Part 6

========================================================================== | |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)

Living Hyla: (A) H. boulengeri (KU 86322) and (B) H. foliamorta (KU 101576), × 2.]

Living Hyla: (A) H. elaeochroa (KU 91688), (B) H. staufferi staufferi (KU 57791), and (C) H. staufferi altae (KU 101688), × 2.]

Audiospectrograms and sections of mating calls of (A) Hyla boulengeri (KU Tape No. 511) and (B) H. foliamorta (KU Tape No. 511) and (B) H. foliamorta (KU Tape No. 288).]

Audiospectrograms and sections of mating calls of (A) Hyla elaeochroa (KU Tape No. 97), (B) H. s. staufferi (KU Tape No. 93), and (C) H. staufferi altae (KU Tape No. 502).]

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.