It is shown that two different supersymmetric extensions of the Harry Dym
equation lead to two different negative hierarchies of the supersymmetric
integrable equations. While the first one yields the known even supersymmetric
Hunter - Saxton equation, the second one is a new odd supersymmetric Hunter -
Saxton equation. It is further proved that these two supersymmetric extensions
of the Hunter - Saxton equation are reciprocally transformed to two different
supersymmetric extensions of the Liouville equation.Comment: typos corrected and references added. To appear in Phys.Lett