Euechinoidea

Euechinoidea

The Euechinoidea include with the exception of the lance urchins ( Chidaridae ) all extant sea urchin species. They are divided into four super-order. The Euechinoidea there since the Triassic.

System

About orders / orders / families ( incomplete)

  • Atelostomata Zittel, 1879 Heart Hedgehog ( Spatangoida )
  • Diadematoida Diadem Sea Urchin ( Diadematidae )
  • Sand dollars ( Clypeasteroida )

Diadematacea and Echinacea were previously combined as Regularia ( sea urchin with radially symmetrical calcareous skeleton ), and Atelostomata gnathostomata formed the Irregularia ( sea urchin with bilateral symmetry). This is now considered obsolete because it occur in the Echinacea both regular and irregular shapes.

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