Part 12

The series of dark dashes on the dorsal edge of the caudal musculature is diagnostic of all stages studied. In life, tadpoles from 15 and 20 kilometers west-southwest of San Isidro el General, Costa Rica, had a tan body, often with an olive-tan tinge; the caudal musculature was tan; the flecks and dashes were dull red or reddish brown. Tadpoles from 6 kilometers east of Golfito, Costa Rica, had bodies with olive-green flecks. The caudal musculature was brown with bluish green flecks; the fins were transparent with reddish brown flecks. The belly was a silvery golden color. Tadpoles from Bajos de Jorco, Costa Rica, had brown bodies with bluish green flecks; the tail and fins had reddish brown flecks and dashes. The iris was a bronze color in specimens from all three localities, as well as in the young mentioned in the following paragraph.

Nine recently metamorphosed young were found on vegetation at the edges of streams in April. These specimens have snout-vent lengths of 13.1 to 15.7 mm. (14.9 mm.) and in life were pale greenish tan or olive-tan above and white below. The hands, feet, and thighs were pale yellowish tan.

Remarks.--The foregoing synonymies indicate that confusion has existed in the application of various names, to this species, as well as in use of the names sordida and gabbi to include the species that we describe and name Smilisca sila. Correct allocation of the names involved was possible only after studying and comparing the type specimens, for the descriptions given by the various authors are not sufficiently explicit to determine the nature of many essential features.

The presence of a rounded snout and a long white throat in males distinguishes S. sordida from S. sila, which has a high truncate snout and short dark throat in males. The two syntypes of Hyla sordida Peters, 1863, (ZMB 3141) are males having snout-vent lengths of 36.9 and 37.0 mm. The two syntypes of Hyla gabbi Cope, 1876 (USNM 30658-9), are females having snout-vent lengths of 52.8 and 53.7 mm., respectively. Also included in the collections made by Gabb is eastern Costa Rica are two males (USNM 30685-6), which Cope (1876) named and described as Hyla nigripes. These specimens are soft and faded, but are recognizable as the same as Hyla sordida Peters; the syntypes of Hyla nigripes have snout-vent lengths of 37.6 and 37.7 mm. We have examined one of the syntypes of Hyla salvini Boulenger, 1882 (BMNH 1947.2.24.13), a female having a snout-vent length of 54.6 mm. We are convinced that all of these type specimens are representatives of one species, the earliest name for which is Hyla sordida Peters, 1863. The type localities for three of the named species are in Costa Rica--H. gabbi from Sipurio on the Caribbean lowlands, H. nigripes from the Caribbean slopes of Pico Blanco, and H. salvini from Cartago on the Meseta Central. The type locality of H. sordida was given as "Veraguas" by Peters (1863). At that time Veraguas was often considered to be most of western Panama. Though we have not seen Panamanian specimens other than the types of S. sordida and one specimen from the Pacific lowlands of western Panama, the species probably occurs on the Caribbean slopes of western Panama. The species has been taken on the Caribbean lowlands of Costa Rica within a few kilometers of Panama; collecting on the Caribbean slopes in the provinces of Bocas del Toro and Veraguas should reveal the presence of Smilisca sordida there.

Distribution.--Smilisca sordida is found along the Pacific slopes and lowlands from Guanacaste, Costa Rica, southeastward to extreme western Panama, to elevations of about 1200 meters on the Meseta Central in Costa Rica, and on the Caribbean slopes and lowlands of Costa Rica and probably adjacent Panama (Fig. 5). One specimen purportedly comes from "Rio Grande, Nicaragua."

Specimens examined.--412, as follows: NICARAGUA: "Rio Grande" (? Depto. Zelaya), MCZ 2634.

COSTA RICA: =Alajuela=: Between Atena and Salto de San Mateo, USC 6185; 8 km. N Ciudad Quesada, USC 7155 (4); La Fortuna, USC 7153 (20); 3 km. E La Fortuna, USC 7150; San Carlos, USNM 29969; Sarchi, KU 32990-9, 36792-3.

=Cartago=: Cartago, BMNH 1947.2.24.13; headwaters of Rio Pacuare, USC 119; Instituto Interamericano de Ciencias Agricolas, Turrialba, KU 37012, USC 420, 437; Rio Reventazon, Turrialba, MCZ 29268: 10 km. N Rio Reventazon bridge, USC 7073; 5 km. SW Rio Reventazon bridge on Paraiso-Orosi road, USC 669; Turrialba, UMMZ 118405, USC 455, USNM 29936-9.

=Heredia=: Puerto Viejo, KU 36791.

=Guanacaste=: Las Canas, USC 7164; Santa Cecilia, MCZ 7924-5; Tilaran, USC 7161 (5).

=Limon=: Bambu, USC 7171 (2), 7183 (13); La Lola, USC 820 (6), 6083-94, 8064, 8071; Pandora, USC 7188 (7), 7189, 7190 (3), 7191 (5); Pico Blanco, USNM 30685-6; Rio Lari, 14-16 km. SW Amubre, USC 7179, 7180 (10); Sipurio, USNM 30658-9; Suretka, KU 36764, 36765 (skeleton), 36766-78.

