A revision of the supraspecific classification of the subclass Calcaronea (Porifera, class Calcarea) Author Borojevic, Radovan Departamento de Histologia e Embriologia, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Caixa Postal 68021, 21941 - 970 Rio de Janeiro (Brazil) radovan @ iq. ufrj. br radovan@iq.ufrj.br Author Boury-Esnault, Nicole Author Vacelet, Jean Centre d’Océanologie de Marseille (CNRS-Université de la Méditerranée, UMR 6540 DIMAR), Station marine d’Endoume, F- 13007 Marseille (France) esnault @ com. univ-mrs. fr jvacelet @ com. univ-mrs. fr text Zoosystema 2000 22 2 203 263 journal article 10.5281/zenodo.5392175 1638-9387 5392175 Family TRICHOGYPSIIDAE n. fam. TYPE GENUS . — Trichogypsia Carter, 1871 by original designation. DIAGNOSIS. — Baeriida with a skeleton entirely formed by diactine spicules. DESCRIPTION We propose to put sponges that have affinities with the Baeriidae , but that have only diactine spicules in the family Trichogypsiidae . As discussed above, one of the characteristics of the Baeriida is the presence of small “mortar-shaped” diactines that make up either all of, or a large part of a specific portion of the skeleton. The Trichogypsiidae have large diactines, which are probably not homologous with “mortar-shaped” diactines. It is difficult to establish whether the absence of triactine spicules is a primitive condition or is a consequence of a secondary reduction of the skeleton. In the Leucosoleniida , diactines are the first spicules to be secreted, but it is not known if this is also true for the Baeriida . All the Trichogypsiidae are very poorly known, having been described in early studies from a small number of specimens; there are no recent studies that provide a detailed description of their cytology or biology. Up to now, the Trichogypsiidae have been only described from boreal or arctic regions.