Redefining the genus Aplanochytrium (Phylum labyrinthulomycota)

In the early 1970's, two similar genera, Labyrinthuloides and Aplanochytriu m, were described within months of one another. Ironically, these two gener a were originally associated with entirely different groups of fungi. Labyr inthuloides was recognized as having morphological similarities to the laby rinthulids (or marine slime nets), and Aplanochytrium was associated with t he thraustochytrid fungi. However, contemporary researchers were beginning to recognize that the thraustochytrids and labyrinthulids were closely rela ted. By the mid 1980's, biochemical and morphological evidence linking Laby rinthuloides and Aplanochytrium was mounting, and suggestions were made tha t these genera were identical. In 1999, Honda et al. published a molecular phylogeny of the Labyrinthulomycota, including ssurDNA sequence data from A planochytrium kerguelensis. Leander and Porter (submitted) also reported a molecular phylogeny of the group, including Labyrinthuloides yorkensis and Labyrinthuloides minuta. We have compared this sequence data from A. kergue lensis, L. minuta, and L. yorkensis, and together with the morphological si milarities, we conclude that Aplanochytrium and Labyrinthuloides are synony mous. Following the IBC rules of nomenclature, Aplanochytrium is recognized as the correct name for this genus by means of precedence. Additionally, t he five species of labyrinthuloides are transferred to Aplanochytrium. We a lso transfer one species of labyrinthula, L. thaisi, to Aplanochytrium base d on morphological similarities.