lol, they are common names. There's about 10 different common names for every animal in the world depending on where you are located. Look at a puma, cougar, mt. lion, panther, ect. If you research some identification sites they give synonyms for most fish also. There are different common names in their native range than what we use. Tiger shovelnose comes from probably the first explorers who described it, and the name stuck when it started getting imported for the hobby.
Here are the common names for
Pseudoplatystoma fasciatum
Surubi atigrado (Argentina), Tiger Shovelnose Catfish/Barred sorubim
Pseudoplatystoma tigrinum
Tiger Shovelnose Catfish/Tiger sorubim
Brachyplatystoma tigrinum
Dourada Zebra (Brazil), Zebra Shovelnose/Tigerstriped catfish
Brachyplatystoma juruense
Gold Zebra Pim, and have seen it many times refered to as Flash Zebra Shovelnose/Zebra catfish
Those are from planetcatfish, and fishbase qouted after the /
In the end most people use tiger shovelnose for P. fasciatum/P. tigrinum in the United States. In your area it may be the exact opposite. Hope this helped, if not making more confusing. Best to qoute an accurate up to date scientific name for not to common species. TSN(P. fasciatum) is a very common, common name, and I for one will continue to call P. fasciatum TSN. Thanks!