In a remarkable evolutionary discovery, a team of scientists co-led by a Virginia Tech geoscientist has discovered what could be among the first trails made by animals on the surface of the Earth roughly a half-billion years ago.

Shuhai Xiao, a professor of geosciences with the Virginia Tech College of Science, calls the unearthed fossils, including the bodies and trails left by an ancient animal species, the most convincing sign of ancient animal mobility, dating back about 550 million years. Named Yilingia spiciformis—that translates to spiky Yiling bug, Yiling being the Chinese city near the discovery site—the animal was found in multiple layers of rock by Xiao and Zhe Chen, Chuanming Zhou, and Xunlai Yuan from the Chinese Academy of Sciences’ Nanjing Institute of Geology and Palaeontology.

The findings are published in the latest issue of Nature. The trials are from the same rock unit and are roughly the same age as bug-like footprints found by Xiao and his team in a series of digs from 2013 to 2018 in the Yangtze Gorges area of southern China, and date back to the Ediacaran Period, well before the age of dinosaurs or even the Pangea supercontinent. What sets this find apart: The preserved fossil of the animal that made the trail versus the unknowable guesswork where the body has not been preserved.

“This discovery shows that segmented and mobile animals evolved by 550 million years ago,” Xiao said. “Mobility made it possible for animals to make an unmistakable footprint on Earth, both literally and metaphorically. Those are the kind of features you find in a group of animals called bilaterans. This group includes us humans and most animals. Animals and particularly humans are movers and shakers on Earth. Their ability to shape the face of the planet is ultimately tied to the origin of animal motility.”

The animal was a millipede-like creature a quarter-inch to an inch wide and up to 4 inches long that alternately dragged its body across the muddy ocean floor and rested along the way, leaving trails as loing as 23 inches. The animal was an elongated narrow creature, with 50 or so body segments, a left and right side, a back and belly, and a head and a tail.

The origin of bilaterally symmetric animals—known as bilaterians—with segmented bodies and directional mobility is a monumental event in early animal evolution, and is estimated to have occurred the Ediacaran Period, between 635 and 539 million years ago. But until this finding by Xiao and his team, there was no convincing fossil evidence to substantiate those estimates. One of the recovered specimens is particularly vital because the animal and the trail it produced just before its death are preserved together.

Remarkably, the find also marks what may be the first sign of decision making among animals—the trails suggest an effort to move toward or away from something, perhaps under the direction of a sophisticated central nerve system, Xiao said. The mobility of animals led to environmental and ecological impacts on the Earth surface system and ultimately led to the Cambrian substrate and agronomic revolutions, he said.

“We are the most impactful animal on Earth,” added Xiao, also an affiliated member of the Global Change Center at Virginia Tech. “We make a huge footprint, not only from locomotion, but in many other and more impactful activities related to our ability to move. When and how animal locomotion evolved defines an important geological and evolutionary context of anthropogenic impact on the surface of the Earth.”

Rachel Wood, a professor in the School of GeoSciences at University of Edinburgh in Scotland, who was not involved with the study, said, “This is a remarkable finding of highly significant fossils. We now have evidence that segmented animals were present and had gained an ability to move across the sea floor before the Cambrian, and more notably we can tie the actual trace-maker to the trace. Such preservation is unusual and provides considerable insight into a major step in the evolution of animals.”

Reference:
Death march of a segmented and trilobate bilaterian elucidates early animal evolution, Nature (2019). DOI: 10.1038/s41586-019-1522-7

Note: The above post is reprinted from materials provided by Virginia Tech.

After resting for decades in the storerooms of the Natural History Museum in London, a fragmentary fossil from the Late Triassic (200 million years ago) has been named as a new species by a Masters’ student at the University of Bristol.

Erin Patrick studied this creature for her MSc Palaeobiology dissertation research under the supervision of Professor Mike Benton and Dr. David Whiteside from Bristol’s School of Earth Sciences.

The fossil is one of several novel species named from Pant-y-ffynnon Quarry in Wales. It was found in the 1950s but has been ignored since then because it was so tiny and hard to study.

Most of the specimen is in two blocks of rock that fit together to form a lump that would sit on a child’s hand. On the surface are small bones, but it revealed its treasures when it was scanned. While no skull is present, these blocks contain a number of vertebrae, ribs, one scapula, and tiny armor plates from its back.

