Ariel’s mother is called Queen Athena in Disney’s 2008 film The Little Mermaid: Ariel’s Beginning.
Athena is King Triton’s wife and the mother of Ariel and her six sisters. The prequel opens with the royal family enjoying music together, but Athena is later killed by a pirate ship while trying to recover a music box. Triton responds by banning music throughout Atlantica.
This character does not appear in the 1989 animated feature’s main story, which is why viewers sometimes assume Ariel’s mother was never named. Athena’s history is developed primarily in the prequel, which explains Triton’s grief and his strict attitude toward music before Ariel challenges the ban.