Desert-Adapted Humans: Differences between Normal Human and one Highly Adapted for a Desert

Question

I am writing a story about a scenario where about 12,000 Americans are dropped onto an alien planet, specifically in a desert region of the aforementioned planet. Because of handwavium, they all survived and gathered into one place, called New Washington. By way of magically accelerated evolution, all of them become adapted for desert life within one year, and actually survive it.

I'd like to know any physical differences between these Desert humans and regular ones. However, rules for the evolution are as follows:

1. They must remain human-like. As in, they give birth to live young, feed them on milk, and have hair at least on their heads (Facial, eyelash, genital, and other hair can go away for all I care). In addition, they must have some hair and eye color variation (Like blue and gray eyes, or red and black hair).

2. However, internal processes can be different, except for reproduction. Give them heat resistance, better sweating, and anything good for desert survival, particularly things that help them retain water.

The planet's system is this:

1. Two K8V stars at the center, orbiting each other at the distance of Mercury and the Sun.

2. The planet orbits at the most habitable region for these stars, while orbiting both of them.

3. There is a gas giant 4 times heavier then Jupiter some ways away from the planet, keeping pesky asteroids away.

4. The planet has one Titan-sized moon, and is otherwise identical to Earth.

5. The desert region has numerous rivers and a number of saltwater lakes, and is between mountains and a sealine.

What would these humans look like after the evolution is complete?

Answer 1

Big flexible feet with pads.

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That one belongs to a camel, but a similar thing on humans is feasible to shield from the hot sand, spread the weight and prevent sinking.

Nostrils that close themselves against the sand/dust as per camelids and humans to a small extent.

Hyperkeratosis, ie. skin that's thick and wrinkly (there are no doubt other options with fur/scales etc.). I mention this, because I'm discarding the idea of a hump as unaesthetically pleasing and a thick keratin layer which can hold water in a similar way to that way in which elephant's skin retains it would act as a great substitute.

Blood that can stand a great range of osmotic potentials - what I mean by this is it should be able to be nice and watery when conditions permit drinking, but be able to cope with lots of water reduction in it's makeup. The same would go for many organs, but most especially the industrial-level rugged kidneys that rid the blood of processed waste.

The ability/reflex to divert blood-flow towards and away from different parts of the body to minimize overheating in the sun (and over-cooling at night).

Rather than the big flappy ears of elephants, or over-sweating, I'd suggest forming a habit that kangaroos have, they lick the inside of their wrists over the radial artery (and associated veins which I can't remember what they're called) to cool the blood.

The brain-case. This is always going to be vulnerable to the sun, so how about a massive head of sun-absorbing hair - be it dark or camel's sand coloured barnet, it'll put a halt to hot-hotheadedness.

Huge sexy eyelashes which interlace when the eyes are open, forming a barrier to sand.

What some of the smaller animals have done is adopt a nocturnal lifestyle or a crepuscular one like the Fennec fox, which'll dig a lair under dunes at the desert edge or dune-islands of relative moisture which are frozen in place by various poverty grasses and other shallow rooted plants. There's just enough moisture to maintain the shape of the landscape for a season or so.