The Echinoid Directory

Order Cassiduloida L. Agassiz & Desor, 1847, p. 143


Neognathostomata with:

  • single tube foot to all ambulacral plates
  • phyllodes (adoral zones of food-harvesting tube-feet) developed adorally
  • no perignathic girdle or lantern.
Lower Jurassic (Toarcian) to Recent.

Neognathostomata have traditionally been divided into a monophyletic Clypeasteroida and a paraphyletic Cassiduloida. Cladistic analysis (Smith 2001) suggests that cassiduloids are a grade taxon comprising a small number of clades leading to the Clypeasteroida. The majority of Jurassic cassiduloids belong to the common stem group of living cassiduloids plus clypeasteroids.

For a key to the modern species of Cassiduloida see Mooi (1990).

The following taxa are Neognathostomata but too poorly known to compare meaningfully:
Anochanus Grube, 1869
Echinanthopsis Munier-Chalmas, 1889
Echinanthus Leske, 1778
Heteronucleus Lambert, 1911
Pseudonucleus Lambert, 1920
Rostropygus Szorenyi, 1955
Tropholampas Clark, 1923.
Mooi, R. 1990. Living cassiduloids (Echinodermata: Echinoidea): a key and annotated list. Proceedings of the Biological Society of Washington 103: 63-85.