Molecular Phylogenetics and Evolution 44 (2007) 685–698 www.elsevier.com/locate/ympev 1055-7903/$ - see front matter  2007 Elsevier Inc. All rights reserved. doi:10.1016/j.ympev.2006.12.019 A molecular phylogeny of the marine mussel genus Perna (Bivalvia: Mytilidae) based on nuclear (ITS1&2) and mitochondrial (COI) DNA sequences Ann R. Wood ¤ , Smita Apte 1 , Elizabeth S. MacAvoy, Jonathan P.A. Gardner Centre for Marine Environmental and Economic Research, School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand Received 1 September 2006; revised 17 December 2006; accepted 20 December 2006 Available online 31 December 2006 Abstract A molecular phylogeny is presented for marine mussels of the genus Perna, based on nuclear (ITS1, ITS2) and mitochondrial (COI) DNA sequence data. The three generally recognised species (Perna viridis, Perna perna and Perna canaliculus) and one putative species (Perna picta) were each sampled from several locations within their known geographic distributions. A range of phylogenetic analyses was used to investigate the current taxonomic assignments, evolutionary relationships and the biogeographical history of the genus. The diVerent analyses produced similar, well supported topologies and veriWed the monophyly of the genus with respect to Wve mytilid out- group species. P. perna (Atlantic), P. viridis (Indo-West PaciWc), and P. canaliculus (New Zealand) each formed distinct clades, conWrming their speciWc status. Putative P. picta from North Africa clustered within the P. perna clade and is not regarded as a separate species. P. perna and P. canaliculus were the most closely related of the three species. Possible biogeographic explanations for the present species distributions are evaluated.  2007 Elsevier Inc. All rights reserved. Keywords: Perna; Bivalves; Mussels; Internal transcribed spacer; ITS; Ribosomal RNA; COI 1. Introduction Mussels of the genus Perna Philipsson 1788 belong to the Mytilidae or true mussels (Mollusca; Bivalvia; Lamelli- branchia; Mytiloida; Mytilidae). This genus contains green and brown mussels from tropical, subtropical, warm tem- perate and cold temperate regions, mostly from the south- ern hemisphere, but also from northern Africa and the northern coasts of South America (Gosling, 2003; Siddall, 1980). Depending on the species in question, they exist in intertidal and shallow subtidal habitats, including estuaries, mangroves and open rocky shores (Gosling, 2003; Hicks, 2001; Siddall, 1980). These mussels are both ecologically and economically important throughout their ranges, and have long constituted an important source of human food (e.g., GriYths and Branch, 1997; Nichol, 1986; Parkington, 1976; Swadling, 1977; Tomalin and Kyle, 1998). Perna spe- cies are cultured and/or harvested from wild populations in countries such as India, the Philippines, Thailand, China, Venezuela and New Zealand (Appukuttan and Nair, 1980; Hickman, 1991; JeVs et al., 1999; Narasimham, 1980; Parulekar et al., 1982; Vakily, 1989). As with other mytilid mussels, the genus Perna has a somewhat confused taxonomic history (Siddall, 1980; Vakily, 1989). The taxonomy, synonymies and geographical distribution of extant Perna species were reviewed by Sid- dall (1980). In addition to the Perna Philipsson 1788 genus under consideration here, the name Perna has also been used to describe the genera Modiolus H & A Adams 1858, * Corresponding author. Fax: +64 4 463 5331. E-mail address: ann.wood@vuw.ac.nz (A.R. Wood). 1 Present address: Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand.