Mammal-like reptiles coexisted with dinosaurs, discovery

This 13 March 2018 video says about itself:

Mystery of the Phantom Fossil Footprints

A new study has re-discovered fossil collections from a 19th century hermit that validate ‘phantom’ fossil footprints collected in the 1950s showing dicynodonts coexisting with dinosaurs.

“The first skeletal evidence of a dicynodont from the lower Elliot Formation of South Africa” by Christian F. Kammerer, North Carolina Museum of Natural Sciences. Published: 3-14-2018, in Palaeontologia Africana.

Video by Adrian Smith

Narrated by Eban Crawford

Illustrations by Matt Celeskey & Dmitry Bogdanov

From the North Carolina Museum of Natural Sciences in the USA:

60-year-old paleontological mystery of a ‘phantom’ dicynodont

March 14, 2018

A new study has re-discovered fossil collections from a 19th century hermit that validate ‘phantom’ fossil footprints collected in the 1950s showing dicynodonts coexisting with dinosaurs.

Before the dinosaurs, around 260 million years ago, a group of early mammal relatives called dicynodonts were the most abundant vertebrate land animals. These bizarre plant-eaters with tusks and turtle-like beaks were thought to have gone extinct by the Late Triassic Period, 210 million years ago, when dinosaurs first started to proliferate. However, in the 1950s, suspiciously dicynodont-like footprints were found alongside dinosaur prints in southern Africa, suggesting the presence of a late-surviving phantom dicynodont unknown in the skeletal record. These “phantom” prints were so out-of-place that they were disregarded as evidence for dicynodont survival by paleontologists. A new study has re-discovered fossil collections from a 19th century hermit that validate these “phantom” prints and show that dicynodonts coexisted with early plant-eating dinosaurs. While this research enhances our knowledge of ancient ecosystems, it also emphasizes the often-overlooked importance of trace fossils, like footprints, and the work of amateur scientists.

“Although we tend to think of paleontological discoveries coming from new field work, many of our most important conclusions come from specimens already in museums“, says Dr. Christian Kammerer, Research Curator of Paleontology at the North Carolina Museum of Natural Sciences and author of the new study.

The re-discovered fossils that solved this mystery were originally collected in South Africa in the 1870s by Alfred “Gogga” Brown. Brown was an amateur paleontologist and hermit who spent years trying, with little success, to interest European researchers in his discoveries. Brown had shipped these specimens to the Natural History Museum in Vienna in 1876, where they were deposited in the museum’s collection but never described.

“I knew the Brown collections in Vienna were largely unstudied, but there was general agreement that his Late Triassic collections were made up only of dinosaur fossils. To my great surprise, I immediately noticed clear dicynodont jaw and arm bones among these supposed ‘dinosaur’ fossils”, says Kammerer. “As I went through this collection I found more and more bones matching a dicynodont instead of a dinosaur, representing parts of the skull, limbs, and spinal column.” This was exciting — despite over a century of extensive collection, no skeletal evidence of a dicynodont had ever been recognized in the Late Triassic of South Africa.

Before this point, the only evidence of dicynodonts in the southern African Late Triassic was from questionable footprints: a short-toed, five-fingered track named Pentasauropus incredibilis (meaning the “incredible five-toed lizard foot”). In recognition of the importance of these tracks for suggesting the existence of Late Triassic dicynodonts and the contributions of “Gogga” Brown in collecting the actual fossil bones, the re-discovered and newly described dicynodont has been named Pentasaurus goggai (“Gogga’s five-[toed] lizard”).

“The case of Pentasaurus illustrates the importance of various underappreciated sources of data in understanding prehistory,” says Kammerer. “You have the contributions of amateur researchers like ‘Gogga’ Brown, who was largely ignored in his 19th century heyday, the evidence from footprints, which some paleontologists disbelieved because they conflicted with the skeletal evidence, and of course the importance of well-curated museum collections that provide scientists today an opportunity to study specimens collected 140 years ago.”


Cuttlefish colours, new study

This February 2018 video says about itself:

Cuttlefish Look Like Squid—and Like Crabs, and Like Algae, and Like Rocks | National Geographic

A new study examines the muscles, nerves, and chemicals that enable cuttlefish—animals related to squid—to change their skin texture, mimicking another animal or their surroundings.

Archaeopteryx could fly indeed

This 2014 video says about itself:

Scanning the Teyler Archaeopteryx fossil at the ESRF Grenoble

2 November 2014

In order to study the Teyler Archaeopteryx fossil, it is being scanned in Grenoble using synchrotron X-ray microtomography. The end of the video shows the specimen fully wrapped and mounted on the object table in front of the beam that is coming out the square hole in the blue box.

