I won’t recommend the deinosuchus over the basilosaurus but I’ve been using these guys to go into the underwater caves on the island and have found success in getting their artifacts. If you try these guys out, make sure their stats are good, they’re imprinted and give them the best saddle you can manage. While in the caves, kill any jellyfish that get too close before they stun you, use the maga-bite to help clear out swarms of creatures, DON’T aggro any dunkleosteus at all cost and avoid the Xiphactinus if you can help it! Do this and you should be fine.