Everyone in Shadowrun who isn't "metasapient" is human; that's why it's "metahumanity". So Prototype Transhuman isn't referring just to the normal human metatype. It is confusing, I admit. But every metatype is still homo sapiens.Tell that to my slaughter humans spell that I cast on my nonhuman metatype runner team when we surrounded.
Saying "Slaughter Humans" is easier and quicker than saying "Slaughter Homo sapiens sapiens"
We know that the various metatypes are defined as follows:
Dwarf: Homo sapiens pumilionis
Elf: Homo sapiens nobilis
Human: Homo sapiens sapiens
Ork: Homo sapiens robustus
Troll: Homo sapiens ingentis
These subtypes were introduced all the way back in 1st edition, and are still in use today (see Run Faster).