Cladida

Cladida Temporal range:
Ulrichicrinus coryphaeus, a eucladid from the Mississippian-age Edwardsville Formation
Scientific classification
Kingdom:	Animalia
Phylum:	Echinodermata
Class:	Crinoidea
Subclass:	Pentacrinoidea
Infraclass:	Inadunata
Parvclass:	Cladida Moore and Laudon (1943)1
Subgroups
†Porocrinoidea †Flexibilia Eucladida †Ampelocrinida †Cyathoformes Articulata

Cladida is a major subgroup of crinoids with a complicated taxonomic history. Cladida was originally applied to a wide assortment of extinct crinoids with a dicyclic calyx. Under this original definition, cladids would represent a paraphyletic order ancestral to several other major crinoid groups, particularly the living Articulata. More recently, Cladida has been redefined as a monophyletic parvclass of pentacrinoids which encompasses articulates and the extinct Flexibilia (flexibles). Cladids also include various minor taxa such as the hybocrinids and "cyathocrines". As flexibles were not originally considered cladids, the new subgroup Eucladida has been erected for cladids which are more derived than flexibles. Cladida is the sister group to Disparida, another large group of extinct crinoids.²

• Parvclass Cladida
  • Superorder †Porocrinoidea
    • Order †Hybocrinida
    • Order †Porocrinida
  • Superorder †Flexibilia
    • Order †Sagenocrinida
    • Order †Taxocrinida
  • Magnorder Eucladida
    • †Ampelocrinida (incertae sedis)
    • Superorder †Cyathoformes² ("primitive cladids")³
      • †"Cyathocrinida"²
      • †"Dendrocrinida"² [in part]
      • †Poteriocrinites³
    • Articuliformes ("intermediate and advanced cladids")³
      • †"Poteriocrinida" [in part]³
      • †"Dendrocrinida" [in part]³
      • Superorder Articulata
        • Order †Encrinida
        • Order †Holocrinida
        • Order †Millericrinida
        • Order †Roveacrinida
        • Order †Uintacrinida
        • Order Comatulida
        • Order Cyrtocrinida
        • Order Hyocrinida
        • Order Isocrinida