Part 3

Hyla microcephala Cope

Diagnosis.--Lateral dark stripe narrow, covering only upper edge of tympanum, bordered above by narrow white stripe; dorsal pattern consisting of pair of longitudinal brown lines and no interorbital bar (eastern populations), or of irregular dark markings forming an X- or )(-shaped mark in scapular region and an interorbital bar (western populations).

Content.--The populations inhabiting the Pacific lowlands of southeastern Costa Rica eastward to Colombia are recognized herein as Hyla microcephala microcephala Cope; the populations in western Costa Rica northward to Mexico are assigned to Hyla microcephala underwoodi Boulenger.

Distribution.--Southern Veracruz and northern Oaxaca southeastward through the Atlantic lowlands of Central America to north-central Nicaragua, thence southeastward on the Pacific lowlands to eastern Panama, and thence into the Cauca and Magdalena valleys (Caribbean drainage) of Colombia (Fig. 1).

Table 1.--Variation in Certain Measurements and Properties in the Hyla microcephala Group. (All Data Based on Adult Males; Mean and Standard Error of Mean Below Observed Range.)

======================================================================== Locality | N | Snout-vent | Tibia length |Foot length| | | length | ------------ | --------- | | | (S-V L) | S-V L | S-V L | ------------------------------------------------------------------------ | H. m. microcephala | Panama: Canal Zone | 25 | 21.5-24.1 | 50.2-56.0 | 40.9-46.6 | | | 22.8+-0.20 | 52.9+-0.37 | 43.5+-0.28 | | | | | | Costa Rica: Golfito | 25 | 18.5-24.5 | 49.1-54.4 | 41.8-48.0 | | | 22.4+-0.27 | 51.6+-0.26 | 45.1+-0.32 | | | H. m. underwoodi | | Nicaragua: La Cumplida | 25 | 23.0-25.6 | 51.0-55.7 | 41.3-46.5 | | | 24.1+-0.19 | 52.9+-0.25 | 43.7+-0.25 | | | | | | Guatemala: Finca Chama | 25 | 21.8-25.0 | 51.0-57.2 | 41.2-47.8 | | | 23.5+-0.16 | 54.3+-0.39 | 44.4+-0.30 | | | | | | Tabasco: Teapa | 25 | 22.7-25.8 | 48.0-54.5 | 40.7-46.8 | | | 24.3+-0.14 | 51.5+-0.29 | 43.3+-0.25 | | | | | | Oaxaca: Donaji-Sarabia | 25 | 22.1-25.9 | 49.8-55.6 | 40.5-46.6 | | | 23.8+-0.19 | 52.8+-0.33 | 43.4+-0.27 | | | | | | Veracruz: Alvarado | 25 | 21.9-25.4 | 49.6-54.4 | 40.7-47.5 | | | 24.1+-0.17 | 51.1+-0.28 | 42.6+-0.34 | | | H. robertmertensi | Guatemala: La Trinidad | 21 | 21.8-24.6 | 47.1-52.8 | 40.9-51.3 | | | 23.4+-0.15 | 49.9+-0.34 | 