Trying to remember the name of an old FPS with dinosaurs and ruins.?

There was a demo on my old computer when I was younger I remember playing. It was about these like space marines going to this lost planet. All the soldiers looks like the Halo 1 soldiers. Anyway on the planet your guys get messed up and you end up searching by yourself. There's dinosaurs galore especially raptors and you also search through a bunch of like ruins that are filled with abandoned research equipment. And I am pretty sure it's not Turok lol