Dinosaurs became extinct, sharks survived

This video from Canada says about itself:

Dr. Mike Newbrey, Royal Tyrrell Museum “The Effects of Climate Change on the Growth Biology and Geographic Distribution of Cretaceous Sharks.”

Originally published April 1, 2011.

From Uppsala University in Sweden:

The end-Cretaceous extinction unleashed modern shark diversity

August 2, 2018

A study that examined the shape of hundreds of fossilized shark teeth suggests that modern shark biodiversity was triggered by the end-Cretaceous mass extinction event, about 66 million years ago.

This finding is reported this week in Current Biology.

As part of a larger scientific endeavour aiming to understand the diversity of fossil sharks, a group of researchers from Uppsala University, Sweden, and the University of New England, Australia, have explored how certain groups of sharks responded to the mass extinction that killed-off non-bird dinosaurs and marked the end of the Cretaceous period and the Mesozoic era.

Much like several other vertebrate groups during the Cretaceous (142-66 million years ago), shark diversity looked very different from today. Ground sharks (Carcharhiniformes) are the most diverse shark group living today, with over 200 different species. However, while dinosaurs dominated terrestrial environments during the Cretaceous, Mackerel sharks (Lamniformes) were the dominant shark forms of the sea.

“Our study found that the shift from lamniform- to carcharhiniform-dominated assemblages may well have been the result of the end-Cretaceous mass extinction“, said project leader and Uppsala doctoral student Mohamad Bazzi.

Sharks are one of the major groups that survived the Cretaceous-Palaeogene mass extinction and, today, carcharhiniforms are typified by forms such as the Tiger, Hammerhead, and Blacktip Reef sharks and lamniforms by the Great White and Mako sharks.

“Unlike other vertebrates, the cartilaginous skeletons of sharks do not easily fossilize and so our knowledge of these fishes is largely limited to the thousands of isolated teeth they shed throughout their lives”, says Mr. Bazzi. “Fortunately, shark teeth can tell us a lot about their biology, including information about diet, which can shed light on the mechanisms behind their extinction and survival.”

The team used “cutting-edge” analytical techniques to explore the variation of tooth shape in carcharhiniforms and lamniforms and measured diversity by calculating the range of morphological variation, also called disparity.

“Going into this study, we knew that sharks underwent important losses in species richness across the extinction“, said Dr. Nicolás Campione at the University of New England, who co-devised the project. “But to our surprise, we found virtually no change in disparity across this major transition. This suggests to us that species richness and disparity may have been decoupled across this interval.”

Despite this seemingly stable pattern, the study found that extinction and survival patterns were substantially more complex. Morphologically, there were differential responses to extinction between lamniform and carcharhiniform sharks, with evidence for a selective extinction of lamniforms and a subsequent proliferation of carcharhiniforms (the largest order of living sharks today) in the immediate aftermath of the extinction.

“Carcharhiniforms are the most common shark group today and it would seem that the initial steps towards this dominance started approximately 66 million years ago”, said Mr. Bazzi, who remarks that further research is still needed to understand the diversity patterns of other shark groups, along with the relationship between diet and tooth morphology.

Although the mechanisms that triggered such a shift in sharks can be difficult to interpret. The team hypothesises that changes in food availability may have played an important role. The end-Cretaceous extinction saw to major losses in marine reptiles and cephalopods (e.g. squids) and the post-extinction world saw the rise of bony fishes. In addition, it is likely that the loss of apex predators (such as lamniforms and marine reptiles) benefited mid-trophic sharks, a role fulfilled by many carcharhiniforms.

“By studying their teeth, we are able to get a glimpse at the lives of extinct sharks”, said Dr. Campione, “and by understanding the mechanisms that have shaped their evolution in the past, perhaps we can provide some insights into how to mitigate further losses in current ecosystems.”

Approximately 50% of the shark species in the IUCN are considered to be either endangered, threatened, or near-threatened.


Dojo loach fish, new study

This 2015 video is called Dojo Loach: Amazing fish.

From Hokkaido University in Japan:

Fish reproduction: Two times a lady

August 2, 2018

A DNA probing technique clarifies the mechanism behind clonal reproduction of female dojo loach fish, also providing insight into the ancestral origin of the clonal population.

Hokkaido University researchers have developed a technique that allows them to track chromosomes during egg production in dojo loach Misgurnus anguillicaudatus. The study uncovered how female clones double their chromosomes twice to assure clonal reproduction.

