‘Asteroid, not volcanoes, killed dinosaurs’


This 2016 video says about itself:

How Asteroids Really Killed The Dinosaurs – Part 1 | Last Days of the Dinosaurs

In the clip from Last Days of the Dinosaur, we learn how the asteroids really killed the dinosaurs

Asteroid Day is celebrated every year on the 30th of June.

This 2016 video says about itself:

How Asteroids Really Killed The Dinosaurs – Part 2 | Last Day Of The Dinosaurs

Did you know that if the asteroid that wiped out the dinosaurs from the face of the Earth would have hit another location, they might still be alive? The shallow waters of the Gulf Of Mexico instantly vaporized as the asteroid hit, causing absolute destruction. This was the Last Day Of The Dinosaurs.

From Yale University in the USA:

In death of dinosaurs, it was all about the asteroid — not volcanoes

January 16, 2020

Volcanic activity did not play a direct role in the mass extinction event that killed the dinosaurs, according to an international, Yale-led team of researchers. It was all about the asteroid.

In a break from a number of other recent studies, Yale assistant professor of geology & geophysics Pincelli Hull and her colleagues argue in a new research paper in Science that environmental impacts from massive volcanic eruptions in India in the region known as the Deccan Traps happened well before the Cretaceous-Paleogene extinction event 66 million years ago and therefore did not contribute to the mass extinction.

Most scientists acknowledge that the mass extinction event, also known as K-Pg, occurred after an asteroid slammed into Earth. Some researchers also have focused on the role of volcanoes in K-Pg due to indications that volcanic activity happened around the same time.

“Volcanoes can drive mass extinctions because they release lots of gases, like SO2 and CO2, that can alter the climate and acidify the world,” said Hull, lead author of the new study. “But recent work has focused on the timing of lava eruption rather than gas release.”

To pinpoint the timing of volcanic gas emission, Hull and her colleagues compared global temperature change and the carbon isotopes (an isotope is an atom with a higher or lower number of neutrons than normal) from marine fossils with models of the climatic effect of CO2 release. They concluded that most of the gas release happened well before the asteroid impact — and that the asteroid was the sole driver of extinction.

“Volcanic activity in the late Cretaceous caused a gradual global warming event of about two degrees, but not mass extinction,” said former Yale researcher Michael Henehan, who compiled the temperature records for the study. “A number of species moved toward the North and South poles but moved back well before the asteroid impact.”

Added Hull, “A lot of people have speculated that volcanoes mattered to K-Pg, and we’re saying, ‘No, they didn’t.'”

Recent work on the Deccan Traps, in India, has also pointed to massive eruptions in the immediate aftermath of the K-Pg mass extinction. These results have puzzled scientists because there is no warming event to match. The new study suggests an answer to this puzzle, as well.

“The K-Pg extinction was a mass extinction and this profoundly altered the global carbon cycle,” said Yale postdoctoral associate Donald Penman, the study’s modeler. “Our results show that these changes would allow the ocean to absorb an enormous amount of CO2 on long time scales — perhaps hiding the warming effects of volcanism in the aftermath of the event.”

The International Ocean Discovery Program, the National Science Foundation, and Yale University helped fund the research.

Giant squid genome research


This 2015 video says about itself:

A giant Architeuthis dux squid was caught on camera when it swam into a harbor in Japan on Christmas Eve. The young squid is estimated to be 12 feet long, and scientists say the species can reach over 40 feet in length.

From the Marine Biological Laboratory in the USA:

The mysterious, legendary giant squid’s genome is revealed

January 16, 2020

How did the monstrous giant squid — reaching school-bus size, with eyes as big as dinner plates and tentacles that can snatch prey 10 yards away — get so scarily big?

Today, important clues about the anatomy and evolution of the mysterious giant squid (Architeuthis dux) are revealed through publication of its full genome sequence by a University of Copenhagen-led team that includes scientist Caroline Albertin of the Marine Biological Laboratory (MBL), Woods Hole.

Giant squid are rarely sighted and have never been caught and kept alive, meaning their biology (even how they reproduce) is still largely a mystery. The genome sequence can provide important insight.

