Neotropical Hylid Frogs, Genus Smilisca.

by William E. Duellman and Linda Trueb.

INTRODUCTION

The family Hylidae, as currently recognized, is composed of about 34 genera and more than 400 species. Most genera (30) and about 350 species live in the American tropics. _Hyla_ and 10 other genera inhabit Central America; four of those 10 genera (_Gastrotheca_, _Hemiphractus_, _Phrynohyas_, and _Phyllomedusa_) are widely distributed in South America. The other six genera are either restricted to Central America or have their greatest differentiation there. _Plectrohyla_ and _Ptychohyla_ inhabit streams in the highlands of southern Mexico and northern Central America; _Diaglena_ and _Triprion_ are casque-headed inhabitants of arid regions in Mexico and northern Central America.

_Anotheca_ is a tree-hole breeder in cloud forests in Middle America.

The genus _Smilisca_ is the most widespread geographically and diverse ecologically of the Central American genera.

The definition of genera in the family Hylidae is difficult owing to the vast array of species, most of which are poorly known as regards their osteology, colors in life, and modes of life history. The genera _Diaglena_, _Triprion_, _Tetraprion_, _Osteocephalus_, _Trachycephalus_, _Aparasphenodon_, _Corythomantis_, _Hemiphractus_, _Pternohyla_, and _Anotheca_ have been recognized as distinct from one another and from the genus _Hyla_ on the basis of various modifications of dermal bones of the cranium. _Phyllomedusa_ is recognized on the basis of a vertical pupil and opposable thumb; _Plectrohyla_ is characterized by the presence of a bony prepollex and the absence of a quadratojugal.

_Gastrotheca_ is distinguished from other hylids by the presence of a pouch in the back of females. A pair of lateral vocal sacs behind the angles of the jaws and the well-developed dermal glands were used by Duellman (1956) to distinguish _Phrynohyas_ from _Hyla_. He (1963a) cited the ventrolateral glands in breeding males as diagnostic of _Ptychohyla_. Some species groups within the vaguely defined genus _Hyla_ have equally distinctive characters. The _Hyla septentrionalis_ group is characterized by a casque-head, not much different from that in the genus _Osteocephalus_ (Trueb, MS). Males in the _Hyla maxima_ group have a protruding bony prepollex like that characteristically found in _Plectrohyla_.

Ontogenetic development, osteology, breeding call, behavior, and ecology are important in the recognition of species. By utilizing the combination of many morphological and biological factors, the genus _Smilisca_ can be defined reasonably well as a natural, phyletic a.s.semblage of species. Because the wealth of data pertaining to the morphology and biology of _Smilisca_ is lacking for most other tree frogs in Middle America it is not possible at present to compare _Smilisca_ with related groups in more than a general way.

_Smilisca_ is an excellent example of an Autochthonous Middle American genus. As defined by Stuart (1950) the Autochthonous Middle American fauna originated from "hanging relicts" left in Central America by the ancestral fauna that moved into South America and differentiated there at a time when South America was isolated from North and Middle America.

The genus _Smilisca_, as we define it, consists of six species, all of which occur in Central America. One species ranges northward to southern Texas, and one extends southward on the Pacific lowlands of South America to Ecuador. We consider the genus _Smilisca_ to be composed of rather generalized hylids. Consequently, an understanding of the systematics and zoogeography of the genus can be expected to be of aid in studying more specialized members of the family.

Acknowledgments

Examination of many of the specimens used in our study was possible only because of the cooperation of the curators of many systematic collections. For lending specimens or providing working s.p.a.ce in their respective inst.i.tutions we are grateful to Doris M. Cochran, Alice G. C.

Grandison, Jean Guibe, Robert F. Inger, Gunther Peters, Gerald Raun, William J. Riemer, Jay M. Savage, Hobart M. Smith, Wilmer W. Tanner, Charles F. Walker, Ernest E. Williams, and Richard G. Zweifel.

