The Echinoid Directory

 Stem group echinoids with:

• test composed of ambulacral and interambulacral plates; plating thin and strongly imbricate
• ambulacral zones narrow and plating biserial; pores double and adradial
• internal perradial flanges on ambulacral plate enclose the radial water vessel
• interambulacra composed of small rhomboidal plates forming rows and columns
• small mamelonate tubercle on interambulacral plates.

Lower Silurian (Llandovery) to Upper Carboniferous, USA, Europe.

Kier (1966) included in this family all forms with imbricate test plating and only two columns of amb plates. The type species of the type genus is very poorly known, however, making diagnosis of this family difficult.

The following genera are probably members of this family but are based on such inadequate material as to be nomina dubia:

Lepidocentrus Muller, 1857

Koninckocidaris Dollo & Buisseret, 1888

Lepidechinoides Olssen, 1912