The world of the dinosaurs just got a bit more bizarre with a newly discovered species of freshwater shark whose tiny teeth resemble the alien ships from the popular 1980s video game Galaga.

Unlike its gargantuan cousin the megalodon, Galagadon nordquistae was a small shark (approximately 12 to 18 inches long), related to modern-day carpet sharks such as the “whiskered” wobbegong. Galagadon once swam in the Cretaceous rivers of what is now South Dakota, and its remains were uncovered beside “Sue,” the world’s most famous T. rex fossil.

“The more we discover about the Cretaceous period just before the non-bird dinosaurs went extinct, the more fantastic that world becomes,” says Terry Gates, lecturer at North Carolina State University and research affiliate with the North Carolina Museum of Natural Sciences. Gates is lead author of a paper describing the new species along with colleagues Eric Gorscak and Peter J. Makovicky of the Field Museum of Natural History.

“It may seem odd today, but about 67 million years ago, what is now South Dakota was covered in forests, swamps and winding rivers,” Gates says. “Galagadon was not swooping in to prey on T. rex, Triceratops, or any other dinosaurs that happened into its streams. This shark had teeth that were good for catching small fish or crushing snails and crawdads.”

The tiny teeth — each one measuring less than a millimeter across — were discovered in the sediment left behind when paleontologists at the Field Museum uncovered the bones of “Sue,” currently the most complete T. rex specimen ever described. Gates sifted through the almost two tons of dirt with the help of volunteer Karen Nordquist, whom the species name, nordquistae, honors. Together, the pair recovered over two dozen teeth belonging to the new shark species.

“It amazes me that we can find microscopic shark teeth sitting right beside the bones of the largest predators of all time,” Gates says. “These teeth are the size of a sand grain. Without a microscope you’d just throw them away.”

Despite its diminutive size, Gates sees the discovery of Galagadon as an important addition to the fossil record. “Every species in an ecosystem plays a supporting role, keeping the whole network together,” he says. “There is no way for us to understand what changed in the ecosystem during the mass extinction at the end of the Cretaceous without knowing all the wonderful species that existed before.”

Gates credits the idea for Galagadon’s name to middle school teacher Nate Bourne, who worked alongside Gates in paleontologist Lindsay Zanno’s lab at the N.C. Museum of Natural Sciences.

Reference:
Terry A. Gates, Eric Gorscak, Peter J. Makovicky. New sharks and other chondrichthyans from the latest Maastrichtian (Late Cretaceous) of North America. Journal of Paleontology, 2019; 1 DOI: 10.1017/jpa.2018.92

Note: The above post is reprinted from materials provided by North Carolina State University.

A new study throws into question the notion that today’s crocodiles and alligators have a simple evolutionary past.

Previous research has pointed to crocodiles and alligators starting with a land-based ancestor some 200 million years ago and then moving to fresh water, becoming the semi-aquatic ambush predators they are today.

But a new analysis, published online today in the journal Scientific Reports, offers a different story. Modern crocodiles and alligators came from a variety of surroundings beginning in the early Jurassic Period, and various species occupied a host of ecosystems over time, including land, estuarine, freshwater and marine.

As University of Iowa researcher and study co-author Christopher Brochu says, “Crocodiles are not living fossils. Transitions between land, sea, and freshwater were more frequent than we thought, and the transitions were not always land-to-freshwater or freshwater-to-marine.”

Brochu and colleagues from Stony Brook University pieced together crocodile and alligator ancestry by analyzing a large family tree showing the evolutionary history of living and extinct crocodylomorphs (modern crocodiles and alligators and their extinct relatives). The team was then able to predict the ancestral habitat for several divergence points on the evolutionary tree.

This suggests a complex evolutionary history not only of habitat, but of form. Those living at sea had paddles instead of limbs, and those on land often had hoof-like claws and long legs. These did not all evolve from ancestors that looked like modern crocodiles, as has long been assumed.

