An ancient snake's cheekbone illuminates the evolution of the modern snake skull: Critical insights into 100-million-year-old snakes provide insights into how modern snake heads have changed.
New research from a collaboration between the Argentinian and the University of Alberta paleontologist adds a new piece to the snake evolution puzzle.
Researchers have examined a remarkable preserved fossil of the late snake Najash rionegrina, located in Argentina. Studies show that nearly 100 million years ago, these legged snakes still have a cheekbone – also known as a jugal bone – that has all but disappeared from their modern descendants.
"Our findings support the idea that the ancestors of modern snakes are large and large and not large – instead of small inflow formulas as previously thought," explains Fernando Garberoglio, from the Fundación Azara at the Universidad Maimónides, in Buenos Aires, Argentina and is the lead author of the study. "The study also revealed that the first snakes kept their hindlimbs for an extended period before the origin of modern snakes was, for the most part, completely empty." limited fossil record. The new fossils presented in this study are important for the reconstruction of the first steps in the evolution of the history of modern snakes.
"This research is changing our understanding of jugal bone in snakes and not snakes," said Michael Caldwell, professor in the Department of Environmental Science and Earth and Atmospheric Sciences, and a co. -author of learning. "After 160 years of error, this paper corrects this important feature not based on prediction, but on empirical proof."
The nearly 100 million-year-old fossils described in this study, located in Northern Patagonia, are closely related to an ancient line of snakes surrounding the southern heminoot circles of Gondwana, and appears to be associated with a small number of vague, modern snakes. The researchers used micro-computed tomography (micro-CT) scans to visualize skeletal structures within the specimen, examining the pathways of the nerves and blood vessels as well as the structure of the skeleton. which is otherwise impossible to see without damaging the fossil. ] "This research is critical to understanding the evolution of the skulls of modern and ancient snakes," Caldwell added.
The paper, "New Skulls and Skeletons of the Cretaceous Legged Snake Najash, and the Evolution of the Modern Snake Body Plan," will be published in Science Advances .
DOI: 10.1126 / sciadv.aax5833
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