Genus Spiculosiphon Christiansen, 1964

Definition modified from Christiansen (1964) to incorporate the shared features of the new species described herein. Large (> 20 mm) astrorhizid foraminifera characterized by a capitate, stalked, monothalamous test, the wall of which is made mostly or exclusively from siliceous sponge spicules agglutinated in an unidentified, organic cement. The stalk consists of a simple or dichotomized (during asexual reproduction), hollow tube that may stand upright respect to the substratum, but never attaches permanently to it. The wall of the stalk is built with elongated fragments of sponge spicules, tightly glued together in parallel to the major axis of the stalk. The stalk end opposite to the substratum becomes a globelike, central structure, from which long, thin tracts made of elongated spicule fragments radiate outwards. This capitate portion of the body is herein defined as being distal, opposite to the proximal stalk end, which is the one contacting the sea bottom. Asexual reproduction appears to be by budding or by fission. Sexual reproduction never observed. Type species: Spiculosiphon radiata Christiansen, 1964, from Norway, 100 m depth.