Molecular systematics of the green algal orders Ulotrichales and Ulvales based on 18S rDNA sequences

The traditional use of thallus morphology to define lineages within the Ulvophyceae proved problematic because parallelism and convergence obscured natural relationships. The advent of transmission electron microscopy led to a re-evaluation of groups on the basis of zoid characters. Within TEM-defin...

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Bibliographic Details
Published in:Journal of phycology 2003-06, Vol.39 (S1), p.61-61
Main Authors: Wysor, B, O'Kelly, C J, Bellows, W K
Format: Article
Language:English
Subjects:
Acroblaste
Bolbocoleon
Brackish
Chlorophyta
Ctenocladales
Ctenocladus
Freshwater
Marine
Phaeophila
Pseudendoclonium
Ulotrichales
Ulvales
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Summary:The traditional use of thallus morphology to define lineages within the Ulvophyceae proved problematic because parallelism and convergence obscured natural relationships. The advent of transmission electron microscopy led to a re-evaluation of groups on the basis of zoid characters. Within TEM-defined lineages, the Ulotrichales and Ulvales were considered closely related orders, and molecular evidence has substantiated this hypothesis. In our molecular systematic studies of ulvophyceous green algae, we have broadened taxon sampling among these two orders. We show that the Ulvales and Ulotrichales are indeed monophyletic orders. However, the phylogenetic placement of species in the genera Bolbocoleon, Ctenocladus, Phaeophila, Pseudendoclonium and Acroblaste indicates that one or more additional lineages, placed between Ulvales and Ulotrichales in gene sequence trees, must be recognized. These species may constitute a separate order (Ctenocladales) consisting of multiple families. Our findings will be compared with taxonomic concepts based on morphological criteria.
ISSN:0022-3646
DOI:10.1111/j.0022-3646.2003.03906002_177.x