Synchrotron infrared analysis helps reveal that enigmatic Devonian fossils were not fungi, but members of a previously unknown lineage of complex life
Researchers studying one of palaeontology’s longest-running mysteries have shown that Prototaxites, giant column-like fossils that dominated Earth’s earliest terrestrial landscapes, do not belong to the fungal kingdom, as long suspected. Instead, new evidence suggests they represent a completely distinct and now extinct branch of complex eukaryotic life.
The findings, published in Science Advances, were supported by experiments carried out on Diamond’s B22 infrared microspectroscopy beamline.
A 400-million-year-old puzzle
Prototaxites fossils date back more than 400 million years to the early Devonian period and could reach several metres in height, making them the largest known organisms on land at the time. They are typically preserved as massive, trunk-like columns found in some of the earliest terrestrial ecosystems, long before trees had evolved. For over 160 years, scientists have debated their biological identity, with fungi long considered the most likely explanation due to their tubular internal structure and lack of obvious plant features.
Most people picture the time of dinosaurs as a steamy, tropical world. But during the Late Cretaceous period, northern Alaska was a different kind of wild. Located far above the Arctic Circle, it endured months of winter darkness and freezing temperatures – even as much of the planet remained warm. Think sub-Arctic Canada today: cold, wet and seasonal.
A diverse, international team of scientists has now uncovered a remarkable discovery: the world’s oldest known relatives of salmon and carp lived in this extreme environment.
Using the latest in 3D imaging technology, Lisa Van Loon and Neil Banerjee from Western and their collaborators analyzed fossilized fish bones found in the rocks of the Prince Creek Formation in Alaska to reveal a previously undiscovered polar ecosystem. The findings were published May 7 in the journal Papers in Paleontology.
“The synchrotron allowed us to virtually reconstruct these fish in 3D, bone by bone. It’s an incredible example of how modern imaging tools are unlocking secrets from the deep past.”— Lisa Van Loon, adjunct research professor, Western
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“These discoveries suggest this remote region may have been an evolutionary launchpad for fish that now dominate northern rivers and lakes worldwide,” said Van Loon, adjunct research professor in the departments of Earth sciences and anthropology at Western.
Some of the fossils discovered in Alaska were barely larger than a pin head and were deeply embedded in rock. Traditional fossil preparation, which involves carefully removing surrounding sediment by hand, wasn’t an option; the specimens were simply too fragile.
Using synchrotron micro-computed tomography (micro-CT) scanning technology at the Advanced Proton Source, with support from the Canadian Light Source, researchers scanned the fossil-bearing rocks without physically disturbing them. The ultra-bright, high-resolution X-ray beams allowed them to digitally reconstruct the anatomy of these ancient fish in 3D, revealing intricate structures such as jaws, teeth and fin rays in remarkable detail.
“Many of these fossils were so delicate and deeply encased in rock that traditional preparation would have destroyed them,” said Banerjee, an Earth sciences professor at Western. “Using synchrotron micro-CT scanning, we were able to peer inside the rock in extraordinary detail – resolving tiny jaw bones and teeth without laying a chisel on them. This technology has completely transformed how we study ancient life.”
The scans made it possible to identify entirely new species, some of which represent the earliest-known members of fish groups that today dominate northern rivers and lakes, such as salmon, carp and pike.
Sivulliusalmo alaskensis, meaning “first salmon of Alaska” in Iñupiaq, is now the earliest known member of the salmon family, eclipsing previous records by nearly 10 million years. The earliest known cypriniform, part of the same group as today’s minnows and carp, was also found, marking its first appearance in North America (as they were previously only found in Asia and Europe).
Newly found species of pike-like fish also lived at Prince Creek Formation, some 73 million years ago, including Archaeosiilik gilmulli and Nunikuluk gracilis, as they successfully adapted to the Arctic’s long winters. Sharks like Squatina (a relative of angel sharks), sturgeon and paddlefish, were also revealed within the fossil samples.
“The synchrotron allowed us to virtually reconstruct these fish in 3D, bone by bone,” said Van Loon. “It’s an incredible example of how modern imaging tools are unlocking secrets from the deep past.”
The feathered limbs, pointed teeth and sharp claws of the oldest known bird-like dinosaurs, the Archaeopteryx, have fascinated naturalists and palaeontologists including Charles Lyell and Charles Darwin who propelled the species to fame especially following publication of his theory of evolution.
So, when a precious 150-million-year-old Ostromia crassipes fossil – formerly known as a specimen of Archaeopteryx – arrived at Diamond Light Source in a high security operation, it naturally caused a great deal of excitement. The rare fossil, which is usually housed at the renowned Teylers Museum in the Netherlands, was brought to Diamond so scientists and students could discover more about its features, including the colour of its feathers. The specimen was studied on the I18 beamline, using its microfocus X-ray, and this was the first time it had been examined in such detail.
Collection manager at the museum, Tim de Zeeuw, described the fossil as the Mona Lisa of the museum’s collection. The Jurassic fossil is so precious, it was secretly brought to the UK by a special transport team and was kept under lock and key around the clock, even while on the beamline at Diamond.
The new research will be the subject of a forthcoming paper and is a collaboration between the University of Utrecht and Teylers Museum. Lead author, Edgar Mulder, a master’s student at the university explained that it was a bit of dream come true to get time to examine the fossil at Diamond and the team worked through the night to get as much information as possible.
The fossil was found in Jachenhausen, a village in southeastern Germany in 1855. When it was discovered, it was thought to be a pterosaur until 1970 when it was identified as an Archaeopteryx.
Professor Dr Anne S. Schulp at the University of Utrecht, said,
In 2017, it was concluded that this sample was more closely related to the Chinese Anchiornis and given the name Ostromia. This new research at Diamond is helping to further determine its features. It is particularly important as the Archaeopteryx and other ‘early birds’ play a key role in the origin of birds.
The Archaeopteryx is called the ‘first true bird’ and is about the same size as a magpie at around 20 inches from head to tail. This Ostromia fossil shows the knee region, part of the wing, claws, ribs, lower stomach bones, and feather imprints.
This week palaeontologists from Curtin University announced that a specimen from the collection of the Australian Age of Dinosaurs Museum in Winton Queensland as the first near complete skull of a sauropod, a massive, long-tailed, long-necked, small-headed plant-eating dinosaur, found in Australia and other parts of the world.
The team took 3D images of the entire group of skull fragments, of which a small piece, the premaxilla bone, was scanned in higher detail on the Imaging and Medical beamline at ANSTO’s Australian Synchrotron.
Instrument beamline scientists Dr Chris Hall and Dr Anton Maksimenko assisted with the IMBL measurements and data processing respectively.
“The synchrotron imaging confirmed there were replacement teeth inside the premaxillary bone,” said Senior Instrument scientist Dr Joseph Bevitt, who often assists palaeontologists’ with neutron scanning of fossils at the Australian Centre for Neutron Scattering and the IMBL instrument at the Australian Synchrotron.
