500-Million-Year-Old “Worm-Like” Fossil Represents Rare Discovery of Ancient Animal in North America

Palaeoscolecid Fossil

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Researchers on the University of Missouri have discovered a uncommon, 500-million-year-old “worm-like” fossil referred to as a palaeoscolecid, which is an unusual fossil group in North America. Credit: University of Missouri

Scientists on the University of Missouri are utilizing an historic discover to unlock new clues surrounding the variety of species following the Cambrian explosion.

Many scientists take into account the “Cambrian explosion” — which occurred about 530-540 million years in the past — as the primary main look of lots of the world’s animal teams within the fossil document. Like including items to an enormous jigsaw puzzle, every discovery courting from this time interval has added one other piece to the evolutionary map of recent animals. Now, researchers on the University of Missouri have discovered a uncommon, 500-million-year-old “worm-like” fossil referred to as a palaeoscolecid, which is an unusual fossil group in North America. The researchers imagine this discover, from an space in western Utah, can assist scientists higher perceive how various the Earth’s animals have been through the Cambrian explosion.

Jim Schiffbauer, an affiliate professor of geological sciences within the MU College of Arts and Science and one of many examine’s co-authors, stated that whereas this fossil has the identical anatomical group as trendy worms, it doesn’t precisely match with something we see on trendy Earth.

“This group of animals are extinct, so we don’t see them, or any modern relatives, on the planet today,” Schiffbauer stated. “We tend to call them ‘worm-like’ because it’s hard to say that they perfectly fit with annelids, priapulids, or any other types of organism on the planet today that we would generally call a “worm.” But palaeoscolecids have the identical normal physique plan, which within the historical past of life has been an extremely profitable physique plan. So, it is a fairly cool addition as a result of it expands the variety of worm-like issues that we find out about from 500 million years in the past in North America and provides to our international occurrences and variety of the palaeoscolecids.”

Fossil’s Microscopic Plates

Images of the fossil’s microscopic plates from an scanning electron microscope. Credit: University of Missouri

At the time, this palaeoscolecid was possible dwelling on an ocean flooring, stated Wade Leibach, an MU graduate instructing assistant within the College of Arts and Science, and lead creator on the examine.

“It is the first known palaeoscolecid discovery in a certain rock formation — the Marjum Formation of western Utah — and that’s important because this represents one of only a few palaeoscolecid taxa in North America,” Leibach stated. “Other examples of this type of fossil have been previously found in much higher abundance on other continents, such as Asia, so we believe this find can help us better understand how we view prehistoric environments and ecologies, such as why different types of organisms are underrepresented or overrepresented in the fossil record. So, this discovery can be viewed from not only the perspective of its significance in North American paleontology, but also broader trends in evolution, paleogeography and paleoecology.”

Leibach, who switched his main from biology to geology after volunteering to work with the invertebrate paleontology collections on the University of Kansas, started this mission as an undergraduate scholar by analyzing a field of a few dozen fossils within the collections of the KU Biodiversity Institute. Initially, Leibach and one in every of his co-authors, Anna Whitaker, who was a graduate scholar at KU on the time and now’s on the University of Toronto-Mississauga, analyzed every fossil utilizing a lightweight microscope, which recognized at the very least one of many fossils to be a palaeoscolecid.

Leibach labored with Julien Kimmig, who was on the KU Biodiversity Institute on the time and is now at Penn State University, to find out that, so as to have the ability to affirm their preliminary findings, he would wish the assistance of further analyses supplied by subtle microscopy tools positioned on the MU X-ray Microanalysis Core, which is directed by Schiffbauer. Using the core facility at MU, Leibach centered his evaluation on the indentations left within the fossil by the traditional animal’s microscopic plates, that are attribute of the palaeoscolecids.

“These very small mineralized plates are usually nanometers-to-micrometers in size, so we needed the assistance of the equipment in Dr. Schiffbauer’s lab to be able to study them in detail because their size, orientation and distribution is how we classify the organism to the genus and species levels,” Leibach stated.

Leibach stated the group discovered a pair causes about why this specific fossil could also be present in restricted portions in North America as in comparison with different elements of the world. They are:

  • Geochemical limitations or totally different environments that could be extra predisposed to preserving a lot of these organisms.
  • Ecological competitors, which can have pushed the sort of organism to be much less aggressive or much less plentiful in sure areas.

The new taxon is called Arrakiscolex aasei after the fictional planet Arrakis within the novel “Dune” by Frank Herbert, which is inhabited by a species of armored worm and the collector of the specimens Arvid Aase.

Reference: “First palaeoscolecid from the Cambrian (Miaolingian, Drumian) Marjum Formation of western Utah” by Wade W. Leibach, Rudy Lerosey-Aubril, Anna F. Whitaker, James D. Schiffbauer and Julien Kimmig, 6 September 2021, Acta Palaeontologica Polonica.
DOI: 10.4202/app.00875.2021

The examine was printed in Acta Palaeontologica Polonica, a global quarterly journal which publishes papers from all areas of paleontology. Funding was supplied by a National Science Foundation CAREER grant (1652351), a National Science Foundation Earth Sciences Instrumentation and Facilities grant (1636643), a University of Kansas Undergraduate Research grant, a scholar analysis grant supplied by the South-Central Section of the Geological Society of America, and the J. Ortega-Hernández Laboratory for Invertebrate Palaeobiology at Harvard University. The examine’s authors wish to thank Arvid Aase and Thomas T. Johnson for donating the specimens analyzed within the examine.

Note: Palaeoscolecid is pronounced “pale-Eo-sko-les-sid.”

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