From the European Synchrotron Radiation Facility:

The early bird got to fly: Archaeopteryx was an active flyer

March 13, 2018

The question of whether the Late Jurassic dino-bird Archaeopteryx was an elaborately feathered ground dweller, a glider, or an active flyer has fascinated palaeontologists for decades. Valuable new information obtained with state-of-the-art synchrotron microtomography at the ESRF, the European Synchrotron (Grenoble, France), allowed an international team of scientists to answer this question in Nature Communications. The wing bones of Archaeopteryx were shaped for incidental active flight, but not for the advanced style of flying mastered by today’s birds.

Was Archaeopteryx capable of flying, and if so, how? Although it is common knowledge that modern-day birds descended from extinct dinosaurs, many questions on their early evolution and the development of avian flight remain unanswered. Traditional research methods have thus far been unable to answer the question whether Archaeopteryx flew or not. Using synchrotron microtomography at the ESRF’s beamline ID19 to probe inside Archaeopteryx fossils, an international team of scientists from the ESRF, Palacký University, Czech Republic, CNRS and Sorbonne University, France, Uppsala University, Sweden, and Bürgermeister-Müller-Museum Solnhofen, Germany, shed new light on this earliest of birds.

Reconstructing extinct behaviour poses substantial challenges for palaeontologists, especially when it comes to enigmatic animals such as the famous Archaeopteryx from the Late Jurassic sediments of southeastern Germany that is considered the oldest potentially free-flying dinosaur. This well-preserved fossil taxon shows a mosaic anatomy that illustrates the close family relations between extinct raptorial dinosaurs and living dinosaurs: the birds. Most modern bird skeletons are highly specialised for powered flight, yet many of their characteristic adaptations in particularly the shoulder are absent in the Bavarian fossils of Archaeopteryx. Although its feathered wings resemble those of modern birds flying overhead every day, the primitive shoulder structure is incompatible with the modern avian wing beat cycle.

“The cross-sectional architecture of limb bones is strongly influenced by evolutionary adaptation towards optimal strength at minimal mass, and functional adaptation to the forces experienced during life”, explains Prof. Jorge Cubo of the Sorbonne University in Paris. “By statistically comparing the bones of living animals that engage in observable habits with those of cryptic fossils, it is possible to bring new information into an old discussion”, says senior author Dr. Sophie Sanchez from Uppsala University, Sweden

Archaeopteryx skeletons are preserved in and on limestone slabs that reveal only part of their morphology. Since these fossils are among the most valuable in the world, invasive probing to reveal obscured or internal structures is therefore highly discouraged. “Fortunately, today it is no longer necessary to damage precious fossils”, states Dr. Paul Tafforeau, beamline scientist at the ESRF. “The exceptional sensitivity of X-ray imaging techniques for investigating large specimens that is available at the ESRF offers harmless microscopic insight into fossil bones and allows virtual 3D reconstructions of extraordinary quality. Exciting upgrades are underway, including a substantial improvement of the properties of our synchrotron source and a brand new beamline designated for tomography. These developments promise to give even better results on much larger specimens in the future.”

Scanning data unexpectedly revealed that the wing bones of Archaeopteryx, contrary to its shoulder girdle, shared important adaptations with those of modern flying birds. “We focused on the middle part of the arm bones because we knew those sections contain clear flight-related signals in birds”, says Dr. Emmanuel de Margerie, CNRS, France. “We immediately noticed that the bone walls of Archaeopteryx were much thinner than those of earthbound dinosaurs but looked a lot like conventional bird bones”, continues lead author Dennis Voeten of the ESRF. “Data analysis furthermore demonstrated that the bones of Archaeopteryx plot closest to those of birds like pheasants that occasionally use active flight to cross barriers or dodge predators, but not to those of gliding and soaring forms such as many birds of prey and some seabirds that are optimised for enduring flight.”

“We know that the region around Solnhofen in southeastern Germany was a tropical archipelago, and such an environment appears highly suitable for island hopping or escape flight”, remarks Dr. Martin Röper, Archaeopteryx curator and co-author of the report. “Archaeopteryx shared the Jurassic skies with primitive pterosaurs that would ultimately evolve into the gigantic pterosaurs of the Cretaceous. We found similar differences in wing bone geometry between primitive and advanced pterosaurs as those between actively flying and soaring birds”, adds Vincent Beyrand of the ESRF.

Since Archaeopteryx represents the oldest known flying member of the avialan lineage that also includes modern birds, these findings not only illustrate aspects of the lifestyle of Archaeopteryx but also provide insight into the early evolution of dinosaurian flight. “Indeed, we now know that Archaeopteryx was already actively flying around 150 million years ago, which implies that active dinosaurian flight had evolved even earlier!” says Prof. Stanislav Bureš of Palacký University in Olomouc. “However, because Archaeopteryx lacked the pectoral adaptations to fly like modern birds, the way it achieved powered flight must also have been different. We will need to return to the fossils to answer the question on exactly how this Bavarian icon of evolution used its wings”, concludes Voeten.

