The Adamanchelid is an enemy in Final Fantasy XIII. It is a young Adamantoise, and is the mark of Mission 33. The Adamanchelid is easily recognizable by its lack of tusks, lack of ankle chains, and comparatively smaller stature, though it still towers over the party members. Because of its smaller size, it does not have targetable forelegs.
Adamanchelids attack by stomping their legs, Bay and Quake, dealing Earth-elemental damage. They are fairly slow and susceptible to status ailments. They are weak to Ice.
The easiest way to bring it down is to exploit its weakness to Daze. This way, even a low-level party can take it down. Having Fang as leader (as she is likely the first to learn Daze) the player can cast it manually and keep reapplying it. Recommended paradigm is the Smart Bomb (SAB/RAV/RAV), with characters who know Blizzard spells as the Ravagers.
Alternatively, the player can create a paradigm with a Synergist to cast Enfrost on a Commando. SAB/RAV/RAV will stagger the Adamanchelid quickly, which lets the player finish it off. With the player continually reapplying Daze, the Adamanchelid may never even get a turn. SAB/MED/MED can be used to heal. The player can also call out the leader's Eidolon and to finish it off.
Once the player is on a higher level they no longer need to manage the battle with Daze, but Smart Bomb still works to stagger it quickly. Once players are of a high level, they can easily crush the Adamanchelid by using Evened Odds (MED/SYN/SAB) until Imperil has been inflicted. After the Synergist applies Faith and Bravery, the party should be able to pummel the enemy down. Slow is effective as well, while having Haste on the party.