The Old World Roccella species outside Europe and Macaronesia: taxonomy, evolution and phylogeny

Abstract

With this paper the genus Roccella is complete and fully revised. The genus contains 24 species of which eight species from the Old World in Asia and Africa are here treated in detail, Roccella applanata, R. babingtonii, R. balfourii, R. boryi, R. minuta (newly described here), R. montagnei, R. phycopsioides (newly described here) and R. sinensis. Roccella tinctoria with a predominantly Macaronesian distribution has some outpost localities in south western Africa is also included in this treatise. A full species phylogeny is presented based on data from four molecular markers, RPB2, nuLSU, ITS 1 and 2 and an anonymous locus. The African–Asian species together with three Macaronesian species (R. allorgei, R. fuciformis, R. maderensis) form a poorly supported monophyletic clade. The sister group to that clade is the significantly supported group containing the American and European–Macaronesian species. Roccella montagnei is the most widespread of all Roccella species ranging from Australia, around the Indian Ocean and further on along the west coast of Africa up north to the Cape Verde Islands. It is a genetically variable species, but morphologically, anatomically and chemically distinct and it is here maintained as one species. The distribution of roccellic acid among the samples within the monophyletic species group Roccella applanata, R. babingtonii, R. boryi, R. montagnei was surprising: sorediate specimens contain roccellic acid whereas fertile specimens, except for four samples, lack roccellic acid.

Key words:

• Arthoniales
• lichenized fungi
• phylogenetic species
• Roccellaceae
• Roccella minuta
• Roccella phycopsioides
• Roccella phylogeny
• roccellic acid
• species pairs

Acknowledgements

We are grateful to Fredrik Ronquist for generously helping with the Bayesian analyses and we want to thank Jens Klackenberg for revising the Latin diagnoses. Keyvan Mirbakhsh, Wim Baert, Francine Demuylder and Patrick Vivignis are thanked for technical support in the laboratory. We thank the curators of the herbaria mentioned in the Materials and methods for the loan of specimens. D.E. is indebted to the staff of the Parc Botanique et Zoologique de Tsimbazaza in Antananarivo and to Prof. E. Fischer, E. Sérusiaux and Dr D. Killmann for their guidance and logistical support during the field trip in Madagascar. We would like to thank the Ministère des Eaux et Forêts for collection and export permits of scientific material in Madagascar. The study was supported financially by Vetenskapsrådet (Swedish Science Research Council) grant 621-2005-5275.