Goblins

[greatelderone]

No: HPFGUIDX 127197


>From jkrowling.com
Just like Dean Thomas (see `Extras'), Flitwick has a
background that I 
now realise will never see its way into the books because it is not 
relevant to the plot. He is human but with a dash of goblin ancestry
– 
something like a great, great, great grandfather. 

http://www.jkrowling.com/textonly/faq_view.cfm?id=95

GEO: Considering how Flitwick apparently has Goblin ancestry does
that 
mean that the goblins are a subspecies of homo sapiens instead of say 
their own distinct species considering they can breed with humans and 
have fertile offspring in the case of Flitwick's ancestors. 

One wonders now if that applies to either the House-Elves and Giants.