The dual discrete $q$-ultraspherical polynomials $D_n^{ (s)}(\mu (x;s)|q)$ correspond to indeterminate moment problem and, therefore, have one-parameter family of extremal orthogonality relations. It is shown that special cases of dual discrete $q$-ultraspherical polynomials $D_n^{ (s)}(\mu (x;s)|q)$, when $s=q^{ -1}$ and $s=q$, are directly connected with $q^{ -1}$-Hermite polynomials. These connections are given in an explicit form. Using these relations, all extremal orthogonality relations for these special cases of polynomials $D_n^{ (s)}(\mu (x;s)|q)$ are found.
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