AD is one role above Principal to my knowledge. 

But in all fairness, it would be best to ask the recruiter. Why?

1. Because they keep on changing the names as the firms and the practices develop. I've been in the consulting world for 7 years and since then have already witnessed significant changes and additions. 

Back in the days, consulting firms used to operate more like law firms, with Associates and Partners. That would mean that somebody would often be an associate for a decade before making it to Partner. 

For many reasons, one of which would be motivating their employees, consulting firms have created almost 3-8 in between roles. 

Most recently, in MBB there was BA, Associate, Manager, Junior Partner, Partner (under different namings). A couple of years ago BCG introduced an intermediary step between Junior Partner/AP and Partner where you would be theoretically called a Partner but you wouldn't be a shareholder. To be a shareholder you'd need to become a ‘Managing partner’. Does it sound complicated? That's because it is. 

2. There are also differences between the regions. 

In some regions, some roles don't even exist e.g., Junior Associate or Senior Business Analyst. 

Best,
Cristian