Oct 21, 2014

6,000-Year-Old Temple with Possible Sacrificial Altars Found

A 6,000-year-old temple holding human-like figurines and sacrificed animal remains has been discovered within a massive prehistoric settlement in Ukraine.

Built before writing was invented, the temple is about 60 by 20 meters (197 by 66 feet) in size. It was a "two-story building made of wood and clay surrounded by a galleried courtyard," the upper floor divided into five rooms, write archaeologists Nataliya Burdo and Mykhailo Videiko in a copy of a presentation they gave recently at the European Association of Archaeologists' annual meeting in Istanbul, Turkey.

Inside the temple, archaeologists found the remains of eight clay platforms, which may have been used as altars, the finds suggested. A platform on the upper floor contains "numerous burnt bones of lamb, associated with sacrifice," write Burdo and Videiko, of the Institute of Archaeology of the National Academy of Sciences of Ukraine. The floors and walls of all five rooms on the upper floor were "decorated by red paint, which created ceremonial atmosphere."

The ground floor contains seven additional platforms and a courtyard riddled with animal bones and pottery fragments, the researchers found.

Massive settlement

The temple, which was first detected in 2009, is located in a prehistoric settlement near modern-day Nebelivka. Recent research using geophysical survey indicates the prehistoric settlement is 238 hectares (588 acres), almost twice the size of the modern-day National Mall in Washington, D.C. It contained more than 1,200 buildings and nearly 50 streets.

A number of other prehistoric sites, of similar size, have been found in Ukraine and other parts of Eastern Europe. These sites are sometimes referred to as belonging to the "Trypillian" culture, a modern-day name. The name is derived from the village of Trypillia in Ukraine, where artifacts of this ancient culture were first discovered.

Archaeologists found that when this prehistoric settlement was abandoned, its structures, including the newly discovered temple, were burnt down, something that commonly occurred at other Trypillian culture sites.

Ornaments and figurines

Fragments of figurines, some of which look similar to humans, were also found at the temple. Like findings at other Trypillian sites, some of the figurines have noses that look like beaks and eyes that are dissimilar, one being slightly larger than the other.

Ornaments made of bone and gold were also discovered at the temple. The gold ornaments are less than an inch in size and may have been worn on the hair, researchers say.

Read more at Discovery News

King Tut Re-Creation Presents a Shocking Image

Tutankhamun’s beautiful golden mask, the embodiment of a man secure in his power, has been flattering the pharaoh for many centuries, according to the most detailed image yet of the teenage king’s face and body.

In the flesh, King Tut had a club foot, a pronounced overbite and girlish hips, says a “virtual autopsy” built using more than 2,000 computerized tomography (CT) scans of the pharaoh’s body.

Built for the BBC documentary, “Tutankhamun: the Truth Uncovered,” the shocking 3-D computer model could shed new light on the death of the boy pharaoh at the age of 19.

Previous theories suggested King Tut may have died as a result of a chariot accident, but the virtual reconstruction showed a different scenario.

“It was important to look at his ability to ride on a chariot and we concluded it would not be possible for him, especially with his partially clubbed foot, as he was unable to stand unaided,” Albert Zink, head of the Institute for Mummies and Icemen in Italy, told the U.K. daily The Independent.

According to Ashraf Selim, an Egyptian radiologist, King Tut “also developed Kohler’s disease or death of the bones, during adolescence, which would have been incredibly painful.”

Indeed, about 130 walking sticks found in King Tut’s treasure-packed tomb would support the theory that the boy pharaoh had to rely on canes to get around.

Zink believes the pharaoh’s early death was most likely caused from his weakened state — a result of genetic impairments inherited from his parents, who were siblings.

Indeed, in 2010 an international genetic study produced a five-generation pedigree of Tutankhamun’s immediate lineage. In the study, the mummy known as KV55 — most likely the “heretic” Akhenaten — and KV35YL, also known as the Younger Lady, were identified as siblings, as well as King Tut’s parents.

The study confirmed the frail king was afflicted by malaria and suffered a badly broken leg, above his knee, just before he died.

“It is difficult to say whether malaria may have been a serious factor in the cause of death,” Zink said.

The boy pharaoh has been puzzling scientists ever since his mummy and treasure-packed tomb were discovered on Nov. 22, 1922, in the Valley of the Kings by British archaeologist Howard Carter.

Read more at Discovery News

500-Year-Old Traces of Monster Hawaii Tsunami Discovered

A powerful earthquake in Alaska sent towering waves up to 30 feet (9 meters) tall crashing down on Hawaii about 500 years ago, leaving behind fragments of coral, mollusk shells and coarse beach sand in a sinkhole located on the island of Kauai, new research finds.

