Sycanthidae Lendenfeld, 1891

Family Sycanthidae Lendenfeld, 1891 View in CoL

Diagnosis (after Borojevic et al., 2000: 228; direct quote with modifications in italics; modifications are needed to accommodate Leucotreton gen. nov. in this family). Leucosoleniida with an irregular syconoid or sylleibid/leuconoid organization, and the articulated skeleton primarily supported by triactine spicules, with occasionally diactines in the distal cones. The large central atrium bears numerous short radial tubes lined by choanoderm or containing numerous small choanocyte chambers. Radial tubes are grouped and fused proximally, each group communicating through a wide opening with the atrial cavity. The distal free or coalescent cones are intercalated by large inhalant spaces, which often reach the external surface of the atrial skeleton. When coalescent, distal cones can have tangential triactines, but there is no continuous cortex covering the choanosome and delimiting the inhalant cavities externally.