Reference:
Eric W. Wilberg, Alan H. Turner, Christopher A. Brochu. Evolutionary structure and timing of major habitat shifts in Crocodylomorpha. Scientific Reports, 2019; 9 (1) DOI: 10.1038/s41598-018-36795-1

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

Paleontologists at the University of Chicago have discovered the first detailed fossil of a hagfish, the slimy, eel-like carrion feeders of the ocean. The 100-million-year-old fossil helps answer questions about when these ancient, jawless fish branched off the evolutionary tree from the lineage that gave rise to modern-day jawed vertebrates, including bony fish and humans.

The fossil, named Tethymyxine tapirostrum,is a 12-inch long fish embedded in a slab of Cretaceous period limestone from Lebanon. It fills a 100-million-year gap in the fossil record and shows that hagfish are more closely related to the blood-sucking lamprey than to other fishes. This means that both hagfish and lampreys evolved their eel-like body shape and strange feeding systems after they branched off from the rest of the vertebrate line of ancestry about 500 million years ago.

“This is a major reorganization of the family tree of all fish and their descendants. This allows us to put an evolutionary date on unique traits that set hagfish apart from all other animals,” said Tetsuto Miyashita, PhD, a Chicago Fellow in the Department of Organismal Biology and Anatomy at UChicago who led the research. The findings are published this week in the Proceedings of the National Academy of Sciences.

The slimy dead giveaway

Modern-day hagfish are known for their bizarre, nightmarish appearance and unique defense mechanism. They don’t have eyes, or jaws or teeth to bite with, but instead use a spiky tongue-like apparatus to rasp flesh off dead fish and whales at the bottom of the ocean. When harassed, they can instantly turn the water around them into a cloud of slime, clogging the gills of would-be predators.

This ability to produce slime is what gave away the Tethymyxine fossil. Miyashita used an imaging technology called synchrotron scanning at Stanford University to identify chemical traces of soft tissue that were left behind in the limestone when the hagfish fossilized. These soft tissues are rarely preserved, which is why there are so few examples of ancient hagfish relatives to study.

The scanning picked up a signal for keratin, the same material that makes up fingernails in humans. Keratin, as it turns out, is a crucial part of what makes the hagfish slime defense so effective. Hagfish have a series of glands along their bodies that produce tiny packets of tightly-coiled keratin fibers, lubricated by mucus-y goo. When these packets hit seawater, the fibers explode and trap the water within, turning everything into shark-choking slop. The fibers are so strong that when dried out they resemble silk threads; they’re even being studied as possible biosynthetic fibers to make clothes and other materials.

Miyashita and his colleagues found more than a hundred concentrations of keratin along the body of the fossil, meaning that the ancient hagfish probably evolved its slime defense when the seas included fearsome predators such as plesiosaurs and ichthyosaurs that we no longer see today.

“We now have a fossil that can push back the origin of the hagfish-like body plan by hundreds of millions of years,” Miyashita said. “Now, the next question is how this changes our view of the relationships between all these early fish lineages.”

Shaking up the vertebrate family tree

Features of the new fossil help place hagfish and their relatives on the vertebrate family tree. In the past, scientists have disagreed about where they belonged, depending on how they tackled the question. Those who rely on fossil evidence alone tend to conclude that hagfish are so primitive that they are not even vertebrates. This implies that all fishes and their vertebrate descendants had a common ancestor that — more or less — looked like a hagfish.

But those who work with genetic data argue that hagfish and lampreys are more closely related to each other. This suggests that modern hagfish and lampreys are the odd ones out in the family tree of vertebrates. In that case, the primitive appearance of hagfish and lampreys is deceptive, and the common ancestor of all vertebrates was probably something more conventionally fish-like.

Miyashita’s work reconciles these two approaches, using physical evidence of the animal’s anatomy from the fossil to come to the same conclusion as the geneticists: that the hagfish and lampreys should be grouped separately from the rest of fishes.

