Could Sotek's Spine be the spine of a Thunder Lizard(or other huge reptile)? I could imagine: It wakes up every 100 years. Unconsiously, it is fed by skinks. Some priest at one point ordered it to get up and pull Lustria away from Naggaroth. Once it was done it curled up making the the big gap between Mexico and Florida. 100 years later, it was ordered to pull Lustria back and sleep again.