| "Jane's great-grandfather" is not an official name. |
Jane's great-grandfather was mentioned in the episode "The Tattletale Frog" when it is mentioned that he gave a flower case to Jane's great-grandmother over 100 years ago. Although brefly mentioned in the episode, no other information about him is known, such as if he is on Grandpa Dave's side of the family or not or who he was the father to.