“In a sense, this resets the agenda of how we understand these animals,” said Michael Coates, PhD, professor of organismal biology and anatomy at UChicago and a co-author of the new study. “Now we have this important corroboration that they are a group apart. Although they’re still part of vertebrate biodiversity, we now have to look at hagfish and lampreys more carefully, and recognize their apparent primitiveness as a specialized condition.

Paleontologists have increasingly used sophisticated imaging techniques in the past few years, but Miyashita’s research is one of a handful so far to use synchrotron scanning to identify chemical elements in a fossil. While it was crucial to detect anatomical structures in the hagfish fossil, he believes it can also be a useful tool to help scientists detect paint or glue used to embellish a fossil or even outright forge a specimen. Any attempt to spice up a fossil specimen leaves chemical fingerprints that light up like holiday decorations in a synchrotron scan.

“I’m impressed with what Tetsuto has marshaled here,” Coates said. “He’s maxed out all the different techniques and approaches that can be applied to this fossil to extract information from it, to understand it and to check it thoroughly.”

The study, “A Hagfish from the Cretaceous Tethys Sea and a Reconciliation of the Morphological-Molecular Conflict in Early Vertebrate Phylogeny,” was supported by the National Science Foundation and the National Science and Engineering Research Council (Canada). Additional authors include Robert Farrar and Peter Larson from the Black Hills Institute of Geological Research; Phillip Manning and Roy Wogelius from the University of Manchester; Nicholas Edwards and Uwe Bergmann from the SLAC National Accelerator Laboratory; Jennifer Anné from the Children’s Museum of Indianapolis; and Richard Palmer and Philip Currie from the University of Alberta.

Note: The above post is reprinted from materials provided by University of Chicago Medical Center. Original written by Matt Wood.

How did the earliest land animals move? Scientists have used a nearly 300-million-year old fossil skeleton and preserved ancient footprints to create a moving robot model of prehistoric life.

Evolutionary biologist John Nyakatura at Humboldt University in Berlin has spent years studying a 290-million-year-old fossil dug up in central Germany’s Bromacker quarry in 2000. The four-legged plant-eater lived before the dinosaurs and fascinates scientists “because of its position on the tree of life,” said Nyakatura. Researchers believe the creature is a “stem amniote”—an early land-dwelling animal that later evolved into modern mammals, birds and reptiles.

Scientists believe the first amphibious animals emerged on land 350 million years ago and the first amniotes emerged around 310 million years ago.

The fossil, called Orabates pabsti, is a “beautifully preserved and articulated skeleton,” said Nyakatura. What’s more, scientists have previously identified fossilized footprints left by the 3-foot-long (90 cm) creature.

Nyakatura teamed up with robotics expert Kamilo Melo at the Swiss Federal Institute of Technology in Lausanne to develop a model of how the creature moved. Their results were published Wednesday in the journal Nature.

The researchers built a life-size replica of the prehistoric beast—”we carefully modeled each and every bone,” said Nyakatura—and then tested the motion in various ways that would lead its gait to match the ancient tracks, ruling out combinations that were not anatomically possible.

They repeated the exercise with a slightly-scaled up robot version , which they called OroBOT. The robot is made of motors connected by 3D-printed plastic and steel parts. The model “helps us to test real-world dynamics, to account for gravity and friction,” said Melo. The team also compared their models to living animals, including salamanders and iguanas.

Technology such as robotics, computer modeling and CT scans are transforming paleontology, “giving us ever more compelling reconstructions of the past,” said Andrew Farke, curator at the Raymond M. Alf Museum of Paleontology in Claremont, California, who was not involved in the study.

Based on the robot model, the scientists said they think the creature had more advanced locomotion than previously thought for such an early land animal. (Think more scampering than slithering.)

“It walked with a fairly upright posture,” said Melo. “It didn’t drag its belly or tail.”

