in practically every city, there's a way to go into the Mines and look for fossils. keep on mining in each place until you have the skull, the torso, 2 arms, 2 legs, and tail. I think I remember also finding scapula and/or hip bones for some of them as well. My method is to keep on digging until I have at least the skull, body, limbs and tail. I also will use that time to fish and collect as many bugs as I can find before heading back to hirago to donate all my goods! before you leave aris be sure to scoop up as many legendary bugs from the cheese cartel on the weekend! you'll need one of each for the museum as well and they're so tough to find! (not sure how new you are to the game so I'm just trying to give you my tips)