Pagani 2006. Carboniferous and Permian bivalves from Patagonia (Chubut, Argentina). Part V: families Trigoniidae, Permophoridae, Cardiniidae, Crassatellidae, Pholadomyidae, Sanguinolitidae and Megadesmidae. Conclusions. Ameghiniana, 43(3), 30 de setiembre 2006: 539-556