University of Maryland paleontologist Thomas R. Holtz, who was not involved in the study, said the research suggests “an upright stance goes further back than we originally thought.”

Stuart Sumida, a paleontologist at California State University in San Bernardino and part of the initial team that excavated Orobates fossils, called it “an exciting study.” Sumida, who was not involved in the robot project, said the work provided “a much more confident window in to what happened long ago. It isn’t a time machine, but Nyakatura and colleagues have given us a tantalizing peek.”

Reference:
John A. Nyakatura et al. Reverse-engineering the locomotion of a stem amniote, Nature (2019). DOI: 10.1038/s41586-018-0851-2

Note: The above post is reprinted from materials provided by The Associated Press.

It has long been known that a quarry near the Dutch town of Winterswijk is an Eldorado for fossil lovers. But even connoisseurs will be surprised just how outstanding the site actually is. A student at the University of Bonn, himself a Dutchman and passionate fossil collector, has now analyzed pieces from museums and private collections for his master’s thesis. He found an amazing amount of almost completely preserved skeletons, all between 242 and 247 million years old. The good condition is presumably due to particularly favorable development conditions. These make Winterswijk, which belongs to the so-called Germanic Basin, a cornucopia for paleontology. The study is published in the Paläontologische Zeitschrift.

Jelle Heijne examined exactly 327 remains of marine reptiles for his master’s thesis — collected partly from public museums, but primarily from about 20 private collections. He was particularly impressed by the high quality of the finds: “Among them were more than 20 contiguous skeletons,” he emphasizes. “Only very few complete skeleton finds are known from the other sites of the Germanic Basin, which stretches from England to Poland.”

In his study, the 25-year-old investigated the question of why the bones, which are over 240 million years old, have been preserved so well here. The reason is probably a combination of fortunate circumstances: At that time the Germanic Basin was a sea, which was extremely shallow in today’s Winterswijk. This is illustrated by the fossil footprints of terrestrial animals that were found not far from the reptile bones. The region probably resembled today’s Wadden Sea of the North Sea coast, but with a bottom that was not sandy but covered in lime silt.

The shallow depth ensured that cadavers quickly hit the ground, where they were then covered by sediment. If dead animals float in the water for a long time and are tossed back and forth by waves and currents, the probability increases that body parts, such as tail, limbs or head, are lost.

Another important factor was a process called “Stick’n’Peel” by paleontologists: The animal is colonized by microorganisms and algae that hold the skeleton together like a skin. “It was probably these two factors in particular that favored the occurrence of well-preserved finds,” explains Heijne.

In fact, there is some evidence for the Stick’n’Peel hypothesis. For example, some skeletons lack individual larger bones, while the small bones are complete — even though the latter are usually most likely to be carried away by the water. “Such unusual patterns typically occur when a skeleton is unevenly colonized and thus protected,” Heijne explains.

It has long been known that Winterswijk stands out among the sites of the Germanic Basin. Nevertheless, the large number of high-quality finds is likely to surprise even connoisseurs, especially since most of the finds are not accessible to the public. “I have been a member of an association of private collectors in the Netherlands for years,” Heijne explains. This was the ideal contact exchange for his study: “The collectors I approached were all proud to be able to contribute to the research on Winterswijk.”

Reference:
Jelle Heijne, Nicole Klein, P. Martin Sander. The uniquely diverse taphonomy of the marine reptile skeletons (Sauropterygia) from the Lower Muschelkalk (Anisian) of Winterswijk, The Netherlands. PalZ, 2019; DOI: 10.1007/s12542-018-0438-0

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

The first appearance of trilobites in the fossil record dates to 521 million years ago in the oceans of the Cambrian Period, when the continents were still inhospitable to most life forms. Few groups of animals adapted as successfully as trilobites, which were arthropods that lived on the seabed for 270 million years until the mass extinction at the end of the Permian approximately 252 million years ago.

