TRICHOGYPSIIDAE, Borojevic & Boury-Esnault & Vacelet, 2000

Borojevic, Radovan, Boury-Esnault, Nicole & Vacelet, Jean, 2000, A revision of the supraspecific classification of the subclass Calcaronea (Porifera, class Calcarea), Zoosystema 22 (2), pp. 203-263 : 254

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.