distinct species. Stuart (1935:38) considered _altae_ to be a synonym of _culex_. Gaige (1936:293) considered _altae_ and _culex_ to be conspecific but regarded _staufferi_ as a different species. She also suggested that _staufferi_ was not related to _eximia_ but belonged to the _rubra_ group. Taylor (1952:865) and Duellman (1966a:274) considered _altae_ and _culex_ to be synonyms of _staufferi_.

The only other worker besides Cope and Günther to consider _Hyla staufferi_ as a member of the _eximia_ group was Blair (1960:129), who suggested the relationship on the basis of similarities in the structure of the calls of _eximia_ and _staufferi_. Taylor (1938:421) and Smith and Taylor (1948:78) excluded _staufferi_ from the _eximia_ group on the basis of morphological characteristics. I consider _culex_ to be inseparable from _staufferi_, whereas _altae_ is recognizable as a Panamanian subspecies of _staufferi_.

_Hyla staufferi staufferi_ Cope, New Combination

_Hyla staufferi_ Cope, Proc. Acad. Nat. Sci. Philadelphia, 17:195, October 1865 [Holotype.--USNM 15317, Orizaba, Veracruz, México; Francis Sumichrast collector], Brocchi, Mission Scientifique au Mexique et dans L'Amerique Centrale, 1881, p. 36. Boulenger, Catalogue, of the Bratrachia Salientia s. Ecaudata, p. 400, February 1, 1882. Kellogg, Bull. U.S. Natl. Mus., 160:173, March 31, 1932. Smith and Taylor, Bull. U.S. Natl. Mus., 194:88, 1948. Taylor, Univ. Kansas Sci. Bull., 35:862, July 1, 1952. Rand, Fieldiana Zool. Chicago Nat. Hist. Mus., 34:518, April 18, 1957. Duellman, Univ. Kansas Publ, Mus. Nat. Hist., 17:274, June 17, 1966.

_Hyla eximia staufferi_ Cope, Bull. U.S. Natl. Mus., 32:14, January 16, 1887.

_Hyla eximia_ (part): Günther, Biologia Centrali-Americana, Reptilia and Batrachia, p. 261, June 1901. Nieden, Das Tierreich, Anura I, p. 245, June 1923.

_Hyla culex_ Dunn and Emlen, Proc. Acad. Nat. Sci. Philadelphia, 84:24, March 22, 1932 [Holotype.--MCZ 16098, Tela Honduras; Raymond A. Stadelman collector]. Stuart, Misc. Publ., Univ. Michigan Mus. Zool., 29:38, October 1935. Gaige, Carnegie Inst. Washington Publ., 457:293, 1936.

_Diagnosis._--Small frogs (Male to 29 mm., Female to 31.6 mm.); dorsolateral stripes irregular; paravertebral stripes usually broken; two or three transverse bars on shanks; thighs spotted or not; arms usually barred; interorbital bar usually present; toes about three fourths webbed; color brown, tan, or olive-green.

_Variation._--Three hundred and sixty males chosen at random from throughout the range have snout-vent lengths of 20.7 to 29 mm. (25.9 mm.). The smallest individuals are from Costa Rica and Nicaragua (means 24.2 and 24.4 mm., respectively). The largest individuals are from Guatemala and El Salvador (mean of each 27.0 mm.). The ratio of the diameter of the tympanum to that of the eye is more than 60 per cent in most samples, but in those from Costa Rica and British Honduras it is smaller. The color pattern is highly variable. Some specimens are dark brown or pale brown in color. Incomplete dorsal stripes are present in 94.6 per cent of the specimens, and transverse bars are present on the shanks in 98.3 per cent of the specimens. The interorbital spot varies from transverse to longitudinal in position, and an irregular white line extends from the upper jaw to the arm in some specimens (Table 7).

