you find him in the pay to dig site in rivet ravine when you take the mine car on the left of the tunnel
You get an Acro in Fossil Fighters in Rivet Ravine. You have to go to tunnel # 1 but you have to have beaten the game. I think it cost's $4,000. I almost forgot the Acro head is hard to clean so get the Super Drill.
Acro fossils are in Tunnel #1 in Rivet Ravine ((the one that's blocked off for a while, pay-2-dig site)(4,000G))
Igno is a king trye from fossil fighters champino
Aro's weakness is probably Fire type attack/large vivasaurs like Giganto.
If you meant Saichan, then Mt. Lavaflow in the regular Fossil Fighters. I'm not sure about Fossil Fighters: Champions.
how to get shoni arms in fossil fighters ds
in the sea
you buy it at the fossil guild
In bb base
At the BB Base
Rivet Riven
in rivet ravine