6.5m-long large theropod
Irritator was quite like Spinosaurus. It is known only from a skull, so the sail is a guess.
The type species, Irritator challengeri was named after Professor Challenger from Arthur Conan Doyle's novel 'The Lost World', published in 1912.
Taxonomy: Dinosauria, Saurischia, Theropoda, Neotherapoda, Tetanurae, Spinosauroidea, Spinosauridae, Spinosaurinae
Named by: Martill, Cruickshank, Frey, Small and Clarke (1996)
Type species: challengeri