Would it then be correct to assume thhat our "pre hominin" cousin genera must have been religious in order that they would have survived in order to produce H s.s descendents?
That's an interesting question. I don't know of a specific answer to that, though it appears there are many theories. But your question is almost impossible to answer considering we don't know if we even need religion to survive currently, never mind in a past that covers millennia!
I do think that without what under pines religion, we are at the least in psychological trouble. And who knows why that even started? Could have been a side effect of some other facility? Its all very bizarre but that's just a shortcut to me admitting that I can't have that knowledge and the confusion it produces regarding answers to these questions that we're screwed for!
Currently reading a book by Leakey (the son) on the differing 'punctuated' human vs gradual human development theories. The book was written in the mid 90's but I believe the debate has not since been settled if the blurbs I've read here and there are indicative of the current state of the debate.
As you might guess:
Punctuated basically states that the earliest ancestors we would consider part of our family tree (which would start with the australopithecines) had pretty much all of the traits we consider human which would include religion, language (in my opinion language = religion) etc. This occurred relatively fast.
The gradual theory is that the transformation took place in steps, first bi-pedal, crude tool development, then language, then religion, etc..with large gaps of time in between each development..
I believe the Gradual theory, till further evidence, currently has more weight and would indicate that our pre sapien ancestors wouldn't necessarily have to have had religion (with the exception of the Neanderthals)..