Temporal range: Early Cretaceous–recent
Pourtalesia wandeli
Scientific classification
Kingdom: Animalia
Phylum: Echinodermata
Class: Echinoidea
Subclass: Euechinoidea
Infraclass: Irregularia
Superorder: Atelostomata
Order: Holasteroida
Durham & Melville, 1957

Holasteroida is an order of irregular sea urchins.


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 peripher 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 :


  1. 1 2 "Holasteroida". Echinoid Directory.

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