We are indebted to Charles J. Cole and Charles W. Myers for able a.s.sistance in the field. The cooperation of Martin H. Moynihan at Barro Colorado Island, Charles M. Keenan of Corozal, Ca.n.a.l Zone, and Robert Hunter of San Jose, Costa Rica, is gratefully acknowledged. Jay M.

Savage turned over to us many Costa Rican specimens and aided greatly in our work in Costa Rica. James A. Peters helped us locate sites of collections in Ecuador and Coleman J. Goin provided a list of localities for the genus in Colombia.

We especially thank Charles J. Cole for contributing the information on the chromosomes, and Robert R. Patterson for preparing osteological specimens. We thank M. J. Fouquette, Jr., who read the section on breeding calls and offered constructive criticism.

Permits for collecting were generously provided by Ing. Rodolfo Hernandez Corzo in Mexico, Sr. Jorge A. Ibarra in Guatemala, and Ing.

Milton Lopez in Costa Rica. This report was made possible by support from the National Science Foundation (Grants G-9827 and GB-1441) and the cooperation of the Museum of Natural History at the University of Kansas. Some of the field studies were carried out in Panama under the auspices of a grant from the National Inst.i.tutes of Health (NIH GM-12020) in cooperation with the Gorgas Memorial Laboratory in Panama.

Materials and Methods

In our study we examined 4151 preserved frogs, 93 skeletal preparations, 88 lots of tadpoles and young, and six lots of eggs. We have collected specimens in the field of all of the species. Observations on behavior and life history were begun by the senior author in Mexico in 1956 and completed by us in Central America in 1964 and 1965.

Osteological data were obtained from dried skeletons and cleaned and stained specimens of all species, plus serial sections of the skull of _Smilisca baudini_. Developmental stages to which tadpoles are a.s.signed are in accordance with the table of development published by Gosner (1960). Breeding calls were recorded in the field on tape using Magnemite and Uher portable tape recorders. Audiospectrographs were made by means of a Vibralyzer (Kay Electric Company). External morphological features were measured in the manner described by Duellman (1956). 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.

Abbreviations for museum specimens are listed below:

AMNH--American Museum of Natural History BMNH--British Museum (Natural History) BYU--Brigham Young University CNHM--Chicago Natural History Museum KU--University of Kansas Museum of Natural History MCZ--Museum of Comparative Zoology MNHN--Museu National d"Histoire Naturelle, Paris UF--University of Florida Collections 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 TNHC--Texas Natural History Collection, University of Texas ZMB--Zoologisches Museum Berlin

=Genus Smilisca= Cope, 1865

_Smilisca_ Cope, Proc. Acad. Nat. Sci. Philadelphia, 17:194, Oct., 1865 [Type species _Smilisca daulinia_ Cope, 1865 = _Hyla baudini_ Dumeril and Bibron, 1841]. Smith and Taylor, Bull. U. S. Natl.

Mus., 194:75, June 17, 1948. Starrett, Copeia, 4:300, December 30, 1960. Goin, Ann. Carnegie Museum, 36:15, July 14, 1961.

_Definition._--Medium to large tree frogs having: (1) broad, well ossified skull (consisting of a minimum amount of cartilage and/or secondarily ossified cartilage), (2) no dermal co-ossification, (3) quadratojugal and internasal septum present, (4) large ethmoid, (5) _M.

depressor mandibulae_ consisting of two parts, one arising from dorsal fascia and other from posterior arm of squamosal, (6) divided _M.

adductor mandibulae_, (7) paired subgular vocal sacs in males, (8) no dermal appendages, (9) pupil horizontally elliptical (10) small amounts of amines and other active substances in skin, (11) chromosome number of N = 12 and 2N = 24, (12) breeding call consisting of poorly modulated, explosive notes, and (13) 2/3 tooth-rows in tadpoles.

_Composition of genus._--As defined here the genus _Smilisca_ contains six recognizable species. An alphabetical list of the specific and subspecific names that we consider to be applicable to species of _Smilisca_ recognized herein is given below.

