The Systematics of the Frogs of the Hyla Rubra Group in Middle America Part 2

[Ill.u.s.tration: Fig. 5. Dorsal views of the skulls of (A) _Hyla foliamorta_ (KU 77687) and (B) _H. elaeochroa_ (KU 68289), 3.]

_Natural History._--_Hyla foliamorta_ inhabits lowland forests in eastern Panama and breeds in temporary ponds. Males have been observed calling from gra.s.ses, bushes, and emergent vegetation near temporary ponds and ditches along roads. William E. Duellman informed me that he found a breeding congregation of this species in June near Chepo, Panama, where males were calling from spiny palms at the edge of a woodland pond. Fouquette (1958) found calling males in May, August, and September near Miraflores Locks, Ca.n.a.l Zone. Calling stations vary from one to two meters above ground. No clasping pairs have been found; only one female is known (KU 101589, from 8 km NE Toc.u.men, Panama); this gravid individual was collected in early June.

The mating call of _Hyla foliamorta_ consists of one pulsed, low-pitched, moderate trill of about O.5 second duration. Each note is repeated at intervals of 5 seconds to a few minutes. The notes have about 50 pulses per second, a fundamental frequency of 56 cycles per second and a dominant frequency of about 3000 cycles per second (Table 2, Pl. 3B).

Egg deposition sites are unknown. No information is available concerning early development, and little is known about the breeding season of _Hyla foliamorta_. Probably its breeding activities are restricted to the rainy months.

_Tadpoles._--Eight tadpoles were collected from a weedy temporary pond near Chepo, Panama, in early June.

A typical tadpole in stage 35 of development (KU 104244) has a body length of 9.5 mm., tail length of 25.0 mm., and a total length of 34.5 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 a.n.u.s; a.n.a.l 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 l.a.b.i.al 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 Panama and Caribbean lowlands of northern Colombia (Fig. 4).

_Specimens Examined._--Panama: _Panama_: 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 Toc.u.men, KU 101579-83, 104349 (skeleton); 8 km NE Toc.u.men, 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 c.r.a.pauds, II:26, 1802.

Daudin, Hist. Nat. Particuliere Reptiles, 8:53, 1803. Gunther, 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 s.p.a.ce; 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) ill.u.s.trated 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 a.s.sume 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 Ca.n.a.l Zone and San Pablo, Panama. I have examined the material of _Hyla rubra_ from Panama 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 Ca.n.a.l Zone or eastern Panama. All museum specimens from Nicaragua, Costa Rica, and western Panama 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 Panama to northern South America and thence through lowlands east of the Andes to northern Argentina (Fig. 6).

_Specimens Examined._--Panama: _Ca.n.a.l Zone_: Gatun, UMMZ 52720 (2); Madden Dam, FMNH 67820; no specific locality, UMMZ 56517 (3), USNM 37863. _Colon_: Cerro Bruja, MCZ 13248. _Darien_: El Real, USNM 140569-70, 140573. _Panama_: Juan Diaz, MCZ 17973; Las Sabanas, MCZ 17581; Rio 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, Limon Province, Costa Rica; William M. Gabb collector]. Gunther, 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]. Gunther, Biologia Centrali-Americana, Reptilia and Batrachia, p. 268, June 1901. n.o.ble, 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 p.r.o.nounced; 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 a.n.u.s 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; s.p.a.ces 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; s.p.a.ces 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 Rincon 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 Tilaran, 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, Panama, 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, Panama, 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 prootic 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: Tilaran | 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: Bataan, | 26 | 26.3-32.7| 0.47-0.54 |0.45-0.66| 0.36-0.44 Limon, 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: Rincon 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) | | | | | Panama: 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)

[Ill.u.s.tration: PLATE 1

Living _Hyla_: (A) _H. boulengeri_ (KU 86322) and (B) _H.

foliamorta_ (KU 101576), 2.]

[Ill.u.s.tration: PLATE 2