Hydrodamalis
The fossil genus "Dusisiren" is regarded as the sister taxon of "Hydrodamalis": together , the two genera form the dugong subfamily Hydrodamalinae . 
<triplet> Dusisiren <subj> Hydrodamalinae <obj> parent taxon <triplet> Hydrodamalis <subj> Hydrodamalinae <obj> parent taxon <triplet> Hydrodamalinae <subj> dugong <obj> parent taxon