427 ORNITOLOGIA NEOTROPICAL 19 (Suppl.): 427–432, 2008 © The Neotropical Ornithological Society DIVERSIFICATION IN THE NEOTROPICS: PHYLOGENETIC PATTERNS AND HISTORICAL PROCESSES John M. Bates 1 , Carlos Daniel Cadena 2 , José G. Tello 3 , & Robb T. Brumfield 4 1 Department of Zoology, Field Museum of Natural History, 1400 S. Lake Shore Dr., Chicago, Illinois 60605, USA. E-mail: jbates@fieldmuseum.org 2 Departamento de Ciencias Biológicas, Universidad de los Andes, Apartado Aéreo 4976, Bogotá, Colombia. 3 Division of Vertebrate Zoology – Ornithology, American Museum of Natural History, Central Park West at 79 th Street, New York, New York 10024, USA. 4 Museum of Natural Science, 119 Foster Hall, Louisiana State University, Baton Rouge, Louisiana 70803, USA. Resumen. – Diversificación en el Neotrópico: Patrones filogenéticos y procesos históricos. – Resumimos los resultados de dos simposios que reunieron un amplio espectro de presentaciones sobre cómo los datos moleculares están aumentando nuestro conocimiento de los patrones y procesos de diver- sificación de las aves Neotropicales, y del momento en que esta diversificación tuvo lugar. Los expositores están asociados con museos de historia natural, lo que asegura que los datos moleculares esten asociados con especímenes de referencia. La sistemática molecular es un campo que avanza rápidamente, y que resulta muy promisorio para mejorar el entendimiento de los procesos evolutivos en los años venideros. Abstract. – We summarize two symposia that brought together a broad spectrum of talks on how molec- ular data are expanding our understanding of the patterns, processes and timing of avian diversification in the Neotropics. Presenters are associated with natural history museums, which ensure that genetic data are associated with vouchered specimens. Molecular systematics is a rapidly evolving field which promises to bring new understandings of the evolutionary process in the years to come. Accepted 21 December 2007. Key words: DNA, phylogenetics, birds, diversification, Neotropics. The earliest naturalists working in the Neo- tropics contemplated the mechanisms that could have produced and maintained such a dazzling array of biological diversity. That gla- cial/interglacial cycles, mountain-building, riverine barriers, dispersal, and genetic differ- entiation were important in the diversification of Neotropical birds has been known for a long time (Wallace 1853, Chapman 1917, Chapman 1923), yet a detailed understanding of the role of these processes in generating and maintaining biological diversity remains poor. This is in part because there are still few well-supported phylogenies available for Neo- tropical birds. In addition, historical diversifi- cation hypotheses have an inherently temporal component that is difficult to assess using phylogenies obtained from morphologi- cal data. Our understanding of speciation patterns and processes in the Neotropics is rapidly progressing with the application of molecular