In preparation for the first early access release, the Steam store page has been updated to better reflect the state of the game. Nonetheless, for the sake of transparency, below is a list of previous marketing and development media shown that had features that were ultimately postponed.
Fish still made it into the game, but schooling and flocking has been postponed. Foundations have been laid, but it hasn't made into the game yet. Similarly, with limited exceptions, AI generally do not yet behave as coherent groups.
Quetz landing (limited)
The first trailer showed Quetz landing. It still does this, but on predefined locations where the player can't currently reach, and quetz fulfills more of a background role right now.
Ocean aquatics (limited)
Aquatics are in the game, but any in the ocean are hard to reach as Coelophysis and have minimal impact on the game. They do swim up and down the coast and are sometimes visible.