“In terms of their genes, we found the giant squid look a lot like other animals. This means we can study these truly bizarre animals to learn more about ourselves,” says Albertin, who in 2015 led the team that sequenced the first genome of a cephalopod (the group that includes squid, octopus, cuttlefish, and nautilus).

Led by Rute da Fonseca at University of Copenhagen, the team discovered that the giant squid genome is big: with an estimated 2.7 billion DNA base pairs, it’s about 90 percent the size of the human genome.

Albertin analyzed several ancient, well-known gene families in the giant squid, drawing comparisons with the four other cephalopod species that have been sequenced and with the human genome.

She found that important developmental genes in almost all animals (Hox and Wnt) were present in single copies only in the giant squid genome. That means this gigantic, invertebrate creature — long a source of sea-monster lore — did NOT get so big through whole-genome duplication, a strategy that evolution took long ago to increase the size of vertebrates.

So, knowing how this squid species got so giant awaits further probing of its genome.

“A genome is a first step for answering a lot of questions about the biology of these very weird animals,” Albertin said, such as how they acquired the largest brain among the invertebrates, their sophisticated behaviors and agility, and their incredible skill at instantaneous camouflage.

“While cephalopods have many complex and elaborate features, they are thought to have evolved independently of the vertebrates. By comparing their genomes we can ask, ‘Are cephalopods and vertebrates built the same way or are they built differently?'” Albertin says.

Albertin also identified more than 100 genes in the protocadherin family — typically not found in abundance in invertebrates — in the giant squid genome.

“Protocadherins are thought to be important in wiring up a complicated brain correctly,” she says. “They were thought they were a vertebrate innovation, so we were really surprised when we found more than 100 of them in the octopus genome (in 2015). That seemed like a smoking gun to how you make a complicated brain. And we have found a similar expansion of protocadherins in the giant squid, as well.”

Lastly, she analyzed a gene family that (so far) is unique to cephalopods, called reflectins. “Reflectins encode a protein that is involved in making iridescence. Color is an important part of camouflage, so we are trying to understand what this gene family is doing and how it works,” Albertin says.

“Having this giant squid genome is an important node in helping us understand what makes a cephalopod a cephalopod. And it also can help us understand how new and novel genes arise in evolution and development.”

Damselfly, dragonfly evolution, new resesarch


This 2014 video is called The Secret World of Dragonflies.

From the University of Minnesota in the USA:

Glimpse into ancient hunting strategies of dragonflies and damselflies

January 16, 2020

Dragonflies and damselflies are animals that may appear gentle but are, in fact, ancient hunters. The closely related insects shared an ancestor over 250 million years ago — long before dinosaurs — and provide a glimpse into how an ancient neural system controlled precise and swift aerial assaults.

A paper recently published in Current Biology, led by University of Minnesota researchers, shows that despite the distinct hunting strategies of dragonflies and damselflies, the two groups share key neurons in the circuit that drives the hunting flight. These neurons are so similar, researchers believe the insects inherited them from their shared ancestor and that the neurons haven’t changed much.

Gaining insight into their ability to quickly process images could inform technological advancements. These findings could inform where to mount cameras on drones and autonomous vehicles, and how to process the incoming information quickly and efficiently.

“Dragonflies and damselflies are interesting from an evolutionary point of view because they give us a window into ancient neural systems,” said Paloma Gonzalez-Bellido, assistant professor in the Department of Ecology, Evolution and Behavior in the College of Biological Sciences and senior author on the paper. “And because there are so many species, we can study their behavior and compare their neural performance. You can’t get that from fossils.”

A noticeable difference between dragonflies and damselflies is the shape and position of their eyes. Most dragonflies today have eyes that are close together, often touching along the top of their head. Whereas damselflies sport eyes that are far apart. The researchers wanted to know whether this made a difference in their hunting habits, and if it affected how their neural system detects moving prey.