43.5+-0.17 | | | | | | Chiapas: Acacoyagua | 25 | 21.4-25.7 | 47.8-52.4 | 41.7-46.3 | | | 24.1+-0.20 | 50.4+-0.45 | 43.9+-0.23 | | | | | | Oaxaca: Tapanatepec | 25 | 22.4-26.4 | 44.1-48.3 | 39.1-44.5 | | | 24.7+-0.18 | 46.4+-0.23 | 41.7+-0.23 | | | H. phlebodes | Panama: Canal Zone | 25 | 19.6-23.2 | 49.1-56.9 | 41.9-47.1 | | | 22.2+-0.16 | 52.8+-0.35 | 45.4+-0.26 | | | | | | Costa Rica: Turrialba | 25 | 19.7-23.6 | 47.4-55.7 | 38.1-46.4 | | | 22.0+-0.18 | 51.1+-0.35 | 42.8+-0.38 | | | H. sartori | Guerrero: Tierra Colorada| 25 | 23.7-26.0 | 47.2-51.4 | 42.4-47.8 | | | 24.8+-0.13 | 49.6+-0.23 | 45.2+-0.27 | ------------------------------------------------------------------------ Table 1. (continued) =============================================================== Locality | Head length | Head width | Tympanum | ----------- | ---------- | -------- | S-V L | S-V L | Eye --------------------------------------------------------------- | H. m. microcephala | Panama: Canal Zone | 28.5-32.8 | 28.1-30.9 | 44.0-54.1 | 31.0+-0.22 | 29.4+-0.11 | 49.0+-0.55 | Costa Rica: Golfito | 30.2-35.5 | 29.0-32.7 | 40.0-57.8 | 33.1+-0.25 | 30.8+-0.16 | 48.4+-1.10 | | H. m. underwoodi | Nicaragua: La Cumplida | 29.7-33.5 | 28.9-31.8 | 42.3-60.0 | 31.6+-0.19 | 30.4+-0.17 | 49.3+-0.97 | Guatemala: Finca Chama | 30.8-35.3 | 29.6-33.6 | 37.5-56.4 | 33.0+-0.16 | 31.3+-0.36 | 45.2+-0.89 | Tabasco: Teapa | 29.5-33.0 | 28.7-31.8 | 40.7-53.8 | 31.7+-0.17 | 30.3+-0.16 | 45.5+-0.38 | Oaxaca: Donaji-Sarabia | 30.4-34.8 | 28.9-32.6 | 37.0-54.1 | 32.8+-0.19 | 30.8+-0.17 | 45.1+-0.76 | Veracruz: Alvarado | 29.9-33.8 | 29.1-32.9 | 40.7-53.8 | 31.4+-0.18 | 30.5+-0.17 | 46.6+-0.65 | | H. robertmertensi | Guatemala: La Trinidad | 30.0-33.3 | 27.3-29.8 | 44.4-50.0 | 31.3+-0.20 | 28.5+-0.23 | 47.4+-0.46 | | | Chiapas: Acacoyagua | 29.1-32.7 | 26.0-30.3 | 42.8-53.8 | 31.2+-0.29 | 28.1+-0.20 | 46.5+-0.50 | | | Oaxaca: Tapanatepec | 26.1-30.4 | 25.4-28.1 | 45.8-58.3 | 28.4+-0.16 | 26.8+-0.14 | 52.9+-0.77 | | H. phlebodes | Panama: Canal Zone | 33.6-37.4 | 32.3-36.0 | 37.9-46.4 | 34.8+-0.18 | 33.8+-0.18 | 41.6+-0.49 | | | Costa Rica: Turrialba | 32.6-35.9 | 30.5-35.0 | 35.7-48.2 | 34.1+-0.16 | 32.9+-0.17 | 40.1+-0.53 | | H. sartori | Guerrero: Tierra Colorada| 29.4-31.8 | 28.9-31.0 | 42.3-52.0 | 30.6+-0.13 | 30.0+-0.12 | 47.4+-0.59 ---------------------------------------------------------------

