This 3 November 2019 video on the Triassic says about itself:
20 years after it originally aired, how scientifically accurate is Walking With Dinosaurs?
This video is that episode of that BBC series.
This video from the USA says about itself:
(9/27/2003) Host Steve Owens gives a tour of the Prehistoric Theme garden at the studio gardens, and talks a little about the ancient plants featured in it.
From Aarhus University in Denmark:
Mutated ferns shed light on ancient mass extinction
October 28, 2019
Most researchers believe that the mass extinction 201 million years ago was caused by release of CO2 by volcanism with global warming as a consequence. Now, new data from fern spores suggest there might have been more to it than that.
At the end of the Triassic around 201 million years ago, three out of four species on Earth disappeared. Up until now, scientists believed the cause of the catastrophe to be the onset of large-scale volcanism resulting in abrupt climate change. Now, new research suggest there might be several factors in play.
An international research team led by the Geological Survey of Denmark and Greenland (GEUS) show that increased concentrations of the toxic element mercury in the environment contributed to the mass extinction. They recently published their finds in Science Advances.
“By looking at fern spores in sediments from the mass extinction, it was evident that these ferns were negatively affected by the mercury levels. Since mercury is accumulated in the food chain, it seems likely that other species have suffered as well,” says lead scientist Sofie Lindström.
“These results suggest that the end-Triassic mass extinction was not just caused by greenhouse gases from volcanoes causing global climate change, but that they also emitted toxins such as mercury wreaking havoc,” she says.
The mercury-volcano link
One of the co-authors of the study, Professor Hamed Sanei from Aarhus University, has previously demonstrated increased mercury levels from volcanism in a Large Igneous Province (LIP) during the most severe mass extinction known, the end-Permian crisis, where perhaps as much as 95% of life on Earth disappeared. Volcanic activity in LIPs is thought to be responsible for four of the five largest mass extinctions during the last 500 million years.
“Prior to industrialism, volcanic activity was the major release mechanism of large amounts of mercury from the Earth’s crust. That makes it possible to use mercury in sediments to trace major volcanic activity in the Earth’s past and in extent tie the extinctions of fossil organisms to LIP volcanism,” Hamed Sanei explains.
Other previous studies have shown elevated mercury concentrations in Triassic-Jurassic boundary sediments over a very large area stretching from Argentina to Greenland and from Nevada to Austria and that made the team curious about the impact on the end-Triassic event.
“We decided to examine whether mercury could have played a role,” Hamed Sanei says.
Fern spores as indicators
When looking at fern spores from core samples dating from 201 million years ago at the end of the Triassic the team indeed saw a link between increased mercury levels and mutations in the spores.
“During the mass extinction the mutated spores become increasingly common, and in turn the mutations get more and more severe. In some of my counts I found almost only mutated spores and no normal ones, which is very unusual,” Sofie Lindström explains.
This rise in mutations happened during a period of increased volcanic activity in a LIP called the Central Atlantic Magmatic Province (CAMP) leading to rising mercury levels. Since mercury is a mutagenic toxin, its’ increased distribution from the volcanic activity could help to explain the sudden deterioration of the ecosystem. Therefore, the fern spores could serve as indicators of increased mercury poisoning.
“This could hint to that the whole food chain might have been negatively affected,” says Sofie Lindström.
Previous studies have found increased amounts of malformed pollen during the end-Permian mass extinction 252 million years ago, which like the end-Triassic crisis is blamed on volcanism. These studies have suggested that the mutations during the end-Permian crisis were caused by increased UVB radiation, due to thinning of the ozone layer from the volcanism.
“This could also be a possible explanation for the mutations that we see during the end-Triassic crisis,” explains co-author Bas van de Schootbrugge from Utrecht University. “However, in our study we found only low amounts of mutated pollen, and during the end-Permian crisis spores do not appear to exhibit the same types of malformations registered during the end-Triassic mass extinction. This may indicate different causes for the plant mutations at the two events.”
Not a simple explanation
However, it is important not to lock on to just one cause when looking at a global crisis such as the end-Triassic event, says Sofie Lindström:
“Generally, we prefer simple explanations to mass extinctions such as meteorite impacts or climate change, but I don’t think it’s that simple. As our study suggests there could very well be a cocktail effect of CO2 and global warming, toxins like mercury, and other factors as well.”
