However, the technical paper itself is not yet posted on the Royal Society Open Science website.
What is available online for free is the MS form of the paper. So until the official paper is posted, here is the next best thing:
Sobral, G, Sookias, R, Bhullar, B-A, Smith, R, Butler, R & Mueller, J (2016)
'New information on the braincase and inner ear of Euparkeria capensis Broom: implications for diapsid and archosaur evolution'
Royal Society Open Science.