A revision of Cladophoropsis Børgesen (Siphonocladales, Chlorophyta)

Abstract

F. Leliaert and E. Coppejans. 2006. A revision of Cladophoropsis Børgesen (Siphonocladales, Chlorophyta). Phycologia 45: 657–679. DOI: 10.2216/06-07.1.

A reassessment of the genus Cladophoropsis results in the recognition of six morphospecies: C. macromeres, C. magna, C. membranacea, C. philippinensis, C. sundanensis and C. vaucheriiformis. The emended genus Cladophoropsis is characterized by mat- or cushion-forming plants attached to the substratum by tenacular cells or by rhizoids that sprout from the proximal pole of the basal cells or are formed in any part of the thallus, cell division by centripetal wall ingrowths or occasionally segregative, cells producing a single lateral but older cells occasionally producing secondary laterals, cross walls at the base of the laterals either absent or their formation markedly delayed and reinforcement of the thallus by entangling of the filaments or by anastomosis of adjacent filaments by tenacular cells. The different species are distinguished from each other based on thallus structure, mode of cell division, organization of branch systems, mode of thallus attachment and reinforcement, shape and dimensions of the cells and shape of the crystalline cell inclusions. Twenty Cladophoropsis species are excluded from the genus, including the widely distributed Indo-Pacific species C. herpestica and C. javanica, which have been found to be unrelated to other Cladophoropsis species but instead allied with species of the Cladophora section Longiarticulatae. Phylogenetic studies based on molecular data have furthermore demonstrated that Cladophoropsis is closely related to Boodlea, Phyllodictyon, Struveopsis, Struvea and Chamaedoris and that the genus probably does not form a natural group within this genus complex. Morphologically this can be illustrated by a number of Cladophoropsis species (e.g. C. magna and C. membranacea) crossing generic boundaries by sharing common features with Chamaedoris, Boodlea, Phyllodictyon and Struvea. For the benefit of taxonomic stability, Cladophoropsis is presently maintained, awaiting additional molecular evidence.

Key Words::

• Cladophora
• Cladophorophyceae
• Cladophorales
• Cladophoropsis
• Siphonocladales
• Siphonocladus
• Spongocladia
• Taxonomy

ACKNOWLEDGMENTS

We are grateful to the curators and researchers of the following herbaria for loans and information on collections: AKU (Anthony Wright), B (Regine Jahn), BISH (Chris Puttock), BM (Jennifer Bryant), BR (Ann Bogaerts), FI (Gianfranco Sartoni and Chiara Nepi), HAW (Isabella Abbott and John Huisman), L (Willem Prud'homme van Reine), LD (Susanna Riebe), M (Dagmar Triebel), MEL (Pembe Ata), MICH (Michael Wynne), NSW (Alan Millar), NY (Ellen Bloch), O (Per Sunding), PC (Bruno de Reviers), S (Marianne Hamnede), SAP (Michio Masuda), UC (Richard Moe and Paul Silva), UPS (Roland Moberg) and W (Uwe Passauer). We thank John Huisman and an anonymous reviewer for valuable comments on the manuscript. We acknowledge C. De maire and C. Van-Kerckhove for laboratory and administrative assistance. Funding was provided by the Fund for Scientific Research Flanders (Research Project 3G002496). F.L. is indebted to the Bijzonder Onderzoeksfonds (Ghent University) for a grant as postdoctoral researcher.