Researchers from Hokkaido University have discovered fossilized remains of ancient, finned octopuses that were likely to reach up to 19 meters and were found in the late Cretaceous oceans 80 million years ago. The remains were discovered using a technique called Digital Fossil Mining, which used high-resolution grinding tomography to physically remove microscopic layers of the rock and digitally extract them. The study suggests that this was not the age of vertebrates, but an apex predator without a backbone. The only fossilized body parts that fossilize are their chitinous jaws, which are difficult to identify due to their thick skin. The discovery of these fossils has led to a delay in evaluation of the fossil record.