Agnostida
A member of the trilobites forming its own order, in the ordovician period this organism became extinct due to the change in climate and lack of food. This group had no eyes, and its life style was being a bottom-dweller. This organism lived on the ocean floor with little to no light and ate food that descended from the surface. This type of trilobite had a hinge between its head and the pygidium, allowing for a ostracodan lifestyle, which is just another organism. This specific organisms lifestyle is a debatable one. Scientists believing that it was a benthic or pelagic lifestyle as well as the ostracodan lifestyle. The benthic lifestyle means never leaving the ocean floor and practically being attached to the bottom. A pelagic lifestyle means in greek "open sea" meaning a lifestyle like this means an organism roams around the ocean.
Besides the normal anatomical features of a trilobite (meaning the thorax, an exo-skeleton cover, a head shield, a dorsal with its own protective covering) the agnostida had a hinge between the head and body as well as a difference in its thorax.
The organisms habitat was the bottom of the ocean, ate food that descended from the surface, even some resulted to cannibalism or pack hunting. When in the need of cover the organism also went into tubes on the ocean floor.
Besides the normal anatomical features of a trilobite (meaning the thorax, an exo-skeleton cover, a head shield, a dorsal with its own protective covering) the agnostida had a hinge between the head and body as well as a difference in its thorax.
The organisms habitat was the bottom of the ocean, ate food that descended from the surface, even some resulted to cannibalism or pack hunting. When in the need of cover the organism also went into tubes on the ocean floor.