Pachyrhachis as marine AI
Habitat: Rivers and lakes
Historical Period: Early Cretaceous (130-120 million years ago)
Size and Weight: About three feet long and 1-2 pounds
Role ingame: Will attack swimming small dinosaurs when too close, including babys and Juveniles. So collecting kelp is more thrilling.
Pachyrhachis is a doozy:
this marine reptile possessed an unmistakably snake-like body, complete with scales, as well as a python-like head, the only giveaway being the pair of nearly vestigial hind limbs a few inches from the end of its tail. The early Cretaceous Pachyrhachis seems to have led an exclusively marine lifestyle; unusually, its fossil remains were discovered in the Ramallah region of modern-day Israel. (Oddly enough, the two other genera of prehistoric snakes possessing vestigial hind limbs--Eupodophis and Haasiophis--were also discovered in the Middle East.) (Source: https://www.thoughtco.com)