Researchers found:

  • dragonflies and damselflies hunt prey differently, with dragonflies using a higher resolution area near the top of their eyes to hunt prey from below and damselflies leveraging increased resolution in the front of their eyes to hunt prey in front of them;
  • in dragonflies with eyes that merge at the top, the eyes work as if they were two screens of an extended display (i.e. the image of the prey, which would be equivalent to the mouse pointer, can fall on either the left or the right, but never in both screens at the same time);
  • damselflies eyes work as duplicated screens, where the prey image is seen by both eyes at once (i.e. they have binocular vision);
  • both designs have pros and cons, and their presence correlates with the type of prey and the environment;
  • despite different strategies, the neurons that transfer information about a moving target from the brain to the wing motor centers are nearly identical in the two groups — indicating they were inherited from the common ancestor.

The different hunting strategies pay off in different environments. Dragonflies tend to hunt in an open area, leveraging the contrast of the sky to help them spot their target. Although they can’t calculate depth using two images, they rely on other cues. Damselflies tend to hunt among vegetation, where the selective pressure for fast reaction may be absent, or the need for depth perception stronger.

Researchers are now looking to understand how the extended versus duplicated images are calculated in the brain, and how the information is implemented into muscle movements.

“There is still a lot we do not understand,” said Jack Supple, first author and a recent PhD graduate from Gonzalez-Bellidos laboratory. “We do not know how these neurons coordinate all the different muscles in the body during flight. If we tried to build a realistic robotic damselfly or dragonfly tomorrow we would have a difficult time.”

In addition to examining the differences amongst the two insect families, researchers continue to explore differences in species within each family. “While most dragonflies have eyes close together, there are a handful of species with eyes far apart,” said Gonzalez-Bellido. “Some of them are abundant in Minnesota and we are eager to leverage the new flight arena to study their behavior in a controlled setting.”

Researchers aim to collect at Cedar Creek Ecosystem Science Reserve and Itasca Biological Station and Laboratories this summer, both areas with diverse populations of dragonflies and damselflies.

Ancient scorpion, oldest land animal?


The fossil (left) was unearthed in Wisconsin in 1985. Scientists analyzed it and discovered the ancient animal's respiratory and circulatory organs (center) were near-identical to those of a modern-day scorpion (right). Images courtesy Andrew Wendruff

From Ohio State University in the USA:

Fossil is the oldest-known scorpion

Researchers think it was one of the first animals to spend time on land

January 16, 2020

Scientists studying fossils collected 35 years ago have identified them as the oldest-known scorpion species, a prehistoric animal from about 437 million years ago. The researchers found that the animal likely had the capacity to breathe in both ancient oceans and on land.

The discovery provides new information about how animals transitioned from living in the sea to living entirely on land: The scorpion‘s respiratory and circulatory systems are almost identical to those of our modern-day scorpions — which spend their lives exclusively on land — and operate similarly to those of a horseshoe crab, which lives mostly in the water, but which is capable of forays onto land for short periods of time.

The researchers named the new scorpion Parioscorpio venator. The genus name means “progenitor scorpion,” and the species name means “hunter.” They outlined their findings in a study published today in the journal Scientific Reports.

“We’re looking at the oldest known scorpion — the oldest known member of the arachnid lineage, which has been one of the most successful land-going creatures in all of Earth history,” said Loren Babcock, an author of the study and a professor of earth sciences at The Ohio State University.

“And beyond that, what is of even greater significance is that we’ve identified a mechanism by which animals made that critical transition from a marine habitat to a terrestrial habitat. It provides a model for other kinds of animals that have made that transition including, potentially, vertebrate animals. It’s a groundbreaking discovery.”

The “hunter scorpion” fossils were unearthed in 1985 from a site in Wisconsin that was once a small pool at the base of an island cliff face. They had remained unstudied in a museum at the University of Wisconsin for more than 30 years when one of Babcock’s doctoral students, Andrew Wendruff — now an adjunct professor at Otterbein University in Westerville — decided to examine the fossils in detail.

Wendruff and Babcock knew almost immediately that the fossils were scorpions. But, initially, they were not sure how close these fossils were to the roots of arachnid evolutionary history. The earliest known scorpion to that point had been found in Scotland and dated to about 434 million years ago. Scorpions, paleontologists knew, were one of the first animals to live on land full-time.