The longer ago organisms lived, the more rare are their fossils and the harder it is to understand their way of life; paleontologists face a daunting task in endeavoring to establish evolutionary relationships in time and space.

Surmounting the difficulties inherent in the investigation of a group of animals that lived such a long time ago, Brazilian scientists affiliated with the Biology Department of São Paulo State University’s Bauru School of Sciences (FC-UNESP) and the Paleontology Laboratory of the University of São Paulo’s Ribeirão Preto School of Philosophy, Science and Letters (FFCLRP-USP) have succeeded for the first time in inferring paleobiogeographic patterns among trilobites.

Paleobiogeography is a branch of paleontology that focuses on the distribution of extinct plants and animals and their relations with ancient geographic features. The study was conducted by Fábio Augusto Carbonaro, a postdoctoral researcher at UNESP’s Bauru Macroinvertebrate Paleontology Laboratory (LAPALMA) headed by Professor Renato Pirani Ghilardi. Other participants included Max Cardoso Langer, a professor at FFCLRP-USP, and Silvio Shigueo Nihei, a professor at the same university’s Bioscience Institute (IB-USP).

The researchers analyzed the morphological differences and similarities of the 11 species of trilobites described so far in the genus Metacryphaeus; these trilobites lived during the Devonian between 416 million and 359 million years ago (mya) in the cold waters of the sea that covered what is now Bolivia, Peru, Brazil, the Malvinas (Falklands) and South Africa.

The Devonian Period is subdivided into seven stages. Metacryphaeus lived during the Lochkovian (419.2-410.8 mya) and Pragian (410.8- 407.6 mya) stages, which are the earliest Devonian stages.

The results of the research were published in Scientific Reports and are part of the project “Paleobiogeography and migratory routes of paleoinvertebrates of the Devonian in Brazil,” which is supported by São Paulo Research Foundation -FAPESP and Brazil’s National Council for Scientific and Technological Development (CNPq). Ghilardi is the project’s principal investigator.

“When they became extinct in the Permian, 252 million years ago, the trilobites left no descendants. Their closest living relatives are shrimps, and, more remotely, spiders, scorpions, sea spiders and mites,” Ghilardi said.

Trilobite fossils are found abundantly all over the world, he explained — so abundantly that they are sometimes referred to as the cockroaches of the sea. The comparison is not unwarranted because anatomically, the trilobites resemble cockroaches. The difference is that they were not insects and had three longitudinal body segments or lobes (hence the name).

In the northern hemisphere, the trilobite fossil record is very rich. Paleontologists have so far described ten orders comprising over 17,000 species. The smallest were 1.5 millimeters long, while the largest were approximately 70 cm long and 40 cm wide. Perfectly preserved trilobites can be found in some regions, such as Morocco. These can be beautiful when used to create cameos or intaglio jewelry. Trilobite fossils from Brazil, Peru and Bolivia, in contrast, are often poorly preserved, consisting merely of the impressions left in benthic mud by their exoskeletons.

“Although their state of preservation is far from ideal, there are thousands of trilobite fossils in the sediments that form the Paraná basin in the South region of Brazil, and the Parnaíba basin along the North-Northeast divide,” said Ghilardi, who also chairs the Brazilian Paleontology Society.

According to Ghilardi, their poor state of preservation could be due to the geological conditions and climate prevailing in these regions during the Paleozoic Era, when the portions of dry land that would one day form South America were at the South Pole and entirely covered by ice for prolonged periods.

During the Devonian, South America and Africa were connected as part of the supercontinent Gondwana. South Africa was joined with Uruguay and Argentina in the River Plate region, and Brazil’s southern states were continuous with Namibia and Angola.

Parsimonious analysis

The research began with an analysis of 48 characteristics (size, shape and structure of organs and anatomical parts) found in some 50 fossil specimens of the 11 species of Metacryphaeus.

“In principle, these characteristics serve to establish their phylogeny — the evolutionary history of all species in the universe, analyzed in terms of lines of descent and relationships among broader groups,” Ghilardi said.

