Sceptrulophora


Sceptrulophora is an order of hexactinellid sponges. They are characterized by sceptrules, a type of microsclere with a single straight rod terminating at a bundle of spines or knobs. An anchor- or nail-shaped sceptrule is called a clavule. A fork-shaped sceptrule, ending at a few large tines, is called a scopule. A broom-shaped sceptrule, ending at many small bristles, is called a sarule.
Unlike members of the order Lyssacinosida, sceptrulophorans have dictyonal strands, meaning that their macroscleres are fully fused together into a 3D framework. They can likewise be differentiated from the order Lychniscosida by the absence of octahedral frames at the nodes of their macroscleres. Glass sponges with these two traits have historically been placed in the order Hexactinosida.
Many species in "Hexactinosida" also qualify as members of Sceptrulophora, though these two proposed orders are not identical. Sponges in the family Dactylocalycidae have dictyonal strands and lack lychniscs, but also lack sceptrules. Genetic testing has argued that dactylocalycids are more closely related to Lyssacinosida, rather than sceptrule-bearing sponges. This renders Hexactinosida polyphyletic while maintaining the monophyly of Sceptrulophora.
Species of the order Sceptrulophora have existed since the Jurassic period, and still flourish today.

Families