saddle irritation ... help

I've had saddle soreness during long bike rides and have toughened up thru the season.  I just did my first Olympic tri (40K bike) and experienced irritation from the saddle.  Definitely different from the saddle soreness that might come with a long bike ride.  I'm guessing it was due to riding that distance in a wet suit, but really don't know.

I've done about 5 sprints and haven't had this issue before.  All with the same bike, saddle and suit.  Only key difference that I can think of was the distance.  Oh yeah ... this was my first salt water race ... I may have just answered my own question.

I typically ride 50 miles each week, so the distance alone does not appear to be the issue.

Is it the distance in a wet suit?  Is it the salt water?  What can I do to prevent/minimize the irritation?  Body glide?