Dissertation Research: Systematics and Biogeography of Cryosophila (Palmae)

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Graduate student Evans, under the direction of faculty adviser Anderson at the University of Michigan is studying the species relationships and geographical distributions of palms of the genus Cryosophila of Central and South America. This is a group of medium-sized, primarily low-elevation rainforest palms, distributed from Pacific coastal Mexico to northwestern Colombia. There are probably fewer than 10 distinct species of Cryosophila, but the exact number as well as the defining characteristics and distributions of each species are unknown. The first objective of this study is to identify, define and classify all Cryosophila species and determine their natural distributions. Once this basic taxonomic information is known, the evolutionary history of the species within the genus will be hypothesized using phylogenetic (cladistic) analysis, including study of Chelyocarpus and Itaya palms. Cryosophila belongs to the most primitive group of palms, the subtribe Thrinacinae. Whereas specialized groups of palms tend to be restricted to either the northern or southern hemisphere, thrinacine palms are more or less equally represented in both hemispheres. In the New World, however, Cryosophila is the only thrinacine palm having a distribution centered in Central America with extensions into both South America and Mexico. The direction of evolution of new species in the genus should help determine areas of speciation and timing of speciation events. The family Palmae is a morphologically diverse tropical to subtropical group having approximately 2600 species, most of which are restricted to rainforest habitats. Due to the rapid destruction of these forests and the fact that a large majority of palm species are found only in the wild and have never been cultivated, species diversity in the palm family is seriously threatened. Since most palms have historically been poorly collected and consequently are greatly under-represented in herbarium collections, the disappearance of palms in the wild will mean that the incredible diversity within the family will forever remain poorly understood. From an economic standpoint, declining palm populations will have major consequences for tropical nations because palms provide an enormous array of useful products for local and regional use as well as for export. Unfortunately, the severity of the problem is difficult to assess and protective measures difficult to implement because many palm species are poorly defined and/or their distributions are only partially understood. That is, good taxonomic and biogeographic data are critical for palm conservation efforts, for only when species are identifiable and their distributions known can actions be taken to harvest them in sustainable fashion and to protect them. The research supported by this grant is designed to provide just such information for one group (the genus Cryosophila) of Mesoamerican palms.