Abstract Detail



Pteridology

Sessa, Emily [1], de Gasper, André Luis [2], Gabriel y Galán, Jose María [3], Testo, Weston [4].

Historical biogeography of the fern family Blechnaceae.

Blechnaceae is a primarily tropical family of ferns in the eupolypods II, and includes approximately 265 species. The family has two major centers of diversity, one in the Neotropics and one in Australasia/Oceania, and most species occur in the southern hemisphere. Individual taxa occupy a wide range of habitats and growth forms, and members of the family are characterized (and easy to identify) morphologically by the presence of multiple vascular bundles in the stipe (as opposed to having two bundles, as the remaining members of eupolypods II do). Recent taxonomic and phylogenetic work on the family has clarified the relationships among major lineages in Blechnaceae and expanded the number of recognized genera from between five and nine up to 24. Some of these genera are relatively large, including Blechnum s.s. (30 spp.), Parablechnum (65 spp.), and Austroblechnum (40 spp.), while most are fairly small, with 15 having ten or fewer species (seven genera are monotypic). We undertook the first historical biogeographic analysis of Blechnaceae, to explore how ancestral movements have led to the present distribution of the family. Our sampling included 153 members of Blechnaceae plus 35 outgroup taxa, to facilitate molecular dating and ancestral range reconstruction at the base of the genus. Preliminary analyses suggest a circum-southern hemisphere distribution of Blechnaceae at the base of the family, around 100 million years ago, which corresponds geologically with the beginning of the breakup of Gondwana. A deep initial split in the family established lineages in the eastern and western hemispheres, but multiple long-distance dispersal events have criss-crossed the globe ever since, and many contemporary species in the Neotropics actually diversified there following a much later dispersal from the Old World.


1 - University Of Florida, Biology, Box 118525, Gainesville, FL, 32611, United States
2 - Universidade Regional de Blumenau, Departamento de Ciencias Naturais, Rua Antonio da Veiga, 140 Victor Konder, Blumenau, SC, 89012-900, Brazil
3 - Universidad Complutense, Department of Plant Sciences I, Faculty of Biology, Avda. Jose Antonio Nováis 12, Madrid, 28040, Spain
4 - University Of Florida, 313 NW 2nd St, Gainesville, FL, 32601, United States

Keywords:
fern
Phylogenetics
Biogeography
Systematics
Gondwana
monilophyte
vicariance
long distance dispersal.

Presentation Type: Oral Paper
Number: 0007
Abstract ID:406
Candidate for Awards:None


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