I've already added the rock gila to my shortlist of potential creatures. Still looking for other creatures to throw at the unsuspecting players. . . .
Since it is a desert environment, what plants are converting the sunlight into useful energy? From there, come up with a few insects, and what herbivores might exist to feed on those plants (ranging from desert mouse to camel sized), and maybe a predator or two (but none big enough to take down a camel).
The DUNE book might give other ideas, such as desert-adapted hawks.
One fun idea might be a locust swarm that homes in on moisture. If one of them sees moisture, it will get the attention of the rest of the swarm, and soon several million are heading towards the PCs, all of them thirsty. And if their jaws happen to grab a bit of skin tissue as well, that is protein and moisture. The swarm will be noisy, but often only the fastest ones were able to eat enough to survive and reproduce, meaning the slower ones tended to die off. So a PC might be in the desert, open their canteen, pour a little over their head, and within a few seconds a massive swarm of locusts is slamming into the group, looking for water and sweat, and each of them taking a small bite out of the characters in the process.
Desert residents (that the PCs likely ignored) know how to use those locusts though. Put out a strong mesh net, and on other sides put up opaque cloth. Fill a thin dish with some water, and slowly dip your hand in it, so the drops refract the sunlight. The locusts swarm in, but are caught by the mesh. From there,
dig in. Just be careful if one of the younger locals offers a plate of snacks to the leader of the PC group.
