The Project Gutenberg eBook of Middle American Frogs of the Hyla microcephala Group
Title: Middle American Frogs of the Hyla microcephala Group
Author: William Edward Duellman
M. J. Fouquette
Release date: December 9, 2010 [eBook #34604]
Most recently updated: January 7, 2021
Language: English
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Typographical Corrections
| Page 533 - | UMZ | => | UMMZ |
| Page 534 - | Diganosis | => | Diagnosis |
| Page 544 - | fontanells | => | fontanelle |
| Page 545 - | prrimary | => | primary |
| Page 547 - | band of of frequencies | => | band of frequencies |
| Page 550 - | ad | => | had |
| Page 551 - | clumbs | => | clumps |
| Page 552 - | acount | => | account |
| Page 557 - | Minchigan | => | Michigan |
Museum of Natural History
WILLIAM E. DUELLMAN AND M. J. FOUQUETTE, JR.
Lawrence
1968
Editors: E. Raymond Hall, Chairman, Henry S. Fitch,
Frank B. Cross
Volume 17, No. 12, pp. 517-557, 4 pls. 9 figs.
Published March 20, 1968
University of Kansas
Lawrence, Kansas
ROBERT R. (BOB) SANDERS, STATE PRINTER
TOPEKA, KANSAS
1968
31-9419
of the Hyla microcephala Group
WILLIAM E. DUELLMAN AND M. J. FOUQUETTE, JR.
| PAGE | |
| Introduction | 519 |
| Acknowledgments | 520 |
| Materials and Methods | 520 |
| Hyla microcephala Group | 521 |
| Key to Species and Subspecies | 522 |
| Accounts of Species and Subspecies | 523 |
| Cranial Osteology | 540 |
| Analysis of Mating Calls | 544 |
| Life History | 550 |
| Phylogenetic Relationships | 552 |
| Literature Cited | 556 |
The small yellow tree frogs, Hyla microcephala and its relatives, are among the most frequently heard and commonly collected frogs in the lowlands of southern México and Central America. The similarities in size, proportions, and coloration of the different species have resulted not so much in a multiplicity of specific names, but in differences of opinion on the application of existing names to the various taxa. For example, the populations on the Atlantic lowlands have been known by three names, two of which have been applied to other taxa. Much of the confusion has been the result of previous workers' unfamiliarity with the animals in life and unawareness of the intraspecific geographic variation in the most widespread species.
Independently we undertook studies of these frogs in the field. The second author worked on the interspecific relationships and isolating mechanisms in Panamá (Fouquette, 1960b) and later studied the species in southern México. As part of his survey of the hylids of Middle America, the first author accumulated field and laboratory data on the frogs throughout their ranges in México and Central America. The purpose of this report is to present our findings on the four species of Middle American frogs that we place in the Hyla microcephala group. In addition to conventional taxonomic characters, we have utilized the features of the cranial osteology and have relied heavily on the data obtained from an analysis of the mating calls. Furthermore, we have included ecological and distributional data in our synthesis of interspecific relationships.
Examination of specimens was made possible by the provision of working space at various institutions or through the loan of specimens. For their generosity in this manner we are grateful to Richard J. Baldauf, Charles M. Bogert, James E. Böhlke, Doris M. Cochran, Robert F. Inger, John M. Legler, Alan E. Leviton, Gerald Raun, Jay M. Savage, Hobart M. Smith, Robert C. Stebbins, Wilmer W. Tanner, Charles F. Walker, Ernest E. Williams, and Richard G. Zweifel.
Duellman is especially grateful to Charles W. Myers, Linda Trueb, Jerome B. Tulecke, and John Wellman for their assistance in the field and to Linda Trueb for her work on the cranial osteology that is incorporated in this report. Fouquette is indebted to H. Morgan Smith and A. C. Collins for assistance in the field, to A. J. Delahoussaye for assistance in the laboratory, and to W. Frank Blair for use of the facilities of the sound laboratory at the University of Texas and for much help in the early stages of this study.
The research reported herein was accomplished mainly through support by the National Science Foundation (grants NSF G-9827 and GB-1441 to Duellman and GB-599 to Fouquette). The latter's field work in México was assisted in part by NSF Grant G-4956 to W. Frank Blair. Some of the field studies carried out in Panamá by Duellman were supported by a grant from the National Institutes of Health (NIH GM-12020).
We are grateful to many persons, too numerous to mention, who in various ways aided our field work in Middle America. We are especially indebted to Dr. Rodolfo Hernandez Corzo and the late Ing. Luis Macías Arellano of the Dirección General de la Fauna Silvestre of the Mexican government for providing permits to collect in México.
