Abstract
A new genus and species of fossil non-marine gastropod, Fretacaeles gautae, is described from the Lower Cretaceous (middle- Upper Albian) opal-bearing rocks of the Griman Creek Formation at Lightning Ridge, northern New South Wales, Australia. The taxon is difficult to place at family level but shares morphological (including conical, globose shell with large aperture [lacking apertural teeth], inflated last whorl, and distinct shouldering), morphometric, and ecological (predominantly estuarine palaeohabitat) characteristics with fossil and living viviparid taxa. Fretacaeles gautae possesses a mosaic of features variably developed in other viviparid genera: relatively high spire, steeply inclined (weakly stepped) shoulders, impressed whorls, reduced ornamentation, and aperture with length greater than width. The significance of F. gautae, as a new member of Australia’s Early Cretaceous non-marine gastropod assemblage, is discussed.