This study expands our previous work on subtribes
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
Existing keys and subgeneric classifications are incomplete and are based upon admittedly artificial classifications.
Phylogenetic relationships within the orchid subtribe Oncidiinae sensu
were inferred using maximum likelihood analyses of single and multilocus DNA
sequence data sets. Analyses included both nrITS DNA and plastid regions (matK
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.
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
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