Hyla microcephala microcephala Cope

Hyla microcephala Cope, Proc. Amer. Philos. Soc., 23:281, February 11, 1886 [Syntypes.--USNM 13473 (2 specimens, now lost) from Chiriqui, Panama; Mr. MacNeil collector]; Bull. U.S. Natl. Mus., 32:14, 1887. Guenther, Biologia-Centrali Americana, Reptilia and Batrachia, p. 265, June, 1901. Dunn, Occas. Papers Boston Soc. Nat. Hist., 5:413, October 10, 1931; Occas. Papers Boston Soc. Nat. Hist., 8:72, June 7, 1933. Stebbins and Hendrickson, Univ. California Publ. Zool., 56:524, February 17, 1959. Fouquette, Evolution, 14:484, December 16, 1960. Busack, Copeia, 2:371, June 21, 1966.

? Hyla cherrei Cope, Proc. Acad. Nat. Sci. Philadelphia, 1894, p. 195, 1894 [Holotype.--location unknown, apparently lost; type-locality: "Alajuela, Costa Rica;" R. Alfaro collector]. Guenther, Biologia Centrali-Americana: Reptilia and Batrachia, p. 264, June, 1901. Taylor, Univ. Kansas Sci. Bull., 35:846, July 1, 1952.

Hyla underwoodi, Ruthven, Misc. Publ. Mus. Zool., Univ. Michigan, 8:55, September 15, 1922. Barbour, Proc. New England Zool. Club, 10:31, March 2, 1928.

Hyla microcephala microcephala, Smith, Herpetologica, 7:185, December 31, 1951. Taylor, Univ. Kansas Sci. Bull., 39:23, November 18, 1958.

Diagnosis.--Brown lateral stripe narrow, extending from nostril along canthus, along upper edge of tympanum to groin, bordered above by narrow white line; pair of dark brown longitudinal lines on dorsum extending to vent; shanks having dark longitudinal line or flecks, no transverse bars; interorbital dark mark lacking.

Description and Variation.--The color pattern is nearly constant. Of 103 males from the Canal Zone, all lack an interorbital dark bar, and all have a dark longitudinal line on the dorsal surface of the shank and a narrow lateral dark stripe, bordered above by a narrow white line, extending to the groin. The longitudinal dark lines on the dorsum are continuous to the groin in 95 specimens and fragmented in two specimens. In two others the lines converge and fuse in the scapular region, and in four specimens auxiliary, fragmented lines are present dorsolaterally.

In all specimens from southeastern Costa Rica (Golfito, Palmar Sur, and Villa Neilly) the pattern is constant, except that in about 10 per cent of the specimens the longitudinal line on the dorsal surface of the shank is replaced by a row of brown flecks.

Of the limited number of Colombian specimens examined, all are patterned normally, except three from Sautata, Choco, three from Curumani, and three from Arcataca, Magdalena, which have flecks on the dorsal surfaces of the shanks, and one from Espinal, Tolima, which has no markings on the shanks.

When active at night most individuals are pale yellowish tan dorsally; the white dorsolateral line is noticeable, but the brown lateral stripe, dorsal brown lines, and lines on shanks are so pale that often they are barely discernible. By day the dorsum changes to tan or pale reddish brown; the stripes are dark brown, and the dorsolateral stripe that is white at night becomes creamy yellow (Pl. 13). Small brown flecks are present on the dorsum of most individuals. The venter always is white, and the iris is pale bronze with a brown tint immediately anterior and posterior to the pupil. In breeding males the vocal sac is pale yellow.

Tadpoles.--Tadpoles of this species have been found in weed-choked ponds in eastern Panama Province. The following description is based on KU 104097, a specimen in developmental stage 34 (Gosner, 1960).

Total length, 20.5 mm.; body length, 8.2 mm.; body slightly wider than deep; snout pointed; nostrils large, situated dorsally, much closer to snout than eyes, directed anteriorly; eyes moderately small, situated dorsolaterally and directed laterally; spiracle sinistral, located just posteroventral to eye; anal tube dextral. Tail xiphicercal; caudal musculature moderately deep, becoming slender posteriorly, extending beyond caudal fin; fins deepest at about one-third distance from body to tip of tail; dorsal fin extending onto body, deeper than deepest part of caudal musculature; ventral fin slightly shallower than musculature. Mouth small, terminal, lacking teeth and fringing papillae, but having finely serrate beaks. In preservative, top of head pale brown; dark stripe from tip of snout through eye to posterior edge of body, narrowing to thin line on proximal one-fourth of tail; venter white; tail creamy tan with fine black flecks most numerous posteriorly; posterior two-thirds of fins edged with black. In life, top of head yellowish tan; lateral stripe brown; belly white; anterior half of tail lacking pigment; posterior half deep orange; iris pale bronze (Pl. 15).

Remarks.--Evidence for intergradation of Hyla microcephala with H. underwoodi is provided by four specimens [USC 818 (2), 6081-2] from 6.1 kilometers northeast of the mouth of the Rio Tarcoles, and nine specimens [USC 8254 (2), 8255, 8256 (4), 8258 (2)] from Parrita, both in Puntarenas Province, Costa Rica. These localities lie about two-thirds the distance from the northwesternmost locality for H. m. microcephala (Palmar Sur) to the southeasternmost locality for H. m. underwoodi (Barranca). Although in most aspects of coloration the frogs are more nearly like H. m. underwoodi than H. m. microcephala, some specimens have longitudinal lines on their shanks, such as are characteristic of H. m. microcephala. The dorsal pattern varies from nearly complete longitudinal lines to broken lines, fused into an X-shaped scapular mark or not.

