Taxonomic studies in the Schizymeniaceae (Nemastomatales, Rhodophyta): on the identity of Schizymenia sp. in the Azores and the generic placement of Nemastoma confusum

Abstract

Gabriel D., Schils T., Parente M.I., Draisma S.G.A., Neto A.I. and Fredericq S. 2011. Taxonomic studies in the Schizymeniaceae (Nemastomatales, Rhodophyta): on the identity of Schizymenia sp. in the Azores and the generic placement of Nemastoma confusum. Phycologia 50: 109–121. DOI: 10.2216/09-67.1

Comparative rbcL sequence analysis indicates that the species going under the name Schizymenia dubyi in the Azores should be referred to as S. apoda. Sequences of Schizymenia specimens from China and Namibia were also identified as S. apoda, of which the type locality is the Cape Province in South Africa. Schizymenia dubyi, described from Atlantic France, is clearly a distinct species that we here report for Japan and Sicily in the Mediterranean Sea. Both Schizymenia species, along with an unreported species from Japan, are distinct from S. pacifica described from Washington, in the Pacific Coast of North America. Secondary pit connections were observed in gametophytes of S. apoda from the Azores, a previously unknown character for the Nemastomatales. Examination of type material of Nemastoma confusum indicates that this species, currently placed in the Nemastomataceae, should be transferred to the genus Platoma in the Schizymeniaceae. A morphological comparison between Platoma confusum (Kraft & John) comb. nov. with descriptions of P. cyclocolpum and P. chrysymenioides suggests that the three species are closely related.

Key Words::

• Azores
• Nemastoma
• Nemastomatales
• Platoma
• rbcL
• Rhodophyta
• Schizymenia
• Schizymeniaceae
• Systematics
• Taxonomy

ACKNOWLEDGEMENTS

We thank the Fundação para a Ciência e Tecnologia (FCT) for PhD grant SFRH/BD/12541/2003, the SYNTHESYS Program from the European Union for the Research Grant NL-TAF-4691, Centro de Investigação de Recursos Naturais da Universidade dos Açores (CIRN/UA) and Direcção Regional da Ciência e da Tecnologia (DRCT/Açores) for the travel grants M3.2.1/I/133/2007 and M3.2.1/I/062/2008. The National Science Foundation grants DEB-0315995, DEB-0328491, DEB 0743024, DEB-0919508 and DEB-0937978 are thanked for financial support. We also would like to thank João Brum, Nuno Álvaro, Patrícia Madeira and Sandra Monteiro for their help in collecting Azorean specimens and Ian Tittley (Herbarium NHM, London), Willem Prud'homme van Reine (NHN, Leiden), Olivier de Clerck (Herbarium Ghent) and other collectors listed in Table 1 for providing vouchers used in this study.