I don't think there is a female equivalent. However, if I had to make one up to say, I'd probably use "Bra". This is for 2 reasons.
1: Because females wear bras so it kinda makes sense
2: I believe with Spanish, if you're referring to a female, you use a word that ends with "a". I say "I believe" because I'm terrible with Spanish so this could be wrong.
But just like what Moon said, I just use "dude" for anything. I don't think of a guy when I say dude, nor do I think of a woman. I just think of an individual. It's more of an informal way to refer to somebody to me.
1: Because females wear bras so it kinda makes sense
2: I believe with Spanish, if you're referring to a female, you use a word that ends with "a". I say "I believe" because I'm terrible with Spanish so this could be wrong.
But just like what Moon said, I just use "dude" for anything. I don't think of a guy when I say dude, nor do I think of a woman. I just think of an individual. It's more of an informal way to refer to somebody to me.