Auraninja
Eh, ragazzo!
Full list of version exclusives:
BD: Caterpie, Metapod, Butterfree, Ekans, Arbok, Growlithe, Arcanine, Seel, Dewgong, Scyther, Electabuzz, Murkrow, Gligar, Scizor, Elekid, Raikou, Entei, Suicune, Larvitar, Pupitar, Tyranitar, Ho-Oh, Seedot, Nuzleaf, Shiftry, Mawile, Zangoose, Solrock, Kecleon, Cranidos, Rampardos, Honchkrow, Stunky, Skuntank, Electivire, Gliscor, Dialga
SP: Weedle, Kakuna, Beedrill, Sandshrew, Sandslash, Vulpix, Ninetales, Slowpoke, Slowbro, Magmar, Pinsir, Articuno, Zapdos, Moltres, Slowking, Misdreavus, Teddiursa, Ursaring, Stantler, Magby, Lugia, Lotad, Lombre, Ludicolo, Sableye, Seviper, Lunatone, Bagon, Shelgon, Salamence, Shieldon, Bastiodon, Mismagius, Glameow, Purugly, Magmortar, Palkia
So they essetntially split the GBA insertion Pokemon where Diamond gets Ruby and Fire Red and Pearl gets Sapphire and Leaf Green. Emerald has two of it's four Pokemon exclusive.