For this report, data has been obtained from 2829 preserved frogs, 42 skeletal preparations, 8 lots of tadpoles and young, and 4 lots of eggs. Much of the material was collected in our independent field work, which has extended over a period of 11 years.
Measurements were taken in the manner described by Duellman (1956). Osteological data were obtained from specimens that were cleared in potassium hydroxide, stained with alizarin red, and stored in glycerine. Recordings were made by means of Magnemite portable tape recorders (Amplifier Corp. America). The calls recorded by Fouquette were analyzed on a Sonagraph (Kay Electric Co.) at the University of Texas; those recorded by Duellman were analyzed mainly on a Vibralyzer (Kay Electric Co.) at the University of Kansas and in part on a Sonagraph at the University of Southwestern Louisiana. Sample calls were analyzed on all three instruments; the slight differences in results were found to be less than the error in measurement, so the data from all sources were combined without correction. The techniques and terminology of the calls are those defined by Fouquette (1960a, 1960b).
In the accounts of the species we have attempted to give a complete synonymy. At the end of each species account the localities from which specimens were examined are listed alphabetically within each state, province, or department, which in turn are listed alphabetically within each country. The countries are arranged from north to south. Localities preceded by an asterisk (*) are not plotted on the accompanying maps due to the crowding of symbols that would have resulted. Abbreviations for museum specimens are listed below:
| AMNH | —American Museum of Natural History |
| ANSP | —Academy of Natural Sciences of Philadelphia |
| BMNH | —British Museum (Natural History) |
| BYU | —Brigham Young University |
| CAS | —California Academy of Sciences |
| FMNH | —Field Museum of Natural History |
| KU | —University of Kansas Museum of Natural History |
| MCZ | —Museum of Comparative Zoology |
| MVZ | —Museum of Vertebrate Zoology |
| SU | —Stanford University |
| UIMNH | —University of Illinois Museum of Natural History |
| UMMZ | —University of Michigan Museum of Zoology |
| USC | —University of Southern California |
| USNM | —United States National Museum |
| UU | —University of Utah |
| TCWC | —Texas Cooperative Wildlife Collection |
| TNHM | —Texas Natural History Museum |
Definition.—Small hylids attaining a maximum snout-vent length of 27 mm. in males and 32 mm. in females; dorsum yellowish tan with brown markings; thighs uniformly yellow, vocal sac in breeding males yellow; snout truncate in lateral profile; tympanum distinct, usually slightly smaller than one-half diameter of eye; vocal sac single, median, subgular; fingers about one-third webbed; toes webbed nearly to bases of discs, except only to middle of antepenultimate or base of penultimate phalanx of fourth toe; tarsal fold weak; inner metatarsal tubercle low, flat, elliptical; axillary membrane present; pupil horizontally elliptical; palpebral membrane unmarked; cranial elements reduced in ossification; sphenethmoid small, short; frontoparietal fontanelle large; tegmen tympani not extensive; quadratojugal greatly reduced; anterior arm of squamosal extending only about one-fourth distance to maxillary; posterior arm of squamosal not having bony connection with proötic; nasals lacking maxillary processes; medial ramus of pterygoid not having bony attachment to proötic; maxillary, premaxilary, and prevomerine teeth present; palatine and parasphenoid teeth absent; Mentomeckelians ossified; tadpoles having xiphicercal tails with deep caudal fins and terminal mouth lacking teeth; mating call consisting of one primary note followed by a series of shorter secondary notes; haploid number of chromosomes, 15 (known only in H. microcephala and H. phlebodes.)
Content.—As recognized here the Hyla microcephala group contains four species, one having two subspecies. An alphabetical list of the specific and subspecific names that we consider to be applicable to the Hyla microcephala group are listed below.
| Names Proposed | Valid Names |
| Hyla cherrei Cope, 1894 | ? = H. m. microcephala |
| Hyla microcephala Cope, 1886 | = H. m. microcephala |
| Hyla microcephala Boulenger, 1898 (nec Cope, 1886) | = H. microcephala underwoodi |
| Hyla microcephala martini Smith, 1951 | = H. microcephala underwoodi |
| Hyla microcephala sartori Smith, 1951 | = H. sartori |
| Hyla phlebodes Stejneger, 1906 | = H. phlebodes |
| Hyla robertmertensi Taylor, 1937 | = H. robertmertensi |
| Hyla underwoodi Boulenger, 1899 | = H. microcephala underwoodi |
Discussion.—The color pattern is the most useful character in distinguishing the species of the Hyla microcephala group from one another. Except in Hyla microcephala, little geographic variation in color pattern is noticeable. The features of color pattern that are helpful in identifying the species are: 1) presence or absence of lateral dark brown stripe; 2) longitudinal extent and width of lateral stripe, if present; 3) presence or absence of a narrow white line just dorsal to the lateral dark stripe; 4) presence or absence of an interorbital dark mark; 5) the arrangement of dark markings on the back, either as longitudinal lines or series of dashes, or in the form of various kinds of transverse markings; 6) presence of dark flecks, longitudinal line, or transverse marks on shanks.
