Baerida
Baerida is an order of sea sponges in the subclass of Calcaronea, first described in 2000 by Radovan Borojevic, Nicole Boury-Esnault and Jean Vacelet. Baerida contains four families; two of these families were formerly placed within the order Lithonida.
Species of the order Baerida are leuconoid calcareous sponges with the skeleton either composed exclusively of micro-diactines, or in which microdiactines constitute exclusively or predominantly a specific sector of the skeleton, such as choano-skeleton or atrial skeleton. Large or giant spicules are frequently present in the cortical skeleton, from which they can partially or fully invade the choanoderm. In sponges with a reinforced cortex, the inhalant pores can be restricted to a sieve-like ostia-bearing region. Dagger-shaped small tetractines are frequently the sole skeleton of the exhalant aquiferous system. Although the skeleton may be highly reinforced by the presence of dense layers of microdiactines in a specific region, an aspicular calcareous skeleton is not.