=Puntarenas=: 6 km. N Dominical, KU 91749-50, 91811 (young), 91812 (tadpoles); Esparta, MCZ 8028; 6 km. E Golfito, KU 91718-41, 91809 (young), 91810 (tadpoles), 91816-9 (skeletons), USC 7103 (23); Quebrada Agua Buena, 3 km. SW Rincon de Osa, USC 7236 (6); Quebrada Boruca, 22 km. E Palmar Norte, KU 64264; Rincon de Osa, Camp Seattle, UMMZ 123680-5, S-2792 (skeleton), USC 705 (5), 6023, 7254; Rio Barranca, USC 7119 (2); Rio Ceiba, 6 km. NW Buenos Aires, KU 91747-8, USC 7112 (7); Rio Ciruelitas, 16 km. NW Esparta, USC 7121 (3); Rio Claro, 14.2 km. NW Villa Neily, USC 7110 (4); Rio Ferruviosa, 7 km. S Rincon de Osa, USC 7235 (4); Rio Lagarto at Pan-American Hwy. (Guanacaste Border), USC 7122 (4); Rio La Vieja, 30 km. E Palmar Norte, KU 87684 (tadpoles), 91743-6, USC 7083 (2); Rio Oro, 28.5 km. NW Villa Neily, KU 91742; Rio Volcan, 10 km. W Buenos Aires, USC 7113; Rio Zapote, 7 km. E Palmar, USC 7100 (4); 3-5 km. W Palmar, USC 7101 (18); 7 km. SE Palmar, KU 64261-3; 1.2 km. NW Villa Neily, USC 8032; 3 km. NW Villa Neily, USC 7109 (20); 5 km. NW Villa Neily, USC 6176, 8035.

=San Jose=: Bajos de Jorco, KU 91813 (tadpoles); Escazu, KU 34863, 34869-75, USC 813; between Monrovia and La Hondura, +- 0.5 km. N Santa Rosa, USC 302 (2); Paso Ancho, Rio Jorco, UMMZ 122649 (6), USC 530 (3); Rio Jorco, near Desamparados, KU 91757-65, 91796-7, 91820-3 (skeletons), USC 228, 513, 7117 (7); Rio Peje, 10 km. SSE San Isidro el General, USC 7115 (3); Rio Tirivi, MCZ 7972; San Isidro el General, CNHM 101096, KU 28201, 32989, UMMZ 72024; 15 km. WSW San Isidro el General, KU 64245-56, 68473 (tadpoles), 68474 (young), 68475 (tadpoles), 86516, 91754-6, 91793-5, USC 7097 (6); 17.1 km. WSW San Isidro el General, USC 6047; 18 km. WSW San Isidro el General, USC 689; 20 km. WSW San Isidro el General, KU 64257-9, 64260 (skeleton), 68468 (young), 68469 (tadpoles), 68470 (young), 68471-2 (tadpoles), 68476 (young), 68633-4 (skeletons), 91751-3; San Jose, AMNH 7501-4, USC 298; Santa Rosa, Rio Virilla, USC 7145.

PANAMA: =Chiriqui=: Rio Jacu, 5.8 km. ESE Paso Canoas, KU 91905. "Veraguas," ZMB 3141 (2).

ANALYSIS OF MORPHOLOGICAL CHARACTERS

Osteology

In attempting to assay the taxonomic significance of skeletal differences we are faced with a dearth of data on the skeletons of frogs in general and hylids in particular. Recent reviews by Brattstrom (1957) and Hecht (1962, 1963) have been concerned with general salientian classification and phylogeny, principally at the family level. Savage and Carvalho (1953), Griffiths (1959), and Baldauf (1959) used osteological characters in determining the taxonomic status of the families Pseudidae, Brachycephalidae, and Bufonidae, respectively. Carvalho (1954) presented osteological evidence for the generic separation of New World microhylids. Zweifel (1956) and Tihen (1962) used osteological characters at the levels of the species-group and species in their respective studies on Scaphiopus and Bufo. Little has been recorded about the skeletons of the hylids. Goin (1961) mentioned dentigerous elements and cranial co-ossification in his synopsis of the genera of hylids. Copland (1957) in his review of the Hyla of Australia, Funkhouser (1957) in her revision of Phyllomedusa, and Zweifel (1958) in his review of Nyctimystes did not consider skeletal characters.

Some osteological studies on hylids have yielded worthwhile information. Mittleman and List (1953) used osteological characters in defining the genus Limnaoedus: Starrett (1960) used cranial characters in combination with jaw musculature in defining the genus Smilisca, and Duellman (1964) used cranial characters in delimiting the Hyla bistincta group. Brief descriptions of cranial structure were given for Phrynohyas (Duellman, 1956) and Ptychohyla (Duellman, 1963a); specific and sexual differences in the skulls of Hyla chaneque and Hyla taeniopus were pointed out by Duellman (1965). Stokely and List (1954) described early cranial development in the hylid Pseudacris triseriata triseriata.

