An article published in the journal “Nature” describes a study that provides a solution to the mystery represented by the animal commonly known as “Tully” monster”. Its scientific name is Tullimonstrum gregarium and it’s a creature that lived just over 300 million years ago in today’s Illinois, USA. For decades no one could figure out what kind of animal it was but according to a team from Yale University led by Dr. Victoria McCoy of the University of Leicester it was a vertebrate related to modern lampreys.