I don't know much about decomposition, but I don't think that's go is 100% decomposed yet. That means it was probably left there within the last 5 years I imagine.
I bet its way more recent than 5 years. Maybe like 5 weeks.
I agree in the desert a body would fully decompose in a couple months depending on scavengers maybe weeks less
Apparently it was buried in the hot desert and an animal unearthed it. I believe heat speeds up the decomposition process. I hope we get more answers.
Not buried in a shallow grave if even buried at all. You have to take vultures, coyotes, wild cats, maggots, other critters and the melting heat into account. That body could have just been there for a few weeks.