A new species of mosasaur, a large carnivorous marine reptile that lived in the Cretaceous period, that is to say about 80 million years ago, has just been identified. Characterized by their large jaws, these beasts are considered the most powerful aquatic animals, capable of preying on tyrannosaurs in video games.
On the basis of fossilized remains discovered in 1975, paleontologist Joshua Lively of the University of Texas looked again at the study of this animal, which allowed him to discover its true identity, aided by the discovery of new parts of his skull.
An error of identification would thus have led those who have already worked on it to make a mistake in its classification. The name “ Prognathodon stadtmani” which was attributed to it in 1999 has therefore been recently revised.
It is a Gnathomortis and not a Prognathodon
For information, the previous description of the animal was carried out with partial elements, in particular a part of the skull and a part of the body, taken from the Mancos shales on the Colorado plateau (United States).
The recent discovery of parts of the roof of the animal's skull, neurocranium and jaw, however, has made it possible to refine the identification of the species. And after reconstitution and analysis of all the found remains, Dr. Lively concluded that the fossils did not ultimately match those of the genus Prognathodon .
The researcher therefore gave it a new name, " Gnathomortis", meaning "jaws of death" because of the size of its jaws, measuring about 1.2 m long.
A bone in the jaw joint makes a difference
The characteristics of a bone called a “quadratum”, located in the jaw joint of Gnathomortis stadtmani , made this species stand out from other mosasaurs. This element is indeed an integral part of his auditory canal, which means that we are in the presence of a transient form between the previous species and the Prognathodon .
For Dr Lively, this specimen is definitely not a Prognathodon . It is a completely different species that lived in the seas of North America, 79 to 81 million years before us, or 3.5 million years before the appearance of the first Prognathodons. . This new study has therefore made it possible to better classify this species of mosasaur.
The researchers' findings were published in the Journal of Vertebrate Paleontology.