Because our knowledge of the skeleton in hylids is so incomplete, we are not attempting to place Smilisca in the general scheme of hylid phylogeny on the basis of skeletal characters. Instead, our purposes are to describe the skeleton and its ontogenetic development in one member of the genus (S. baudini), and to make comparisons that show taxonomic differences in osteological characters among species of Smilisca.

The study of 68 dried skeletons and 25 cleared and stained preparations, including an ontogenetic series of S. baudini, has resulted in an understanding of the progressive development of skeletal elements and a knowledge of interspecific and intraspecific variation in these elements. Furthermore, investigations of the osteology have provided correlations between some cranial characters and certain aspects of external morphology.

Descriptive Osteology of Smilisca baudini

The following description is based primarily on an adult female (KU 68184):

Skull.--The skull is large, solid, and broader than long; the greatest width is between the sutures of quadratojugal and maxillary on either side of the skull (Pls. 2-3). The maxillaries bear well-developed dorsal flanges, curve gently, join the moderately convex premaxillaries anteriorly and form a slightly truncate snout. The combined premaxillary width is about one-fourth the width of the skull. The premaxillaries are separated medially, and laterally from the maxillaries by sutures. Each premaxillary bears a dorsomedial alary process, which is anteriorly convex and four times as high as the depth of the lateral wing of premaxillary; each premaxillary also has a ventromedial palatine process that projects dorsally from the lingual edge of the premaxillary. The septomaxillaries are closely associated dorsally with the premaxillaries immediately lateral to the prenasal processes.

The nasals are large, widest anteriorly and narrowing posteriorly, parallel to maxillaries, and not separated from the ethmoid by cartilage. The nasals bear long, delicate maxillary processes extending nearly to the maxillaries. Anteriorly, the nasals are widely separated by the partially ossified internasal septum, which is in contact with the premaxillaries between the prenasal processes; the anterior points of the nasals lie approximately one-half the distance between the anterior ends of the ethmoid and the premaxillaries. The ethmoid is large and completely ossified; the margins are smooth. The trunate anterior edge lies between the nasals and is in contact with the internasal septum. The frontoparietals are large, smooth-margined, and bear large supraorbital flanges curving posterolaterally at the rear of the orbit. A small, oval foramen involves the posterior part of the ethmoid and anterior portion of frontoparietals; continued ossification in older specimens fills in the foramen, thereby resulting in a solidly roofed cranium. The auditory regions are relatively massive and bear narrow tegmen tympani; the distal ends of the tegmen tympani are medial to the lateral edge of the pterygoids in dorsal view. The squamosals are large; the long anterior arm is separated from the maxillary by a suture. The delicate, spindle-shaped columellae lie ventral to the tegmen tympani and squamosals, are spatulate distally, and have a broad basal attachment to the auditory region.

The vomers are moderately large and are in contact anteriorly with the premaxillaries and posteriorly with the ethmoid. Each vomer has two wide serrated flanges laterally. The tooth-bearing parts of the vomers are widely separated and at a slight angle to one another; the vomers terminate medially in two pointed processes on the ethmoid. The palatines are edentate, but bear strong ridges throughout their lengths. They are broadly in contact with the maxillary, are narrow medially, and are attached by pointed processes to the medial part of the ethmoid. The pterygoids are large, attached to the maxillaries immediately anterior and medial to the squamosal-maxillary connection, bear well-developed pedicles, which are broadly attached to the prooetic, and a wide wing is in contact posteriorly with the distal two-thirds of the quadrate.

The angular makes up most of the lower jaw, bears a broad articular surface posteriorly, and has a small coronoid process on the lingual edge; anteriorly the angular is separated from the dentary and mentomecklian by Meckel's cartilage. The dentary lies external to the angular and extends from the mentomecklian to approximately the mid-length of the angular. The mentomecklians are ossified, but separated by cartilage medially.

Hyoid.--The hyoid plate is curved, thin, and mostly cartilaginous, but calcined posteriorly (Fig. 6). The anterior cornua are slender, cartilaginous, and curve anteromedially from the hyoid plate and thence laterally and posteriorly, to attach to the posterior surface of the prooetics. The lateral cornua are broad, flat, cartilaginous lateral extensions from the bases of the anterior cornua. The posterior cornua are bony, except distally.

Vertebral Column.--The atlas lacks transverse processes and a neural crest, whereas transverse processes are present on the other seven presacral vertebrae, and knoblike neural crests are present on the second, third, and fourth vertebrae; a faint neural ridge is visible on the fifth vertebra. The transverse processes are directed laterally on the second and sixth vertebrae, ventrolaterally on the third, posterolaterally on the fourth and fifth, and anterolaterally on the seventh and eighth. The processes are slightly expanded on the fourth, and more so on the fifth, vertebra. The sacral diapophyses are expanded and have a border of calcified cartilage laterally. There are two sacral condyles. The slender coccyx has a thin dorsal ridge on the anterior three-fourths of its length.