Fossil Panopea floridana Fossil panopea floridana is not broke with the large gap on the one side the animal that was inside was to large for its shell and they lived about 3 to 4 feet. There contractile siphons can stretch nearly 4 feet and are so large that they cannot be completely withdrawn into the shell , the actually animal in present day to weigh up to 12 lbs. They inhabit mud flats in burrows. The present day panopea is called a geoduck, king clams, gooeys or giant clams. The oldest known present day panopea is 147 years old in Canada. Panopea age can be calculated by the annual growth rings like a tree. So when they died the shells filled up the shell with dirt, mud etc. Modern day panopea are considered a delicacy since they are so hard to find. Present day panopeas are known to live in depths of 2 feet to more than 250 feet deep. Panopea's are the largest burrowing clams in the world. For those know about these fossil shells you know what a rare find this is.