Dunkleosteus Essay Example | Topics and Well Written Essays - 500 words

Dunkleosteus - Essay Example The living organisms in this classification include sharks, rays, chimearas, ray-finned fishes, and land vertebrates. The clade of Placodermi is now in extinction because of the incapacity of the organisms to survive. The Placoderm are characterized by the presence of dermal armor comprising of a head armor and thoracic armor. Their thoracic armor is distinct because the foremost dental plates forms a ring around the body and include one median dorsal plate (Janvier 3). The order Anthrodita is comprised of organisms in Placodermi which have movable joints between the armor surrounding the head and the body. The organisms belonging to this class is also distinct for their two sets of upper tooth plates, gnathal plates which are tuberculated, and large endocrinal postorbital process (Janvier 4). These structures allow the lower jaw to move down while the head shield also budge for a large opening. Together with their extinctions of these prehistoric armored fish, their primary characteristics of having armors which covers their entire head and some of their body.