Known as a parsimonious analysis, this method is widely used to establish relationships among organisms in a given ecosystem, and in recent years, it has also begun to be used in the study of fossils.

According to Ghilardi, parsimony, in general, is the principle that the simplest explanation of the data is the preferred explanation. In the analysis of phylogeny, it means that the hypothesis regarding relationships that requires the smallest number of characteristic changes between the species analyzed (in this case, trilobites of the genus Metacryphaeus) is the one that is most likely to be correct.

The biogeographic contribution to the study was made by Professor Nihei, who works at IB-USP as a taxonomist and insect systematist. The field of systematics is concerned with evolutionary changes between ancestries, while taxonomy focuses on classifying and naming organisms.

“Biogeographic analysis typically involves living groups the ages of which are estimated by molecular phylogeny, or the so-called molecular clock, which estimates when two species probably diverged on the basis of the number of molecular differences in their DNA. In this study of trilobites, we used age in a similar manner, but it was obtained from the fossil record,” Nihei said.

“The main point of the study was to use fossils in a method that normally involves molecular biogeography. Very few studies of this type have previously involved fossils. I believe our study paves the way for a new approach based on biogeographic methods requiring a chronogram [a molecularly dated cladogram] because this chronogram can also be obtained from fossil taxa such as those studied by paleontologists, rather than molecular cladograms for living animals.”

As a vertebrate paleontologist who specializes in dinosaurs, Langer acknowledged that he knows little about trilobites but a great deal about the modern computational techniques used in parsimonious analysis, on which his participation in the study was based. “I believe the key aspect of this study, and the reason it was accepted for publication in as important a journal as Scientific Reports, is that it’s the first ever use of parsimony to understand the phylogeny of a trilobite genus in the southern hemisphere,” he said.

Gondwanan dispersal

The results of the paleobiogeographical analyses reinforce the pre-existing theory that Bolivia and Peru formed the ancestral home of Metacryphaeus.

“The models estimate a 100% probability that Bolivia and Peru formed the ancestral area of the Metacryphaeus clade and most of its internal clades,” Ghilardi said. Confirmation of the theory shows that parsimonious models have the power to suggest the presence of clades at a specific moment in the past even when there are no known physical records of that presence.

In the case of Metacryphaeus, the oldest records in Bolivia and Peru date from the early Pragian stage (410.8-407.6 mya), but the genus is believed to have evolved in the region during the Lochkovian stage (419.2-410.8 mya).

Parsimony, therefore, suggests Metacryphaeus originated in Bolivia and Peru some time before 410.8 mya but not earlier than 419.2 mya. In any event, it is believed to be far older than any known fossils.

According to Ghilardi, the results can be interpreted as showing that the adaptive radiation of Metacryphaeus to other areas of western Gondwana occurred during episodes of marine transgression in the Lochkovian-Pragian, when the sea flooded parts of Gondwana.

“The dispersal of Metacryphaeus trilobites during the Lochkovian occurred from Bolivia and Peru to Brazil — to the Paraná basin, now in the South region, and the Parnaíba basin, on the North-Northeast divide — and on toward the Malvinas/Falklands, while the Pragian dispersal occurred toward South Africa,” he said.

Fossil trilobites have been found continuously in the Paraná basin in recent decades. Trilobites collected in the late nineteenth century in the Parnaíba basin were held by Brazil’s National Museum in Rio de Janeiro, which was destroyed by fire in September 2018.

“These fossils haven’t yet been found under the rubble and it’s likely that nothing is left of them. They were mere shell impressions left in the ancient seabed. Even in petrified form, they must have dissolved in the blaze,” Ghilardi said.