The Wisconsin fossils, the researchers ultimately determined, are between 1 million and 3 million years older than the fossil from Scotland. They figured out how old this scorpion was from other fossils in the same formation. Those fossils came from creatures that scientists think lived between 436.5 and 437.5 million years ago, during the early part of the Silurian period, the third period in the Paleozoic era.

“People often think we use carbon dating to determine the age of fossils, but that doesn’t work for something this old,” Wendruff said. “But we date things with ash beds — and when we don’t have volcanic ash beds, we use these microfossils and correlate the years when those creatures were on Earth. It’s a little bit of comparative dating.”

The Wisconsin fossils — from a formation that contains fossils known as the Waukesha Biota — show features typical of a scorpion, but detailed analysis showed some characteristics that were not previously known in any scorpion, such as additional body segments and a short “tail” region, all of which shed light on the ancestry of this group.

Wendruff examined the fossils under a microscope, and took detailed, high-resolution photographs of the fossils from different angles. Bits of the animal’s internal organs, preserved in the rock, began to emerge. He identified the appendages, a chamber where the animal would have stored its venom, and — most importantly — the remains of its respiratory and circulatory systems.

This scorpion is about 2.5 centimeters long — about the same size as many scorpions in the world today. And, Babcock said, it shows a crucial evolutionary link between the way ancient ancestors of scorpions respired under water, and the way modern-day scorpions breathe on land. Internally, the respiratory-circulatory system has a structure just like that found in today’s scorpions.

“The inner workings of the respiratory-circulatory system in this animal are, shape-wise, identical to those of the arachnids and scorpions that breathe air exclusively,” Babcock said. “But it also is incredibly similar to what we recognize in marine arthropods like horseshoe crabs. So, it looks like this scorpion, this lineage, must have been pre-adapted to life on land, meaning they had the morphologic capability to make that transition, even before they first stepped onto land.”

Paleontologists have for years debated how animals moved from sea to land. Some fossils show walking traces in the sand that may be as old as 560 million years, but these traces may have been made in prehistoric surf — meaning it is difficult to know whether animals were living on land or darting out from their homes in the ancient ocean.

But with these prehistoric scorpions, Wendruff said, there was little doubt that they could survive on land because of the similarities to modern-day scorpions in the respiratory and circulatory systems.

How remora fishes hitchhike with sharks, whales


This June 2016 video says about itself:

Everything You Need to Know About Those Fish That Attach to Sharks

It’s called a remora, and you’ve probably seen it before. It attaches to fish and marine mammals all the time. But get this: It doesn’t attach with its mouth. It’s got a suction cup it wears as a hat.

From the New Jersey Institute of Technology in the USA:

Discovery reveals how remora fishes know when to hitch a ride aboard their hosts

January 15, 2020

Summary: Researchers have detailed the discovery of a tactile-sensory system stowed within the suction disc of remora, believed to enable the fish to acutely sense contact pressure with host surfaces and gauge ocean forces in order to determine when to initiate their attachment, as well as adjust their hold on hosts while traversing long distances.

Remoras are among the most successful marine hitchhikers, thanks to powerful suction discs that allow them to stay tightly fastened to the bodies of sharks, whales and other hosts despite incredible drag forces while traveling through the ocean. But how do these suckerfish sense the exact moment when they must “stick their landing” and board their speedy hosts in the first place?

A team of biologists at New Jersey Institute of Technology (NJIT), Friday Harbor Labs at University of Washington (FHL-UW) and The George Washington University (GWU) now offers an answer.

In findings published in the Journal of the Royal Society Open Science, researchers have detailed the discovery of a tactile-sensory system stowed within the suction disc of remora, believed to enable the fish to acutely sense contact pressure with host surfaces and gauge ocean forces in order to determine when to initiate their attachment, as well as adjust their hold on hosts while traversing long distances.

Specifically, the study describes the discovery of groupings of push-rod-like touch receptors, or mechanoreceptor complexes, embedded in the outer lip of the remora adhesive disc, which have been known to aid other organisms in responding to touch and shear forces.

