The ghastly snark evolved after small packs of snarks continued to move deeper and deeper, to avoid the occasional food shortages they encounter whenever the larger packs began to overfeed. As it doesn't interfere with it's ancestor's habitat it split from the snark. It evolved in the far northern areas of the LadyM and traveled towards more open water to their new habitat, the Jujubee Ocean. Down at the bottom there is little food large enough to require chewing or actively ingesting, so the ghastly snark now only filters out centifins, much like some species of whales filter out krill on Earth. Without the need to turn rapidly because they no longer use much energy, conserving it for when they feed, the ghastly snark's dorsal fin now hangs uselessly behind it in an elongated form.