Reference:
Fábio Augusto Carbonaro, Max Cardoso Langer, Silvio Shigueo Nihei, Gabriel de Souza Ferreira, Renato Pirani Ghilardi. Inferring ancestral range reconstruction based on trilobite records: a study-case on Metacryphaeus (Phacopida, Calmoniidae). Scientific Reports, 2018; 8 (1) DOI: 10.1038/s41598-018-33517-5

Note: The above post is reprinted from materials provided by Fundação de Amparo à Pesquisa do Estado de São Paulo. Original written by Peter Moon.

New clues emerging from fossils found in the oldest soils on Earth suggest that multicellular, land-dwelling organisms possibly emerged much earlier than thought.

The evidence for such a conclusion emerged from fossil assemblages, previously considered to be ocean organisms, found in thin layers of silt and sand located between thicker sandstone beds in South Australia. The sediments date to between 542 million to 635 million years ago – during a geological period known as the Ediacaran.

“These Ediacaran organisms are one of the enduring mysteries of the fossil record,” said Greg Retallack, fossil collections director at the University of Oregon’s Museum of Natural and Cultural History. “Were they worms, sea jellies, sea pens, amoebae, algae? They are notoriously difficult to classify, but conventional wisdom has long held that they were marine organisms.”

Retallack’s new study, published online in November and in the January issue of the journal Sedimentary Geology, suggests otherwise based on a geochemical and microscopic re-examination of both the age and environmental associations in the thin, silty-to-sandy layers.

The sediments, known as interflag sandstone laminae, reveal telltale marks of ancient wind erosion—phenomena more closely associated with modern river banks than with oceans or seas. These thin, alternating layers, which are light in color and rich in fine grain sizes, appear similar to sheets of white paper between books bound in brown and red, Retallack noted.

“Such wind-drifted layers are widespread on river levees and sandbars today. They are present throughout the Flinders Ranges of South Australia and also in Ediacaran rocks of southern Namibia,” he said.

The emergence of multicellular life on land dates to about 565 million years ago, although there is debate on whether Ediacaran fossils of that age originated from organisms in the sea or on land, Retallack said.

If the sediments themselves were deposited on dry land, it would follow that the organisms fossilized there were land dwellers, said Retallack, who also is a professor in the UO’s Department of Earth Sciences. The organisms that left the fossils, he said, would have been from multicellular organisms visible with the naked eye. Such life would have preceded the emergence of green plant vegetation, which is believed to have started between 470 million and 583 million years ago.

Last November, Retallack and Nora Noffke of Old Dominion University had reported on traces of life left in 3.7 billion-year-old soils in a metamorphic rock formation in southwestern Greenland. In the journal Palaeogeography, Palaeoclimatology, Palaeoecology, they identified isotopic ratios of carbon potentially indicative of early land-dwelling microbes.

While the Ediacaran organisms remain enigmatic when it comes to biological classification, Retallack’s new study offers some important clues.

“The investigation points to a terrestrial habitat for some of these organisms, and combined with growing evidence from studies of fossil soils and biological soil crust features, it suggests that they may have been land creatures such as lichens,” Retallack said.

For the paper, Retallack also re-examined well-known interflag sandstone laminae at four southern Indiana locations, which date to the Pennsylvanian period, and a central Colorado site from the Eocene epoch. These locations and examination of modern rivers showed the same sedimentary processes seen in Ediacaran rocks of South Australia and Africa.

Reference:
Gregory J. Retallack. Interflag sandstone laminae, a novel sedimentary structure, with implications for Ediacaran paleoenvironments, Sedimentary Geology (2018). DOI: 10.1016/j.sedgeo.2018.11.003

Gregory J. Retallack et al. Multiple Early Triassic greenhouse crises impeded recovery from Late Permian mass extinction, Palaeogeography, Palaeoclimatology, Palaeoecology (2010). DOI: 10.1016/j.palaeo.2010.09.022

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

A nearly metre-long skull of a giant fossil marine ichthyosaur found in a farmer’s field more than 60 years ago has been studied for the first time.

Using cutting-edge computerised tomography (CT) scanning technology, the research reveals new information including details of the rarely preserved braincase.

