Holasteroida

Holasteroida

Holasteroida

Order of sea urchins

Holasteroida is an order of irregular sea urchins.

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Characteristics

Ceratophysa ceratopyga by A. Agassiz (1881)

These irregular sea urchins are characterized by a particularly marked bilateral symmetry, including for the apical system, which is highly elongated. In some contemporary abyssal groups such as Pourtalesiidae, some species are even bottle-shaped. The mouth (peristome) does not contain an Aristotle's lantern. The anus (periproct) has migrated towards the periphery of the test. The plastron is never amphisternous.[1]

This order seems to have appeared at the lower Cretaceous.[1]

List of families

According to World Register of Marine Species :

  • † Family Disasteridae Gras, 1848
    • genus † Disaster L. Agassiz, 1835
  • Family Hemipneustidae (Lambert, 1917) †
    • genus Hemipneustes L. Agassiz, 1835 †
    • genus Medjesia Jeffery, 1997 †
    • genus Opisopneustes Gauthier, 1889 †
    • genus Plesiohemipneustes Smith & Wright, 2003 †
    • genus Toxopatagus Pomel, 1883 †
  • Suborder Meridosternata (Lovén, 1883)
    • Infraorder Cardiasterina †
      • Family Cardiasteridae Lambert, 1917 †
      • Family Stegasteridae Lambert, 1917f †
    • Family Echinocorythidae Wright, 1857 †
    • Family Holasteridae Pictet, 1857 †
      • Genus Salvaster Saucède, Dudicourt & Courville, 2012 †
    • Infraorder Urechinina
  • Family Pseudholasteridae (Smith & Jeffery, 2000) †
    • genus Eoholaster Solovjev, 1989 †
    • genus Giraliaster Foster & Philip, 1978 †
    • genus Pseudholaster Pomel, 1883 †
    • genus Taphraster Pomel, 1883 †
  • Family Stenonasteridae (Lambert, 1922) †
    • genus Stenonaster Lambert, 1922 †

References

  1. [1]
    "Holasteroida". Echinoid Directory.


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