Order LITHONIDA Vacelet, 1981
Diagnosis
Calcaronea with reinforced skeleton consisting either of linked or cemented basal actines of tetractines, or of a rigid basal mass of calcite. Diapason spicules generally present. Canal system leuconoid.
ID Keys
KEY TO GENERA
(1) Skeleton including a solid mass of calcite --------------------------------------------------------------------Petrobiona
Skeleton without a solid mass of calcite --------------------------------------------------------------------------------------- 2
(2) Basal skeleton made of uncemented tri- and tetractines interlaced by their basal actines ----------- Tulearinia
Basal skeleton made of tetractines cemented in a rigid network ---------------------------------------------------------- 3
(3) Rigid network of tetractines embedded in a cement ----------------------------------------------------- Minchinella
Rigid network of tetractines not embedded in a cement ------------------------------------------------------------------- 4
(4) Basal skeleton made of a single category of tetractines --------------------------------------- Monoplectroninia
Basal skeleton made of two categories of tetractines----------------------------------------------------------------------- 5
(5) Basal skeleton forming a thin basal layer (in Recent species) ------------------------------------------ Plectroninia
Basal skeleton with ascending radial lines -------------------------------------------------------------------- Petrostroma
Diagnosis References
Vacelet, J., Borojevic, R., Boury-Esnault, N. & Manuel, M. 2002. Order Lithonida Vacelet, 1981, Recent. pp. 1185-1192 in Hooper, J.N.A. & Soest, R.W.M. Van (eds). Systema Porifera. A guide to the classification of sponges. New York : Kluwer Academic/Plenum Publishers Vol. 2 [1185]