Few consistent differences in measurements and proportions exist among the species (Table 1). The most obvious morphological difference is that the head is noticeably narrower in H. robertmertensi than in the other species. Hyla phlebodes is the smallest species; adult males attain snout-vent lengths of only 23.6 mm. The body is slender in H. microcephala and robertmertensi, slightly wider in phlebodes, and noticeably broader in sartori.
Distribution.—The composite range of the Middle American frogs of the Hyla microcephala group includes the lowlands of southern México and Central America, in some places to elevations of 1200 meters, southeastward from southern Jalisco and southern Veracruz, excluding arid regions (northern Yucatán Peninsula, Balsas-Tepalcatepec Basin, Plains of Tehuantepec, Grijalva Valley, Salamá Basin, and upper Motagua Valley) to the Pacific lowlands and the Cauca and Magdalena valleys in Colombia.
| 1. | Lateral dark stripe, bordered above by narrow white line, extending from snout at least to sacral region2 |
| Lateral dark stripe, if present, not extending posteriorly to sacral region and not bordered above by narrow white line4 | |
| 2. | Lateral dark stripe continuous to groin; dark flecks or longitudinal line on shanks; interorbital dark bar absent; dorsal pattern usually consisting of pair of longitudinal dark lines or series of dashes3 |
| Lateral dark stripe usually extending only to sacral region; dark transverse bars on shanks; interorbital bar usually present; dorsal pattern usually consisting of interconnecting dark lines, sometimes forming transverse marksH. microcephala underwoodi | |
| 3. | Lateral dark stripe narrow, covering only upper edge of tympanum; dorsal longitudinal stripes continuous, extending to ventH. microcephala microcephala |
| Lateral dark stripe wide, encompassing entire tympanum; dorsal markings consisting of longitudinal series of flecks or dashes, or of two lines, usually not extending to vent H. robertmertensi | |
| 4. | Lateral dark stripe indistinct, present only above tympanum and insertion of arm; dorsal markings consisting of narrow lines and dashes, sometimes interconnected; transverse bars on shanks narrow relative to interspacesH. phlebodes |
| Lateral dark stripe absent; dorsal markings consisting of two broad chevron-shaped marks; transverse bars on shanks wide relative to interspacesH. sartori | |
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 México 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 Panamá, and thence into the Cauca and Magdalena valleys (Caribbean drainage) of Colombia (Fig. 1).
Fig. 1. Map showing locality records for Hyla microcephala.
| Locality | N | Snout-vent length (S-V L) | Tibia length S-V L | Foot length S-V L | Head length S-V L | Head width S-V L | Tympanum Eye |
H. m. microcephala | |||||||
| Panamá: Canal Zone | 25 | 21.5-24.1 | 50.2-56.0 | 40.9-46.6 | 28.5-32.8 | 28.1-30.9 | 44.0-54.1 |
| 22.8±0.20 | 52.9±0.37 | 43.5±0.28 | 31.0±0.22 | 29.4±0.11 | 49.0±0.55 | ||
| Costa Rica: Golfito | 25 | 18.5-24.5 | 49.1-54.4 | 41.8-48.0 | 30.2-35.5 | 29.0-32.7 | 40.0-57.8 |
| 22.4±0.27 | 51.6±0.26 | 45.1±0.32 | 33.1±0.25 | 30.8±0.16 | 48.4±1.10 | ||
H. m. underwoodi | |||||||
| Nicaragua: La Cumplida | 25 | 23.0-25.6 | 51.0-55.7 | 41.3-46.5 | 29.7-33.5 | 28.9-31.8 | 42.3-60.0 |
| 24.1±0.19 | 52.9±0.25 | 43.7±0.25 | 31.6±0.19 | 30.4±0.17 | 49.3±0.97 | ||
| Guatemala: Finca Chamá | 25 | 21.8-25.0 | 51.0-57.2 | 41.2-47.8 | 30.8-35.3 | 29.6-33.6 | 37.5-56.4 |
| 23.5±0.16 | 54.3±0.39 | 44.4±0.30 | 33.0±0.16 | 31.3±0.36 | 45.2±0.89 | ||
