Pretty sure the wiki is out of date. I'm also fairly sure I saw the devs say they will be using some default assets for common plants and animals, so we'll likely see regular mice and wolves and foxes running around with the dryas elk and canis rabbits that have been created. For a world this size they can't realistically create everything from scratch.

I think that, as development goes on, they'll be adding more and more finer details to the game along the way. They just need to focus on core mechanics first.

I would much rather have main gameplay aspects like combat and crafting smoothed out than have ten dozen different kinds of flowers. Wouldn't surprise me if they added more detail into the game world after the full release though.

Impressive that you have paid close attention to the details so far but as others have said, it's likely that they havnt delved into the more mundane animals yet and considering we havnt seen any video of biomes other than the basic grassland, that accounts for a lot of missing flora and fauna. Its likely that it simply hasnt been worked on yet.

If you havn't made your way to the discord yet, perhaps you should. It is generally a good place to use as a sounding board for any ideas that you have which might prove beneficial for the game.