Species delimitation, taxonomy and biogeography of dictyota in Europe (Dictyotales, Phaeophyceae)

Taxonomy of the brown algal genus Dictyota has a long and troubled history. Our inability to distinguish morphological plasticity from fixed diagnostic traits that separate the various species has severely confounded species delineation. From continental Europe, more than 60 species and intraspecifi...

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Bibliographic Details
Published in:Journal of Phycology
Main Authors: Tronholm, Ana, Steen, Frederique, Tyberghein, Lennert, Leliaert, Frédérik, Verbruggen, Heroen, Siguan-Ribera, Antonia, De Clerck, Olivier
Format: Article in Journal/Newspaper
Language:English
Published: 2010
Subjects:
Biology and Life Sciences
DICHOTOMA
RHODOPHYTA
biogeography
Dictyota
Dictyotales
diversity
molecular phylogenetics
taxonomy
DNA
CHEMICAL DEFENSE
ARTIFICIAL HYBRIDS
PHYLOGENETIC INFERENCE
NORTH-ATLANTIC
FUCUS-EVANESCENS
MEDITERRANEAN SEA
BENTHIC MARINE-ALGAE
North Atlantic
Online Access:https://biblio.ugent.be/publication/1246502
http://hdl.handle.net/1854/LU-1246502
https://doi.org/10.1111/j.1529-8817.2010.00908.x
https://biblio.ugent.be/publication/1246502/file/1246511
Description
Summary:Taxonomy of the brown algal genus Dictyota has a long and troubled history. Our inability to distinguish morphological plasticity from fixed diagnostic traits that separate the various species has severely confounded species delineation. From continental Europe, more than 60 species and intraspecific taxa have been described over the last two centuries. Using a molecular approach, we addressed the diversity of the genus in European waters and made necessary taxonomic changes. A densely sampled DNA data set demonstrated the presence of six evolutionarily significant units (ESUs): Dictyota dichotoma (Huds.) J. V. Lamour., D. fasciola (Roth) J. V. Lamour., D. implexa J. V. Lamour., D. mediterranea (Schiffn.) G. Furnari, D. spiralis Mont., and the newly described D. cyanoloma sp. nov., which was previously reported as D. ciliolata from the Mediterranean Sea. Species distributions, based on DNA-confirmed occurrence records, indicate that all species are geographically confined to the NE Atlantic Ocean with the exception of D. dichotoma and D. implexa, which also occur in South Africa and Bermuda, respectively. To investigate potential hybridization between D. dichotoma and D. implexa, which were previously shown to be sexually compatible in culture, we compiled and analyzed sets of mitochondrial, plastid, and nuclear markers to detect putative hybrids or introgression in natural populations. Failure to detect natural hybrids indicates that effective pre- and postzygotic isolation mechanisms are at play in natural populations and supports the by-product hypothesis of reproductive isolation.

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