Cladus: Eukaryota
Supergroup: Unikonta
Cladus: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Deuterostomia
Phylum: Echinodermata
Subphylum: Eleutherozoa
Superclassis: Cryptosyringida
Classis: Echinoidea
Subclassis: Euechinoidea
Superordo: Gnathostomata
Ordines: Clypeasteroida - Holectypoida

The Gnathostomata are a superorder of sea urchins, including the familiar sand dollars.

Gnathostomatans are irregular in shape, but unlike other irregular sea urchins, possess a feeding lantern. The mouth is located in the centre of the lower surface, as it is in most other sea urchins, but the anus is found to one side of the upper surface, rather than being central. The members of the group are adapted for burrowing in soft-bottomed marine environments.

Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. p. 981. ISBN 0-03-056747-5.

Biology Encyclopedia

Echinodermata Images

Source: Wikipedia, Wikispecies: All text is available under the terms of the GNU Free Documentation License