As noted by Rivero (1961:135), Hyla microcephala seems to be closely related to Hyla misera Werner, a species having a wide distribution east of the Andes in South America. Despite the similarity in color pattern, size, and structure, we are reluctant to place the two taxa in the same species until data on coloration in life, mating calls, and life history are available for Hyla misera and compared with those of Hyla microcephala.

The status of Cope's Hyla cherrei is questionable. Since the type, the only specimen ever referred to the species, apparently is lost, the only extant information regarding the taxon is contained in the original description (Cope, 1894). There the species was characterized as having a narrow dorsolateral white stripe and lacking pigment on the upper arms and thighs. These characteristics of the color pattern combined with the statements "vomerine teeth few, opposite the middle of the very large choanae" and "tympanic drum distinct, one half the area of eye" serve to distinguish H. cherrei from all other Costa Rican hylids, except H. m. microcephala and H. m. underwoodi. No statements in the type description will definitely associate cherrei with one or the other of these subspecies. Since it seems obvious that H. cherrei can be associated with H. microcephala, we prefer to place the name in the synonymy of the nominate subspecies, thereby preserving the commonly used name H. underwoodi (Boulenger, 1899) as a subspecies of H. microcephala.

Distribution.--Hyla microcephala microcephala inhabits coastal lowlands from the area of Golfo Dulce (apparently absent from the Osa Peninsula) in southeastern Costa Rica eastward in Panama, including the Azuero Peninsula to northern Colombia and thence southward in the valleys of the Rio Cauca and Rio Magdalena in Colombia (Fig. 1). Except for the central area of the Canal Zone the subspecies is unknown from the Caribbean drainage in Central America, but in Colombia the subspecies occurs only in the Caribbean drainage. In Central America this frog occurs mostly on the coastal lowlands; the highest recorded elevation is 560 meters at El Valle, Cocle, Panama. Throughout most of its range Hyla microcephala microcephala occurs in disturbed habitats--cut-over forests, secondary growth, and pastureland. It does not seem to be an inhabitant of either primary forest or of Curatella-savanna.

Specimens examined.--522, as follows: +Costa Rica+: Puntarenas: Golfito, KU 32172-207; 3 km. E Golfito, KU 86399, USC 2757-8; Palmar Sur, KU 64591-608, USC 2650 (14), UU 3907-32; *1.5-2.5 km. ESE Palmar Sur, KU 68293-7 (skeletons), 93957-62; Parrita, USC 8254 (2), 8255, 8256 (4), 8258 (2) [intergrades with H. m. underwoodi]; 3 km. NW Piedras Blancas, KU 103689; 6.1 km. NE mouth of Rio Tarcoles, USC 818 (2), 6081-2 [intergrades with H. m. underwoodi]; Villa Neilly, USC 2651; *1-5 km. WNW Villa Neilly, USC 6182-4, 8003 (4), 8031 (3), 8032; *10.5 km. WNW Villa Neilly, KU 64609-27, 68398 (eggs).

