Otodus obliquus is an extinct species of large mackerel shark that lived in Early Paleocene to Early Eocene, between 65 and 54 million years ago. It is considered one of first members of Otodus sharks and the type species of genus. It is considered the ancestor of the famous giant mackerel shark, Megalodon. The largest individuals would have measured long.
Taxonomy History
As is the case with most sharks of the genus Otodus, the history of classification of O. obliquus is still a subject of debate. In 1838, the naturalist Louis Agassiz named O. obliquus as a species of the genus Lamna, naming it L. obliqua. However, about 5 years after its naming, Louis Agassiz reclassified the same shark into a new genus, Otodus, but still within the same family, Lamnidae. In the same year, he renamed several other species of sharks previously classified in the genus Lamna and Carcharodon, such as O. lanceolatus and O. giganteus. However, in 1942, Maurice Leriche reclassified O. giganteus as a junior synonym of O. obliquus. In 1923 it was suggested that Megalodon and many of its relatives be moved to the genus Carcharocles, with its family still uncertain. In 1964, the paleontologist Glickman grouped Otodus obliquus, Carcharocles megalodon, C. subauriculatus and C. chubutensis in the now extinct family Otodontidae, moving C. megalodon, C. subauriculatus and C. chubutensis to a new genus, Megaselachus.
Current classification In most recent studies, O. obliquus is grouped in the family Otodontidae, along with its closest relatives, such as O. megalodon and O. auriculatus for example, currently with the most widely accepted classification placing them in the genus Otodus, with mostly older, alternate classifications placing them in the genus Carcharocles. O. obliquus and O. megalodon bear similarities to modern lamnids including the modern Salmon shark (Lamna ditropis) and the modern Great white shark (Carcharodon carcharias), is, according to current research, due to evolutionary convergence, which is when two unrelated groups or species develop similar appearances and anatomy due to similar evolutionary pressures.
Although the afforementioned otodontids shared certain characteristics with the modern Great white shark, the sharks considered the true ancestors of the modern Great white shark are members of the genus Carcharodon such as Carcharodon hastalis, Carcharodon plicatilis, and C. hubbelli, instead of Otodus.
Description Size
Similar to other members of the genus Otodus, O. obliquus was a very large species of shark, with a maximum length estimates from . A sexually mature individual of O. obliquus would have measured about long.
Paleoecology
Diet Otodus obliquus was likely an apex predator, hunting large fish, turtles, other sharks, and small species of early cetaceans.
Distribution Like all sharks, the body of O. obliquus was made of cartilage, not bones, therefore, most of the fossils of O. obliquus are known only by teeth and some vertebrae. Fossils of O. obliquus have been found almost all over the world, having a cosmopolitan distribution, from the Americas to Asia.
References
External links