The range of dogs runs clean from tiny terriers and lapdogs at one end, up to huskies and mountain dogs at the other end which are physically almost indistinguishable from wolves. So mankind *has* created a new species in the domestic dog.
Seems to me your own first sentence above is in direct conflict with the second. Breeding has introduced great variations, but that whole range of "caninitude" from wolf to Pekingese are interbreedable (if there's such a word), so no new species.