Systematics of the green macroalgal genus Chamaedoris Montagne (Siphonocladales), with an emended description of the genus Struvea Sonder

Abstract

F. Leliaert, A. J. K. Millar, C. Vlaeminck and E. Coppejans. 2007. Systematics of the green macroalgal genus Chamaedoris Montagne (Siphonocladales), with an emended description of the genus Struvea Sonder. Phycologia 46: 709–725. DOI: 10.2216/07–51.1

Critical reinvestigation of the four presently recognised species of the green macroalgal genus Chamaedoris (C. auriculata, C. delphinii, C. peniculum and C. orientalis) based on morphological and molecular data reveals that at least one species, C. orientalis, is actually a member of the genus Struvea and is herein transferred to that genus as S. okamurae nom. nov. This has also necessitated a revised circumscription of the genus Struvea. Morphological features traditionally used to delimit the three other species of Chamaedoris (shape of capitulum and number of cells split off from the distal pole of the stipe) are not diagnostic, and the traditional species delineations need to be reassessed. Detailed morphological and morphometric analyses reveal that more subtle differences exist among the three species, including cell dimensions and crystalline cell inclusions. Observations and molecular phylogenetic analyses of new collections over the past 27 years allow us to update knowledge of their biogeographic distributions and determine their relationships with species of the closely related genera Apjohnia, Boodlea, Cladophoropsis, Phyllodictyon and Struvea.

Key Words::

• Chamaedoris
• Cladophorales
• Cladophorophyceae
• Molecular phylogeny
• Morphology
• Struvea
• Segregative cell division

ACKNOWLEDGMENTS

We sincerely thank Tom Schils, Olivier De Clerck, Heroen Verbruggen, Christian Boedeker, Olivier Dargent and Herre Stegenga for collecting specimens. John West, Jeanine Olsen and Wytze Stam are gratefully acknowledged for providing cultures of Apjohnia laetevirens, Phyllodictyon orientale and Struvea elegans. We are grateful to Ruth Nielsen (C), Willem Prud'homme van Reine (L), Ellen Bloch (NY), Bruno de Reviers (PC), Marianne Hamnede (S) and Michio Masuda (SAP) for loans and information on collections. The authors greatly appreciate the editorial efforts of David Ballantine and two anonymous reviewers. This research was funded by FWO-Flanders (grants G.0136.01 and G.0142.05) and the Flemish Government (bilateral research grant 01/46). FL is indebted to BOF (Ghent University) for a postdoctoral fellowship grant.