Alfonso de Portago’s name is awesome! Especially the “Cabeza de Vaca” part, which means “Cow Head”, I think.
About Senna, I think he dropped the “da Silva” because it’s waaaaaaaaaaaaaaaaaaaaaaaaay too common! I think about 1/10 people in portuguese-speaking countries are called “Silva” :P
He was called as “da Silva” in his F3 days though…