Quick Update
Visited Lisbon Zoo this week for the second time - my first visit was in 2005.
As noted in this thread and elsewhere, the zoo has changed almost out of all recognition since my last visit.
Most of the old outdated houses are now gone, with only the old tiger house, 'monkey village' and 'cell block chimp' remaining.
The old tiger house and cage now holds Hamadryas baboon. Looked like their old barred (but very large) cage has also now gone.
The 'monkey village' now holds quite a large group of Japanese macaque (pretty sure it held Rhesus macaque in 2005), but the enclosure looks pretty much the same.
The old chimp house and cages (by the reptile house and cattle enclosures) were screened off but some monkeys could be seen in one or two of the cages (Debrazza guenon and Capuchins).
Other bits and pieces:
Feline hill (also new since 2005, replacing old cat cage row) now houses Northern Lynx (2 enclosures), Snow Leopard, Puma, Persian Leopard and Fishing Cat. No Jaguars, Ocelot or Clouded Leopard.
The hoofstock enclosures next to the bears now hold Addax and Nyala.
The extreme upper part of the zoo remains closed and can only be viewed from the cable car. The lower (viewable by foot) enclosures (by the cheetahs) held Sable, Roan, Eland and Sitatunga (not labelled). More Sitatunga could be seen in a separate enclosure just past the 'no access' barrier.
Much of the post 2005 development is very impressive, most notably the ape house and enclosure. I wonder if any individuals of gorilla or chimp remain from the previous enclosures?
Overall, Lisbon now represents a really attractive zoo. In terms of species, most are those seen often by the seasoned zoo visitor but black cheeked white nose guenon are a relative rarity and the parrot collection is superb (if held in cages that make photography quite difficult!).