Close, but no cigar: Tramuntana.

ITC Stone Serif Semibold Italic is also very similar, but not a match.

Stone Serif is similar, but Tramuntana is incredibly so. It might even be that the poster features a previous version or modification of Tramuntana.

Top: Tramuntana
Center: Original sample
Bottom: Stone Serif

If you look at the fonts of the pdf file http://www.app.pt/docs_app/encontros/10ENAPP_desdobravel.pdf, you see it is indeed Tramuntana.

Great find. Thanks for the confirmation! We’d probably have to ask the Tiponautas themselves if this is an old or a new version of Tramuntana.

The postscript file obtained from the pdf contains the following notice

/Notice (Copyright \(c\) 2012 by Tiponautas. All rights reserved.) readonly def

for each embedded font.

Hello guys,
We just caught your post by coincidence. That's a new (and unreleased) version of Tramuntana. Ricardo Santos is the designer of Tramuntana and he decided to use this new version for that specific poster and some other design elements related to the event.
We are going to release this new version shortly so stay tuned. You guys really have eagle eyes!