Holasteroida

From Infogalactic: the planetary knowledge core
Jump to: navigation, search
Holasteroida
Temporal range: Early Cretaceous–recent
Pourtalesia wandeli.png
Pourtalesia wandeli
Scientific classification
Kingdom:
Phylum:
Class:
Subclass:
Infraclass:
Superorder:
Order:
Holasteroida

Durham & Melville, 1957

Lua error in Module:Taxonbar/candidate at line 22: attempt to index field 'wikibase' (a nil value).

Holasteroida is an order of irregular sea urchins.

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 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 :

References

  1. 1.0 1.1 Lua error in package.lua at line 80: module 'strict' not found.


<templatestyles src="Asbox/styles.css"></templatestyles>