Isocrinida

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

Isocrinida Temporal range: Anisian to Recent PreꞒ Ꞓ O S D C P T J K Pg N
Isocrinus nicoleti columnals; Middle Jurassic; Carmel Formation; Utah.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Echinodermata
Class:	Crinoidea
Subclass:	Articulata
Order:	Isocrinida

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]

Families

• Suborder Isocrinina Sieverts-Doreck, 1952
  • family Cainocrinidae Simms, 1988 -- 1 genus (1 species)
  • family Isocrinidae Gislén, 1924 -- 3 genus (3 species)
  • family Isselicrinidae Klikushkin, 1977 -- 4 genus (18 species)
  • family Proisocrinidae Rasmussen, 1978 -- 1 genus (1 species)
• Suborder Pentacrinitina Gray, 1842 †
  • family Pentacrinitidae Gray, 1842 †

• 
  Neocrinus decorus (Isocrinidae)
• 
  Metacrinus rotundus (Isselicrinidae)
• 
  Proisocrinus ruberrimus (Proisocrinidae)
• 
  Endoxocrinus sp.
• 
  Endoxocrinus parrae
• 
  Isocrinus asteria

  

  Isocrinus fossil, Shamshak Formation, Alborz Province, Iran