Trading Fossil for Fossil!

[Kangaskhan]

These are the ones i need:
Spinosaurus tail
Dimetrodon tail
Mammoth head
Megacerops head

If i get all 4 of these i will have completed all my fossils!

I have to trade:
Amber x2
Pachysaurus skull x2
Sabertooth torso
Parasaur skull
Peking man
Megacero tail
Trilobite
Styraco tail
Raptor skull
Mammoth torso
Stego skull
Apato torso
Plesio torso
Stego torso x2
Tricera skull
Dimetrodon skull