Names proposed Valid names

_Hyla baudini_ Dumeril and Bibron, 1841 = _S. baudini_ _Hyla baudini dolomedes_ Barbour, 1923 = _S. phaeota_ _Hyla beltrani_ Taylor, 1942 = _S. baudini_ _Hyla gabbi_ Cope, 1876 = _S. sordida_ _Hyla l.a.b.i.alis_ Peters, 1863 = _S. phaeota_ _Hyla manisorum_ Taylor, 1954 = _S. baudini_ _Hyla muricolor_ Cope, 1862 = _S. baudini_ _Hyla nigripes_ Cope, 1876 = _S. sordida_ _Hyla pansosana_ Brocchi, 1877 = _S. baudini_ _Hyla phaeota_ Cope, 1862 = _S. phaeota_ _Hyla phaeota cyanosticta_ Smith, 1953 = _S. cyanosticta_ _Hyla puma_ Cope, 1885 = _S. puma_ _Hyla salvini_ Boulenger, 1882 = _S. sordida_ _Hyla sordida_ Peters, 1863 = _S. sordida_ _Hyla vanvlietii_ Baird, 1854 = _S. baudini_ _Hyla vociferans_ Baird, 1859 = _S. baudini_ _Hyla wellmanorum_ Taylor, 1952 = _S. puma_

_Distribution of genus._--Most of lowlands of Mexico and Central America, in some places to elevations of nearly 2000 meters, southward from southern Sonora and Rio Grande Embayment of Texas, including such continental islands as Isla Cozumel, Mexico, and Isla Popa and Isla Cebaco, Panama, to northern South America, where known from Caribbean coastal regions and valleys of Rio Cauca and Rio Magdalena in Colombia, and Pacific slopes of Colombia and northern Ecuador.

Key to Adults

1. Larger frogs ([M] to 76 mm., [F] to 90 mm.) having broad flat heads and a dark brown or black pos...o...b..tal mark encompa.s.sing tympanum 2

Smaller frogs ([M] to 45 mm., [F] to 64 mm.) having narrower heads and lacking a dark brown or black pos...o...b..tal mark encompa.s.sing tympanum 4

2. Lips barred; flanks cream-colored with bold brown or black mottling in groin; posterior surfaces of thighs brown with cream-colored flecks _S. baudini_, p. 289

Lips not barred; narrow white l.a.b.i.al stripe present; flanks not cream-colored with bold brown or black mottling in groin; posterior surfaces of thighs variable 3

3. Flanks and anterior and posterior surfaces of thighs dark brown with large pale blue spots on flanks and small blue spots on thighs _S. cyanosticta_, p. 303

Flanks cream-colored with fine black venation; posterior surfaces of thighs pale brown with or without darker flecks or small cream-colored spots _S. phaeota_, p. 308

4. Fingers having only vestige of web; diameter of tympanum two-thirds that of eye; dorsum pale yellowish tan with pair of broad dark brown stripes _S. puma_, p. 314

Fingers about one-half webbed; diameter of tympanum about one-half that of eye; dorsum variously marked with spots or blotches 5

5. Snout short, truncate; vocal sacs in breeding males dark gray or brown; blue spots on flanks and posterior surfaces of thighs _S. sila_, p. 318

Snout long, sloping, rounded; vocal sacs in breeding males white; cream-colored or pale blue flecks on flanks and posterior surfaces of thighs _S. sordida_, p. 323

Key to Tadpoles

1. Pond tadpoles; tail about half again as long as body; mouth anteroventral 2

Stream tadpoles; tail about twice as long as body; mouth ventral 5

2. l.a.b.i.al papillae in two rows 3

l.a.b.i.al papillae in one row 4

3. First upper tooth row strongly arched medially; third lower tooth row much shorter than other rows; dorsal fin deepest at about two-thirds length of tail; tail cream-colored with dense gray reticulations _S. puma_, p. 314