Researchers say the finding marks the first time such touch-sensory complexes have been described in fishes, as the structure was previously only known in extant monotremes — platypus and echidnas.

“One of the wildest things about this work was not only finding a mechanoreceptor complex not previously known to fishes, but that the only other organisms known to possess them are monotremes,” said Brooke Flammang, NJIT professor of biological sciences and lead author of the study. “This is exciting because it shows how much we as integrative comparative biologists still have to learn about the sensory world of organisms.”

“When I was in graduate school, conventional wisdom was that fishes did not have such mechanoreceptors,” said Patricia Hernandez, one of the study’s authors at The George Washington University. “The discovery that these fishes share convergent receptors with echidnas is really exciting and points us in the right direction for discovering similar convergence in other fishes.”

While conducting various imaging studies to examine the head and disc of Echeneis naucrates, a common sharksucker remora, the team successfully identified the complexes: dome-like protrusions along the surface of the soft tissue lip surrounding the remora’s adhesive disc. Each dome packs below it a column of cells with three vesicle chains containing sensory nerves that stretch from the disc’s epidermal layer down to its dermal layer. In addition to sensing contact, these complexes are thought to respond to shear stress, which would provide feedback information to the remora if it was losing its grip and sliding backward on its host.

“When we first noticed these structures we were a little thrown off,” said Karly Cohen, a Ph.D. biology student at FHL-UW and an author on the study. “We knew they had to be sensory because of the plethora of nerves, but they didn’t look like lateral line structures, which are one of the main ways fishes sense their environment. We dove into the literature to try and find structures that fit the morphology of those we saw in the remora histology. Finally landing on the push-rod receptors known in echidnas was so exciting. … It was validation of the morphology we were seeing and it took us into a realm of mechnosensation that we were not necessarily considering when thinking about how the remora stick.”

Notably, in further examining seven other remora species, the team found that those species known to frequently piggyback on larger and faster hosts, like pelagic billfish, are equipped with nearly double the mechanoreceptor complexes of remora species that typically hitchhike on slower swimmers, such as reef fishes.

“On animals swimming very fast where the remora may be under increased drag conditions, the need to recognize loss of contact and make an instant correction is more crucial than on slower swimming hosts,” noted Flammang.

Flammang and colleagues say that the touch-signaling complexes found in remoras suggest not only that fishes may be able to sense their environment in ways not previously realized, but that specialized mechanoreceptors may also be a much more common feature among basal vertebrates than was previously thought as well.

“The interesting aspect here is that push-rods are only otherwise known in platypus and echidnas,” said Flammang. “Obviously, there is no close phylogenetic relationship between remoras and monotremes, so this likely means that there are a lot of mechanoreceptors in vertebrates that just haven’t been found in a wide breadth of organisms. We hope this paper brings this structure to the attention of other researchers for comparative study on how their organisms sense the environment.”

Feathered dinosaurs differed from birds


This 2013 BBC video says about itself:

With its feathered plumage acting as camouflage Sinornithosaurus moves unseen through the treetops. Recent studies suggest Sinornithosaurus was capable of hunting at night as well as delivering a lethal poison in its bite.

From San Diego Natural History Museum in the USA:

New feathered dinosaur shows dinosaurs grew up differently from birds

January 15, 2020

A new species of feathered dinosaur has been discovered in China, and described by American and Chinese authors and published today in the journal The Anatomical Record.

The one-of-a-kind specimen offers a window into what the earth was like 120 million years ago. The fossil preserves feathers and bones that provide new information about how dinosaurs grew and how they differed from birds.

“The new dinosaur fits in with an incredible radiation of feathered, winged animals that are closely related to the origin of birds“, said Dr. Ashley Poust, who analyzed the specimens while he was a student at Montana State University and during his time as a Ph.D. student at University of California, Berkeley. Poust is now postdoctoral researcher at the San Diego Natural History Museum.

“Studying specimens like this not only shows us the sometimes-surprising paths that ancient life has taken, but also allows us to test ideas about how important bird characteristics, including flight, arose in the distant past.”

