Yes, you can trade it or evolve your own duskull. (Evolves at lvl 37) Not sure if they are found naturally though.
Mantine is not available in the wild in Platinum.
In the wild, on Route 221.
The evolved form of Rhyhorn is Rhydon
Sadly you can NOT find a wild magnezone. but you can evolve a mageton by leveling-up in mount. coronet.
For Mothim, you must evolve it because it is not wild. Same for Wormadam
You can find Feebas the pre-evolved form of Milotic in the foggy room of Mt. Coronet however you will need to use a Super Rod in order to find it.
It is impossible to find an evolved kirlia in the wild. You have to catch a kirlia or ralts and evolve it. P.S. Its REALLLLYYY easy to evolve a kirlia into whatever depending on its gender.
Gallade is a evolved form of Kirlia (Evolved form of Ralts) but has to be a boy Kirlia. If it is, then you can evolve it with a Dawn Stone, and it will be a Gallade.
You have to get a finneon,and evolve it yourself
no were. i think you have 2 evolve it urself
You have to evolve your metacross who is the evolved form of beldum.
In the great marsh in Pastoria city with the super rod after you beat the elite four and get the National Dex.