The Zoroasteridae comprise a small but widespread family of asteroids distributed throughout the deep-sea. Although poorly understood, they are often collected in the hundreds, suggesting that they occupy important ecological roles. A phylogenetic analysis including 24 terminal taxa and 70 morphological characters was performed, resulting in a single most-parsimonious tree. The tree separated zoroasterids with open, reticulate skeletons (e.g., Myxoderma) as more basal than those with more heavily armored, imbricate skeletons (e.g., Zoroaster) which were more derived. In addition to agreement with established genera, a new genus is supported by the phylogeny as the sister taxon to Myxoderma. The cladistic analysis was performed in conjunction with a revisionary survey of zoroasterid species, resulting in in taxonomic changes to species in nearly every genus. Bathymetric and physiographic shifts were observed between the reticulate and imbricate zoroasterid clades. Zoroasterids possess a single marginal plate series, which occurs in basal sister-group neoasteroids (crown group asteroids). Phylogenetic results suggest that the morphololgical resemblance between zoroasterids and Paleozoic taxa, such as Calliasterella is convergent but a paraphyletic Zoroasteride can not be rejected and remains consistent with basal crown-group affinities. Although the phylogenetic position of the Eocene Zoroaster aff. fulgens was not strongly supported, its presence within a derived cluster of Zoroaster spp. suggests a relatively recent (ie Cenozoic) diversification into the deep-sea. Taxonomic revisions, geographic, and bathymetric range extensions are also included.
