They are completely different plants. Pallidiflorum is from the section Porphyrochitomium. It is what is termed a 'sub-velvet leaved' anthurium. Meaning the leaves have some sheen, but fall short of the 'real' velvet leaved plants in section Cardiolonchium. In addition, the petioles are very long before the real leaf blade starts. And the midrib of the leaf is noticeably raised and white, sometimes termed 'silver'. This species also grows much much larger than vittarifolium. It comes from Ecuador.
Vittarifolium is a species in the section Urospadyx. It is a strap leaf also, but the leaves are flat (no velvet) and the petioles are short. It has purple berries as fruit and comes from Colombia.
Don't be taken in. These 2 plants are VERY OFTEN confused by sellers who do not really know what they are selling, and pallidiflorum would be more rare and expensive than vittarifolium