Using CT scanning, these tiny bones (some mere millimeters wide and long) could be studied in three-dimensional detail, allowing Erin to examine fossils otherwise hidden in the rock.

When she first saw the scans, Erin commented: “I was amazed. The rock and small fossils looked like nothing in particular, but the scans showed up fantastic detail. I worked on the images at ten times magnification to see all the minute features.”

When the fossil was found, its discoverers dubbed it “Edgar,” but as a new species it has now been given the formal name Aenigmaspina pantyffynnonensis.

The first part of the name refers to its enigmatic spine table, a feature of the vertebrae that supported the armor plates on the back. The second part of the name refers to Pant-y-ffynnon quarry in South Wales where it was found.

Erin added: “While creating the 3-D models, I was looking for anatomical features that would say what this new beast was.

“We could see it wasn’t a dinosaur, and the spine tables and armor plates put it on the crocodile side of the evolutionary tree.

“During the Triassic, there was a flurry of different reptile groups emerging related to modern crocodiles, but most of these were pretty huge and had special features not present in Aenigmaspina.”

Professor Benton said: “We were able to code Aenigmaspina for 100 or so characters and calculate its most likely position in the tree of life, but the answers were not 100 percent certain. It seems to be a relative of another little armored beast called Erpetosuchus known from the Late Triassic of north-east Scotland and the eastern United States.”

Dr. Whiteside said: “Erin’s work has added important knowledge to our understanding of Late Triassic faunas worldwide and particularly to the animals present in South Wales during that time.

“We know that Aenigmaspina lived on a small limestone island, part of a sub-tropical archipelago and this brings the number of major new species described from Pant-y-ffynnon quarry to four, two of which have been named by Bristol Masters students.”

Reference:
Erin L. Patrick et al. A new crurotarsan archosaur from the Late Triassic of South Wales, Journal of Vertebrate Paleontology (2019). DOI: 10.1080/02724634.2019.1645147

Note: The above post is reprinted from materials provided by University of Bristol.

Mapping the evolution of life on Earth requires a detailed understanding of the fossil record, and scientists are using synchrotron-based technologies to look back—way, way back—at the cell structure and chemistry of the earliest known woody plant.

Dr. Christine Strullu-Derrien and colleagues used the Canadian Light Source’s SM beamline at the University of Saskatchewan to study Armoricaphyton chateaupannense, an extinct woody plant that is about 400 million years old. Their research focused on lignin, an organic compound in the plant tracheids, elongated cells that help transport water and mineral salts. Lignin makes the cells walls rigid and less water permeable, thereby improving the conductivity of their vascular system.

Strullu-Derrien, a scientific associate at the Natural History Museum in London, England and the Natural History Museum in Paris, France, had described A. chateaupannense some years ago and returned to it for this project.

“Studies have been done previously on Devonian plants but they were not woody,” she said. “A. chateaupannense is the earliest known woody plant and it’s preserved in both 2-D form as flat carbonaceous films and 3-D organo-mineral structures. This allows for comparison to be done between the two types of preservation,” she said.

Although the fossils used in the study were collected in the Armorican Massif, a geologically significant region of hills and flatlands in western France, Strullu-Derrien said early Devonian woody plants have also been found in New Brunswick and the Gaspé area in Quebec “although these are 10 million years younger than the French one.”

One of the challenges in this kind of study is that the fossilization process modifies soft plant tissue, which alters or obscures its original biochemical structure and makes it difficult to precisely reconstruct the original chemistry. This study, however, aided by advanced visualization technologies, identified lignified cells in the fossils, suggesting the plant contained decay-resistant lignin compounds.

“Analyses show that both the 2-D and 3-D fossils have the same chemical composition, which is different than modern lignin, but the chemical signal of lignin is not completely lost in the fossilization process,” she said. Although the type of preservation of the plant fossils is not unique, “the combination of synchrotron methods used to study the structure and the chemistry of the wood at this level of detail is novel.”

The results of the research are in a paper entitled “On the Structure and Chemistry of Fossils of the Earliest Woody Plant,” published by Palaeontology.