_Distribution._--_Hyla staufferi staufferi_ inhabits savanna and subhumid and xeric forests in the lowlands and moderate elevations from southern Tamaulipas southward to Nicaragua on the Caribbean versant and from Guerrero, México to northwestern Costa Rica on the Pacific lowlands (Fig. 7). Duellman (1963:226) commented that a specimen from Chinajá, Guatemala, possibly was transported there in the cargo from Toocog, because with this one exception the species is unknown in tropical rainforest in Guatemala.

_Specimens Examined._--México: _Campeche_: 5 km S Champotón KU 71296-7; 7 km W Escárcega, KU 71298-308; 13 km W, 1 km N Escárcega, KU 71309-10, 75090-4. _Chiapas_: 32 km S Arriaga, KU 57789-92; 4 km N Ixtapa, KU 5776-81; 3.6 km SW Las Cruces, KU 37740; 17 km S Las Cruces, KU 57793-4; 24 km S Las Cruces, KU 104160 (tadpoles); 11 km S Tapachula, KU 57782-8, 60000 (young). _Guerrero_: El Limoncito, near La Venta, KU 31392-401; Mexcala, near Balsa River, KU 31391; Organos, S El Trienta, KU 31390. _Oaxaca_: 26 km N Matías Romero, KU 33878-82; 2.5 km S Pochutla, KU 59924-7 (skeletons); 5 km S Pochutla, KU 57795-801; 3.2 km E Tapanatepec, KU 37877-902; 17.6 km WNW Tapanatepec, KU 65033-4; Temascal, USC 8243 (8); 3.2 km S Tolocita, KU 39657-8; 0.5 km Tuxtepec, KU 87073-81, 87610 (tadpoles); 17 km S Tuxtepec, KU 65035-7; 1 km W Zanatepec, KU 104161 (tadpoles). _Quintana Roo_: Isla Cozumel, 3.5 km N San Miguel, KU 71710-11 (young). _San Luis Potosí_: Valles, KU 31490. _Tabasco_: Teapa, UMMZ 118887 (3), 119203 (13); 9.6 km N Teapa, UMMZ 119202; 24 km N Teapa, UMMZ 119961 (5); 29 km N Teapa, UMMZ 119960; 3.5 km S Villahermosa, UMMZ 119201 (2); 17.6 km S Villahermosa, UMMZ 119200 (8). _Tamaulipas_: 1 km E Chamal, UMMZ 110706; Gómez Farías, UMMZ 110701 (3); 5 km SE Gómez Farías, UMMZ 110705; 8 km NE Gómez Farías, UMMZ 11282 (2), 11283 (3); Kilometer 615 between Río Limón and Llera, UMMZ 80455 (2); 5 km W San Geraldo, UMMZ 110702 (4), 110703 (3); 8 km W San Geraldo, near Río Frío, UMMZ 110704 (5). _Veracruz_: 3 km SW Boca del Río, KU 10494-8; 5 km SW Boca del Río, KU 23701; 5 km ESE Córdoba, KU 104162 (tadpoles); Cuautlapán, KU 57098-102, 26787; Hacienda Tamiahua, Cabo Rojo, KU 62871; 2 km ENE Mata Oscura, KU 105627; 5 km SE Paso del Toro, KU 40144; Portrero Viejo, KU 23911-2, 26786, 27413, 57094-7.

Guatemala: _Alta Verapaz_: Chinajá, KU 57769; Finca La Cubilquitz, UMMZ 90871, 90872 (5), 91379 (2). _Baja Verapaz_: 1 km S San Jerónimo, UMMZ 84077 (7), 84078 (14). _Chiquimula_: 1.6 km SE Chiquimula, UMMZ 98114 (2); Esquipulas, UMMZ 106784 (4), 106785 (14). _El Petén_: No specific locality, USNM 25143, 24825-6; La Libertad, FMNH 27096-7, KU 57770, UMMZ 75339 (15), 75340 (15), UMMZ 94341-2. _Esquintla_: 20 km N San José, AMNH 74369-76. _Guatamala_: 16 km NE Guatamala, KU 43539. Izábal: Puerto Barrios, TCWC 16671-73, 16646-56; 2.5 km NE Río Blanco, KU 57774-5. _Jalapa_: Jalapa, UMMZ 106788 (44). _Jutiapa_: Finca La Trinidad, UMMZ 107730 (12), 107731 (16); Jutiapa, UMMZ 106786 (2). _Zacapa_: 14 km ENE Mayuelas, KU 57773; 7 km ENE Río Hondo, KU 57771-2, 59999 (young).

