Gastropoda - Tonnoidea - Ranellidae
Synonyms: Eutritonium (Monocirsus) Cossmann 1889, Sassia (Monocirsus) Cossmann 1889, Triton (Monocirsus) Cossmann 1889
Parent taxon: Sassia according to Bellardi 1872
See also Beu 1978, Beu 1998, Beu 2005, Cossmann 1919 and Sepkoski 2002
Sister taxa: Charonia (Sassia) angusta, Charonia (Sassia) danica, Sassia (Byramia), Sassia (Personella), Sassia apenninica, Sassia armata, Sassia carlea, Sassia carmenensis, Sassia indica, Sassia kampyla, Sassia leucostomoides, Sassia lewisi, Sassia melpangi, Sassia morgani, Sassia nucleoides, Sassia parvula, Sassia philomelae, Sassia radialis, Sassia tatei, Sassia warreni, Austrotriton tumulosus, Austrotriton woodsii, Austrotriton gibbus, Austrotriton protensus, Austrotriton cyphus, Austrotriton textilis, Proxicharonia palmeri, Austrosassia crassicostatus, Austrosassia annectans, Austrosassia tortirostris, Austrosassia abbotti
Subtaxa: Eutritonium (Monocirsus) namnetense Sassia (Sassia) marshalli Sassia (Sassia) neozelanica Sassia (Sassia) zealta
Ecology: epifaunal carnivore
Distribution:
• Miocene of New Zealand (2 collections)
• Oligocene of France (1), New Zealand (1)
Total: 4 collections including 5 occurrences