Crinozoa is a subphylum of mostly sessileechinoderms, of which the crinoids, or sea lilies and feather stars, are the only extant members.[1][2] Crinozoans have an extremely extensive fossil history.[citation needed]
Classes within Crinozoa
As published in the Treatise on Invertebrate Paleontology, Crinozoa included all stemmed groups except for the few stemmed basal solutes.[3] When Blastozoa was erected to contain stalked forms with brachioles rather than arms, only Crinoidea and Paracrinoidea remained within Crinozoa.[4][5] Recent cladistic work has placed Paracrinoidea under Blastozoa,[6] although some sources continue to include Paracrinoidea.[2]
One proposal for the cladistic placement of the Homalozoan classes groups Stylophora together with crinoids to form Crinozoa.[7] 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.[8]
If neither Paracrinoidea nor Stylophora can be included, Crinozoa would be equivalent to the Crinoidea total group.
David, Bruno; Lefebvre, Bertrand; Mooi, Rich; Parsley, Ronald (December 2000). "Are homalozoans echinoderms? An answer from the extraxial-axial theory". Paleobiology. 26 (4): 520–555. doi:10.1666/0094-8373(2000)026<0529:AHEAAF>2.0.CO;2.
Limbeck, Maggie R.; Bauer, Jennifer E.; Deline, Bradley; Sumrall, Colin D. (2024). "Initial quantitative assessment of the enigmatic clade Paracrinoidea (Echinodermata)". Paleontology. 67 (3). doi:10.1111/pala.12695.
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