| Tabasco: Teapa | 25 | 22.7-25.8 | 48.0-54.5 | 40.7-46.8 | 29.5-33.0 | 28.7-31.8 | 40.7-53.8 |
| 24.3±0.14 | 51.5±0.29 | 43.3±0.25 | 31.7±0.17 | 30.3±0.16 | 45.5±0.38 | ||
| Oaxaca: Donají-Sarabia | 25 | 22.1-25.9 | 49.8-55.6 | 40.5-46.6 | 30.4-34.8 | 28.9-32.6 | 37.0-54.1 |
| 23.8±0.19 | 52.8±0.33 | 43.4±0.27 | 32.8±0.19 | 30.8±0.17 | 45.1±0.76 | ||
| Veracruz: Alvarado | 25 | 21.9-25.4 | 49.6-54.4 | 40.7-47.5 | 29.9-33.8 | 29.1-32.9 | 40.7-53.8 |
| 24.1±0.17 | 51.1±0.28 | 42.6±0.34 | 31.4±0.18 | 30.5±0.17 | 46.6±0.65 | ||
| H. robertmertensi | |||||||
| Guatemala: La Trinidad | 21 | 21.8-24.6 | 47.1-52.8 | 40.9-51.3 | 30.0-33.3 | 27.3-29.8 | 44.4-50.0 |
| 23.4±0.15 | 49.9±0.34 | 43.5±0.17 | 31.3±0.20 | 28.5±0.23 | 47.4±0.46 | ||
| Chiapas: Acacoyagua | 25 | 21.4-25.7 | 47.8-52.4 | 41.7-46.3 | 29.1-32.7 | 26.0-30.3 | 42.8-53.8 |
| 24.1±0.20 | 50.4±0.45 | 43.9±0.23 | 31.2±0.29 | 28.1±0.20 | 46.5±0.50 | ||
| Oaxaca: Tapanatepec | 25 | 22.4-26.4 | 44.1-48.3 | 39.1-44.5 | 26.1-30.4 | 25.4-28.1 | 45.8-58.3 |
| 24.7±0.18 | 46.4±0.23 | 41.7±0.23 | 28.4±0.16 | 26.8±0.14 | 52.9±0.77 | ||
H. phlebodes | |||||||
| Panamá: Canal Zone | 25 | 19.6-23.2 | 49.1-56.9 | 41.9-47.1 | 33.6-37.4 | 32.3-36.0 | 37.9-46.4 |
| 22.2±0.16 | 52.8±0.35 | 45.4±0.26 | 34.8±0.18 | 33.8±0.18 | 41.6±0.49 | ||
| Costa Rica: Turrialba | 25 | 19.7-23.6 | 47.4-55.7 | 38.1-46.4 | 32.6-35.9 | 30.5-35.0 | 35.7-48.2 |
| 22.0±0.18 | 51.1±0.35 | 42.8±0.38 | 34.1±0.16 | 32.9±0.17 | 40.1±0.53 | ||
H. sartori | |||||||
| Guerrero: Tierra Colorada | 25 | 23.7-26.0 | 47.2-51.4 | 42.4-47.8 | 29.4-31.8 | 28.9-31.0 | 42.3-52.0 |
| 24.8±0.13 | 49.6±0.23 | 45.2±0.27 | 30.6±0.13 | 30.0±0.12 | 47.4±0.59 | ||
Hyla microcephala Cope, Proc. Amer. Philos. Soc., 23:281, February 11, 1886 [Syntypes.—USNM 13473 (2 specimens, now lost) from Chiriquí, Panamá; Mr. MacNeil collector]; Bull. U.S. Natl. Mus., 32:14, 1887. Günther, 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]. Günther, 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, Chocó, 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 Panamá 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 Río 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 Panamá, including the Azuero Peninsula to northern Colombia and thence southward in the valleys of the Río Cauca and Río 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, Coclé, Panamá. 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 Río Tárcoles, 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 Gatún 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; *Río Chagres, AMNH 55430, 55439; *Río Cocolí, 3.5 km. N Miraflores Locks, TNHC 23410; *Summit, ANSP 23365-71, FMNH 22966-9, KU 97783-87. Chiriqui: 5.5 km. E Concepción, AMNH 69772; *14.4 km. E Concepción, AMNH 69773-8; 2 km. S David, AMNH 69779; *Progreso, UMMZ 58252, 58253 (2), 58254, 58436; Río Gariché, 8.3 km. ESE Paso Canoas, KU 103065-8. Coclé: 1 km. SE El Caño, KU 103042-51; El Valle de Antón, AMNH 59614-18 (10), 69785, ANSP 23502-5, KU 77201-14, MVZ 66578-83, UIMNH 46532. Colón: Cement Plant, Transisthmian Highway, FMNH 60394-5. Darién: El Real, KU 80454-5, 103052-64, UMMZ 125036 (10), USNM 140567-8; Río Canclon at Río Chucunaque, UMMZ 125035; *Río Chucunaque, near Yavisa, AMNH 59523. Los Santos: Tonosí, KU 101606-9. Panamá: 5 km. S Bejuco, AMNH 69782; 3 km. W Chepo, KU 77172-4, 104097-8 (tadpoles); *6 km. WSW Chepo, KU 77175; *Chico, Río 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; *Río La Laja, near Chamé, ANSP 21845; *Río Tapia, MCZ 10048; *Tapia, AMNH 18930, 18950, 18952-3; *18 km. E Tocumen, MVZ 78662.
