TL;DR: Murrayonida Vacelet (Calcarea, Calcinea) contains three families, three valid Recent genera, and only three Recent species from coral reef caves and deep fore-reefs, mostly from the tropical Indo-Pacific region, with affinities to a larger ancient group of fossil taxa.
Abstract: Murrayonida Vacelet (Calcarea, Calcinea) contains three families, three valid Recent genera, and only three Recent species from coral reef caves and deep fore-reefs, mostly from the tropical Indo-Pacific region, with affinities to a larger ancient group of fossil taxa. The order is characterized among Calcinea by a reinforced skeleton of a calcareous aspicular network, or calcareous plates, or spicule tracts generally composed of diapason triactines, reminiscent of the reinforced skeleton of fossil ‘pharetronids’.