Best way to tame them right here.

1. Find a shadowmane on its own. Preferbly away from aggressive dinos.

2. Make a 2x2 stone floor. Surround with 2 high stone walls, 16 in total. Add a wooden ramp on one side.

3. Aggro the shadowmane and fly above the trap, you'll get attacked a couple of times and it MAY take multiple tries but it WILL go in.

4. Fly high so it stops aggro. You'll have to fly so it goes off screen.

5. Wait for it to sleep and feed it fish from fish baskets by walking up to where it'd tail is. You can feed it through the wall (I'd recommend 1.0 or bigger, if they're timer is running out just take a dip in some water. It'll reset the timer.)

5. When you feed it fish it'll wake up. You don't have to move as it won't aggro cause it can't see you. Repeat until tamed.

100% guaranteed to work. I've tamed a bunch this way. Just gotta watch out for enemy dinos and make sure you have plenty of fish baskets full.