Transfer of house property on wife's name without son's knowledge

I am a married Hindu. My father died on 02.08.15. After that very recently my mother was transferred in to her name in the municipal records in place of my father name. the house was constructed on my grand father's self acquired land after demolishing the existing old house which was constructed by my grand father without my knowledge. We have 3 sisters and I am the only son to my father. My question is weather I am loosing the rightes on existing house or can I challenge in municipality or in a court of law the change of name and I want to know that by changing the name itself is transferring all rights on that property to the new changed person. To my knowledge my father was not written any will. If after wards fabricated that I don't know. Kindly answer my querry. Very very thanks in advance.