The Temnopleuroida are an infraorder

Order (biology)

In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...

 of sea urchin

Sea urchin

Sea urchins or urchins are small, spiny, globular animals which, with their close kin, such as sand dollars, constitute the class Echinoidea of the echinoderm phylum. They inhabit all oceans. Their shell, or "test", is round and spiny, typically from across. Common colors include black and dull...

s in the order Camaradonta. They are distinguished from other sea urchins by the presence of large fused plates on top of the feeding lantern. The test

Test (biology)

A test is a term used to refer to the shell of sea urchins, and also the shell of certain microorganisms, such as testate foraminifera and testate amoebae....

is usually sculpted to some degree, and has perforated tubercles.

Temnopleuridea is now the accepted name according to the World Register of Marine Species.