The Echinoid Directory

Family Diadematidae Peters, 1855, p. 6

[= Centrechinidae Jackson, 1912, 202 (objective); subsumes Lissodiadematidae Fell, 1966, p. U352, type Lissodiadema Mortensen, 1903 by monotypy]


Diadematoida with:

  • test depressed; coronal plating rigid to slightly flexible especially adapically
  • apical disc relatively small; generally hemicyclic with posterior oculars insert; genital plates strongly projecting interradially. Periproctal plating well-developed peripherally
  • ambulacral plating trigeminate, with an enlarged element and two smaller demiplates
  • pore-pairs uniserial; arranged into weak arcs. May become crowded adorally to form phyllodes
  • interambulacral plates usually with multiple subequal tubercles forming a row. If one, then adradial and interradial zones well developed and with secondary tubercles
  • sphaeridial pit close to every third pore-pair from peristome to apex
  • tubercles perforate and almost always crenulate
  • peristome small; buccal notches rounded, with associated tags. Perradial notch also present
  • spines verticillate and hollow or with sparse open mesh
  • larva with just two arms.
Lower Cretaceous (Aptian) to Recent; worldwide.
Classification and/or Status Euechinoidea, Acroechinoidea, Diadematoida
Remarks Peters, W. K. H. 1855. Ueber die an der Kuste von Mossambique beobachten Seeigel und isbesondere uber die Gruppe von Diademen. Koenig Akademie der Wissenschafteen, Berlin