Like Pokémon Diamond & Pearl, Pokémon Platinum is set up so that if you have one of the 5 GBA games inserted into your DS, changes appear to the Wild Pokémon. Most of the time in some areas it's just like say a Level 2 Staravia in Lake Verity. However, there are a fair few Pokémon that are exclusive to this method. So for you to catch them all, you will need the respective game plugged into the 2nd slot of the DS while you play. Below is the list;

Ruby | Sapphire | Emerald | FireRed | LeafGreen | All

Ruby in the GBA Slot

Nat No. Pic Name Type 1 Type 2 Location
#273 Seedot   Route 203
Route 204
Route 210 (South)
Eterna Forest
#274 Nuzleaf Route 210 (South)
Route 229
#303 Mawile   Iron Island
#335 Zangoose   Route 208
Route 210 (South)
#338 Solrock Lake Verity
Lake Acuity
Lake Valor
Mt. Coronet
Spring Path
Turnback Cave

Sapphire in the GBA Slot

Nat No. Pic Name Type 1 Type 2 Location
#270 Lotad Route 203
Route 204
Route 205 (North)
Route 212 (South)
#271 Lombre Route 212 (South)
Route 229
#302 Sableye Iron Island
#336 Seviper   Route 208
Route 210 (South)
#337 Lunatone Lake Verity
Lake Acuity
Lake Valor
Mt. Coronet
Spring Path
Turnback Cave

Emerald in the GBA Slot

Nat No. Pic Name Type 1 Type 2 Location
#204 Pineco   Route 203
Route 204
Route 210 (South)
Route 229
Eterna Forest
#213 Shuckle Route 224
#216 Teddiursa   Route 211
Lake Acuity
#217 Ursaring   Acuity Lakefront
Route 216
Route 217

FireRed in the GBA Slot

Nat No. Pic Name Type 1 Type 2 Location
#010 Caterpie   Route 204
Eterna Forest
#011 Metapod   Eterna Forest
#023 Ekans   Route 212 (South)
#024 Arbok   Great Marsh
#058 Growlithe   Route 201
Route 202

LeafGreen in the GBA Slot

Nat No. Pic Name Type 1 Type 2 Location
#013 Weedle Route 204
Eterna Forest
#014 Kakuna Eterna Forest
#027 Sandshrew   Wayward Cave
#028 Sandslash   Route 228
#037 Vulpix   Route 209
Route 214

Any Pokémon Game in the GBA Slot

Nat No. Pic Name Type 1 Type 2 Location
#094 Gengar Old Chateau (Room with Eyes on Wall)