SPECIES LIMITS IN MESOAMERICAN AULACORHYNCHUS TOUCANETS

Abstract

Abstract We examined geographic patterns of variation and differentiation in morphological characters of the emerald toucanets (Aulacorhynchus spp.) of Mesoamerica. Bill lengths showed flat frequency distributions, suggesting that no “adult” size is reached, and raising the possibility that bill growth in toucanets may be indeterminate. Sparse lowland populations in the Pet;aaen region are of uniformly small body size, suggesting that they may consist of subadult individuals. Patterns of variation support recognition of four species in Mesoamerica: A. wagleri in western Mexico, A. prasinus in eastern Mexico and northern Central America, A. caeruleogularis in Costa Rica and western Panama, and A. cognatus in eastern Panama, as well as several additional forms (A. lautus, A. albivitta, and A. nigrogularis) in South America. RESUMEN.—Se analizaron los patrones de variaciaon y diferenciacion de los caracteres morfologicos en las tucanetas (Aulacorhynchus) de Mesoamerica. La longitud del pico mostro una distri...