Short Communication A new Symbiodinium clade (Dinophyceae) from soritid foraminifera in Hawai’i Xavier Pochon * , Ruth D. Gates Hawai’i Institute of Marine Biology, University of Hawai’i, Ka ¯ ne’ohe, HI, USA article info Article history: Received 13 November 2009 Revised 28 March 2010 Accepted 31 March 2010 Available online 4 April 2010 Keywords: Ribosomal genes Dinoflagellate Symbiodinium Symbiosis Cryptic diversity abstract Dinoflagellates in the genus Symbiodinium are crucial components of coral reef ecosystems in their roles as endosymbionts of corals and other marine invertebrates. The genus Symbiodinium encompasses eight lineages (clades A–H), and multiple sub-clade types. Symbiodinium in clades A, B, C, and D are most com- monly associated with metazoan hosts while clades C, D, F, G, and H with large soritid foraminifera. Recent studies have described a diversity of new Symbiodinium types within each clades, but no new clades have been reported since 2001. Here, we describe a new clade of Symbiodinium isolated from sori- tid foraminifera from Hawai’i. Published by Elsevier Inc. 1. Introduction Dinoflagellates in the genus Symbiodinium are crucial compo- nents of coral reef ecosystems in their role as endosymbionts of cor- als, other marine invertebrates, and some protists (Trench, 1993). The genus Symbiodinium encompasses eight lineages, delineated phylogenetically using nuclear and chloroplast ribosomal DNA (rDNA), referred to as clades A through H (Pochon et al., 2004). Each clade is further divided into multiple genetic strains based on the nuclear internal transcribed spacer (ITS) regions (e.g., LaJeunesse, 2001; Rodriguez-Lanetty, 2003; van Oppen et al., 2005). Molecular clock inferences have estimated that clade A, the most ancestral Symbiodinium lineage, originated 65–50 Million years ago (MYA) and the other clades diverged from each other throughout the Eo- cene era, until the mid-Miocene (15 MYA) when a dramatic with- in-clade diversification occurred (Pochon et al., 2006; Tchernov et al., 2004). Symbiodinium in clades A, B, C, and D are commonly associated with metazoan hosts and representatives in clades C, D, F, G, and H with the large benthic foraminifera sub-family Soriti- nae (Pochon and Pawlowski, 2006). In recent years, researchers have focused on Symbiodinium with the goal of understanding their evolution, distribution and role in responding to present and future environmental conditions that are threatening the integrity of reefs worldwide (Baker et al., 2008; van Oppen et al., 2008). For example, recent studies conducted in both the Western Atlantic and Indo-Pacific Oceans have surveyed Symbiodinium across host taxa and a variety of spatial and temporal scales (reviewed in Coffroth and Santos, 2005; Stat et al., 2006). These studies have collectively described a diversity of new Symbiodinium types within each clade, but no new clades have been reported since 2001. Here, we describe a new clade of Symbiodinium isolated from soritid foraminifera from Hawai’i. 2. Materials and methods 2.1. Data collection As part of a more detailed study that will be described else- where, hundreds of soritid foraminiferan samples were collected between May 2007 and June 2008 from sites across the entire Hawaiian Archipelago. Genomic DNA was isolated from approxi- mately 100 of these forams using a guanidinium-based extraction protocol (Pochon et al., 2001) and screened for Symbiodinium sub- clade types by amplifying, cloning and sequencing the ITS-2 rDNA using the primers ‘ITS-DINO’ and ‘its2rev2’ (primer set 1) and con- ditions described in Stat et al. (2009). All recovered sequences were identified to sub-clade type or closest relative using the Basic Local Alignment Search Tool (BLAST) in GenBank. Four samples, from two sites on Oahu, Hawai’i (Fig. 1A), amplified ITS-2 Symbiodinium sequences that did not match any published Symbiodinium type closely. To further examine the diversity of Symbiodinium in these DNAs, the primers ‘ITS-DINO’ and ‘L_O’ (primer set 2) were used to amplify the nuclear partial 5.8S, the ITS-2, and the D1–D3 region of the 28S (Pochon et al., 2001) and the primers ‘23S4F’ and ‘23S7R’ (primer set 3) to amplify the chloroplast large subunit Domain V (cp23S; Pochon et al., 2006). 1055-7903/$ - see front matter Published by Elsevier Inc. doi:10.1016/j.ympev.2010.03.040 * Corresponding author. Address: HIMB, 46-007 Lilipuna Road, Ka ¯ ne’ohe, HI 96744, USA. Fax: +1 808 236 7443. E-mail addresses: pochon@hawaii.edu (X. Pochon), rgates@hawaii.edu (R.D. Gates). Molecular Phylogenetics and Evolution 56 (2010) 492–497 Contents lists available at ScienceDirect Molecular Phylogenetics and Evolution journal homepage: www.elsevier.com/locate/ympev