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Pretty similar are:
Hypselodoris maculosa which has multiple longitudinal white lines and up to three reddish bands on the white rhinophores,
Thorunna cf. florens which differs by 2 broad dark pink longitudinal bands, outlined in opaque white, by orange rhinophores with a white spot, and by a transverse orange patch on the front of the mantle,
Mexichromis aurora which differs by 3 wide whitish yellow longitudinal bands each outlined with opaque white, and by purple or blue spots between the bands and near the margin, and by small opaque white submarginal spots.
More information on Thorunna australis are on Bill Rudman's Sea-Slug Forum!