Otodus auriculatus[1] is an extinct species of large sharks in the genus Otodus of the family Otodontidae, closely related to the sharks of the genus Otodus, and also closely related to the later species megalodon. The largest individuals were about 9.5m (31.2feet) long. Its teeth were large, having coarse serrations on the cutting edge, and also with two large cusplets. The teeth can reach up to 130mm, and belonged to a large "megatoothed" shark.
It is known that there is at least one genus in the family Otodontidae, that being Otodus. But the names and number of the genera in Otodontidae is controversial and the family's accepted phylogeny varies among paleontologists in different parts of the world. In the US and Britain the most widespread genus name for otodontids with serrated teeth is Carcharocles, and the owners of unserrated ones Otodus. In countries of the former USSR, like Ukraine or Russia, all of these genera were attributed to Otodus, because scientists like Zhelezko and Kozlov[2] thought that the absence or presence of tooth serrations is not enough to place these sharks in different taxa.
O. auriculatus was a large lamniform shark, with the largest individuals reaching a body length of 9.5m (31.2feet).[3] The tooth length of O. auriculatus is relatively large - from 25mm114mm. However, it is smaller than that of megalodon and Otodus angustidens; the tooth length of O. megalodon is 38mm178mm and O. angustidens 25mm117mm.[4] Smaller individuals were about 4m (13feet) long.[5]
Most O. auriculatus teeth come from South Carolina and North Carolina. However, many Eocene shark teeth are known from Khouribga Plateau, in Morocco and Seymour Island, in Antarctica. Fossil teeth have also been found in the United Kingdom and Kazakhstan, and the shark enjoyed a fairly global distribution.[6]