Well this thick inbred... (according to our delightful, charming, witty, intelligent friend in here, lfc19something or other

)... hasn't got a clue, so pray, do explain to me and any other ignorant alledged dead 'eds.
lol. Short version: Spanish surnames are actually two "names", and if you put a hyphen between them are similar to our double-barreled surnames (father and mother's surnames combined). So "Torres-Sanz" is nothing like "Llorente-Torres", even though I allude to it in my post.
Long version: It's more complicated than that because everyone has a double surname, but the important thing is that the father's line is carried through. If we take "Fernando José Torres Sanz" (our no. 9), we can see that his father's line is Torres while his mother's line is Sanz (actually his mom's father's "first" surname). So although "Fernando Llorente Torres" is also technically part of the wider Torres family, that's on his mother's side. Since one can't put a million letters on the back of a football jersey they just go by the first part (imagine if everyone in your country had something like "Wright-Phillips", on the back of his shirt).
EDIT: both names form the surname, so they're never omitted in Spanish; think of Arantxa Sanchez Vicario of the tennis world.