The dojo loach is a bottom-dwelling freshwater fish native to East Asia. The majority are sexually reproducing male and female fish. Their ‘somatic’ non-reproductive cells contain a full set of 50 chromosomes — 25 from each parent — while their reproductive egg and sperm cells contain 25 chromosomes.

However, a population of female clones of the species can be found in Hokkaido Island and other areas of Japan. Unlike the sexually reproducing female population, both their somatic and reproductive eggs contain 50 chromosomes, assuring their clonal reproduction. How the reproductive process leads to 50 chromosomes in egg cells has been unclear.

To better understand this mechanism, a research team including Masamichi Kuroda and Takafumi Fujimoto of Hokkaido University’s Graduate School of Fisheries Sciences developed DNA probes to track the chromosomes in dojo loach’s somatic and reproductive cells. Previous studies have suggested that the female clone population arose when two genetically distinct groups within the species, called A and B for simplicity, mated. Kuroda and his colleagues developed a fluorescent DNA probe that binds to specific chromosomal regions derived from type B.

According to the results published in Chromosome Research, the fluorescent signals indicated that somatic cells of the female clones have 25 chromosomes derived from type B, providing evidence that their ancestral origin arose when type A and B mated. They then looked into the process of egg production using the DNA probes. In the sexually reproducing dojo loach, reproductive cells divided through the normal process of meiosis, in which a single cell containing a full set of 50 chromosomes produces one egg containing 25 chromosomes. This requires doubling chromosomes once.

In the female clones, the team found that the chromosomal material doubles twice so that when it divides, each results in an egg cell containing a full set of 50 chromosomes. Fish sperm activates these egg cells to start developing embryos without incorporating their genetic material into them.

Moreover, their data suggested that sister chromosomes doubled from the same chromosome make pairs so that recombination between the chromosomes does not affect their clonality. Such recombination normally occurs between paternally-derived and maternally-derived chromosomes.

“This is the first time that ‘cytogenetic’ evidence has been found for this type of chromosomal duplication in a unisexual, ray-finned fish. Further study could help develop a seedling production that can produce a large population of clone fish with desirable characteristics”, says Takafumi Fujimoto.

Facebook censors United States anti-nazis, opponents of Trump’s xenophobia

The United States No Unite the Right 2 – DC anti-nazi rally announcement removed by Facebook

By Andre Damon in the USA:

Facebook censors anti-fascist rally in Washington

2 August 2018

The social media giant Facebook carried out a major escalation in the campaign to censor the Internet Monday, deleting the official event page for an anti-fascist rally scheduled for August 12 in Washington, D.C. on the grounds that it was engaged in “coordinated inauthentic behavior.”

The event, entitled “No Unite the Right 2 – DC”, was scheduled as a counter-protest to a fascist demonstration called for August 12 by the organizers of last year’s Nazi rally in Charlottesville, Virginia, during which a right-wing extremist murdered counter-protestor Heather Heyer.

The rally’s organizers include Chelsea Manning, the whistleblower imprisoned and tortured for six years by the Obama administration for revealing American war crimes. Manning told the New York Times the demonstration was “real and organic,” declaring “Folks from D.C. and Charlottesville have been talking about this since at least February.”

As Facebook censors this and so much else, meanwhile, eg, the Dutch Nederlandse Volks-Unie neonazis are free to spout their praise of Adolf Hitler, racism, sexism, marches promoting that, etc. on their Facebook page. So, according to Facebook, the NVU nazis are not ‘inauthentic’ at all and welcome; like Holocaust deniers from all countries are welcome at Facebook.

A number of activists and organizers in the Washington, DC area are disputing Facebook’s decision to remove a counter-protest event for a rally organized by Jason Kessler, the white nationalist figure who planned the deadly 2017 rally in Charlottesville, Virginia: here.

While Facebook shuts down left-wing pages, groups and events with growing regularity, this latest action is particularly significant both because of its prominence—a major demonstration likely to draw large numbers of participants—and because Facebook has publicly boasted about it.

The closure of the event page was a centerpiece of a blog post published Tuesday by Facebook outlining its efforts to crack down on groups aiming to “sow division using social media” ahead of the 2018 election. In addition to shutting down the rally’s event page, Facebook announced that it had shut down 32 other pages, including those opposing police violence and defending immigrant rights.

