I recently overhauled this skeletal:
Aucasaurus is pretty plain by abelisaur standards. It's head isn't quite as derived as Carnotaurus. It's body isn't as strangely proportioned as Majungasaurus. It's so "stock" that in his last book Greg Paul suggested it may be synonymous with Abelisaurus itself.
Yet even a plain-jane abelisaur is plenty weird. It has a hypertrophied cnemial crest, giving it ginormous calve musles. The transverse processes on the tail are swept up and over the neural spines, giving it a "flat-topped" tail that had a lot of junk in its trunk in terms of leg-retracting muscles. And of course it still has those ludicrously small arms, that almost make T. rex arms seem normal in comparison. Yet all of those features are "normal" for abelisaurs.
So I guess Aucasaurus is weird in a very average way.
Edit: Reposed, with minor revisions to the soft tissue anatomy to bring it up to date.