Isocrinida is an order of sea lilies which contains four families.

Characteristics

Members of this order are characterised by having a "heteromorphic" stalk; the stalk consists of a series of nodes with cirri, interspersed by several nodes without cirri. There are additionally a whorl of cirri at the base on which the animal perches. The calyx is a shallow cup consisting of five basals and five radials.

They are more mobile than other stalked crinoids, and can be found as shallow as 100–170 m (300–600 ft), and on rare occasions below 400 m (1,300 ft), but is most common at depths of 200–300 m (700–1,000 ft).

Families

Ordo Isocrinida

  • Family Balanocrinidae Roux, 1981 Subfamily Balanocrininae Roux, 1981 Subfamily Diplocrininae Roux, 1981 Subfamily Isselicrininae Klikushkin, 1977 Subfamily Proisocrininae Rasmussen, 1978
  • Family Cainocrinidae Simms, 1988
  • Family Isocrinidae Gislén, 1924 Subfamily Isocrininae Gislén, 1924 Subfamily Metacrininae Klikushin, 1977
  • Family †Pentacrinitidae Gray, 1842 Subfamily Eocomatulinae Simms, 1988 Subfamily Pentacrinitinae Blumenbach, 1804
  • Hess H (2011) Isocrinida. In: Hess, H., Messing, C.G., Ausich, W.I. (Eds.), Treatise on Invertebrate Paleontology, Part T, Echinodermata 2 Revised, Crinoidea, vol. 3. University of Kansas Press, Lawrence, Kansas, pp. 42–69.