-Three species of Colostethus were found at 1800 m in the cloud forest of the Pacific slopes of the Cordillera Occidental of Colombia, including C. abditaurantius, C. fraterdanieli, and a new species. Sonagrams are given for all three species. Chromatic sexual dimorphism in C. abditaurantius is described. Range extensions derived from material in the Colecci6n de Anfibios y Reptiles of the Universidad del Valle are given for C. lehmanni, which is placed in the Cordillera Occidental and in southern Colombia. The C. ramosi group is named for the clade delimited by the synapomorphy of black, apparently glandular tissue on the ventral surface at the distal end of the upper arm and often extending distad along the inner surface of the lower arm (=black arm band) in adult males. RESUMEN.-En estudios herpetol6gicos a los 1800 m en un bosque nublado de la vertiente del Pacifico de la Cordillera Occidental de Colombia, se encontraron tres especies de Colostethus: C. abditaurantius, C. fraterdanieli, y una nueva especie. Se presentan sonogramas para las tres especies. Se describe el dimorfismo sexual cromitico de C. abditaurantius. Con base en los ejemplares examinados de la Colecci6n de Anfibios y Reptiles de la Universidad del Valle, se reportan ampliaciones de los limites de distribuci6n de C. lehmanni, que se registra en la Cordillera Occidental y en el sur de Colombia. Se nombra el grupo C. ramosi para el clado delimitado por la sinapomorfia de tejido aparentemente glandular negro en la superficie ventral de la parte distal del brazo, frecuentemente extendiendose distalmente por la superficie interior del antebrazo (=banda negra del brazo) en machos. The dendrobatid genus Colostethus Cope, 1866 is a widely distributed assemblage of roughly 100 species united by plesiomorphy. Most of the speces groups that have been proposed (and given generic rank in some cases) lack unambiguous synapomorphies and are reflective only of phenetic similarity (Coloma, 1995). While the aposematic/toxic dendrobatids have received much attention in recent years, resulting in a greater understanding of their biology and evolution, basic data on distribution, natural history, and systematics are unavailable for most Colostethus. A large number of species appear to be highly endemic, but for many this is probably an artifact created by the lack of distribution records in the literature. Such is the case for the nominal species reported herein. Specimens of the following nominal species of Colostethus have been reported from the Cordillera Occidental (including the Pacific foothills): C. agilis Lynch and Ruiz-Carranza, 1985; C. alacris Rivero and Granados Diaz, 1990; C. betancuri Rivero and Sera, 1991; C. brachistriatus Rivero and Serna, 1986; C. breviquartus Rivero and Serna, 1986; C. chocoensis (Boulenger, 1912); C. furviventris Rivero and Serna, 1991; C. imbricolus, Silverstone, 1975; C. inguinalis (Cope, 1868); C. lacrimosus Myers, 1991; C. latinasus (Cope, 1863); C. mertensi (Cochran and Goin, 1964); C. nubicola (Dunn, 1924); C. pratti (Boulenger, 1899); C. talamancae (Cope, 1875); and C. yaguara Rivero and Serna, 1991. In this paper we provide accounts for three more Colostethus, including one new species, and report localities in the Cordillera Occidental for a fourth species. MATERIALS AND METHODS The study site is known as Hacienda San Pedro, about 6 km (by road and trail) south of El Queremal, Municipio de Dagua, Departamento del Valle del Cauca, Colombia (3?29'N, 76?42'W), at 1800 m on the Pacific slopes of the Cordillera Occidental. This area represents an extension of the protected forests of Parque Nacional Natural Los Farallones de Cali. Much of the area has been cleared for pasture, but there remain many fairly extensive, often interconnected sections of relatively undisturbed forest along the main streams and smaller creeks. Calls were recorded using a Sony WM D6C Professional Walkman and a Sony ECM 909 microphone. Recordings were digitized and edited using CSRE 4.5 pc-based signal analysis software. Call and note duration was taken from expanded waveforms. Call rate was measured directly from tapes with a stopwatch. Frequences were obtained through fast Fourier transform (window widths 512 and 1024 points). All collected material was killed in Chloretone solution, fixed in 10% formalin, and stored in 70% ethanol or formalin. At present, all material is deposited in the Colecci6n de Anfibios This content downloaded from 157.55.39.104 on Sun, 19 Jun 2016 06:24:18 UTC All use subject to http://about.jstor.org/terms CLOUD FOREST COLOSTETHUS y Reptiles of the Universidad del Valle, although some paratypes will eventually be distributed among different institutions. Specimens were measured to 0.1 mm with dial calipers under a dissecting microscope. Unless otherwise specified, measurements are given only for adults and are expressed in mm. Adult females were diagnosed as having differentiated ova and enlarged, convoluted oviducts; sexual maturity in males was confirmed by the presence of testes and open vocal slits. Type material at the Natural History Museum of Los Angeles County was examined and compared directly with material collected at the study site. Additional comparisons were made with specimens in the collection at the Universidad del Valle and the Instituto de Ciencias Naturales of the Universidad Nacional de Colombia, original descriptions and subsequent literature. Appendix I includes only those speces for which accounts are provided or whose range is extended in this paper. Diagnoses are based on examined material and are intended to complement original descriptions. Color descriptions are derived from the first author's notes taken on live specimens in the field. Colombian distribution data have been taken from examined material and from original descriptions only; although Rivero and Serna (1989) give general distribution patterns for Colombian Colostethus, they do not specify localities (other than those published in the original descriptions) or list examined specimens for the species discussed herein. Staging of larvae follows Gosner (1960); description of larval morphology follows Altig (1970). The following collection abbreviations appear throughout the text: AMNH (American Museum of Natural History), BM (British Museum of Natural History), ICN (Instituto de Ciencias Naturales), LACM (Natural History Museum of Los Angeles County), UVC (Coleccion de Anfibios y Reptiles, Universidad del Valle). Other nominal species of anurans collected at the study site include Gastrotheca antomia, G. dendronastes, Hyla alytolylax, H. columbiana, Eleutherodactylus babax, E. brevifrons, E. calcaratus, E. cerastes, E. deinops, E. ervthropleura, E. gracilis, E. juanchoi, E. mantipus, E. molybrignus, E. orpacobates, E. palmeri, E. platychilus, E. thectopternus, E. w-nigrum, Centrolene geckoideum, C. robledoi, Cochranella ignota, C. griffithsi, C. ruizi, and C. savagei.