Maritime 2

In Maritime 2, get access to sea creatures (excluding Xiphactinus and Mosasaurus.) This branch is an underwater creature one.

Mosasaurs
There is only one free mosasaur for this game, the Platecarpus. This mosasaur is built to "glitch" dinosaurs. Platecarpus can kill drinking dinosaurs. I recommend you DO NOT go by the big dinosaurs and you can kill ANY pterosaur as this mosasaur except Quetzalcoatlus and Hatzegopteryx.

Plesiosaurs
There is only one plesiosaur, the Hydrotherosaurus. This plesiosaur you should NOT research. It does not do as much damage as Platecarpus and can get killed by ANY dinosaur.