Isocrinida Explained

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.^[1]

They are more mobile than other stalked crinoids, and can be found as shallow as NaN-2NaN-2, and on rare occasions below 400-2NaN-2, but is most common at depths of NaN-2NaN-2.^[2]

Families

Ordo Isocrinida^[3]

• 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.

Notes and References

1. Book: O'Hara, Timothy. Byrne, Maria. Australian Echinoderms: Biology, Ecology and Evolution . 2017 . Csiro Publishing . 978-1-4863-0763-0 . 192.
2. https://www.nature.com/articles/s42003-018-0048-0 Globally discordant Isocrinida (Crinoidea) migration confirms asynchronous Marine Mesozoic Revolution
3. Marc Eleaume. 123095. Isocrinida.