I was under the impression that artificial speciation had been achieved. Have I misunderstood http://en.wikipedia.org/wiki/Speciation#Artificial_speciatio...?
flies - but they say only a "mating preference" was achieved. Well sure, there are different kinds of dogs and they probably prefer their own kind, but they are still just one species.
domestic cattle - this is a non-example, as the article points out, because they are all capable of interbreeding
sheep - two kinds of sheep are apparently different species. However, I would take issue with this statement: "For example, domestic sheep were created by hybridisation"... it seems inconsistent with the other one: "but the initial dates and methods of the initiation of such species are not clear". How do they know they were created by hybridisation?