Scientists named the dinosaur Wulong bohaiensis. Wulong is Chinese for “the dancing dragon” and references the position of the beautifully articulated specimen.

Wulong bohaiensis

About the discovery

The specimen was found more than a decade ago by a farmer in China, in the fossil-rich Jehol Province, and since then has been housed in the collection of The Dalian Natural History Museum in Liaoning, a northeastern Chinese province bordering North Korea and the Yellow Sea. The skeletal bones were analyzed by Poust alongside his advisor Dr. David Varricchio from Montana State University while Poust was a student there.

Larger than a common crow and smaller than a raven, but with a long, bony tail which would have doubled its length, Wulong bohaiensis had a narrow face filled with sharp teeth. Its bones were thin and small, and the animal was covered with feathers, including a wing-like array on both its arms and legs and two long plumes at the end of its tail.

This animal is one of the earliest relatives of Velociraptor, the famous dromaeosaurid theropod dinosaur that lived approximately 75 million years ago. Wulong’s closest well-known relative would have been Microraptor, a genus of small, four-winged paravian dinosaurs.

The discovery is significant not only because it describes a dinosaur that is new to science, but also because it shows connection between birds and dinosaurs.

“The specimen has feathers on its limbs and tail that we associate with adult birds, but it had other features that made us think it was a juvenile,” said Poust. To understand this contradiction, the scientists cut up several bones of the new dinosaur to examine under a microscope. This technique, called bone histology, is becoming a regular part of the paleontology toolbox, but it’s still sometimes difficult to convince museums to let a researcher remove part of a nice skeleton. “Thankfully, our coauthors at the Dalian Natural History Museum were really forward-thinking and allowed us to apply these techniques, not only to Wulong, but also to another dinosaur, a close relative that looked more adult called Sinornithosaurus.”

The bones showed that the new dinosaur was a juvenile. This means that at least some dinosaurs were getting very mature looking feathers well before they were done growing. Birds grow up very fast and often don’t get their adult plumage until well after they are full-sized. Showy feathers, especially those used for mating, are particularly delayed. And yet here was an immature dinosaur with two long feathers extending beyond the tip of the tail.

“Either the young dinosaurs needed these tail feathers for some function we don’t know about, or they were growing their feathers really differently from most living birds,” explained Poust.

An additional surprise came from the second dinosaur the scientists sampled; Sinornithosaurus wasn’t done growing either. The bone tissue was that of an actively growing animal and it lacked an External Fundamental System: a structure on the outside of the bone that vertebrates form when they’re full size. “Here was an animal that was large and had adult looking bones: we thought it was going to be mature, but histology proved that idea wrong. It was older than Wulong, but seems to have been still growing. Researchers need to be really careful about determining whether a specimen is adult or not. Until we learn a lot more, histology is really the most dependable way.”

In spite of these cautions, Poust says there is a lot more to learn about dinosaurs.

“We’re talking about animals that lived twice as long ago as T. rex, so it’s pretty amazing how well preserved they are. It’s really very exciting to see inside these animals for the first time.”

About the Jehol Biota

The area in which the specimen was found is one of the richest fossil deposits in the world. The Jehol biota is known for the incredible variety of animals that were alive at the time. It is also one of the earliest bird-rich environments, where birds, bird-like dinosaurs, and pterosaurs all shared the same habitat.

“There was a lot of flying, gliding, and flapping around these ancient lakes,” says Poust. “As we continue to discover more about the diversity of these small animals it becomes interesting how they all might have fit into the ecosystem.” Other important changes were happening at the same time in the Early Cretaceous, including the spread of flowering plants. “It was an alien world, but with some of the earliest feathers and earliest flowers, it would have been a pretty one.”

Naturalis museum video


This 15 January 2020 video from Leiden in the Netherlands says about itself:

We are Naturalis Biodiversity Center. Through our impressive collection, knowledge and data, we record all life on Earth. This is important, as our future depends on biodiversity. Everything in nature is connected, and balance is vitally important for its continued existence. Naturalis has a passion for nature. We research nature in order to preserve biodiversity. This is how we contribute to solutions for major, global issues involving climate, living environment, food supply and medicine.