As published in the
Treatise on Invertebrate Paleontology, Crinozoa included all stemmed groups except for the few stemmed basal
solutes. When
Blastozoa was erected to contain stalked forms with
brachioles rather than arms, only
Crinoidea and
Paracrinoidea remained within Crinozoa. Recent
cladistic work has placed Paracrinoidea under Blastozoa, although some sources continue to include Paracrinoidea. A 2024 survey of recent research finds more support for Homalozoa as a paraphyletic assemblage along the echinoderm stem group, but noted that the position of Stylophora in particular was uncertain. If neither Paracrinoidea nor Stylophora can be included, Crinozoa would be equivalent to the Crinoidea
total group. ==See also==