It is now clear that Archaeopteryx is a representative of the first wave of dinosaurian flight strategies that eventually went extinct, leaving only the modern avian flight stroke directly observable today.

Hogfish colours, new study

This 2015 video says about itself:

Hogfish at Cleaning Station – Turks and Caicos

A very rare sighting to capture on camera, a hogfish at a cleaning station. After approaching the Hogfish very slowly and passively we managed to capture some fantastic footage of the hogfish being cleaned by some small reef fish. Whilst the hogfish hangs motionless the other fish enter and clean inside of the mouth and gill area. Shot on a GoPro Hero 3 Silver Edition by Kieran Bown.

From Duke University in the USA:

Color-changing hogfish ‘sees’ with its skin

Fish’s skin senses light differently from eyes

March 12, 2018

Summary: The hogfish can go from white to reddish in milliseconds as it adjusts to shifting conditions in the ocean. Scientists have long suspected that animals with quick-changing colors don’t just rely on their eyes to tune their appearance to their surroundings — they also sense light with their skin. But exactly how remains a mystery. A study reveals that hogfish skin senses light differently from eyes.

Some animals are quick-change artists. Take the hogfish, a pointy-snouted reef fish that can go from pearly white to mottled brown to reddish in a matter of milliseconds as it adjusts to shifting conditions on the ocean floor.

Scientists have long suspected that animals with quick-changing colors don’t just rely on their eyes to tune their appearance to their surroundings — they also sense light with their skin. But exactly how “skin vision” works remains a mystery.

Now, genetic analysis of hogfish reveals new evidence to explain how they do it. In a new study, Duke University researchers show that hogfish skin senses light differently from eyes.

The results suggest that light-sensing evolved separately in the two tissues, said Lori Schweikert, a postdoctoral scholar with Sönke Johnsen, biology professor at Duke.

With “dermal photoreception”, as it is called, the skin doesn’t enable animals to perceive details like they do with their eyes, Schweikert said. But it may be sensitive to changes in brightness or wavelength, such as moving shadows cast by approaching predators, or light fluctuations associated with different times of day.

Schweikert, Johnsen and Duke postdoctoral associate Bob Fitak focused on the hogfish, or Lachnolaimus maximus, which spends its time in shallow waters and coral reefs in the western Atlantic Ocean, from Nova Scotia to northern South America. It can make its skin whitish to blend in with the sandy bottom of the ocean floor and hide from predators or ambush prey. Or it can take on a bright, contrasting pattern to look threatening or attract a mate.

The key to these makeovers are special pigment-containing cells called chromatophores, which, when activated by light, can spread their pigments out or bunch them up to change the skin’s overall color or pattern.

The researchers took pieces of skin and retina from a single female hogfish caught off the Florida Keys and analyzed all of its gene readouts, or RNA transcripts, to see which genes were switched on in each tissue.

Previous studies of other color-changing animals including cuttlefish and octopuses suggest the same molecular pathway that detects light in eyes may have been co-opted to sense light in the skin.

But Schweikert and colleagues found that hogfish skin works differently. Almost none of the genes involved in light detection in the hogfish’s eyes were activated in the skin. Instead, the data suggest that hogfish skin relies on an alternative molecular pathway to sense light, a chain reaction involving a molecule called cyclic AMP.

Just how the hogfish’s “skin vision” supplements input from the eyes to monitor light in their surroundings and bring about a color change remains unclear, Schweikert said. Light-sensing skin could provide information about conditions beyond the animal’s field of view, or outside the range of wavelengths that the eye can pick up.

Together with previous studies, “the results suggest that fish have found a new way to ‘see’ with their skin and change color quickly”, Schweikert said.

Over 3,000 lichens in Alps mountains

This 2014 video is called Lichen Biology.

From ScienceDaily:

The Alps are home to more than 3,000 lichens

March 12, 2018

Summary: Widely used as biomonitors of air quality, forest health and climate change, lichens play a vital role. However, no overview of their diversity across the emblematic Alps had been provided up until recently, when an international team of lichenologists concluded their 15-year study. Their annotated checklist includes more than 3,000 lichens and presents a long-missed benchmark for scientists studying mountain systems around the globe.

Historically, the Alps have always played an emblematic role, being one of the largest continuous natural areas in Europe. With its numerous habitats, the mountain system is easily one of the richest biodiversity hotspots in Europe.

Lichens are curious organisms comprising a stable symbiosis between a fungus and one or more photosynthetic organisms, for example green algae and/or cyanobacteria. Once the symbiosis is established, the new composite organism starts to function as a whole new one, which can now convert sunlight into essential nutrients and resist ultraviolet light at the same time.

Being able to grow on a wide range of surfaces — from tree bark to soil and rock, lichens are extremely useful as biomonitors of air quality, forest health and climate change.

