Not entirely true ... the jury is still out on Grant's/ steppe zebra ... even Eastern vs. Southern subspecies ....!!!
With subspecies the jury is ALWAYS still out! (though I'd be pretty surprised to find Equus quagga borensis being confirmed as valid!) I think we're steadily working towards an increased number of recognised species and a decreased number of recognised subspecies. Anything distinctive is increasingly split off to a new species, and lots of traditional 'subspecies' are being shown to be invalid by DNA and other studies.
