Fossils from the lower globigerina limestone formation at Wardija, Gozo (Miocene, Aquitanian), with a description of some new pteropod species (Mollusca, Gastropoda)

Abstract

Phosphatised fossil assemblages of four samples from the Lower Globigerina Limestone Formation at Wardija (SE Gozo, Malta) were analysed, with special emphasis on holoplanktonic molluscs (Gastropoda: Heteropoda and Pteropoda). The upper sample (sample 4) is from the lower main phosphorite level (C 1), samples 1 to 3 are respectively from c. 3 m, 5 m and 7.50 m above the base of the Lower Globigerina Limestone. Phosphatised faunal elements were separated from the limestone sediment by formic acid treatment. The fossil assemblages yielded a surprising number of species new for the Maltese Archipelago, or even new to science. Comparison with other holoplanktonic mollusc assemblages, especially those from the Aquitaine Basin in France demonstrates that there is a certain resemblance with the Chattian fauna of e.g. st. Etienne-d'Orthe (Spoelia torquayensis, Vaginella? tricuspidata), but the presence of some other species, such as Gamopleura melitensis and Vaginella sannicola indicate that the age of the Lower Globigerina Limestone presumably is Early Aquitanian. Samples 2-3 yielded also a comparatively rich assemblage of benthic molluscs (especially small-sized gastropods), most of which are illustrated here (PIs 1-3). The holoplanktonic molluscs are illustrated on PIs 3-4. The following species are introduced: Heliconoides vanderweideni sp. nov., Bowdenatheca miocenica sp. nov., Clio (s. lat.) ghawdexensis sp. nov., and Edithinella bonaviai sp. nov.