Family Acarnidae Dendy, 1922

There are also extremely rare cladotylotes found in the studied material. Even though the fragment of the cladotylote (the pointed end) is absent (see Fig. 21 N), the size and the morphology of the rest of the spicule suggest that it most probably belongs to the poecilosclerid genus Acarnus Gray, 1867a . There are 6 species of this cosmopolitan genus currently known in Australian waters: Acarnus bergquistae van Soest, Hooper & Hiemstra, 1991, A. guentheri (Dendy, 1896), A. hoshinoi van Soest, Hooper & Hiemstra, 1991, A. tenuis Dendy, 1896, A. ternatus Ridley, 1884, and A. wolffgangi Keller, 1889 (Atlas of Living Australia) so it is most probable is that they belong to one of these species. The spicules described here may belong to A. ternatus as they possess very similar cladotyles (compare with van Soest et al. 1991, pl. 3, fig. 6) but a certain assignment is not possible because other species of Acarnus (e.g., A. hoshinoi) also have similar spicules. Acarnus is noted today from temperate and tropical seas, including Australia (Atlas of Living Australia), in predominantly shallow waters (Hooper 2002a).

The articulated spicules of this genus were already recorded from the Miocene of Blake-Bahama Basin (western Central Atlantic) by Bukry (1978, pl. 10, fig. 8).