Mrs McDuck was a female anthropomorphic duck.
This woman married one of Scrooge McDuck's ancestors. Though her husband was at any rate related to Seafoam McDuck, it is unclear if he was Seafoam's son (and therefore Scrooge's great-great-great-uncle), or Seafoam's father (which would make him Scrooge's great-great-great-grandfather, and consequently make his wife Scrooge's great-great-great-grandmother).
Behind the scenesEdit
Mrs McDuck appeared in 1999 in Johannes A. Grote's Duck Family Tree.
The lack of clarity regarding Mrs McDuck and her husbands' place in the family tree is due to the erroneous translations of the Carl Barks stories on which Grote based his efforts, as they led to Seafoam McDuck being depicted by Grote as Scrooge McDuck's great-great-great-great-grandfather, while an anonymous character, Seafoam's grandson, became Scrooge's great-great-grandfather. This means that depending on how one looks at it, Mrs McDuck's husband might either be Seafoam's father (if his place as Scrooge's great-great-great-grandfather is given precedence) or Seafom's son (if that family link is deemed more important).