Is the pull up exercise alone enough to develop the chest musculature without any other chest exercise or will not doing any chest specific exercise but only pull ups result in muscle loss on the chest area?
Short answer: No.
Long answer: The pullup is a pulling exercise, whereas the chest muscles are used primarily for pushing motions.
Whether or not you lose muscle mass in your chest area is dependent on whether or not you activate those muscles. Your body isn't by default going to maintain or build expensive muscle mass if it gets the notion that you're not using it. So if you're just pulling things all day, you won't be maintaining muscles used for pushing.
I would strongly advise that any exercise plan should include pulling, pushing, and some form of leg training. If that means simply doing pullups, pushups, and squats, then that's better than nothing.
If you have a plan of actively growing your muscles, then a workout program should include a good bit more than just those three things, but that's an answer for another question.