The almost 200 million year old fossil, which was found in 1955 at Fell Mill Farm in Warwickshire, had never formally been studied prior to this research.

Now, thanks to data collected from CT scans, the research team were able to digitally reconstruct the entire skull in 3D. It is the first time a digital reconstruction of a skull and mandible of a large marine reptile has ever been made available for research purposes and to the public.

Although thousands of ichthyosaur fossils have been unearthed in the UK, this specimen is particularly important and unusual because it is three-dimensionally preserved and contains bones of the skull that are rarely exposed.

In 2014, as part of a project at Thinktank Science Museum, Birmingham, palaeontologists Dean Lomax, from The University of Manchester, and Nigel Larkin began to study the skull and its incomplete skeleton for the first time and were soon convinced of its importance.

Dean, the lead author and one of the world’s leading ichthyosaur experts, explains: “The first time I saw this specimen I was puzzled by its excellent preservation.

Ichthyosaurs of this age (Early Jurassic) are usually ‘pancaked’, meaning that they are squished so that the original structure of the skull is either not preserved or is distorted or damaged. So to have a skull and portions of the skeleton of an ichthyosaur of this age preserved in three dimensions, and without any surrounding rock obscuring it, is something quite special.”

The ichthyosaur was originally identified as a common species called Ichthyosaurus communis, but after studying it closer, Dean was convinced it was a rarer species. Based on various features of the skull, he identified it as an example of an ichthyosaur called Protoichthyosaurus prostaxalis. With a skull almost twice as long as any other specimen of Protoichthyosaurus, this is the largest specimen so far known of the species.

Co-author Nigel Larkin added: “Initially, the aim of the project was to clean and conserve the skull and partially dismantle it to rebuild it more accurately, ready for redisplay at the Thinktank Museum. But we soon realised that the individual bones of the skull were exceptionally well preserved in three dimensions, better than in any other ichthyosaur skull we’d seen. Furthermore, that they would respond well to CT scanning, enabling us to capture their shape digitally and to see their internal details. This presented an opportunity that couldn’t be missed”

The skull isn’t quite complete, but several bones of the braincase — which are rarely preserved in ichthyosaurs — are present. To unlock information contained in the skull, these bones were micro-CT scanned at Cambridge University in 2015 by expert palaeontologist and co-author, Dr Laura Porro of University College London (UCL).

The fossil only preserved bones from the left side of the braincase; however, using CT scans these elements were digitally mirrored and 3D printed at life size to complete the braincase. Finally, the entire skull was CT scanned at the Royal Veterinary College (RVC) using a scanner typically reserved for horses and other large animals.

Dr Porro added: “CT scanning allows us to look inside fossils — in this case, we could see long canals within the skull bones that originally contained blood vessels and nerves. Scans also revealed the curation history of the specimen since its discovery in the ’50s. There were several areas reconstructed in plaster and clay, and one bone was so expertly modelled that only the scans revealed part of it was a fake. Finally there is the potential to digitally reconstruct the skull in 3D. This is hard (and risky) to do with the original, fragile and very heavy fossil bones; plus, we can now make the 3D reconstruction freely available to other scientists and for education.”

The use of modern technologies, such as medical scanners, have revolutionised the way in which palaeontologists are able to study and describe fossils.

Dean added: “It’s taken more than half a century for this ichthyosaur to be studied and described, but it has been worth the wait. Not only has our study revealed exciting information about the internal anatomy of the skull of this animal, but our findings will aid other palaeontologists in exploring its evolutionary relationship with other ichthyosaurs.”

Reference:
Dean R. Lomax, Laura B. Porro, Nigel R. Larkin. Descriptive anatomy of the largest known specimen of Protoichthyosaurus prostaxalis (Reptilia: Ichthyosauria) including computed tomography and digital reconstruction of a three-dimensional skull. PeerJ, 2019; 7: e6112 DOI: 10.7717/peerj.6112

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