Some calthrops occurring in the studied material (Figs. 5 I, J) belong most likely to calthropellid sponges. This small astrophorid family is, like the family Pachastrellidae, characterized by calthrop megascleres, modified triaenes and tetractines, mesotriaenes and oxeas (van Soest & Hooper 2002 b). Thus some of the calthrops discussed here may belong to the Calthropella -like sponge. However, the more precise taxonomic assignment of studied spicules is not possible unless the whole set of spicules is preserved.
Calthropellids are reported from warmer parts of the oceans, from moderately deep water (about 600 m depth) and occasionally from the littoral zone, with records from the North Atlantic, Mediterranean, South and East Africa, Indonesia, and New Zealand (van Soest & Hooper 2002 b). There are two species of Calthropella recorded from Australia adjacent areas: C. (Pachataxa) enigmatica (Lévi & Lévi, 1983) from New Caledonia and C. (Corticellopsis) novaezealandiae (Bergquist, 1961) from New Zealand, so the studied spicules may belong to one of these species, or to a related fossil species. Because of these doubts, these spicules are assigned only to Calthropella sp.