Most of the prehistoric mass extinctions have indeed come in the wake of LIP volcanism, causing climate change and emitting toxic substances, Sofie Lindström says.
“Still, it is very difficult to say how big the importance of one factor is, because mass extinctions like this are very likely very complex events. Our study shows that mercury affected the ferns and likely also other plants, and it may also have had an impact on the entire food chain.”
Present pollution looks like past volcanism
The researchers point out that their study of the end-Triassic mass extinction in many ways draws parallels to the current global situation.
“Our global society emits a lot of the same substances and greenhouse gases as these huge volcanic provinces did during these mass extinctions. Therefore, studies in what happened back then might help us to prevent it from happening again,” says Sofie Lindström.
This April 2017 video says about itself:
Genetics Used To Pinpoint When Early Mammals Became Nocturnal
Using genetic analysis of modern species, researchers have confirmed what has long been assumed to be the case – the early mammals that evolved when dinosaurs were roaming the land became nocturnal early on, most likely to avoid the reptiles that were snacking on them.
“This method is like using the genome as a fossil record, and with it we’ve shown when genes involved in night vision appear”, says Liz Hadly, co-author of the study published in Scientific Reports, in a statement.
From the University of Chicago Press Journals in the USA:
Did early mammals turn to night life to protect their sperm?
October 15, 2019
Humans are diurnal — we are active in the day and sleep at night. But diurnalism is by far the exception rather [than] the rule in mammals. About 250-230 million years ago, the mammalian ancestors, called the therapsids, became exclusively nocturnal, and stayed so until the demise of the dinosaurs 66 million years ago. All of our mammal ancestors lived in the dark for about 200 [million] years, and the majority still do to this day. Humans are, essentially, nocturnal animals that have reverted back to living in the sun.
There has been much speculation about why the therapsids became nocturnal. The traditional argument is that the archosauriforms and the dinosaurs became ecologically dominant during the Triassic. To avoid being eaten by the multitude of new carnivorous reptiles, the archaic mammals, it is argued, fled into the dark, where reptiles had yet to dominate. In a new paper, “Obligatory nocturnalism in Triassic archaic mammals: Preservation of sperm quality?”, Barry G. Lovegrove proposes a simple, new, alternative hypothesis based purely upon physiological constraints.
The therapsids were becoming rapidly endothermic (producing more of their own internal heat through metabolism) to fuel new energy demands and to defend the consequent elevated body temperature, especially as they got smaller during the Triassic. And herein lies a problem. As their body temperature started to approach that of the air, around 93.2°F (34°C), they would not have been able to offload excessive heat generated by being active during the day without losing vast amounts of body water through evaporative cooling, such as by sweating or panting.
Archaic mammals did not have scrotums, in which the testes are kept cool, and if there had not been a way to keep sperm cool, quality would have declined through the accumulation of free radicals with the increases in temperature during sperm maturation. By becoming active during the cooler nights, these mammals were able to preserve sperm quality. A nocturnal lifestyle could solve this problem, now that they were “warm-blooded,” with the newly acquired thermoregulatory toolkit to cope with the cooler night air.
This BBC video is called Walking with Dinosaurs – “Postosuchus“.
Postosuchus was a Triassic carnivorous rauisuchid reptile.
From the University of the Witwatersrand in South Africa:
Croc-like carnivores terrorized Triassic dinosaurs in southern Africa 210 million years ago
Rauisuchians fed on vegetarian dinosaurs
September 23, 2019
Summary: Giant, predatory croc-like animals that lived during the Triassic period in southern Africa preyed on early dinosaurs and mammal relatives 210 million years ago. These predators, known as ‘rauisuchians’ preyed on early herbivore dinosaurs and … mammal relatives living at the time.
“These ancient fossils provide us with evidence of how at least two predator species hunted these vegetarian dinosaurs 210 million-years-ago. It is amazing to follow the clues left behind in fossilised teeth, jaws, limbs and other fossils to help us tell the ancient story of life in southern Africa,” says Tolchard.
The fossils studied by Tolchard include teeth, pieces of jaws, hind limbs and body armour, all of which are can be described as parts of rauisuchians.
