The oddly shaped chompers, fingers and ear bones of an extinct reptile could tell us quite a bit about the resilience of life on Earth, according to a new study.
In fact, paleontologists from Yale, Sam Houston State University and the University of the Witwatersrand say the 250-million-year-old reptile known as Palacrodon, fills an important gap in our understanding of reptile evolution. It’s also a signal that reptiles, plants and ecosystems may have fared better or recovered faster than previously thought after a mass extinction wiped out most plant and animal species on the planet.
“We now know that Palacrodon descends from one of the last genera to branch off from the reptile tree of life before the evolution of modern reptiles,” said Kelsey Jenkins, a doctoral student in Yale’s Department of Earth and Planetary Sciences in the Faculty of Arts and Sciences and first author of the study, which appears in the Journal of Anatomy. “We know that too” Palacrodon lived in the wake of the most devastating mass extinction in Earth’s history.”
That would be the Permian-Triassic extinction, which happened 252 million years ago. Known as “the Great Dying”, it killed 70% of terrestrial species and 95% of marine species.
While a large number of reptile species eventually bounced back from this extinction, the details of how that happened are murky. Researchers have spent decades filling the gaps in our understanding of the key adaptations that allowed reptiles to thrive after the Permian-Triassic extinction — and what those adaptations might reveal about the ecosystems they lived in.
Palacrodon may help answer some of those questions, Jenkins said.
But first, she and her colleagues had to take a closer look at the tiny reptile.
What was known about it until recently? Palacrodon came from examining skull fragments from fossils found in South Africa and Arizona. However, the information extracted from those fossils was so limited that Palacrodon was omitted from most scientific analyzes of reptile evolution.
For the new study, Jenkins and her colleagues — including co-corresponding author Bhart-Anjan S. Bhullar, an assistant professor of Earth & planetary science at Yale and an assistant curator at the Yale Peabody Museum of Natural History — brought a new analytical approach to patience while investigating Palacrodon.
In particular, they used computed tomographic (CT) scanning and microscopy to get the most complete Palacrodon specimen, a fossil from Antarctica. Bhullar’s lab at Yale is best known for its innovative use of CT scanning and microscopy to create 3D images of fossils. (Jenkins and Bhullar also did fieldwork in South Africa and the US Southwest regarding) Palacrodon.)
Using the technology for this study, the researchers were able to obtain features of the reptile’s teeth, as well as other physical features. It revealed that Palacrodon’s teeth were best suited for grinding plant material and that the reptile was likely able to occasionally climb or cling to vegetation, they said.
“Palacrodon’s unusual teeth, and a few other specialized features of its anatomy, indicate that it was likely herbivorous or interacted in some way with plant life,” Jenkins said. “This indicates the early revival of plants, and more in general the revival of ecosystems after this mass extinction.”
Jenkins said the study points to the need for further examination of fossils from the period just after the Permian-Triassic extinction.
Tiny prehistoric lizard sheds light on reptile evolution
Kelsey M. Jenkins et al, Redescription of the early Triassic diapsid Palacrodon from the lower Fremouw Formation of Antarctica, Journal of Anatomy (2022). DOI: 10.1111/joa.13770
Quote: What Reptilian Bones Can Teach Us About Earth’s Dangerous Past (2022, October 1), retrieved October 1, 2022 from https://phys.org/news/2022-10-reptile-bones-earth-perilous .html
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