The genus "Spinosaurus", from which the family, subfamily (Spinosaurinae), and tribe (Spinosaurini) borrow their names, is the longest-known terrestrial predator from the fossil record, with an estimated length of up to . The closely related genus "Sigilmassasaurus" may have reached a similar or greater size, though its taxonomy is disputed. Direct fossil evidence and anatomical adaptations indicate that spinosaurids were at least partly piscivorous (fish-eating), with additional fossil finds indicating they also fed on other dinosaurs and pterosaurs. The osteology of spinosaurid teeth and bones has suggested a semiaquatic lifestyle for some members of this clade. This is further indicated by various anatomical adaptations, such as retracted eyes and nostrils; and the deepening of the tail in some taxa, which has been suggested to have aided in underwater propulsion akin to that of modern crocodilians.