Bryological and Lichenological Section/ABLS
Fisher, Kirsten M. .
Cryptic lineages and reproductive patterns in the Syrrhopodon involutus Schwaeg. complex.
This study examines a possible example of cryptic lineage diversity in the Syrrhopodon involutus Schwaeg. complex, a small clade of mosses that occurs in both continental, near-continental and remote islands throughout the Paleotropics. Maximum likelihood phylogenetic analysis was conducted for 18 exemplars (and one outgroup) of the complex using sequence data from the second internal transcribed spacer (ITS2) of the nuclear ribosomal DNA. The resulting trees identify cryptic moss lineages on islands in both the western Indian Ocean and the eastern South Pacific. Maximum likelihood optimization of geographic data on the ITS2 tree supports a continental S. E. Asian / Indomalaysian origin for the S. involutus complex. Plants of the S. involutus complex are dioecious and display weak to strong sexual size dimorphism characterized by male plants that are smaller than female plants. Some taxa in the complex display phyllodioecy, the most extreme case of this dimorphism in which minute dwarf males grow epiphytically on the leaves of the female plants. A secondary aim of this study was to characterize the reproductive condition exhibited by individuals of the S. involutus complex from throughout its range, and to assess any potential correlations between phylogeographic and reproductive patterns. Using the maximum likelihood phylogeny, comparative analyses were conducted with geographic and reproductive data collected from 262 collections of the study group. These analyses show a significant negative correlation between the presence of gametangia and the distance from mainland S.E. Asia that a specimen was collected. Collectively, the results support an attenuation of sexual reproduction in members of the S. involutus complex on remote oceanic islands.
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1 - California State University, Los Angeles, Department of Biological Sciences, 5151 State University Dr., Los Angeles, CA, 90032, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Magpie B/Cliff Lodge - Level B
Date: Monday, July 27th, 2009
Time: 9:00 AM