The phylogenetic position of Myxozoa: exploring conflicting signals in phylogenomic and ribosomal data sets.

Myxozoans are a diverse group of microscopic endoparasites that have been the focus of much controversy regarding their phylogenetic position. Two dramatically different hypotheses have been put forward regarding the placement of Myxozoa within Metazoa. One hypothesis, supported by ribosomal DNA (rDNA) data, place Myxozoa as a sister taxon to Bilateria.

Correction: Phylogenetic placement of the enigmatic parasite, Polypodium hydriforme, within the Phylum Cnidaria.

Correction to Evans, N.M., Lindner, A.

Phylogenetic placement of the enigmatic parasite, Polypodium hydriforme, within the Phylum Cnidaria.

Background: Polypodium hydriforme is a parasite with an unusual life cycle and peculiar morphology, both of which have made its systematic position uncertain. Polypodium has traditionally been considered a cnidarian because it possesses nematocysts, the stinging structures characteristic of this phylum. However, recent molecular phylogenetic studies using 18S rDNA sequence data have challenged this interpretation, and have shown that Polypodium is a close relative to myxozoans and together they share a closer affinity to bilaterians than cnidarians.