What is the link between Stapelton and Hugo Baskerville

Hugo Baskerville is the long-deceased Baskerville whose treachery and wickedness supposedly inspired the curse of the Baskervilles. Mr. Jack Stapleton, a "naturalist" who studies butterflies and plants out on the moor, presents himself as an eccentric but is actually the mystery's insidious villain. Born Rodger Baskerville, he has used several aliases in the past, including Mr. Vandeleur, and once managed a school. He is discovered to be a nephew of Sir Charles Baskerville, meaning he is therefore Sir Henry's cousin.