Rauisuchians are closely related to crocodiles as we know them today. They had a diversity of body shapes and sizes during the Triassic period. The specimens described in this research include some of the largest carnivorous members of this group, that were possibly up to 10 metres long, with huge skulls full of serrated, curved teeth.
The study, published online in the Journal of African Earth Sciences last week, shows that the rauisuchians were some of the latest-surviving members of their group, and that when they were alive, they were thriving close to the Antarctic Circle — the theoretical limit for their physiology.
“In the Triassic period, rauisuchians were widespread and their fossils are known from all continents except Antarctica,” adds Tolchard. “They went extinct about 200 million years ago, paving the way for dinosaurs to become the dominant large land animals.”
“Rick’s study demonstrates the value of re-examining old specimens, and now we finally know what was preying on all those herbivorous dinosaurs!” says Professor Jonah Choiniere, Rick’s advisor and Professor of Comparative Palaeobiology at the Wits Evolutionary Studies Institute.
Tolchard studied fossils from collections based at the the University of the Witwatersrand, the Iziko South African Museum and the National Museum in Bloemfontein. He was joined in the research by an international team, including researchers from the USA, Argentina and the UK.
This May 2014 video says about itself:
The rove beetles are a family (Staphylinidae) of beetles, primarily distinguished by their short elytra that leave more than half of their abdomens exposed. With approximately 58,000 species in thousands of genera, the group is currently recognized as the largest family of beetles. It is an ancient group, with fossil rove beetles known from the Triassic, 200 million years ago, and possibly even earlier if the recently described Leehermania proves to be a member of this family. They are an ecologically and morphologically diverse group of beetleI, and commonly encountered in terrestrial ecosystems.
I did not leave all these inverts together, this video was taken just after I dumped what i’d found into a container to sort through them (I brought a small container with me in the woods).
From the Field Museum in the USA:
Identity crisis for fossil beetle helps rewrite beetle family tree
September 9, 2019
There are more different kinds of beetle than just about any other kind of animal — scientists have described about 5,800 different species of mammals, compared with nearly 400,000 species of beetles. Of those 400,000 kinds of beetles, more than 64,000 species are members of the rove beetle family, Staphylinidae. These mostly small earwig-looking insects are found all over the world, and they’ve been around since the time of the dinosaurs. But scientists are still figuring out exactly when rove beetles first evolved. A new study in Systematic Entomology suggests that the fossil beetle species believed to be the oldest rove beetle isn’t a rove beetle at all, meaning the beetle family tree needs a rewrite.
The beetle at the center of this mix-up, about the size of Franklin D. Roosevelt’s nose on the U.S. dime, is Leehermania prorova. When the fossils of Leehermania were first discovered in the 1990s along the Virginia and North Carolina border, they were believed to be the oldest rove beetles ever discovered — by about 50 million years.
Until 2012, the only public information on the fossils was two images, published in 1996 and 2005, but no formal description. Anyone who didn’t have direct access to the fossils of the species could only make guesses about its placement in the tree of life based on those photos.
So, when a formal description of the beetle was finally published, beetle scientists around the world were excited to read it.
“When Leehermania was formally described, and more photos came out, we thought to ourselves ‘that doesn’t look quite right for a staphylinid,'” says Margaret Thayer, a scientist at the Field Museum in Chicago and one of the paper’s nine authors. It didn’t look like the rove beetles that Thayer has spent her career studying.
“I happened to be at the museum when I first read the paper, so I went and looked through the specimens in our collection to compare,” said Alfred Newton, also a Field Museum scientist and paper author. His hunch was that this beetle might be more closely related to Hydroscaphidae, a living family of miniature insects known as skiff beetles, placed in a different suborder from rove beetles.
Across the Atlantic, Martin Fikáček recalled a similar feeling upon comparing the description and photos with the classification of Leehermania as a staphylinid. To Fikáček, a scientist at the National Museum in Prague, the beetle seemed to be a closer fit in the Myxophaga — the suborder that contains skiff beetles. Scientist Chenyang Cai at China’s Nanjing Institute of Geology and Paleontology and several other authors came to the same conclusion.
