Kitefin Sharks of the Ice Age Oceans

230-MYH the Global Ocean is by far the largest habitat on the planet stretching for thousands of square miles. As cold polar currents meet at the narrow strand of sea between the southern glacier and the continent keep these waters churned up. This results in highly nutrient-rich waters around the south continental shelf and it is here that the highest amount of ocean biodiversity can be found including the largest animals alive at this time. 

Were the continental shelf meets the open ocean and cold upwells bring swarms of nutrients from the depths out of the blue one may spot the elusive Great Blue Gulper.  These are the largest animals to evolve since the extinction of the Squidtaceans although they evolved from the whale shark-like Shimmer Fin. With nothing else to compete with for the marine filter-feeding niche many Shimmer Fins have evolved to larger sizes and the largest of them is the Great Blue Gulper reaching a massive 38-foot leviathan making it by far the largest Squaliform-shark and one of the largest Chondrichthyes of all time. 

Like many other large filters, Great Blue Gulpers are cosmopolitan migrants following the continental shelf in a constant search for small food particles which with their size includes baitfish, Silverswimmer larva, and various types of zooplankton. Well, Gulpers are gargantuan there are still other sharks either large enough to hunt them. It thus camouflages itself with its luminescent patches alternating shades of blue that cloak the shark's appearance near the surface.     

Far below the sunlight waters of the continental shelf out of Gulpers sights other Sharks lurk in the depths. Sharks closely related to the Gulper both evolved from a small kitefin shark that survived the day glow fire, but unlike the filter-feeding Gulpers, these ones are predators using their bioluminescence to coordinate their hunting. 

Dark Sharks represent the other side of the Kitefin family tree evolving from the Sharkopath reaching lengths of 14 feet Dark Sharks hunt excessively in dark water either at great depths or in the dark of the night. Dark sharks aren’t adept at tackling large filter feeders like Gulpers and the role of the large game hunter is taken by related Speckle Shark’s.  

Dark Sharks primarily hunt schools of smaller prey like deep-water fish and cephalopods that come to the surface at night. Like Sharkopath's Dark Sharks communicate via their bioluminescent stripes often being the only part of them visible in the gloom of the night. Their stripes alternate in flashes of yellows, oranges, and greens and are used like the colorful sails of swordfish to avoid colliding or biting each other in low light visibility they hunt in.        

Dark sharks thus have especially good close-range among fish with a Tapetum Lucidum extremely good at reflecting light and seeing in dim light. The downside is that Dark sharks are extremely near sited as they only need to see things close to their eyes and can only see clearly about 20 feet in front of them and rely on their other senses for finding things at long ranges. 

The only animals with better vision are Blish who by the necessity of flight have excellent vision both near and far-sighted and Tera Squids whose Cephalopod eyes and ability to filter light through their unique pupal shape give them even better vision then vertebrates.