The announcement was framed as a follow-up to the company’s announcement in September 2017 that “Russia-linked” Facebook pages bought some $100,000 in ads related to “divisive social issues”. In addition to serving as a pretext for major new censorship measures by Facebook, the 2017 announcement was connected to allegations by the Democratic Party that US President Trump “colluded” with the Russian government to win the 2016 election.

However, with the Democrats’ anti-Russia campaign increasingly bogged down by the bitter factional battle in Washington, it appears that those sections of the state apparatus leading the drive to censor the Internet are hoping to decouple their efforts from allegations about Russian “meddling”.

Facebook and its outgoing Chief Security Officer Alex Stamos explicitly declined to attribute the claims to the Russian government. “Today we’re shutting down 32 Pages and accounts engaged in coordinated inauthentic behavior without saying that a specific group or country is responsible”, Stamos wrote in a post accompanying its announcement.

While the alleged “Russian” ads described by Facebook in 2017 included statements in support of both sides of the political spectrum, the latest batch of pages shut down were all left-wing, including those opposing police violence, attacks on immigrant rights, and the Trump administration’s right-wing policies.

On Monday, the day before Facebook announced that it had shut down the page, the company turned its latest blacklist over to the Atlantic Council, a prominent military think-tank. Its analysis makes clear that Facebook is deliberately targeting left-wing groups.

An event against Trump's separation of children from their parents, published by one of the groups taken down by Facebook

The Atlantic Council’s report said the pages shut down by Facebook targeted “the left of the political spectrum”, and that the pages were an attempt to “infiltrate left-wing American communities.” These pages “sought to promote divisions and set Americans against one another.”

Events created by “inauthentic” groups “did have a very real, organic, and engaged online community; however, the intent of the inauthentic activity appeared to be designed to catalyze the most incendiary impulses of political sentiment.“

These groups promoted “activism against fascism”. One of the groups, according to the Atlantic Council, “created an event in protest of the Trump administration’s policy of separating the children of undocumented migrants from their families.”

Another promoted event included “protests against U.S. Immigration and Customs Enforcement (ICE), U.S. President Donald Trump’s tax plan, protests against Trump’s Muslim ban, and a ‘March against rapist cops.’”

At times, the Atlantic Council report adopts wholesale conceptions advanced by the fascist right, such as that left-wing protesters are the instigators of violence in clashes with fascists. In justifying the censorship of the Washington anti-fascist protest, the think-tank claimed its organizers “suggested a desire to provoke further confrontations and violence.”

In another instance, the report characterized Internet content “focusing on the plight of Native Americans and modern immigrants” as promoting “anti-white” viewpoints.

Both Democratic and Republican lawmakers praised Facebook’s action. Democratic Senator Mark Warner, the top Democrat on the Senate Intelligence Committee, declared that the disclosure “is further evidence that the Kremlin continues to exploit platforms like Facebook to sow division and spread disinformation.” Warner, who has led the campaign for censorship, ignored the fact that Facebook provided no evidence

indeed, explicitly denied there was evidence

that Russia had anything to do with the pages.

Facebook’s latest action must be taken as an urgent warning. Two years after the start of the campaign to censor the Internet in the guise of fighting “fake news” spread by “Russian trolls”, the social media giants, working with the US intelligence agencies, are increasingly making clear that their real target is left-wing political sentiment among growing sections of workers and young people. In so doing, they are following the path blazed by Google, which last year announced plans to censor “alternative” news, leading to a drop in search traffic to left-wing sites of up to 80 percent.

With opposition growing among 260,000 UPS workers to a sellout contract being demanded by … their employer, a growing international strike movement among airline workers [see also here], and simmering anger among teachers and other sections of the working class in the US, the ruling class is concerned above all that workers will use the Internet not only to organize and coordinate their struggles, but to rally around a socialist perspective.

United States anti-nazi demonstrators

Facebook Deleted The “No Unite The Right 2” Event — But Organizers Insist They’re Not Trolls: here.

This [Haitian] asylum seeker is still waiting for his release from [United States] prison — three court decisions later.

Speaking of imperialism, The Guardian covers a report from Global Media which describes Facebook’s Free Basics program as “digital colonialism.” “Facebook is not introducing people to open internet where you can learn, create and build things. It’s building this little web that turns the user into a mostly passive consumer of mostly western corporate content”, says Ellery Biddle, Global Voices’ advocacy director: here.

