Protist, Vol. 165, 317–329, May 2014 http://www.elsevier.de/protis Published online date 1 April 2014 ORIGINAL PAPER Haplomyxa saranae gen. nov. et sp. nov., a New Naked Freshwater Foraminifer Marc Dellinger a,1 , Amandine Labat a , Loïc Perrouault b , and Philippe Grellier a a “Molécules de Communication et Adaptation des Microorganismes”, UMR 7245 CNRS - MNHN, Muséum national d’Histoire naturelle, CP 52, 57 rue Cuvier, 75005 Paris, France b “Structure et Instabilité des Génomes”, UMR7196 CNRS - MNHN and INSERM U565, Muséum national d’Histoire naturelle, CP 26, 57 rue Cuvier, 75005 Paris, France Submitted November 20, 2012; Accepted March 14, 2014 Monitoring Editor: David Moreira A new naked foraminifer, Haplomyxa saranae gen. nov. sp. nov., is described from an established cell line made from a single cell isolated from a freshwater garden pond. The new species was morpho- logically close to Reticulomyxa filosa, the only valid naked freshwater foraminifer species. However the two species differed when it came to the morphology of the cell body, the number of cysts, and the nutrition. The 18S rRNA gene had one of the longest sequences to date (4863 nucleotides), and it contained many insertions that are typical of Foraminifera. The size of this gene was 45% longer than the one of R. filosa due to the elongation of A+T rich regions, but molecular phylogeny based on conserved regions of the 3 ′ -end placed the new species in the same morphological clade K. This report includes both morphological and genetic data which undoubtedly show that the new species is a new naked freshwater foraminifer and the second species of the clade K. © 2014 Elsevier GmbH. All rights reserved. Key words: 18S rDNA; Foraminifera; phylogeny; protist; Reticulomyxa. Introduction Foraminifera (d’Orbigny, 1826) are single cell pro- tists that often form a multilocular test and share a common specific net-like organization of pseudo- podia (Bowser and Travis 2002; Lee et al. 2002). Classifications were primarily based on the mor- phological description of the test (Cavalier-Smith 1993) and differentiated between multilocular (Poly- thalamea Ehrenberg, 1838), unilocular (Monotha- lamia Haeckel, 1862) and testless (Athalamia Haeckel, 1862) forms, while recent classifications were rather based on the test structure (Sen 1 Corresponding author; fax +33 140 793 499 e-mail dellinge@mnhn.fr (M. Dellinger). Gupta 1999 and references therein), excluding test- less organisms. All organisms with this particular pseudopodial organization were grouped into a single phylum (Granuloreticulosa Lee, 1990), that was divided into testless (Athalamea) and tes- tate (Foraminifera Lee, 1990) forms (Lee et al. 2002). However, molecular data, when available, grouped all these organisms together in a mono- phyletic rank based on specific insertions in the 18S small subunit ribosomal gene (18S rDNA) (Pawlowski 2000), thus making the phylum Gran- uloreticulosa synonymous with Foraminifera (Lipps et al. 2011). The most recent protist classification (Adl et al. 2012) divided Foraminifera (d’Orbigny, 1826) into three ranks: (i) one rank (Monothala- mids Pawlowski et al. 2003) included all species with a single chamber test (monothalamous), no http://dx.doi.org/10.1016/j.protis.2014.03.007 1434-4610/© 2014 Elsevier GmbH. All rights reserved.