British Honduras: BELIZE: Belize, FMNH 4406. _El Cayo_: San Agustín, UMMZ 80741 (8). _Stann Creek_: 10 km S Stann Creek on Hummingbird Highway, UMMZ 125720-1.

El Salvador: _Cuscatlán_: 7 km WNW Cojutepeque, TNHC 32004-10. _La Libertad_: 16 km NW Santa Tecla, KU 43540-1. _La Union_: 2.5 km Santa Rosa, TCWC 16669-70. _Morazán_: Dividendero, USNM 73288-92. _San Salvador_: San Salvador, FMNH 65101-06, KU 61932-44, 61989-92, 62152 (eggs), USNM 117588, 118391 (3), 118394; 1.6 km NW San Salvador, KU 43162-3.

Honduras: _Atlantidad_: Ceiba, USNM 117592. _Choluteca_: Choluteca, KU 85361-6; 2 km E Choluteca, UMMZ 118395 (7); 3.2 km NE Choluteca, KU 100500-01; 6.2 km E Choluteca, KU 65046-56; 10 km E Choluteca, KU 65045: 5 km S Choluteca, USC 2700 (4). _Colón_: Isla Guanaja (Islas de la Bahía), TCWC 21551, TNHC 32011. _Cortés_: Agua Azul, TCWC 19178-9; East side Lago Yojoa, KU 65038-44. _El Paraiso_: Valle de Jamastrán, AMNH 54800-04. _Francisco Morazán_: Escuela Agrícola Panamericana, AMNH 54963-73; 14.5 km NW Comayaguela, KU 100499; El Zamorano, KU 103224; 29 km N Tegucigalpa, TNHC 32003, 32012.

Nicaragua: _Chinandega_: Finca San Isidro, 10 km S Chinandega, KU 85311-33. _Managua_: 13 km E Managua, KU 85339; 2 km S Tipitapa, KU 85334-8. _Rivas_: 9.5 km SE Rivas, KU 85355-6; 18 km SE Rivas, KU 85354; 7.7 km NE San Juan del Sur, KU 85346-53; 16.5 km NE San Juan del Sur, KU 85340-5; 5 km SE San Pablo, KU 43151-61. _Zelaya_: Isla Grande del Maiz, KU 85357-60.

Costa Rica: _Alajuela_: _Los Chiles_, USC 7215 (2), 7217. _Guanacaste_: 4 km W Bagaces, USC 7019 (5); Finca Taboga, KU 102265-5; 12 km S La Cruz, USC 8091; Las Cañas, KU 41113 (skeleton); 27 km N Las Cañas, USC 8171 (5); Guardia, Río Tempisque, USC 8214; 10 km N Guardia, KU 102266-7; 1.6 km N Guayabo de Bagaces, USC 7023 (3); Liberia, KU 36510-22; 4 km W Liberia, KU 36449-64, USC 102 (10), 103 (9), 104 (7), 105; 6 km N Liberia. USC 8096; 8 km NNW Liberia, KU 65032; 14.5 km N Liberia, USC 8079, 8138 (2); 14.5 km S Liberia, USC 8238 (5); 6 km N Nicoya, USC 8229 (11); 4 km S Nicoya, USC 8230, 8231; Peñas Blancas, KU 102263; 8.6 km ESE Playa del Coco, USC 8137 (14); 21 km E Playa del Coco, USC 8138 (2); Santa Cruz, USC 8232 (2); 3 km E Santa Rosa, TCWC 16663-68; Tenorio, KU 32159; Tilarán, KU 36509. _Puntarenas_: 10 km WNW Esparta, KU 65022-9, 68614 (skeleton); 4.5 km WNW Esparta, KU 65030; 12 km WNW Esparta, KU 65031; 6 km E Esparta, KU 86477; Hotel Maribella, KU 32157-8; 3 km W Puntarenas, TCWC 16657-62.

