You of course should ask for a compensation that is appropriate to the qualification and your role in the company. In most of the cases a startup can not financially compensate people at the right level - that's why they are offering options and equity to close the gap. The only other way is a deferred payment (they are saying that they will pay you back when they get funding). But equity is the most common way.

Talk to founder(s), CEO and CFO...
There is no 'rule' on how it is done, but the earlier you join, the bigger piece of the action you should be able to claim.