Amphidiscosa

(invertebrate zoology) An order of hexactinellid sponges in the subclass Amphidiscophora characterized by amphidisc spicules, that is, spicules having a stellate disk at each end.

An order of the subclass Amphidiscophora in the class Hexactinellida. These sponges are distinguished from the order Hemidiscosa in that the birotulates are amphidiscs. Examples of this order are Pheronema, Monorhaphis, and Hyahnema. The record of fossil Amphidiscosa is poor, but goes back to the Carboniferous Uralonema. See also Hemidiscosa.