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 , and on rare occasions below , but is most common at depths of .Globally discordant Isocrinida (Crinoidea) migration confirms asynchronous Marine Mesozoic Revolution
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
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. 42–69.