Creative reconstruction of Funcusvermis gilmorei (foreground) and the crocodile relative Acaenasuchus geoffreyi (background) in the tropical forest of Petrified Forest National Park about 220 million years ago. Art Work by Andrey Atuchin. Credit: Image courtesy of the National Park Service and the Petrified Forest Museum Association
New geosciences research study reveals Triassic fossils that expose origins of living amphibians.
A group of Virginia Tech paleontologists, led by doctoral prospect Ben Kligman, have found the very first Triassic-era caecilian fossils, the oldest-known of their kind, in Arizona. The discover helps fill an enormous space of approximately 90 million years in the historical record of caecilians where no fossils had actually been formerly found, confusing researchers.
The tiniest of newly discovered fossils can overthrow what paleontologists learn about our history.
A team of paleontologists from Virginia Tech and the U.S. Petrified Forest National Park, amongst others, have found the first “unmistakable” Triassic-era caecilian fossil– the oldest-known caecilian fossils– therefore extending the record of this small, burrowing mammal by approximately 35 million years. The find likewise fills a space of at least 87 million years in the known historical fossil record of the amphibian-like creature.
Prior to this brand-new research study, released today in the journal Nature, just 10 fossil caecilian occurrences were known, dating back to the Early Jurassic Period, about 183 million years back.” The discovery of the earliest caecilian fossils highlights the essential nature of new fossil evidence. “Fossil caecilians are extremely unusual, and they are found unintentionally when paleontologists are browsing for the fossils of other more typical animals. The discovery of the fossils was made in 2019 by Kligman and Petrified Forest National Park student intern Xavier Jenkins, now a Ph.D. student at Idaho State University, while the duo was processing fossiliferous sediment from the parks nicknamed Thunderstorm Ridge via a microscopic lense. Funcusvermis actually shares skeletal functions related more with early frog and salamander fossils, enhancing proof for a shared origin and close evolutionary relationship between caecilians and these 2 groups.
The fossil was first co-discovered by Ben Kligman, a doctoral trainee in the Department of Geosciences, part of the Virginia Tech College of Science, at Arizonas Petrified Forest National Park during a dig in 2019. Called by Kligman as Funcusvermis gilmorei, the fossil extends the history of caecilians 35 million years back to Triassic Period, roughly 250 million to 200 million years ago.
Microscopic photo of a lower jaw from Funcusvermis gilmorei not long after it was recovered throughout microscopic sorting of sediment from the Thunderstorm Ridge fossil site in the Petrified Forest National Park Paleontology Lab. Credit: Photo by Ben Kligman for Virginia Tech
Prior to this new study, released today in the journal Nature, just 10 fossil caecilian incidents were understood, going back to the Early Jurassic Period, about 183 million years back. Previous DNA research studies estimated evolutionary origins of caecilians back to the Carboniferous or Permian periods, some 370 million to 270 million years ago, according to Kligman, marking that 87-million-year space. However, no such fossils had been found.
” The discovery of the oldest caecilian fossils highlights the important nature of new fossil proof. “Fossil caecilians are extremely rare, and they are discovered unintentionally when paleontologists are searching for the fossils of other more common animals.
The discovery of the fossils was made in 2019 by Kligman and Petrified Forest National Park student intern Xavier Jenkins, now a Ph.D. student at Idaho State University, while the duo was processing fossiliferous sediment from the parks nicknamed Thunderstorm Ridge via a microscope. Funcusvermis was found in a layer of the Chinle Formation dated to approximately 220 million years back, when Arizona was positioned near the equator at the main part of the supercontinent Pangaea, Kligman said. This area at the time went through a hot, humid climate. Today, Arizona is still hot, but has low humidity.
Ben Kligman at the Thunderstorm Ridge fossil website at the National Petrified Forest in Arizona. Credit: Photo courtesy by Adam Marsh
” Seeing the very first jaw under the microscopic lense, with its distinct double row of teeth, sent out chills down my back,” Kligman said. “We instantly knew it was a caecilian, the earliest caecilian fossil ever discovered, and an once-in-a-lifetime discovery.”
Previous to this find, the 87-million-year space in the fossil record concealed the early evolutionary history of caecilians, causing a decades-long debate among scientists over the relationships of caecilians to their amphibian relatives, frogs and salamanders.
” Funcusvermis extends the humid equatorial pattern of occurrence seen in all understood fossil and living caecilians, recommending that the biogeographic history of caecilians has been guided by restriction to these environmental settings, likely due to physiological constraints connected to humidity, and constrained by the drift of continental plates into and out of the humid-equatorial zone after the fragmentation of Pangaea,” Kligman said.