Colombia: Chocó: Sautatá, Atrato, FMNH 74918 (2), 74919. Magdalena: Aracataca, ANSP 19755-7; Curumani, MCZ 21465-74, UIMNH 28855; UMMZ 90168, USNM 118247; El Banco, Río Magdalena, ANSP 25061; Fundación, UMMZ 48281-2. Tolima: Espinal, MCZ 15068; Mariquita, FMNH 81822-3. Valle: Sevilla, MCZ 13751-3.
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 Chiriquí, Panamá).
Hyla underwoodi Boulenger, Ann. Mag. Nat. Hist., ser. 7, 3:277, April, 1899 (substitute name for Hyla microcephala Boulenger, preoccupied). Günther, 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.
Hyla phlebodes, Cole and Barbour, Bull. Mus. Comp. Zool., 50:154, November, 1906. Kellogg, Bull. U. S. Natl. Mus., 160:172, March 31, 1932.
Hyla microcephala martini Smith, Herpetologica, 7:187, December 31, 1951 [Holotype.—UIMNH 20965 from Encarnacion, Campeche, México; H. M. Smith collector]. Stuart, Contr. Lab. Vert. Biol., Univ. Michigan, 68:46, November, 1954. Fugler and Webb, Herpetologica, 13:105, July 10, 1957. Stuart, Contr. Lab. Vert. Biol., Univ. Michigan, 75:17, June, 1958. Neill and Allen, Publ. Research Div., Ross Allen's Reptile Inst., 2:26, November 10, 1959. Duellman, Univ. Kansas Publ., Mus. Nat. Hist., 13:62, August 16, 1960. Stuart, Herpetologica, 17:74, July 11, 1961. Hensley and Smith, Herpetologica, 18:70, April 9, 1962. Stuart, Misc. Publ. Mus. Zool., Univ. Michigan, 122:36, April 2, 1963. Holman and Birkenholz, Herpetologica, 19:144, July 3, 1963. Duellman, Univ. Kansas Publ., Mus. Nat. Hist., 15:225, October 4, 1963; Univ. Kansas Publ., Mus. Nat. Hist., 15:588, June 22, 1965.
Hyla microcephala underwoodi, Smith, Herpetologica, 7:188, December 31, 1951.
Diagnosis.—Brown lateral stripe narrow, extending to groin or only to sacral region, bordered above by narrow white line; dorsal pattern bold, consisting of X- or )(-shaped mark in scapular region or pair of interconnected dark lines on back; interorbital dark mark usually present; shanks usually having dark transverse bars.
Description and Variation.—The dorsal color pattern is highly variable. The various permutations of the X-shaped scapular mark and dark sacral marks differ proportionately in different samples. The variation in color pattern in 12 samples is summarized in Table 2. In samples from the southern part of the range (southern Nicaragua and Guanacaste Province, Costa Rica) more (40-93%) individuals have the lateral stripes extending to the groin than in northern samples (0-42%) from southern México and Guatemala. Likewise, the percentage of specimens lacking bars on the shanks and a dark interorbital bar is higher in the Costa Rican samples than elsewhere in the range. The X- or )(-shaped scapular markings and /\- or / \-shaped sacral markings are most prevalent in northern samples, whereas to the south the dorsal markings are more commonly arranged in a pattern of paired lines, which usually are discontinuous and usually extend posteriorly only to the sacral region. Thus, the color pattern in H. m. underwoodi in the southern part of its range shows trends towards the pattern characteristic of H. m. microcephala. Intergrades between these two subspecies have been discussed in the account of the nominate subspecies.