Short Communication Multigene phylogenetic analyses support recognition of the Sporolithales ord. nov. Line Le Gall a, * , Claude E. Payri b , Lucie Bittner c , Gary W. Saunders a a Centre for Environmental and Molecular Algal Research, Department of Biology, P.O. Box 4400, University of New Brunswick, Fredericton, NB, Canada E3B 5A3 b UMR 7138/UR R148. ‘‘Systématique, Adaptation, Evolution”, Institut de Recherche pour le Développement, B.P. A5, 98848 Nouméa cedex, Nouvelle-Calédonie, France c UMR 7138 ‘‘Systématique, Adaptation, Evolution”, Département ‘‘Systématique et évolution”, Muséum National d’Histoire Naturelle, CP 39, 75231 Paris cedex 05, France article info Article history: Received 31 March 2009 Revised 22 May 2009 Accepted 26 May 2009 Available online 31 May 2009 Keywords: Corallinales Corallinophycidae Elongation factor 2 (EF2) Heydrichia Large subunit ribosomal DNA (LSU) Red algal systematics Small subunit ribosomal DNA (SSU) Sporolithaceae Sporolithon abstract Ó 2009 Published by Elsevier Inc. 1. Introduction Recently, Le Gall and Saunders (2007) published a supraordinal phylogeny of the Florideophyceae that revealed a strong alliance between the Corallinales and Rhodogorgonales resulting in these orders being assigned to a new subclass, the Corallinophycidae. The Corallinales and Rhodogorgonales are unique among marine red algae for the presence of calcite (Borowitzka, 1977; Norris and Bucher, 1989) and they share pit plugs with domed outer caps (although not unique to these two taxa; Pueschel, 1989). Currently, the Corallinales includes three families: the Corallinaceae, Hapalid- iaceae and Sporolithaceae (Harvey et al., 2003). Unfortunately, Le Gall and Saunders (2007) did not include in their analyses repre- sentatives of the Sporolithaceae, a family for which the taxonomic placement has been an ongoing debate. Sporolithon, proposed by Heydrich (1897), was either placed in its own tribe within the Melobesioideae (Johansen, 1969), or in its own subfamily within the Corallinaceae (Cabioch, 1972), and then elevated to familial rank based on distinctive features of tetrasporangial development (cruciately arranged tetrasporangia and absence of tetrasporangial conceptacles; Verheij, 1993). Townsend et al. (1994) expanded this family with a second genus, Heydrichia, and currently the Sporo- lithaceae contains 17 species (Guiry and Guiry, 2008). Interestingly, Harvey et al. (2002) resolved a strong alliance be- tween the Sporolithaceae and Rhodogorgon carriebowensis J.N. Nor- ris and Buchner, Rhodogorgonales, in their SSU phylogenies, but posited that ‘‘a possible explanation for the linking of the seem- ingly less closely related Sporolithaceae and Rhodogorgonaceae may be that they are not related, but group together because they are both very different from the well supported Corallinaceae”. Broom et al. (2008) assessed the utility of two molecular markers (SSU and psbA) to infer the phylogenetic affinities of New Zealand Corallinales and resolved the Sporolithaceae variously as a para- phyletic or monophyletic sister to the remaining Corallinales, but decided ‘‘not to use Rhodogorgon carriebowensis as an outgroup taxon as its SSU sequence has a number of unusual features, mak- ing alignment difficult and suggesting that the taxon has been sub- ject to extensive selection pressure and may not retain ancestral characters relevant to the analysis of the Corallinales”. Unfortu- nately, based on the results of Harvey et al. (2002), Rhodogorgon is not an outgroup but an ingroup, which, if correct, means that Broom et al. (2008) analyzed a paraphyletic ingroup by excluding the putative sister lineage to the Sporolithaceae, which had the po- tential artefact of rendering this family sister to the remaining Corallinales. In light of the previous, we generated SSU, LSU and EF2 se- quences for Sporolithon ptychoides Heydrich and included them in the published alignments of Le Gall and Saunders (2007), along with a previous SSU sequence for Heydrichia, with the aim of 1055-7903/$ - see front matter Ó 2009 Published by Elsevier Inc. doi:10.1016/j.ympev.2009.05.026 * Corresponding author. Fax: +33 1 40 79 35 94. E-mail address: legall@mnhn.fr (L. Le Gall). Molecular Phylogenetics and Evolution 54 (2010) 302–305 Contents lists available at ScienceDirect Molecular Phylogenetics and Evolution journal homepage: www.elsevier.com/locate/ympev