_Hyla staufferi altae_ Dunn, New Combination

_Hyla altae_ Dunn, Occas. Papers Boston Soc. Nat. Hist., 8:61, June 7, 1933 [Holotype.--MCZ 17972, Summit, Canal Zone, Panamá; Emmett R. Dunn collector].

_Hyla culex_: Stuart, Misc. Publ. Univ. Michigan Mus. Zool., 29:38, October 1, 1935. Gaige, Carnegie Inst. Washington Publ., 457:293, 1936.

_Hyla staufferi_: Taylor, Univ. Kansas Sci. Bull., 35:862, July 1, 1952. Duellman, Univ. Kansas Publ., Mus. Nat. Hist., 17:274, June 17, 1966.

_Diagnosis._--Small frogs (Male to 26 mm., Female to 27 mm.); dorsolateral and paravertebral stripes complete; longitudinal dark gray stripe on shank; thighs unmarked; interorbital bar usually absent; toes about three fifths webbed; gray to brownish gray above.

_Variation._--_Hyla staufferi altae_ is less variable in size, proportions, and color pattern than is _H. s. staufferi_. The size varies from 21.7 to 26 mm. (23.6) in 72 males. The ratio of tibia to snout-vent length is 0.42 to 0.50 (0.45), slightly less than in the northern subspecies. In color pattern 94.5 per cent of the individuals have complete dorsal stripes, and all have a longitudinal stripe on the shank (Table 7).

_Distribution._--This subspecies is restricted to subhumid forests and savannas on the Pacific lowlands of Panamá. _Hyla s. altae_ is presently known to occur from Chepo in east-central Panamá through the Azuero Peninsula to Concepción, Chiriquí, in western Panamá (Fig. 7).

_Specimens Examined._--Panamá: _Canal Zone_: No specific locality, TNHC 24406; 2.8 km SW Fort Kobbe, KU 101679. _Chiriquí_: 14.4 km E Concepción, AMNH 69799-801; 6.6 km N David, TNHC 32013-4; 2 km S David, AMNH 68802. _Coclé_: 1 km NE El Caño, KU 101662-75; El Valle de Antón, AMNH 59601-5, KU 77333-47; 7 km SSW Penonomé, KU 101654-61. _Los Santos_: Tonosí, KU 101246 (tadpoles), 101697-701. _Panamá_: 2 km WSW Chepo, KU 101680-8; 6 km WSW Chepo, KU 77324-27; El Cangrejo (Panamá), KU 101676-8; Nueva Gorgona, AMNH 69991, 69798; 1.5 km W Pacora, KU 77328-32; 2 km N Tocumen, KU 101689-95; 8 km NE Tocumen, KU 101696.

EVOLUTIONARY HISTORY

My assumptions regarding the evolutionary history of the _Hyla rubra_ group in Central America were derived partly from interpretations of the evolutionary history of other animal groups (Simpson, 1943, 1965; Dunn, 1931b; Stuart, 1950; Duellman, 1958, 1960, 1963, 1965; and Duellman and Trueb, 1966). The origin and early evolution of the group probably occurred prior to the Mid-Pliocene in the lowlands of South America, because the greatest diversity of the group is in Brazil. Differentiation into two or more subgroups took place in South America prior to the late Pliocene. At the end of the Pliocene, shortly after the closure of the Colombian Portal, many South American animals migrated into Central America (Simpson, 1943, Maldonado-Koerdell, 1964, and Savage, 1966). It is likely that the _Hyla rubra_ group entered Central America at that time; apparently two stocks (_rubra-elaeochroa-staufferi_ stock and _boulengeri-foliamorta_ stock) migrated into Central America.

