Mario and Luigi's niece

A niece of Mario and Luigi, appearing in The Super Mario Bros. Movie, is shown as a member of their family during a dinner gathering. She is presumably the daughter of Uncle Arthur and Aunt Marie, judging by the fact that they are always seen sitting by each other by the dinner table.

The Super Mario Bros. Movie
In The Super Mario Bros. Movie, the niece is shown at the dinner table during the family gathering. She wears a pink cap backwards and a blue shirt. She appears focused on her phone during the scene, not paying attention to the conversation about her uncles Mario and Luigi's Super Mario Bros. Plumbing commercial.

Trivia

 * In The Super Mario Bros. Super Show!, another niece of the Mario brothers appeared in the episode "Wild Thing": Marilyn.