+Panama+: Canal Zone: Albrook Air Base, TNHC 23389, 23497; Balboa, ANSP 19555-6; *Fort Clayton, UIMNH 42008-12; *2.8 km. SW Fort Kobbe, KU 96015-25; *Frijoles, MCZ 19208; *Bamboa, MCZ 21507; *8.3 km. N Gatun Locks, TNHC 23441; *Juan Diaz, MCZ 13747; *Juan Mina, AMNH 55436-7, ANSP 21811-2, UMMZ 126734, 126735 (6), UU 3900-6; *8-14 km. N Miraflores Locks, TNHC 23374-88, 23390-409, 23411-38, 23440, 23442-60, 23462-76; 23478-83, 23492, 23555-60, 23562-76; *Rio Chagres, AMNH 55430, 55439; *Rio Cocoli, 3.5 km. N Miraflores Locks, TNHC 23410; *Summit, ANSP 23365-71, FMNH 22966-9, KU 97783-87. Chiriqui: 5.5 km. E Concepcion, AMNH 69772; *14.4 km. E Concepcion, AMNH 69773-8; 2 km. S David, AMNH 69779; *Progreso, UMMZ 58252, 58253 (2), 58254, 58436; Rio Gariche, 8.3 km. ESE Paso Canoas, KU 103065-8. Cocle: 1 km. SE El Cano, KU 103042-51; El Valle de Anton, AMNH 59614-18 (10), 69785, ANSP 23502-5, KU 77201-14, MVZ 66578-83, UIMNH 46532. Colon: Cement Plant, Transisthmian Highway, FMNH 60394-5. Darien: El Real, KU 80454-5, 103052-64, UMMZ 125036 (10), USNM 140567-8; Rio Canclon at Rio Chucunaque, UMMZ 125035; *Rio Chucunaque, near Yavisa, AMNH 59523. Los Santos: Tonosi, KU 101606-9. Panama: 5 km. S Bejuco, AMNH 69782; 3 km. W Chepo, KU 77172-4, 104097-8 (tadpoles); *6 km. WSW Chepo, KU 77175; *Chico, Rio La Jagua, USNM 129070; *La Joya, Cacora, ANSP 25129-33; Madden Dam, FMNH 67819; Nueva Gorgona, AMNH 69780-1; *1.6 km. W Nueva Gorgona, AMNH 69783-4; 1.5 km. W Pacora, 77176-200; *Rio La Laja, near Chame, ANSP 21845; *Rio Tapia, MCZ 10048; *Tapia, AMNH 18930, 18950, 18952-3; *18 km. E Tocumen, MVZ 78662.

+Colombia+: Choco: Sautata, Atrato, FMNH 74918 (2), 74919. Magdalena: Aracataca, ANSP 19755-7; Curumani, MCZ 21465-74, UIMNH 28855; UMMZ 90168, USNM 118247; El Banco, Rio Magdalena, ANSP 25061; Fundacion, UMMZ 48281-2. Tolima: Espinal, MCZ 15068; Mariquita, FMNH 81822-3. Valle: Sevilla, MCZ 13751-3.

Hyla microcephala underwoodi Boulenger

Hyla microcephala Boulenger, Proc. Zool. Soc. London, p. 481, October 1, 1898 [Syntypes.--BMNH 94. 11. 1532-33 from Bebedero, Guanacaste Province, Costa Rica; C. F. Underwood collector] (not Hyla microcephala Cope, Proc. Amer. Philos. Soc., 23:281, February 11, 1886, from Chiriqui, Panama).

Hyla underwoodi Boulenger, Ann. Mag. Nat. Hist., ser. 7, 3:277, April, 1899 (substitute name for Hyla microcephala Boulenger, preoccupied). Guenther, Biologia-Centrali Americana, Reptilia and Batrachia, p. 278, September, 1901. Dunn and Emlen, Proc. Acad. Nat. Sci. Philadelphia, 84:25, March 22, 1932. Stuart, Misc. Publ. Mus. Zool., Univ. Michigan, 29:39, October 1, 1935. Taylor, Proc. Biol. Soc. Washington, 50:44, April 21, 1937. Stuart, Occas. Papers Mus. Zool., Univ. Michigan, 471:15, May 17, 1943. Taylor and Smith, Proc. U. S. Natl. Mus., 95:586, June 30, 1945. Stuart, Misc. Publ. Mus. Zool., Univ. Michigan, 69:35, June 12, 1948. Smith and Taylor, Bull. U. S. Natl. Mus., 194:85, June 17, 1948; Univ. Kansas Sci. Bull., 33:316, March 20, 1950. Stuart, Contr. Lab. Vert. Biol., Univ. Michigan, 45:48, May, 1950. Taylor, Univ. Kansas Sci. Bull., 35:891, July 1, 1952; Univ. Kansas Sci. Bull., 39:25, November 18, 1958.