The Echinoid Directory

Family Unnamed taxon 1

Diagnosis	Micrasterine spatangoids with: apical disc ethmolytic; madreporic plate extending to rear of posterior ocular plates; petals short; weakly to moderately depressed; perradial zone narrower than the width of a pore-pair; labral plate longitudinally elongate; extending to at least half-way long the second ambulacral plate sternal plates symmetrical; episternal plates tapering to posterior; paired; subanal fasciole present; shield-shaped and crossing adorally through the middle of plates 5.b.3, 5.a.3.; peripetalous fasciole present.
Range	Eocene to Recent; worldwide.
Remarks	Amongst the various taxa previously grouped as Brissidae are a small number of taxa with a longitudinally elongate labral plate and short petals. In true Brissidae the labral plate is short and wide and never extends further back than half-way along the first ambulacral plate. These probably represent a clade but are currently left in open nomeclature. One other taxon, Protobrissus Lambert, 1907, from the late Palaeocene of France may also belong here but is so poorly known that t is omitted from the following key.