Halisaurus

Halisaurus is an extinct genus of mosasaur named by Othniel Charles Marsh in 1869. The holotype, consisting of an angular and a basicranium fragment discovered near Hornerstown, New Jersey, already revealed a relatively unique combination of features and prompted a new genus to be described. Its name is a portmanteau of the Ancient Greek ἅλς (háls; "sea") and σαῦρος (saûros; "lizard"). It was renamed by Marsh to Baptosaurus in 1870, since he believed the name to already be preoccupied by the fish Halosaurus. According to modern rules, a difference of a letter is enough and the substitute name