One of the clues that Leehermania wasn’t really a staphylinid was its mandibles — the pincer-like jaws. “Staphylinids all have exposed mandibles, from at least some angle,” says Newton. “In Leehermania, what were originally interpreted as mandibles are actually maxillary palpi — a different mouthpart structure entirely. The mandibles aren’t exposed here at all, at least from what we can see.”
Another hallmark of staphylinid beetles is their somewhat club-shaped antennae, which start with a narrow base and get wider toward the tip. In Leehermania, the antennae were club-shaped, but the club was more narrowed toward the tip.
Given the hidden mandibles, distinct antennal shape, and other features, including “paratergites” — little plates on the sides of most staphylinid abdomens that are absent in Leehermania — and the shape of the female insects’ genitalia, something wasn’t adding up. Leehermania seemed to be a much better fit in the suborder Myxophaga than in Staphylinidae.
Thanks to the power of the internet, the scientists were able to collaborate freely and quickly across four continents. “The international collaboration that occurred here was really important to the success of the study,” said Shûhei Yamamoto, a Field Museum scientist and paper author who studies staphylinidae and other beetles.
As the group’s hunch turned to a theory, then a study, then a formal analysis, the tests they ran showed Leehermania fitting nicely as a member of the beetle suborder Myxophaga, likely as a sister to the ancestors of today’s skiff beetles. This discovery means that the rove beetle family isn’t yet documented to be as old as scientists thought, but the skiff beetle family is now way older — Leehermania lived 226 million years ago, 100 million years before the next oldest fossil skiff beetle known.
Misclassification of extinct species happens all the time in science, for a variety of reasons.
For one, fossils can be extremely difficult to decipher. Since compression fossils like Leehermania are trapped in a sheet of rock, there is often only one viewing angle, though two in this case: a bird’s-eye-view called “dorsal,” or the top surface, and the “lateral” or side view. Any information about the species has to be gathered from these limited perspectives, so some information on colors, textures, patterns, anatomical details, and of course life-cycle information may be impossible to retrieve. Analysis is even more challenging when your specimens are only 2-3 mm long.
Lack of comparative data also causes problems for researchers. Not only are many characteristics of the insects lost in fossils, but until 2011, the large amount of data used here to test Leehermania’s placement in different families didn’t exist.
“Our analysis made use of a huge data set of morphological characters of beetles gathered for the ‘Beetle Tree of Life’ [BToL] project,” says Thayer. “That project was really crucial to our analysis and provided a framework upon which we were able to analyze Leehermania.” Four authors of the new paper, including Thayer and Newton, were among the authors of the published version of the BToL morphology paper. DNA-based analyses published by the BtoL project and other researchers were also essential to the Leehermania analyses.
Testing and revising the placement of living things in the tree of life is like working on a huge sudoku puzzle with contributors from all over the world. You have methods to figure out where the numbers should go, but if they’re incorrectly placed, you only know — eventually — based on their relationships to the surrounding numbers. If you carry on with the puzzle for too long with an incorrect placement, numbers filled in after the fact might also be incorrect. Revisiting Leehermania’s classification was important to help other researchers avoid using the fossils incorrectly to date analyses of beetles as a whole or identify other beetles as staphylinids based on Leehermania.
For the staphylinid family, losing their oldest ancestor produces new questions about how the family evolved.
“The re-classification of Leehermania means that staphylinids are now 50 million years younger than we thought,” says Fikáček. “But if staphylinids are so much younger, that means that this family evolved into many lineages much more rapidly than we thought they did.” Of course, older staphylinidae fossils are likely to turn up in the future and new analyses will be needed.
At a time in the Earth’s history when life was still recovering after a mass extinction, the appearance of Leehermania and staphylinidae is a testament to how resilient and adaptable beetles can be to diverse, and often harsh, living conditions.
“Throughout history, beetles have survived conditions that other animals have not,” says Fikáček. “As we study these insects, we might reveal some secret to evolutionary success that beetles possess.”
This 14 August 2019 video says about itself:
Was This Dinosaur a Cannibal?
Paleontologists have spent the better part of two decades debating whether Coelophysis ate its own kind. It turns out, the evidence that scientists have had to study in order to answer that question includes some of the strangest and grossest fossils that any expert would ever get to see.