Modern caecilians are limbless amphibians with cylindrical bodies with a compact, bullet-shaped skull that assists them burrow underground. Now exclusively house to South and Central America, Africa, and southern Asia, caecilians invest their lives burrowing in leaf-litter or soil browsing for prey such as bugs and worms. This underground existence has made studying caecilians difficult for researchers. Kligman, tongue in cheek, explains modern-day caecilians as an “eyeless sock puppet with the body of a worm.”
Funcusvermis in fact shares skeletal features related more with early frog and salamander fossils, reinforcing proof for a shared origin and close evolutionary relationship in between caecilians and these 2 groups. Funcusvermis likewise shares skeletal functions with an ancient group of amphibians understood to paleontologists as dissorophoid temnospondyls. Kligman adds, “Unlike living caecilians, Funcusvermis lacks lots of adaptations connected with burrowing underground, suggesting a slower acquisition of features associated with an underground way of life in the early stages of caecilian development.”
Call that tune
Now, heres the enjoyable part: The genus name Funcusvermis was motivated by the Ohio Players 1972 song “Funky Worm” from their album Pleasure, a favorite tune of the authors that was typically played while excavating fossils at Thunderstorm Ridge. Funcus is stemmed from the Latinized kind of the English word Funky for the upbeat, rhythmic kind of dance music, while vermis is stemmed from the Latin word for worm. (Its an outstanding tune, by the method. Instant earworm, so to speak.).
The species name, gilmorei, honors Ned Gilmore, the collections supervisor at the Academy of Natural Sciences of Philadelphias Drexel University. (Kligman is from Philadelphia and volunteered with Gilmores herpetology damp collection as an undergraduate student. “He was an important coach who helped influence my interest in amphibians and fossils,” Kligman said.).
Virginia Tech and Petrified Forest National Park Paleontologists digging at Thunderstorm Ridge in the summer of 2018. Credit: Photo by Ben Kligman.
Co-authors on the study include Michelle Stocker, an assistant teacher, and Sterling Nesbitt, an associate teacher, in the Virginia Tech Department of Geosciences and members of the Global Change Center that becomes part of the Fralin Life Sciences Institute. Other authors include Adam Marsh, lead paleontologist; Matthew Smith, museum curator; and William Parker, chief of science and resource management, all at the Petrified Forest National Park; and Bryan Gee, postdoctoral fellow at the University of Washingtons Burke Museum and Department of Biology.
” As the eponymous tune says, its the funkiest worm in the world,” Marsh quipped.
Stocker added, “What we gather actually determines what we can state about which animals that were present, the number of them there were, and what they looked like. Without using these techniques for fossil collection and analysis we would be losing out on understanding many important elements of this Triassic community. Now that we have a search picture of what bones to look for and how to try to find them, it will be interesting to see what other fossil regions preserve these early lissamphibians.”.
Nesbitt stated discovers such as this can reset the game board on paleontology, in the best sense of the phrase. “This discover clearly demonstrates that some fossils that you can hardly see can considerably alter our understanding of whole groups that you can see today,” he stated.
Whats occurred because 2019.
At the Petrified Forest National Park, where the initial discovery was found in 2019, the lower jaws of at least 70 individuals of Funcusvermis have been recovered as of summertime 2022, making the area “the most plentiful fossil caecilian-producing bonebed ever found,” Kligman said.
Just a handful of bones of Funcusvermis have been found, including upper and lower jaws, a vertebra, and part of a hind-limb, Kligman stated. All of the discovered bones were disarticulated, not as total skeletons. Without total skeletons, Kligman and his fellow scientists can not exactly determine the body length of Funcusvermis, however reasonings from separated aspects, such as the lower jaw being less than a quarter of an inch long, indicate that Funcusvermis was a tiny animal.
” Since its discovery in 2017, the Thunderstorm Ridge site has produced a varied assemblage of over 60 animals ranging from freshwater sharks to dinosaurs,” Kligman stated. “Several other new types discovered at this site have actually been recently described. Lots of other brand-new species from this website are currently under study and will be released in upcoming years.”.
To put it simply, fully expect more overthrowing of what paleontologists learn about the history of fossils.
Referral: “Triassic stem caecilian supports dissorophoid origin of living amphibians” by Ben T. Kligman, Bryan M. Gee, Adam D. Marsh, Sterling J. Nesbitt, Matthew E. Smith, William G. Parker and Michelle R. Stocker, 25 January 2023, Nature.DOI: 10.1038/ s41586-022-05646-5.