I had heard the largest freshwater shell length went to Pelochelys bibrioni, the Bulldog softshell. Alligator snapper is the heaviest, but Orlitia is close. I believe the oldest was a tortoise on St. Helena island (where Napoleon was exiled for the last time) that lived a documented 175 years. Not sure if it was an Aldabara or Galapagos. Not sure abouit the age of the Tonga Tortoise ( a radiated tortoise) that was a national monument.