In Ab, build a trap two stone doorframes high, ramp, and dino gate on other end. Get high level spino with health and aggro and have it chase you into trap. Spino can walk right through trap. Megalo gets stuck.
Tame the mega during the day! It is extremly slower during the day due to wanting a rest. It is a very strong dino, it has been tested to be even stronger than the allo! Be careful if you tame it at night ;) caw