Given how ubiquitous and important wood is as a structural component of modern plants, Strullu-Derrien’s investigation advances the knowledge around when and how wood first evolved. Yet, questions remain: “Wood first appears in small plants but did it have a different function than it does today in trees, for example?” posed Strullu-Derrien.

To find an answer, she will apply the same techniques used in this study on plants of other geological ages “to follow the evolution of their structure and to be able to find when, or in what condition of preservation, the remaining organic matter has kept a chemical signal of lignin.”

“Our study illustrates the capabilities of synchrotrons to investigate the early evolution of tissue systems in plants. It’s crucial to have access to these techniques to reach the level of resolution needed for getting chemical signals such as lignin. This represents a developing and promising area for the study of fossils that will complement the morpho-anatomical data and help to interpret the structures,” she said.

Reference:
Christine Strullu‐Derrien et al. On the structure and chemistry of fossils of the earliest woody plant, Palaeontology (2019). DOI: 10.1111/pala.12440

Note: The above post is reprinted from materials provided by Canadian Light Source.

It has long been thought that the brain size of anthropoid primates — a diverse group of modern and extinct monkeys, humans, and their nearest kin — progressively increased over time. New research on one of the oldest and most complete fossil primate skulls from South America shows instead that the pattern of brain evolution in this group was far more checkered. The study, published today in the journal Science Advances and led by researchers from the American Museum of Natural History, the Chinese Academy of Sciences, and the University of California Santa Barbara, suggests that the brain enlarged repeatedly and independently over the course of anthropoid history, and was more complex in some early members of the group than previously recognized.

“Human beings have exceptionally enlarged brains, but we know very little about how far back this key trait started to develop,” said lead author Xijun Ni, a research associate at the Museum and a researcher at the Chinese Academy of Sciences. “This is in part because of the scarcity of well-preserved fossil skulls of much more ancient relatives.”

As part of a long-term collaboration with John Flynn, the Museum’s Frick Curator of Fossil Mammals, Ni spearheaded a detailed study of an exceptional 20-million-year-old anthropoid fossil discovered high in the Andes mountains of Chile, the skull and only known specimen of Chilecebus carrascoensis.

“Through more than three decades of partnership and close collaboration with the National Museum of Chile, we have recovered many remarkable new fossils from unexpected places in the rugged volcanic terrain of the Andes,” Flynn said. “Chilecebus is one of those rare and truly spectacular fossils, revealing new insights and surprising conclusions every time new analytical methods are applied to studying it.”

Previous research by Flynn, Ni, and their colleagues on Chilecebus provided a rough idea of the animal’s encephalization, or the brain size relative to body size. A high encephalization quotient (EQ) signifies a large brain for an animal of a given body size. Most primates have high EQs relative to other mammals, although some primates — especially humans and their closest relatives — have even higher EQs than others. The latest study takes this understanding one step further, illustrating the patterns across the broader anthropoid family tree. The resulting “PEQ” — or phylogenetic encephalization quotient, to correct for the effects of close evolutionary relationships — for Chilecebus is relatively small, at 0.79. Most living monkeys, by comparison, have PEQs ranging from 0.86 to 3.39, with humans coming in at an extraordinary 13.46 and having expanded brain sizes dramatically even compared to nearest relatives. With this new framework, the researchers confirmed that cerebral enlargement occurred repeatedly and independently in anthropoid evolution, in both New and Old World lineages, with occasional decreases in size.

High-resolution x-ray computed tomography (CT) scanning and 3D digital reconstruction of the inside of Chilecebus’ skull gave the research team new insights into the anatomy of its brain. In modern primates, the size of the visual and olfactory centers in the brain are negatively correlated, reflecting a potential evolutionary “trade-off,” meaning that visually acute primates typically have weaker senses of smell. Surprisingly, the researchers discovered that a small olfactory bulb in Chilecebus was not counterbalanced by an amplified visual system. This finding indicates that in primate evolution the visual and olfactory systems were far less tightly coupled than was widely assumed.

Other findings: The size of the opening for the optic nerve suggests that Chilecebus was diurnal. Also, the infolding (sulcus) pattern of the brain of Chilecebus, although far simpler than in most modern anthropoids, possesses at least seven pairs of sulcal grooves and is surprisingly complex for such an ancient primate.

