Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Echinodermata
Subphylum: Eleutherozoa
Superclassis: Cryptosyringida
Classis: Echinoidea
Subclassis: Euechinoidea
Superordo: Diadematacea
Ordo: Pedinoida
Familia: Pedinidae
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.
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.
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