Cretaceous Scaphopoda (Mollusca) of Australia and their palaeobiogeographic significance

Abstract

The Cretaceous scaphopod (molluscan) fauna of mainland Australia is characterised by a rather depauperate and poorly known assemblage of five species: dentaliids Dentalium (Dentalium) n. sp. A (probably Aptian), Dentalium (Dentalium) n. sp. B (Cenomanian), and Dentalium (Dentalium) n. sp. C (Maastrichtian); fustiariid Fustiaria wollumbillaensis (Etheridge, Jr., 1892) (Late Aptian-Albian?); and laevidentaliid Laevidentalium cretaustralium n. sp. (Late Albian). Each species is endemic to either the Great Artesian Basin or Carnarvon Basin of Australia. A probable sixth species is recorded from Cenomanian deposits of Bathurst Island, but the affinity of this taxon is uncertain. In some shell beds of the Allaru Formation, scaphopods dominate the preserved macrobenthos. Although at species level the fauna is endemic, strongly cosmopolitan genus level links of the scaphopods mirror that of other groups of molluscs (bivalves, gastropods, cephalopods), indicating derivation from evolutionary separation from pre-ex...