Be wary that the Megalosaurus received a major nerf in the form of the latest raptor TLC. Raptors can now dismount Megalosaurus riders and seem to attack them on sight. Megalosaurus often use their grab attack while the raptor will still have you pinned even while it is in the Megalosaurs mouth. The raptors allies will then proceed to eat you and then kill you in that order.
These guys are a must-have in Aberration; they are always awake (at least in the bioluminescent area), and thus always have their night buff. Of course, this also means you must always be wary of wild ones while in their territory.
When out at night, be sure to take this with a raft or quetzal with platform, so when it is tired, you can get it back to base without it being attacked. Just a tip to ensure that your prized Megalosaurus doesn't die whilst you are out.