Characterization of two frequently confused species, Bonnemaisonia asparagoides and Bonnemaisonia clavata (Bonnemaisoniales, Rhodophyta), on the basis of morphological and molecular evidence

Abstract

N. Salvador, A. Gómez Garreta and M.A. Ribera Siguan. 2008. Characterization of two frequently confused species, Bonnemaisonia asparagoides and Bonnemaisonia clavata (Bonnemaisoniales, Rhodophyta), on the basis of morphological and molecular evidence. Phycologia 47: 177–190. DOI: 10.2216/07-24.1

The similar morphology of Bonnemaisonia clavata and Bonnemaisonia asparagoides and the rarely reported vegetative and reproductive characters of the former have resulted in considerable difficulty distinguishing these two taxa as well as uncertainty concerning the taxonomic status of B. clavata. We have reassessed the relationship between these two species using both morpho-anatomical and molecular data. Observations on gametophytes confirm a suite of distinguishing features including structure of the thallus (monopodial vs sympodial), axial cell size, presence or absence of a spiral trichogyne, pericarp symmetry and number of carposporangia per cystocarp. Investigation of the ‘Hymenoclonium’ prostrate phase developed from cultured carpospores provided additional distinguishing characters including carpospore germination pattern and morphology of ‘Hymenoclonium’ developmental stages. The characteristics utilized by previous authors to distinguish B. asparagoides and B. clavata are discussed and evaluated. Partial chloroplast-encoded rbcL sequences for B. clavata and B. asparagoides were 7.66% different. This level of divergence supports the morphological evidence that B. clavata and B. asparagoides are distinct species.

Key Words::

• Algal culture
• Bonnemaisonia
• Bonnemaisoniales
• ‘Hymenoclonium’ phase
• Rhodophyta
• rbcL
• Taxonomy

ACKNOWLEDGMENTS

This study was supported by the Spanish Department of Science and Technology (REN 2001-1473-C03/GLO). The authors thank M. C. Barceló, J. Rull Lluch, A. Manghisi, J. A. Morais de Silva and L. Lavelli (University of Barcelona) and I. Barbara (University of A Coruña) for providing fresh material of B. asparagoides and B. clavata and helpful suggestions; C. Casares for sending Atlantic material of B. asparagoides; T. Grace Johnson for reviewing the English text; N. Montes Moreno and E. Clavero Oms (University of Barcelona) for technical assistance; M. Morabito and M. Gargiulo (University of Messina) for introducing us to molecular techniques; B. de Reviers for providing typus material; D. Wilson Freshwater and D.F. Kapraun (University of North Carolina) for critically reading the manuscript, and P. Gabrielson and the anonymous reviewers for their exhaustive and helpful revision.