Genus Plakortis Schulze, 1880

Synonymy. Plakortis Schulze, 1880: 449; Placortis Topsent, 1895:557; Roosa de Laubenfels, 1934:2 (after Topsent, 1937:7).

Type species. Plakortis simplex Schulze, 1880:430 (by original designation).

Diagnosis. Thinly to massively encrusting plakinids with a skeleton mostly formed by small (50–200 µm) diods with triods in varying abundance. Deformed calthrops can be found in some specimens. Some species have microrhabds (5–20 µm) distributed regularly in the sponge body. Aquiferous system intermediate between sylleibid­like and leuconoid, with eurypylous choanocyte chambers regularly distributed around exhalant canals. Both ectosomal inhalant cavities and basal exhalant cavities are usually present. Skeleton confused, dense, without ectosomal specialization or differential location of spicules (Muricy & Díaz 2002).