Phylogenetic reassessment of the mastophoroideae (Corallinaceae, rhodophyta) using molecular and morphological data

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Jennifer E. Gabel (Creator)
Institution
The University of North Carolina Wilmington (UNCW )
Web Site: http://library.uncw.edu/

Abstract: Nuclear encoded small ribosomal subunit gene sequences were determined for six species of coralline algae (Corallinaceae, Rhodophyta) representing three genera classified in the Mastophoroideae and two species of Amphiroa (Lithophylloideae). These data were combined with previously published 18S rRNA gene sequences for 39 other coralline taxa and one unpublished sequence. Analyses were performed using parsimony and maximum likelihood methods to determine the phylogenetic position of the Mastophoroideae within the Corallinaceae as well as the relationships among Hydrolithon, Metamastophora, Neogoniolithon, and Spongites. In addition, partial sequences were determined for the nuclear-encoded large ribosomal subunit for five of the six species of mastophoroids and combined with unpublished 26S rRNA gene sequence data for 16 coralline taxa. Sequence data was analyzed using parsimony and maximum likelihood methods for an independent 26S rRNA data set and a taxonomically congruent combined 18S/26S rRNA data set. Results for the 26S and combined data sets were consistent with analysis of the 18S data. The Mastophoroideae is resolved as a polyphyletic taxon with four independent lineages. Neogoniolithon spp. were allied with geniculate members of the Corallinoideae and Hydrolithon spp. were resolved as sister to the geniculate Metagoniolithoideae. Based on these analyses, Porolithon pachydermum is transferred to Hydrolithon as H. pachydermum (Foslie) Bailey, Gabel et Freshwater. An independent morphological data set was also assembled to assess the phylogenetic significance of particular reproductive and vegetative characteristics within the Corallinales. This analysis implies that the mode of tetrasporangial conceptacle development, orientation of cells lining the pore canal, location of formation of spermatangia within the male conceptacle, location of gonimoblast filament origin along the fusion cell, and appearance of the fusion cell provide additional features that are taxonomically and phylogenetically significant at the rank of subfamily.

Additional Information

Publication
Thesis
A Thesis Submitted to the University of North Carolina Wilmington in Partial Fulfillment of the Requirements for the Degree of Master of Science
Language: English
Date: 2009
Keywords
Coralline algae--Classification, Coralline algae--Molecular diagnosis, Coralline algae--Morphology
Subjects
Coralline algae -- Morphology
Coralline algae -- Molecular diagnosis
Coralline algae -- Classification