Why is there 3 threads from you guys in Hong Kong about this, haha? Cited from the African bullfrog Wikipedia - "The African bullfrog (Pyxicephalus adspersus) is a species of frog in the Ranidae family. It is also known as the pixie frog due to its Latin name. It is found in Angola, Botswana, Kenya, Malawi, Mozambique, Namibia, South Africa, Swaziland, Tanzania, Zambia,Zimbabwe, and possibly Democratic Republic of the Congo." From the sources and what I've seen they are both the same african bullfrog "Pyxicephalus adspersus". If you wanted to really find out you would need to be in contact with someone who is an experienced breeder or a herpetologist who has studied these animals in different regions. It seems to be genetics to be honest.