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Paleontologists at the Smithsonian National Museum of Natural History have discovered a previously unknown prehistoric species: a 270-million-year-old amphibian with wide eyes and a cartoonish smile, and its name refers to an iconic frog-like figure.
Kermit the Frog meets Kermitops for free, It is the latest ancient amphibian to be identified after examining a small fossilized skull that once sat unexamined in the Smithsonian fossil collection for 40 years, according to a paper published Thursday in the Journal of Zoology of the Linnean Society.
Kermitops, which predated dinosaurs, is thought to have roamed the lower Clear Fork Formation of Texas during the Early Permian Period, between 298.9 and 272.3 million years ago. The ancient amphibian’s skull, just over an inch (about 2.5 centimeters) long, has large oval eye sockets and a lopsided smile that researchers say reminded them of the Muppet icon because of its slightly squashed shape.
The discovery of the new amphibian species may provide some answers to how frogs and salamanders evolved to acquire their unique characteristics today, the authors wrote in the paper.
“What Kermitops really shows is that the origins of modern amphibians are a little more complex than some research suggests,” said study co-author Arjan Mann, a postdoctoral paleontologist at the Smithsonian National Museum of Natural History.
“And that really means that people should continue to study these issues, because looking at museum collections like this fossil has the potential to change our ideas about evolutionary hypotheses about living lineages.” The fossil was first unearthed in 1984 by museum paleontologist Nicholas Hotton IIII, who excavated the fossil from the Red Beds area in Texas, known to be rich in Permian age artifacts.
Kermitops not frog
The fossil was first unearthed in 1984 by museum paleontologist Nicholas Hotton IIII, who excavated the fossil from the Red Beds area in Texas, known to be rich in Permian age artifacts.
Researchers have uncovered a large cache at the site, including the remains of synapsids, the precursors of ancient reptiles, amphibians and mammals. The resulting collection contained so many finds that paleontologists were unable to examine some specimens, including the newly named Kermitops. That changed in 2021, when the skull came to the attention of Mann, then a postdoctoral researcher, who was examining the Texas collection to see if any notable specimens had been overlooked.
“(The skull) was not only well-prepared by someone, but it also had characteristics that set it apart from anything else I had seen in the group,” Mann said. Calvin So, the lead author of the new paper and a doctoral student at George Washington University, began studying the skull for a doctoral paper in early 2023.
Kermitops is not classified as a frog because prehistoric amphibians do not share the same features and anatomy as modern frogs, So said. But the researchers determined that the specimen was from the temnospondyls group, believed to be the most common ancestor of all lissamphibians; this category includes frogs, salamanders, and caecilians. Mann added.
Researchers noted many characteristics that ancient amphibians shared with their modern-day relatives; These include a similar location of the eardrum at the back of the skull, a small opening between the nostrils that produces a sticky mucus that helps frogs capture prey, and even evidence of the bicuspid, stalked teeth that are unique to amphibians and are found in most modern amphibian species.
Characteristics of ancient amphibians
The presence of teeth and other modern features of this prehistoric species could help researchers better understand the evolutionary transition amphibians went through to acquire their unique features, such as teeth, today. A June 2021 study found that some frog species lost and re-evolved their teeth several times throughout their lineage.
“This study is important because it reveals yet another distinct early distant relative of our modern amphibians,” said David Blackburn, co-author of the 2021 study and curator of amphibians and reptiles at the Florida Museum of Natural History at the University of Florida. , via email.
“The last 20 to 30 years have seen the discovery and description of many new species of these distant relatives, and each discovery tends to reshape our knowledge of the evolutionary tree,” Blackburn added.
However, Kermitops had many features that differed from its modern relatives. The creature’s intact skull likely had additional bones and elements that disappeared with evolution, and its long snout paired with a short region of the skull behind the eyes was unique to the species and likely served to help capture insects.
Marc Jones, curator of reptile fossils at London’s Natural History Museum, said the fossil’s features, a mix of modern and prehistoric features, strengthened previous claims that the evolution of amphibians was complex.
“This further increases the diversity of Early Permian animals, which are likely evolutionary cousins of modern amphibians. This underscores the need for more fossils from the Late Permian,” Jones said via email, adding that he appreciated the amphibian’s name. “It’s not a frog, but it’s not technically Kermit either. “He has five fingers and frills like a lizard.”
Preservation of small fossils
According to a news release published by the Smithsonian Institution, the first fossil records of lissamphibians are considered to be fragmentary, and it is stated that these records are largely due to the small size and delicate bone structure of the creatures, making the fossils difficult to preserve and find later. .
“What we see today is only a small percentage of everything that has ever lived in Earth history,” So added. “And one of the conditions that significantly enhances fossil preservation is their size, because if it is larger, it will be more resistant to some of the erosional forces that we experience, such as wind erosion and water erosion.”
What’s more, although prehistoric species are generally thought to be large, Kermitopes may help fill the gap in amphibian evolution and explain how some of today’s creatures reached small sizes.
The skull of Kermitops is similar in size to that of Gerobatrachus, another well-known Early Permian amphibian, with a head about an inch long (2.5 centimeters). But many frogs today have bodies shorter than that length, Blackburn said.
“’Weren’t there really very small vertebrates in the past that were similar in size to miniature species today?’ you may wonder. My bet is that yes, they existed, but our ability to find them in the fossil record is very elusive,” Blackburn added.
So they said they hoped the species’ name would draw attention to the remarkable discoveries paleontologists have made by examining museum collections of prehistoric fossils, including ones less spectacular than dinosaurs.
“We wanted to call it Kermitops because we wanted to draw attention to this unique fossil, which is really small and most people wouldn’t notice if you put it next to a Tyrannosaurus in the gallery,” So said.
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