In their study, researcher William Deakin and his colleagues at the University of Bristol collected data on the shapes of some of the oldest jawbones discovered to date. They also created mathematical models of other types of jaws that might have existed early in their evolution.
Their goal was to understand how the gill arches, the structures that support the gills of fish, evolved from a respiratory role to a biting role.
The models allowed the British team to imagine a large number of jaw shapes that could have appeared early in vertebrate evolution. These jaws
theoretical were then tested for resistance (when biting) and speed (opening and closing efficiency).
In evolution, these two functions are usually traded off, meaning that increasing resistance usually results in decreasing speed, or vice versa.
Comparison of real and theoretical jaw shapes revealed that jaw evolution has been limited to shapes exhibiting the highest possible speed and force.explain in a press release the authors of this work published in the journal Science AdvancesHave (New window)Have (in English).
According to them, these results show that the first forms of jaws were optimized for rapid closure and resistance to stress, which suggests that they had a predatory feeding function.
” The oldest vertebrates exhibit jaws of all shapes and sizes, which have long been thought to reflect adaptation to different functions. Our study shows that most of these variations were also optimal for strength and speed, making them formidable predators. »
Subsequently, the shape of the jaws has continuously evolved by exploiting previously unoccupied morphological spaces. This evolution led, over time, to many differentiations that laid the foundations for a wide variety of feeding strategies and, ultimately, the great success of jawed vertebrates.
Prof. Emily Rayfield, also a co-author of the study, believes that the new software created by her colleague William Deakin to analyze the evolution of jawed vertebrates is unique.
It allows us to map the times of appearance of key anatomical innovations, such as the jaws, and to determine their functional properties. We plan to use it to uncover many more secrets of evolutionary history.she concludes.