Since this research doesn't mention some hard to quantify ties, it missed on the painting the picture of the most interesting actual family in mathematics: the Bernoullis. Brothers Jacob and Johann sprung up seemingly out of nowhere to continue Leibnitz's work in Basel as some of Europe's greatest mathematicians of their time.
The most remarkable part is how Johann tutored the son of a local pastor, a friend of the family. After noticing his talent, he convinced the father to let the young boy focus on mathematics instead of joining the clergy. That young boy was Euler, and when we add Johann's son Daniel into consideration (who turned out to be a mathematician of similar caliber to his father) I'd venture to say that there is an actual family at the core of modern mathematics that would by itself be an object of study.