Board Thread:Naruto Discussions/@comment-33276259-20171006221012/@comment-25122992-20171029135442

Plus, Oonoki was never called "Oonoki Kamizuri", just stated to be a member of the clan (but members don't always have the clan name as their family name, as witnessed by Nagato or Kimimaro never using "Uzumaki" or "Kaguya" as the family name), while Yagura was called "Yagura Karatachi" right away, even before we learned that he's Kagura's grandfather.