During the live letter one of the Allagan dungeons featured a bunch of Ixal in glass tubes. Unlike those we're used to in Eorzea, however, these Ixal had wings.

The Ixali beast tribe quests revealed to us that the Ixal did indeed used to have wings when they lived on the floating continent of Ayatlan. At some point they lost them somehow, and were stranded in Eorzea building flying contraptions and worshiping Garuda in hopes of restoring their ability to fly.

It would seem we may find out what actually happened to them in the expansion. It's nice to see that the current beast tribe lore won't be completely left to gather dust as we move on to new tribes though.