Some of the oldest known benthic marine organisms are black corals of genus Leopathes.  These ancient deep-sea corals (Leiopathes spp.) are very slow-growing black coral species.  In the Gulf, large colonies of the black coral Leiopathes glaberrima have been estimated to be over 2,000 years old.  They are characterized by their black or dark brown skeleton which is covered by lighter colored polyps.  The black skeleton of Leiopathes corals grow in a plant-like manner.  Colonies tend to have a middle stem that grows upward, with branches or arms that extend from the middle structure.  The main stem stops growing after a certain time, and a new branch grows out from the side.  Leiopathes colonies are abundant and widespread throughout the Gulf, with some colonies reaching heights of more than a 1 m, which make them important providers of benthic habitat. Read more about the Ancient deep-sea corals from here.