The article is long and I don't have time to read this, but the article seems to imply that "neutral" mutations aren't driving the split between species. I wo

The article is long and I don't have time to read this, but the article seems to imply that "neutral" mutations aren't driving the split between species. I would have thought though that for a given species in a given timeframe facing many-dimensional gradient pressure for "fitness" that: - few outlandishly positive mutations would crop up - natural selection would quickly weed out deleterious mutations (the article addresses this) - over time a very large number of "neutral" mutations and therefore neutral variations within the species would accumulate since their effect is completely orthogonal to the current pressures the species faces (the article implies that this is not relevant for evolution, however I think it would be extremely relevant as I describe following ...) The "neutral" mutations would form the "library" of variations that would become relevant at a LATER time when conditions change for a subset of the population of the species and a different gradient becomes relevant. Some of the previously neutral changes would become deleterious in the new setting, while others would provide outright advantages. It is these surviving mutations that would give the sub-group of the original species its new identity. Conclusion: I would think that the mutations that drive the new species' initial offshoot would come from the inherent variation built up by the prior neutral mutations ... i.e., the evolution was already primed by the prior library of previously neutral mutations and not something that happened solely after isolation and changes in conditions. EDIT: wording