Does parent need to pay taxes on joint account with minor who is the primary account holder?

The dependent minor was the primary account holder with parent as joint account holder. The minor will therefore receive the 1099-INT.
The account was a short term, high interest CD that paid $515 in interest (The account is now closed).

The child had no other income.

Because this unearned income is less than the threshold ($2,200), the child does not need to pay taxes.

However, since this is a joint account with a parent;

1. Does the parent need to show what part of the money belongs to the child/parent?
2. Is the parent required to pay taxes on the parent's share of the interest?