First of all, calling ethnicities subspecies creates a political mess and such arguments have often been used for all kind of injustices. Secondly I'd say that

First of all, calling ethnicities subspecies creates a political mess and such arguments have often been used for all kind of injustices. Secondly I'd say that the differences are very fluid and it's hard to pinpoint any hard barriers. The "European" ethnicity only developed in the past 4000 years. Migrations during all that time make the picture even more difficult.