“During his epic voyage on the Beagle, Charles Darwin explored the mouth of the canyon where Chilecebus was discovered 160 years later. Shut out of the higher cordillera by winter snow, Darwin was inspired by ‘scenes of the highest interest’ his vista presented. This exquisite fossil, found just a few kilometers east of where Darwin stood, would have thrilled him,” said co-author André Wyss from the University of California Santa Barbara.

Reference:
Xijun Ni, John J. Flynn, André R. Wyss and Chi Zhang. Cranial endocast of a stem platyrrhine primate and ancestral brain conditions in anthropoids. Science Advances, 2019 DOI: 10.1126/sciadv.aav7913

Note: The above post is reprinted from materials provided by American Museum of Natural History.

In recent years, scientists have teased out many of the secrets of biomineralization, the process by which sea urchins grow spines, mollusks build their shells and corals make their skeletons, not to mention how mammals and other animals make bones and teeth.

The materials that animals make from scratch to build protective shells, razor sharp teeth, load-bearing bones and needlelike spines are some of the hardest and most durable substances known. The recipe for making those materials was one of nature’s closely held secrets, but powerful new analytical tools and microscopes have peeled back much of the mystery, showing, at the nanoscale, exactly how a wide array of animals use precisely the same mechanisms and starter chemicals to make the biomineral structures they depend on.

Now, in a report published today (Aug. 19, 2019) in the Proceedings of the National Academy of Sciences (PNAS), a team led by Pupa Gilbert, a University of Wisconsin–Madison professor of physics, shows that the recipe for making shells, spines, and coral skeletons is not only the same across many modern animal lineages, but is ancient—dating back 550 million years—and evolved independently more than once.

The findings are important because they help stitch together an evolutionary narrative of biomineralization. The fuller picture of a process ubiquitous to animal life on our planet not only tells us something important about our world, but the details may one day be harnessed by humans to produce harder, lighter, more durable materials; tools that never need sharpening; more faithful biomedical implants; and the possibility of human intervention in things like rebuilding the world’s coral reefs.

“The finding that biomineralization evolved independently multiple times, using the same mechanism, tells us that there is a strong physical or chemical reason for doing so,” says Gilbert, a world expert on the process of biomineralization. “If one organism starts making its biomineral that way, it outcompetes all others that either don’t make biomineral or make them differently, it doesn’t get eaten, and gets to transmit that good idea down the lineage.”

The new PNAS report builds on a series of seminal discoveries by Gilbert and her colleagues. In past studies, the Wisconsin physicist has shown that the process of biomineralizations works the same in vastly different classes of animals, ranging from mollusks like abalone, to echinoderms such as sea urchins, and to cnidaria, a large group of animals that includes corals, jellyfish, and sea anemones. These phyla, or broad groups of animals, have no common ancestor that was already biomineralizing, thus they must have evolved biomineralization mechanisms independently. Therefore, Gilbert says, “it is extremely surprising that when they started biomineralizing in the Cambrian (more than 500 million years ago) these three phyla started doing it in precisely the same way: using attachment of amorphous nanoparticles.”

“Biomineralization illustrates both the unity and diversity of nature,” explains Andrew Knoll, a professor of natural history and of Earth and planetary sciences at Harvard University, and a corresponding co-author of the new report. “Biomineralized skeletons may have evolved as many as twenty times within animals alone. That means that no two of these biomineralizing groups share a common ancestor that, itself, fashioned a biomineralized skeleton.”

Gilbert and her colleagues have shown that different biominerals form beginning with amorphous calcium carbonate nanoparticles, which are produced in cells and are the critical starter chemical for all of the materials that form in the biomineralization process, be it the nacre, or mother-of-pearl, that lines an abalone shell or the rock-grinding teeth of a sea urchin. “More than one biomineral forms by these amorphous precursor nanoparticles,” says Gilbert. “It doesn’t matter if it is a sea urchin spicule, a tooth, a spine, nacre, or coral. All of these systems have the same amorphous precursors.

“Amorphous calcium carbonate nanoparticles,” adds Gilbert, “are stabilized in confinement, and reversibly so. Thus, crystals don’t nucleate and grow at the wrong place and time, but they can and do at the right place and time, that is, on the growing surface of a shell, a coral skeleton, a sea urchin spine.”

