Complex sentence: The names of her mother's sisters Eliza and Susan became the basis for ZaSu's unique first name, which has been (incorrectly) spelled as Zazu Pitts or Zasu Pitts in many film credits and articles.
Split into simpler sentences: The names of her mother's sisters Eliza and Susan became the basis for ZaSu's unique first name. Her name has been (incorrectly) spelled as Zazu Pitts or Zasu Pitts in many film credits and articles.