giganteus, meaning "giant Earth lizard", is known from Western Europe (Germany) of the Late Jurassic (Early Tithonian). It was originally named Lacerta gigantea by von Sömmerring. Geosaurus grandis, first described by Wagner in 1858, was formerly considered a species of Cricosaurus. It is known from a complete skull. Geosaurus lapparenti is known from south-east France and dates to the early Cretaceous period (Valanginian). It was named in honour of French palaeontologist Albert-Félix de Lapparent, and is based upon isolated skull and post-cranial bones (neck and tail vertebrae and a partial pelvic girdle) from the Early Cretaceous (Valanginian) of France. It was originally classified as a species of Dakosaurus. A large species of Geosaurus is known only from a single tooth from the Nusplingen Plattenkalk of Germany. Cladogram after Cau & Fanti (2010). Reclassified species In 2009, Young and de Andrade published a re-description of Geosaurus, examining its relationships and the validity of species lumped into the genus. After performing a phylogenetic analysis of metriorhynchids, they found that many species were grouped in a paraphyletic manner or with the wrong genera. Specifically, they found that several species formerly classified as Geosaurus, including G. suevicus, G. saltillense, G. vignaudi, and G. araucanensis were actually examples of the related Cricosaurus. Rhacheosaurus gracilis, another long-snouted species, was also at one time considered a species of Geosaurus (as G. gracilis). Geosaurus carpenteri, also formerly referred to Dakosaurus, is known from a partial skull. Teeth identical to the known teeth of this species are also known from Yorkshire, UK. It was assigned to its own genus, Torvoneustes by Andrade et al., 2010. An unnamed specimen classified as Geosaurus was found in the Oxfordian Jagua Formation of Cuba, though further study has shown this species to be more closely related to Cricosaurus as well. Additionally, Geosaurus fossils have been reported from the Vaca Muerta of Argentina. Palaeobiology Niche partitioning Several species of metriorhynchids are known from the Mörnsheim Formation (Solnhofen limestone, early Tithonian) of Bavaria, Germany: Geosaurus giganteus, Dakosaurus maximus, Cricosaurus suevicus and Rhacheosaurus gracilis. It has been hypothesised that niche partitioning enabled several species of crocodyliforms to co-exist. The top predators of this Formation appear to be G. giganteus and D. maximus, which were large, short-snouted species with serrated teeth. The long-snouted C. suevicus and R. gracilis would have fed mostly on fish, although the more lightly built Rhacheosaurus may have specialised towards feeding on small