Monday evening, the English language page of the television network Telesur, which is published by the Venezuelan government, was taken down by Facebook in a direct act of censorship of content critical of US government policy. After administrators received a notice that the Telesur English page had violated Facebook’s “Terms of Use,” the page reappeared two days later, with Facebook claiming, in an unserious and unconvincing manner, “that there was instability on the platform, which caused this problem, but now everything should be in order.” The Facebook page of another media outlet aligned politically with the Venezuelan government, Venezuela Analysis, which is based in New York, was also temporarily taken down on August 9, only four days before, for allegedly violating “Facebook Pages Terms.” The site’s administrators, however, have not received any explanation about the suspension: here.

As Facebook CEO Mark Zuckerberg travels around the US to “learn about people’s challenges”, one of his employees, living out a a garage, suggests maybe Zuck pay attention to inequalities in his own backyard.

And Trump’s son, Eric, is accused of making anti-Semitic comments in reference to Bob Woodward’s new book about his father’s White House.

Jurassic dinosaur discovery in China

This video says about itself:

Dinosaur species named the ‘amazing dragon of Lingwu’ proves Diplodocoid reptiles were in Pangaea

24 July 2018

Giant long-necked dinosaurs were roaming the supercontinent of Pangaea up to 29 million years earlier than previously thought, a new study suggests. Fossils of a newly discovered species, dubbed the ‘amazing dragon of Lingwu’, prove advanced diplodocoids were alive during the early Middle Jurassic of China – 174 million years ago. Researchers previously believed that advanced diplodocoids, known as neosauropods, did not appear until after the break up of Pangaea, the giant land mass from which modern continents formed.

From University College London in England:

New dinosaur found in the wrong place, at the wrong time

August 1, 2018

A new dinosaur called Lingwulong shenqi or ‘amazing dragon from Lingwu’ has been discovered by an Anglo-Chinese team involving UCL.

The announcement, published in Nature Communications, reports the surprising discovery of the new dinosaur which roamed the Ningxia Autonomous Region, northwest China, approximately 174 million years ago. This is in a place they were never thought to roam and 15 million years earlier than this type of dinosaur was thought to exist.

Lingwulong is the earliest known example of a type of advanced sauropod dinosaur called a ‘neosauropod’ — one of the long-necked, gigantic herbivores that are the largest land animals known, including famous forms such as Brontosaurus and Diplodocus.

Sauropods originated around 200 million years ago, but they only started to truly dominate terrestrial ecosystems by developing gigantic body size (up to 70 metric tonnes) and numerous new adaptations for obtaining and processing plant food.

These giant neosauropod descendants were thought to originate around 160 million years ago, rapidly diversifying and spreading across the world during a time window perhaps as short as just 5 million years.

“We were surprised to find a close relative of Diplodocus in East Asia 174 million years ago. It’s commonly thought that sauropods did not disperse there until 200 million years ago and many of their giant descendants reached this region much later, if at all”, explained study co-author Professor Paul Upchurch (UCL Earth Sciences).

“Our discovery of Lingwulong demonstrates that several different types of advanced sauropod must have existed at least 15 million years earlier and spread across the world while the supercontinent Pangaea was still a coherent landmass. This forces a complete re-evaluation of the origins and evolution of these animals.”

The new evidence also reinforces the growing realisation that the Early Jurassic (200-175 million years ago), was a key time in dinosaur evolution, witnessing the origins and diversification of many groups that went on to dominate the later Jurassic and Cretaceous.

“Diplodocus-like neosauropods were thought to have never made it to East Asia because this region was cut-off from the rest of the world by Jurassic seaways, so that China evolved its own distinctive and separate dinosaur fauna. However, Lingwulong shows that these Diplodocus-like sauropods were present after all, and implies that the isolation of East Asia was less profound and short-lived than we realised,” said lead author, Dr Xing Xu (Institute of Vertebrate Paleontology & Paleoanthropology, Chinese Academy of Sciences, Beijing, China).

For the study, palaeontologists analysed the fossilised skeletons of 7-10 individual dinosaurs that were found together in rocks in 2005 and have been dated at approximately 174 million years old. Funding secured in 2016 by National Geographic Research enabled the formation of this Anglo-Chinese project to study the specimens in detail.

The team conclude that finding such a dinosaur ‘in the wrong place, at the wrong time’, emphasises the gaps in our knowledge of the fossil record and suggests that there are many surprises still to come.