2217 Systematics and biogeography of Eastern Caribbean frogs (Leptodactylidae: Eleutherodactylus), with the description of a new species from Dominica HINRICH KAISER 1 AND DAVID M. GREEN Redpath Museum and Department of Biology, McGill University, 859 Sherbrooke Street West, Montreal, QC H3A 2K6, Canada AND MICHAEL SCHMID Institut fiir Humangenetik, Universitiit Wiirzburg, Biozelllrum, Am Hubland, 97074 Wiirzburg, Germany Received April 5, 1994 Accepted October 12, 1994 KAISER, H., GREEN, D.M., and SCHMID, M. 1994. Systematics and biogeography of Eastern Caribbean frogs (Lepto- dactylidae: Eleutherodactylus), with the description of a new species from Dominica. Can. J. Zoo!. 72: 2217-2237. Populations of Eleutherodactylus on the island of Dominica, West Indies, differ from other Lesser Antillean members of the genus by their vocalizations, morphology, sexual size dimorphism, allozymes, and chromosomes. Thus, these populations comprise a new endemic species, closely related to E. johnstonei and E. martinicensis. The new species is most abundant in montane forest habitats at elevations of more than 500 m. Females commonly attain snout-vent lengths of more than 35 mm, making them the largest Lesser Antillean Eleutherodactylus. Frogs are brown during the day, but change color to . dark orange when active at night. This species is the ninth Eastern Caribbean Eleutherodactylus species and the fifth single- island endemic. A phylogenetic analysis of external and internal morphological characteristics shows that Eastern Caribbean Eleutherodactylus are members of two distinct clades, one of South American origin, the other of Greater Antillean ancestry. We suggest that the present distribution of these species results from the dispersal of elements of the larger herpetofaunas from the Greater Antilles and South America, and that rapid divergence of the Eastern Caribbean Eleutherodactylus fauna may be continuing. The phylogenetic analysis also confirms that morphological characters of Eleutherodactylus species can be highly homoplastic. KAISER, H., GREEN, D.M., et SCHMID, M. 1994. Systematics and biogeography of Eastern Caribbean frogs (Lepto- dactylidae: Eleutherodactylus), with the description of a new species from Dominica. Can. J. Zoo!. 72 : 2217-2237. Les populations d' Eleutherodactylus de la Dominique, dans les Antilles, different des autres membres du genre dans les Petites Antilles par leurs cris, leur morphologie, leur dimorphisme sexuel quant 11 la taille, leurs allozymes et leurs chromo- somes. Ces populations constituent une nouvelle espece endemique fortement apparentee 11 E. johnstonei et E. martinicensis. La nouvelle espece abonde surtout dans les habitats forestiers montagneux aux altitudes superieures 11 500 m. Les femelles mesurent souvent plus de 35 mm (longueur museau -event) et sont ainsi les Eleutherodacrylus les plus grands des Petites Antilles. Les grenouilles sont brunes durant la journee, mais prennent une coloration orangee foncee lorsqu'elles sont actives la nuil. Cette esp(:ce est la neuvieme espece d'Eleutherodactylus de I'est des Antilles et la cinquieme espece endemique dans une seule lie. Une analyse phylogenetique des caracteres morphologiques internes et externes a demontre que les Eleuthero- dactylus de l'est des Antilles appartiennent 11 deux clades distincts, un d'origine sud-americaine, I'autre derivant d'un ancetre vivant dans les Grandes Antilles. La repartition actuelle des especes resulte probablement de la dispersion des grandes herpetofaunes des Grandes Antilles et de l' Amerique du Sud et la divergence rapide de la faune des Eleutherodactylus de l'est des Antilles se fait probablement encore. L'analyse phylogcnetique a egalement revele que les caracteres morphologiques des especes d' Eleutherodactylus peuvent etre tres homoplastiques. [Traduit par la Redaction] Introduction The neotropical frog genus Eleutherodactylus is the most speciose vertebrate genus, represented by over 500 described species (Duellman 1993). Although some of its members have very distinctive external features (e.g., Lynch 1975, 1980), it is often difficult to differentiate species of Eleutherodactylus morphologically. Intraspecific variability can be considerable, yet the many species are variants, albeit sometimes extreme, of a conservative morphotype, a small brownish frog (Lynch and La Marca 1993). Previous phylogenetic analyses of rela- tionships within Eleutherodactylus at various levels of classifi- cation have been conducted with varying degrees of success (e.g., Miyamoto 1983, 1984, 1986; Hedges 1989; Joglar 1989). The use of biochemical characters in post hoc tests of a given data set invariably improved the resolution of sys- tematic relationships (Hedges 1989; Kaiser 1993). Ipresent Address: Institut £iir Humangenetik, Universitiit Wiirz- burg, Biozentrum, Am Hubland, 97074 Wiirzburg, Germany. Primed in Canada I Impril11c au Canada The 128 West Indian species of Eleutherodactylus have been classified (Hedges 1989) into the subgenera Eleutherodactylus (comprising 2 species groups), Euhyas (12), and Pelm'ius (2), with 70 species still unassigned to species groups within Eleutherodactylus or Euhyas. Eight species are known to inhabit the Eastern Caribbean (Table I), a region comprising the Lesser Antilles, Trinidad, and Tobago (Fig. 1). Many of these are single-island endemics whose origin and systematic relationships are as yet unresolved. The detailed synopsis of these taxa by Schwartz (1967) provides few data to support sister-group relationships or wider ranging affinities for these taxa. Their tentative inclusion in the Greater Antillean auricu- latus section, which comprises 44 species (Hedges 1989; the "auriculatus group" of Schwartz 1969), is supported by six characteristics: (1) external submandibular vocal sac in males; (2) "patch-like" vomerine teeth; (3) areolate venter; (4) highly vocal; (5) above-ground calling sites; and (6) prominent digital disks. However, the phylogenetic significance of these charac- ters is still uncertain (Hedges 1989). Hedges (1989) also