Nevertheless, while the Alps are one of the best studied parts of the world in terms of their biogeography, no overview of the Alpine lichens had been provided up until recently, when an international team of lichenologists, led by Prof. Pier Luigi Nimis, University of Trieste, Italy, concluded their 15-year study with a publication in the open access journal MycoKeys.

The scientists’ joint efforts produced the first ever checklist to provide a complete critical catalogue of all lichens hitherto reported from the Alps. It comprises a total of 3,138 entries, based on data collected from eight countries — Austria, France, Germany, Italy, Liechtenstein, Monaco, Slovenia and Switzerland. In their research paper, the authors have also included notes on the lichens’ ecology and taxonomy.

They point out that such catalogue has been missing for far too long, hampering research all over the world. The scientists point out that this has been “particularly annoying,” since the data from the Alps could have been extremely useful for comparisons between mountainous lichen populations from around the globe. It turns out that many lichens originally described from the Alps have been later identified in other parts of the world.

“It was a long and painstaking work, which lasted almost 15 years, revealing a surprisingly high number of yet to be resolved taxonomic problems that will hopefully trigger further research in the coming years,” say the authors.

“We think that the best criterion to judge whether a checklist has accomplished its task for the scientific community is the speed of it becoming outdated,” they conclude paradoxically.

The new checklist is expected to serve as a valuable tool for retrieving and accessing the enormous amount of information on the lichens of the Alps that has accumulated over centuries of research. It offers a basis for specimen revisions, critical re-appraisal of poorly-known species and further exploration of under-explored areas. Thus, it could become a catalyst for new, more intensive investigations and turn into a benchmark for comparisons between mountains systems worldwide.

How turtles got their shells, video

This video from the USA says about itself:

How the Turtle Got Its Shell

12 March 2018

Where did turtles come from? And how did the they get their shells? The answers to these questions would eventually cause scientists to rethink the entire history of reptile evolution.

Pre-Cambrian worm discoveries in Mongolia

Reconstruction of the late Ediacaran (ca. 550 million years ago) sea floor with burrows of a worm-like animal.This was the first discovery of such deeply penetrating burrows. Credit: © Nagoya University

From Nagoya University in Japan:

Digging up the Precambrian: Fossil burrows show early origins of animal behavior

March 12, 2018

Researchers led by Nagoya University discover penetrative trace fossils from the late Ediacaran of western Mongolia, revealing earlier onset of the “agronomic revolution”.

In the history of life on Earth, a dramatic and revolutionary change in the nature of the sea floor occurred in the early Cambrian (541–485 million years ago): the “agronomic revolution.” This phenomenon was coupled with the diversification of marine animals that could burrow into seafloor sediments. Previously, the sea floor was covered by hard microbial mats, and animals were limited to standing on, resting on, or moving horizontally along those mats. In the agronomic revolution, part of the so-called Cambrian Explosion of animal diversity and complexity, vertical burrowers began to churn up the underlying sediments, which softened and oxygenated the subsurface, created new ecological niches, and thus radically transformed the marine ecosystem into one more like that observed today.

This event has long been considered to have occurred in the early Cambrian Period. However, new evidence obtained from western Mongolia shows that the agronomic revolution began in the late Ediacaran, the final period of the Precambrian, at least locally.

A team of researchers, primarily based in Japan, surveyed Bayan Gol Valley, western Mongolia, and found late Ediacaran trace fossils in marine carbonate rocks. They identified U-shaped, penetrative trace fossils, called Arenicolites, from 11 beds located more than 130 meters below the lowermost occurrence of Treptichnus pedum, widely recognized as the marker of the Ediacaran–Cambrian boundary. The researchers confirmed the late Ediacaran age of the rocks, estimated to be between 555 and 541 million years old, based on the stable carbon isotope record.

“It is impossible to identify the kind of animal that produced the Arenicolites traces,” lead author Tatsuo Oji says. “However, they were certainly bilaterian animals based on the complexity of the traces, and were probably worm-like in nature. These fossils are the earliest evidence for animals making semi-permanent domiciles in sediment. The evolution of macrophagous predation was probably the selective pressure for these trace makers to build such semi-permanent infaunal structures, as they would have provided safety from many predators.”

These Arenicolites also reached unusually large sizes, greater than one centimeter in diameter. The discovery of these large-sized, penetrative trace fossils contradicts the conclusions of previous studies that small-sized penetrative traces emerged only in the earliest Cambrian.

“These trace fossils indicate that the agronomic revolution actually began in the latest Ediacaran in at least one setting,” co-author Stephen Dornbos explains. “Thus, this revolution did not proceed in a uniform pattern across all depositional environments during the Cambrian radiation, but rather in a patchwork of varying bioturbation levels across marine seafloors that lasted well into the early Paleozoic.”