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 , 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 , and on rare occasions below , but is most common at depths of .
Families
Ordo Isocrinida
- Family Balanocrinidae <small>Roux, 1981</small>
- Subfamily Balanocrininae <small>Roux, 1981</small>
- Subfamily Diplocrininae <small>Roux, 1981</small>
- Subfamily Isselicrininae <small>Klikushkin, 1977</small>
- Subfamily Proisocrininae <small>Rasmussen, 1978</small>
- Family Cainocrinidae <small>Simms, 1988</small>
- Family Isocrinidae <small>Gislén, 1924</small>
- Subfamily Isocrininae <small>Gislén, 1924</small>
- Subfamily Metacrininae <small>Klikushin, 1977</small>
- Family Pentacrinitidae <small>Gray, 1842</small>
- Subfamily Eocomatulinae <small>Simms, 1988</small>
- Subfamily Pentacrinitinae <small>Blumenbach, 1804</small>
References
- 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. 42âÂÂ69.