Priarcodon fruitaensis, an early mammal, was well adapted for powerful and precise biting. It also had a diverse faunivorous diet that possibly comprised insects and small vertebrates, a University of Bonn-led study indicates.
A Sci-News report specified that Priacodon fruitaensis lived roughly 150 million years back, during the Jurassic period, in what is presently Colorado, the United States.
More so, the prehistoric animal was less than eight inches long and had a mass from 41 to 61 grams. The said early mammal was initially described in the early 1980s from a fossilized jaw discovered in rocks of the Upper Jurassic Morrison Formation.
The early mammal is part of the Triconodontidae, "an extinct family of early crown mammals" with a fossil record from the Late Jurassic until the Late Cretaceous epoch.
In a new study, Dr. Kai Jager, together with his colleagues from the Institute of Geosciences at the University of Bonn and Oklahoma's Museum of Natural History, investigated the molar obstruction, movement of the jaw, and morphology of the ancient mammal.
In more developed mammals, the research also found that, in more developed mammals, the teeth' rows are ‘shifted against each other.’
Special Tomography Approach
It was not clear precisely how the teeth in the Priacodon fruitaensis' upper and lower jaws fit well together until this time.
Institute of Geosciences at the University of Bonn paleontologist Professor Thomas Martin, also the co-author of the study, said they have now "been able to answer that question."
The study authors used a special tomography approach to produce high-resolution 3D images of the molars of Priacodon fruitaensis.
In their study, the researchers specified that the upper and law jaws each have several molars. Specifically, in the mammals' predecessors, Martin emphasized, "Molar 1 of the upper jaw would bite down precisely on" the lower jaw's molar 1 when chewing.
Nevertheless, in more developed mammals, the research also found that, in more developed mammals, the teeth's rows are "shifted against each other."
Researchers' Observation
The co-author also explained, as a result, Molar 1 at the top is hitting exactly between Molar 1 and Molar 2 when they bite down so that it gets into contact with a pair of molars instead of just one.
Jagger said they compared both options using the computer. This exhibited that the mammal bit down as if it is a modern animal.
The expert also said the Priacodon fruitaensis' dentition must have made it simple to cut its prey's flesh. Nonetheless, the animal was, perhaps, not an all-carnivore mammal.
Its molars are characterized by cone-shaped elevations, the same as the peaks of a mountain. Such cusps are specifically functional for perforating and destroying coverings of insects.
Therefore, they are found to, in the present time's insectivores. Nevertheless, the carnivore and insectivore teeth' combination is probably distinctive in this form.
Noticeable Cusps
According to the research, with findings published in the Scientific Reports journal, the cusps are noticeable in other ways. They practically have a similar size in molars, making the definition tremendously precise and effective.
The advantages, though, came a cost: minor changes in the cusps' structure would perhaps, have dramatically worsened the performance, particularly the one related to chewing.
This possibly "made it harder for dental apparatus to evolve," explained Dr. Jager. He also said this type of dentition is actually survived nearly unchanged in some lineages of evolutionary history over an 80-million-year period.
However, at some point, its owners turned out to be extinct, probably due to the fact that their teeth could not adjust to the changing food conditions.
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