%0 Journal Article %J European Journal of Phycology %D 2015 %T Phaeocystis rex sp. nov. (Phaeocystales, Prymnesiophyceae): a new solitary species that produces a multilayered scale cell covering %A Andersen, Robert A. %A Bailey, J. Craig %A Decelle, Johan %A Probert, Ian %K 2015 %K algae %K organic scales %K Phaeocystales %K Phaeocystis rex %K Prymnesiophyceae %K rcc %K RCC4025 %K RCC?o?dd %K SBR$_\textrmP$hyto$_\textrmE$PPO %K systematics %K ultrastructure %X A morphologically distinct marine species, Phaeocystis rex sp. nov., was described on the basis of light microscopy, transmission electron microscopy and DNA sequence comparisons. Non-motile cells were solitary (non-colonial), 6–10 µm in diameter and 8–15 µm long, and possessed chloroplasts with distinctive finger-like lobes. TEM observations demonstrated the presence of two short flagella and a very short haptonema that arose from an invagination of the protoplast. Non-motile cells were surrounded by one to several dense layers composed of scales, presumably unmineralized, and an amorphous material. Phylogenetic analyses based upon combined partial nucleotide sequences for five nuclear-or plastid-encoded genes (18S rRNA, 28S rRNA, 16S rRNA, psbA and rbcL) from cultured strains and from uncharacterized acantharian symbionts confirmed that P. rex was a distinct species. These analyses implied that P. rex occupies an intermediate evolutionary position between solitary and colonial Phaeocystis species. %B European Journal of Phycology %V 50 %P 207–222 %G eng %U http://www.tandfonline.com/doi/full/10.1080/09670262.2015.1024287 %R 10.1080/09670262.2015.1024287