The Ancestral Trail? 'Neanderthal' by John Darnton (1996)

A project that was almost certainly greenlit following the immense success of the novel and movie Jurassic Park, John Darnton’s 1996 novel ‘Neanderthal’ is a relatively rare 1990s example of a literal ‘lost world’ tale. Two paleontologists travel to the Pamir mountains in Tajikistan to follow up on a rumour that a surviving band of Neanderthals is hiding out there. Frontloaded by lots of ‘real’ cryptozoological nuggets from the work of investigators Myra Shackley and Boris Porshnev, Neanderthal gets off to a good start. But will things stay positive as our heroes go native in this particular lost world and follow their ancestral trail?