Marine Biodiversity » Marine Sponges » Calcarea » Calcarea Classification » Subclass Calcinea

Definition: Tubular, branching or regularly anastomosing cormus, either with many oscules or with a large atrium and a single osculum; sponge wall composed of a distinct cortex and choanosome; skeleton of choanosome and atrial wall absent or composed of small and dispersed triradiates and quadriradiates.

Scope: There are four named genera (three valid), and a fourth incertae sedis.

Reviews: Hartman (1958), Burton (1963), Borojevic (1968), Borojevic et al. (1990).

Genera:
Ascandra Haeckel, 1872 (type species: Ascandra falcata Haeckel, 1872) - solitary or compound, subpyriform, clathrate, substipitate; surface minutely hispid; oscules apical; soft texture; choanoderm forms folds inside the choanocoel which isolate radially arranged shallow cavities or true radial tubes; choanosomal folds are supported by apical rays of external quadriradiates only; spicules regular triradiates, regular quadriradiates and sickle-shaped oxeas (Burton, 1963; Borojevic et al., 1990).
Leucaltis Haeckel, 1872 (type species: Leucaltis clathria Haeckel, 1872) (syn. Leucaltusa Haeckel, 1872; Artynaltis Haeckel, 1872; Heteropegma Poléjaeff, 1884) - body composed of large ramified and anastomosed clathrous tubes; surface even, smooth; oscules small, scattered; texture friable; each tube has a distinct cortex, a choanoderm composed of elongated and ramified choanocyte chambers and central atrium; choanoderm and atrial wall have a secondary skeleton composed of small triradiates and quadriradiates; ectosomal skeleton of several tangential layers of regular triradiates with facial rays of subectosomal regular quadriradiates; chamber layer with centipetally-directed apical rays of subectosomal quadriradiates, regular to sagittal, and small irregularly scattered quadriradiates; choanosomal skeleton with several tangential layers of quadriradiates (Burton, 1963; Borojevic et al., 1990). GBR species: Leucaltis clathria Haeckel 1872.
Leucettusa Haeckel, 1872 (type species: Leucetta corticata Haeckel, 1872) - composed of a clathrate mass of anastomosing tubes; ectosomal skeleton of several tangential layers of regular triradiates; skeleton of chamber layer and of choanosomal surfaces of small sagittal triradiates, with those of inner parts of chamber layer with swollen ends to rays (Burton, 1963); simple tubular body a large atrium and choanocyte chambers which are either elongated, spherical or both (Borojevic et al., 1990).
Leuclathrina Borojevic & Boury-Esnault, 1987 (incertae sedis) (type species: Leuclathrina asconoides Borojevic & Boury-Esnault, 1987) - skeleton restricted to the ectosomal cortical region, and the choanosome lacks spicules completely (Borojevic et al., 1990); globular growth form, apical oscules with slightly raised fringe; smooth, porous surface; ectosomal cortex supported by equiangular and equiradiate triactines; choanosome without mineral skeleton; leuconoid aquiferous system (Borojevic & Boury-Esnault, 1987).