The ability of many animals to make hard, protective or defensive structures, says Knoll, was likely a broad response to the evolution of carnivores, reflected in a “burst of biomineralization” seen in fossils from the Cambrian period, beginning some 541 million years ago.

The microscopic particles of calcium carbonate produced in animal cells are the same stuff that forms “lime” deposits in pipes and plumbing fixtures. In an animal, it is transformed at the site of biomineralization by attaching to the site and forming crystals in which individual atoms are neatly aligned to make a lattice, a scaffold of sorts for whatever structure an animal is building. The process has been teased out by Gilbert’s team using a novel microscope that employs the soft X-rays produced by synchrotron radiation to observe at the nanoscale how the structures come together as they are formed.

Gilbert’s team went back in time applying the same techniques to probe the deep fossil record in three distinct phyla, or broad groups of related animals, going as far back as 550 million years to sample the oldest known animal biomineral: the Cloudina skeleton with its characteristic series of funnels nestled into one another.

Gilbert notes that while animal remains undergo significant changes in the process of fossilization, the nanoparticle biomineralization signature remains intact and is observed by cracking open fossils and using a scanning electron microscope to probe the site of the fracture for the telltale signs of nanoparticles during the original crystallization process. “We stepped back in time as far as possible, to the very first fossils, and biomineralization by particle attachment looks the same as in modern animals.”

The biomineralization story unraveled by Gilbert and her colleagues may inform the development of novel materials useful for industry.

“We don’t know how to make amorphous calcium carbonate or any other material form a space-filling solid and then crystallize, but cells in marine organisms do,” Gilbert explains. “What we learn from them, we can reproduce in the lab and in industry, and make materials that are far better than the sum of their parts, as all biominerals are.”

Reference:
Pupa U. P. A. Gilbert et al. Biomineralization by particle attachment in early animals, Proceedings of the National Academy of Sciences (2019). DOI: 10.1073/pnas.1902273116

Note: The above post is reprinted from materials provided by University of Wisconsin-Madison.

Scientists could be set to reveal the most accurate depictions of ancient vertebrates ever made after a world-first discovery at University College Cork (UCC) in Ireland.

UCC palaeontologists have discovered a new way to reconstruct the anatomy of ancient vertebrate animals, analyzing the chemistry of fossilized melanosomes from internal organs.

The study, published today in the journal Proceedings of the National Academy of Sciences of the United States of America, was led by UCC’s Valentina Rossi and her supervisor Dr. Maria McNamara in collaboration with an international team of chemists from the US and Japan.

The team used cutting-edge synchrotron techniques to analyze the chemistry of the fossil and modern melanosomes using X-rays, allowing them to peer inside the anatomy of fossils and uncover hidden features.

Until recently, most studies on fossil melanin have focused on the skin and feathers, whereas here the pigment is linked to visible color. Unexpectedly, the new study also showed that melanin is abundant in internal organs of modern amphibians, reptiles, birds and mammals, and their fossil counterparts.

“This discovery is remarkable in that it opens up a new avenue for reconstructing the anatomy of ancient animals. In some of our fossils we can identify skin, lungs, the liver, the gut, the heart, and even connective tissue,” said senior author Dr. Maria McNamara.

“What’s more, this suggests that melanin had very ancient functions in regulating metal chemistry in the body going back tens, if not hundreds, of millions of years.”

The team made the initial discovery of internal melanosomes last year on fossil frogs. “After the pilot study, we had a hunch that these features would turn out to be more widespread across vertebrates. But we never guessed that the chemistry would be different in different organs,” Rossi said.

The advent of new synchrotron X-ray analysis techniques “allows us to harness the energy of really fast-moving electrons to detect minute quantities of different metals in the melanosomes.”

The fossils are so well-preserved that even the melanin molecule can be detected.

Reference:
Valentina Rossi et al. Tissue-specific geometry and chemistry of modern and fossilized melanosomes reveal internal anatomy of extinct vertebrates, Proceedings of the National Academy of Sciences (2019). DOI: 10.1073/pnas.1820285116

Note: The above post is reprinted from materials provided by University College Cork.