_Hyla elaeochroa_ is closely related to _rubra_ and probably differentiated from _rubra_ through spatial isolation. Thus, we have _elaeochroa_ in Central America and _rubra_ in South America; most likely only in relatively recent times has _rubra_ migrated into eastern Panamá from northern South America. The differentiation and dispersal of _elaeochroa_ and _staufferi_ took place in Central America after the Pliocene. Probably the events of the Pleistocene resulted in the isolation of populations. One of these (_Hyla staufferi_ stock) was restricted in the subhumid Pacific lowlands, whereas the _Hyla elaeochroa_ stock occupied the tropical wet forests of the Caribbean lowlands. _Hyla elaeochroa_ apparently more closely resembled the parental stock by being restricted to the tropical rain forests, whereas _staufferi_ adapted to subhumid environments and thereby was able to disperse throughout most of the subhumid regions of Central America.

After geographical separation took place the initial genetic divergence between the two populations was maintained by means of ecological and ethological isolating mechanisms. Under these circumstances it can be supposed that the different ecological preferences of _elaeochroa_ and _staufferi_ depend on the climatic changes that took place during the Pleistocene. On this basis it may be proposed that when the original prototype broke up into the two incipient species, the _staufferi_ stock became physiologically and behaviorally adapted to subhumid conditions and dispersed into dry areas of the lowlands of Middle America. The tropical evergreen forests on the Caribbean side of lower Central America and the uplift of the Talamanca range in the Pliocene were barriers to the dispersal of _staufferi_. Consequently, this frog dispersed along the Pacific lowlands.

At the present time _staufferi_ occupies the length of the Pacific lowlands in Central America, except in the rainforest of the Golfo Duce region, which apparently is a relict stand and now separates the ranges of two subspecies of _Hyla staufferi_. This species crossed the central Nicaraguan lowlands and reached the Caribbean lowlands of Nicaragua and nuclear Central America. The species migrated through the subhumid corridor in northern Honduras and eastern Guatemala (Comayagua Valley in Honduras and the Motagua Valley of Guatemala) to the Isthmus of Tehuantepec. Duellman (1960) hypothesized "that during the times of glacial advances (Pleistocene) the lowlands of the Isthmus probably were more extensive and had more semiarid tropical environments than at the present" and that when semiarid environments were continuous from the Pacific slope across the isthmus to the Gulf lowlands _staufferi_ and other amphibians migrated northward to southeastern Tamaulipas, México.

_Hyla elaeochroa_ dispersed along Caribbean lowland routes. This species not only occurs in the wet forests of the Golfo Dulce region but also in Guanacaste. It is possible that _elaeochroa_ entered Guanacaste and moved to the Golfo Dulce region when the intervening area was less xeric than now (Duellman, 1966b). _Hyla elaeochroa_ extended its range to eastern Nicaragua, but even though northeastern Nicaragua has over 2,000 mm. of precipitation annually (Vivo Escoto, 1964), this species has not spread into Honduras and Guatemala.

_Hyla boulengeri_ is widespread in Amazonian and northern South America, whereas _foliamorta_ occurs only in eastern Panamá and in north-central Colombia. The ancestral _boulengeri-foliamorta_ stock probably invaded Central America in the late Pliocene and dispersed through humid forested environments to Nicaragua. Apparently a peripheral population established itself in the dry Pacific lowlands of Panamá. This population differentiated from _boulengeri_ of the humid Caribbean lowlands and evolved into _foliamorta_, which subsequently expanded its range into Colombia.

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_Transmitted February 7, 1969._