Pedinoida

Pedinoida is an order of sea urchins, containing the single living genus Caenopedina. The group was much more diverse during the Mesozoic, and represents the oldest surviving order of euechinoid sea urchins.

Pedinoida Temporal range: Early Triassic–Recent PreꞒ Ꞓ O S D C P T J K Pg N
Diademopsis crinifera fossils
Scientific classification
Kingdom:	Animalia
Phylum:	Echinodermata
Class:	Echinoidea
Subclass:	Euechinoidea
Superorder:	Echinothuriacea
Order:	Pedinoida Mortensen, 1939
Family:	Pedinidae Pomel, 1883
Genera
See text

They are distinguished from other sea urchins by the presence of a rigid test with tessellated plates. While their primary spines are solid, the smaller ones may be hollow, further distinguishing them from the closely related orders Diadematoida and Echinothurioida, which possess only hollow spines.

References

• Barnes, Robert D. (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. p. 980. ISBN 0-03-056747-5.
• National History Museum. "Pedinoida". Retrieved 20 Dec 2009.