As of this writing there are 954 known species of tarantulas in the world, with dozens upon dozens of described genus names. As research continues on these fascinating animals, new genus and species names are created and animals are being shifted into new nomenclature. You just never know when what you had yesterday as a Brachypelma smithi could now be Brachypelma hamorii tomorrow. What one day was Avicularia versicolor is now Caribena versicolor. As new species are discovered and more research is done, I am sure these shifts will continue.