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Assembling the Tree of Life: Orchidaceae ONCIDIINAE (ORCHIDACEAE) University of Florida Herbarium Home

This study expands our previous work on subtribes Maxillariinae, Oncidiinae, Zygopetalinae, and Stanhopeinae.


In recent years, orchid systematists have made great progress in clarifying evolutionary relationships among orchid genera, based largely upon cladistic analyses of both molecular and morphological/anatomical data sets. A well-supported outline of tribal and subtribal relationships is quickly emerging, limited primarily by the rate that rare taxa can be collected and analyzed. As such broad scale studies progress, it is becoming clear that one of the most daunting remaining tasks will be the phylogenetic revision of very large, species rich genera (e.g., Bulbophyllum, Epidendrum, Maxillaria, Pleurothallis). An even greater problem is that few taxonomists have the years of intensive study and breadth of knowledge to work with these large taxa. For example, few taxonomists are able to accurately identify a randomly-chosen Pleurothallis or Maxillaria species. Existing keys and subgeneric classifications are incomplete and are based upon admittedly artificial classifications.


ABSTRACT

Phylogenetic relationships within the orchid subtribe Oncidiinae sensu Chase were inferred using maximum likelihood analyses of single and multilocus DNA sequence data sets. Analyses included both nrITS DNA and plastid regions (matK exon, trnH-psbA intergenic spacer, and two portions of ycf1 exon) for 738 individuals representing approximately 600 species plus 7 outgroup taxa. Based on the well resolved and highly supported results (bootstrap consensus), we recognize 61 genera in Oncidiinae. Mimicry of oil-secreting Malpighiaceae and other floral syndromes evolved in parallel across the subtribe, and many clades exhibit extensive variation in pollination-related traits. Because previous classifications heavily emphasized these floral features, many genera in earlier classifications were non-monophyletic. Our classification based on monophyly will facilitate focused monographs and clarifies the evolution of morphological and biochemical traits of interest within this highly diverse subtribe.


ACKNOWLEDGMENTS

The authors thank the curators of the herbaria of la Pontificia Universidad Católica de Quito (QCA), la Universidad de Panamá (PMA), and la Universidad de Costa Rica (USJ), as well as el Ministerio del Ambiente del Ecuador and el Autoridad Nacional del Ambiente de Panama for facilitating our research and issuing permits. We are especially grateful to the Portilla family and their staff at Ecuagenera Ltd. (Ecuador), to Andrés Maduro and staff at Finca Dracula (Panama), to researchers and staff at Jardín Botánico Lankester (Costa Rica), the Marie Selby Botanical Gardens (Sarasota, Florida, USA), the Atlanta Botanical Garden (Atlanta, Georgia, USA), Steve Beckendorf (Berkeley, CA, USA), Harry and Andy Phillips (Encinitas, California), and Günter Gerlach (Munich Botanical Garden, Munich, Germany) for allowing us generous access to their orchid collections. Delsy Trujillo contributed Peruvian specimens. Samantha Koehler, Universidade Federal de Săo Paulo, SP, Brazil and Aparacida de Faria, Universidade Estadual de Maringá, PR, Brazil contributed data for Brazilian taxa. Robert L. Dressler and Calaway H. Dodson helped to initiate this project and provided access to specimens, taxonomic advice, and assistance with field work, and Stig Dalström provided invaluable determinations of many specimens and stimulating discussions, although they do not necessarily agree with our conclusions. DNA sequencing was performed by the ICBR core facility at the University of Florida. This work was supported by NSF grants DEB-9815821 to NHW, DEB-9509071 to WMW, DEB-0234064 to NHW and WMW, and IOB-0543659 to JCC, NHW, and WMW, by grants from the American Orchid Society Fund for Education and Research, the Florida Museum of Natural History, and the Royal Botanic Gardens, Kew. Additional funding was provided by Furniss Foundation graduate student fellowships from the American Orchid Society to Mario A. Blanco and Lorena Endara and by a Kew Latin American Research Fellowship to Mario A. Blanco to study specimens in European herbaria.


I thank Steve Beckendorf of Berkeley, California for the use of the photos of Onc. lepturum, Onc. karwinskii, Rhynchostele aptera, Rhyn. candidula, Rhyn. cervantesii, Rhyn. madrensis, Rhyn. majalis, and Rhyn. rossii. Steve has a very good Flickr site with many interesting photographs of Oncidiinae.

Mark Whitten supplied many of the photographs used here, too many to mention individually, and I thank him profusely. Thanks also to James D. Ackerman (UPRRP) for providing the photograph of Cyrtochilum meirax; Kurt Neubig who also supplied many photographs used here; Mario Blanco and Günter Gerlach for most of the photographs of Lockhartia; and special thanks to Samantha Koehler for providing many photographs of Gomesa species.

I especially thank Kent D. Perkins, Senior Biologist and Collection Manager, FLAS, Florida Museum of Natural History, University of Florida, for help with setting up this web site. His knowledge, helpfulness, good cheer, and friendship have been invaluable. He is mostly responsible for the images in the Phylogenetics section, especially the images for the herbarium specimens. Also, Sarah Fazenbaker, of the FLMNH Office of Museum Technology, was extremely helpful in helping me get the code right.


Key Words: elaiophores - euglossine pollination - hummingbird pollination -matK - mimicry - Neotropics - oil-collecting bees - nrITS - trnH-psbA - ycf1


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