Re: Interbreeding and species
This is oxymoronic. To a good first approximation, the definition of a species divide is that (fertile) interbreeding does not occur across the boundary.
If all things were nice and neat and tidy, then that would be a good definition of a species, however inter-species breeding is not uncommon, and whilst most interspecific hybrids are infertile, some individuals are not, which can lead to a new hybrid species. For example, ligers (lion/tiger) and tiglons (tiger/lion) are largely infertile, but certain individuals are not and have reproduced.
Besides which, there is a good argument for saying this it is intra-specific hybridization between H. sapiens sapiens and H. sapiens neanderthalis, both being sub species of H. sapiens.
Even if they are not sub species, interspecific hybrids forming new species is not unknown either - the Red Wolf may be (opinions differ) a coyote/grey wolf hybrid.