Thermos aquaticus
Well-Known Member
Not wishing to be pedantic or difficult, but don't fox/canine hybrids occur?
There appears to be a difference in chromosome counts between foxes and wolves which prevents crossbreeding, and the only accounts of hybrids I can find from a quick internet scan don't appear to be that reliable.
NOTE: It is still possible for species to interbreed with different chromosome counts, but it can still be a barrier to interbreeding in many cases.