The quake, likely a magnitude 9.0, sent the mighty waves toward Hawaii sometime between 1425 and 1665, the study found. It's possible that another large Alaskan earthquake could trigger a comparable tsunami on Hawaii's shores in the future, experts said.

The tsunami was at least three times the size of the damaging 1946 tsunami, which was driven by an 8.6-magnitude earthquake off the Aleutian Islands. Mammoth tsunamis, like the one described in the study, are rare, and likely happen once every thousand years. There's a 0.1 percent chance it could happen in any given year, the same probability that northeastern Japan had for the 9.0-magnitude 2011 Tohoku earthquake and related tsunami, said Gerald Fryer, a geophysicist at the pacific Tsunami Warning Center in Ewa Beach, Hawaii, who was not involved in the study.

Results of the study have already prompted Honolulu officials to revise their tsunami evacuation maps, Fryer said. The new maps, which will affect nearly 1 million people who live in Honolulu County, would include more than twice the area of evacuation in some areas, Fryer said in a statement. County officials hope to distribute the new maps by the end of 2014, Fryer said.

"You're going to have great earthquakes on planet Earth, and you're going to have great tsunamis," said the study's lead researcher, Rhett Butler, a geophysicist at the University of Hawaii at Manoa. "People have to at least appreciate that the possibility is there."

Evidence of the colossal tsunami surfaced in the late 1990s during the excavation of the Makauwahi sinkhole, a collapsed limestone cave on the south coast of Kauai. About 6.5 feet (2 meters) below the surface, study researcher David Burney found a bounty of old debris that must have come from the ocean.

Curiously, the sinkhole's mouth is 328 feet (100 m) away from the present-day shore, and 23 feet (7 m) above sea level, suggesting the enormous quantities of corals and shells were probably carried there by a gigantic wave, Burney, a paleoecologist at the National Tropical Botanical Garden in Kalaheo, said. But he needed more evidence to back up his claim.

Tsunami surge

The debris remained a mystery until the 2011 Tohoku earthquake hit Japan. The earthquake triggered a rapid surge of water that stood 128 feet (39 m) above sea level and pummeled the Japanese coast. Soon after, researchers revisited Hawaii's tsunami evacuation maps. The maps are largely based on the 1946 tsunami, which caused water to rise 8 feet (2.5 m) up the side of the Makauwahi sinkhole.

"[The Japan earthquake] was bigger than almost any seismologist thought possible," Butler said. "Seeing [on live TV] the devastation it caused, I began to wonder, did we get it right in Hawaii? Are our evacuation zones the correct size?"

Butler and his colleagues assembled a wave model to predict how a tsunami might flood Kauai's coastline. They simulated earthquakes ranging between magnitudes 9.0 and 9.6 along the Aleutian-Alaska subduction zone, a 2,113-mile-long (3,400 kilometers) ocean trench where the Pacific tectonic plate slips under the North American plate.

In the aftermath of a large earthquake, the eastern Aleutians' distinctive geography could send a large tsunami toward Hawaii, the researchers found. In fact, a magnitude- 9.0 earthquake in just the right spot could easily direct water levels of 26 to 30 feet (8 to 9 m) high toward Kauai, carrying debris into the Makauwahi sinkhole, they found.

The researchers also looked for tsunami evidence in other places. Radiocarbon dating showed that the marine deposits in the sinkhole, on Sedanka Island off the coast of Alaska and along the west coasts of Canada and the United States all date back to the same time period, and may have come from the same tsunami.

"[The researchers] stitched together geological evidence, anthropological information as well as geophysical modeling to put together this story that is tantalizing for a geologist, but it's frightening for people in Hawaii," Robert Witter, a geologist at the U.S. Geological Survey in Anchorage, Alaska, who was not involved in the study, said in the statement.

More evidence is needed to determine whether the deposits came from the same tsunami, Witter said. For instance, radiocarbon dating, which the study researchers relied on, only gives a rough time estimate. It's possible that multiple tsunamis between 350 and 575 years ago deposited the debris at the three locations, he said.

Read more at Discovery News

When Massive Black Holes Snuff Out Star Birth

As galaxies mature, they stop forming stars — but why? Now astronomers are hot on the trail of finding the culprit.

By now we know that the vast majority of galaxies have supermassive black holes in their cores. These galactic behemoths generate some energetic phenomena, especially when matter falls onto their accretion disks and event horizons. Often, the energy generated by active galactic nuclei (where these rambunctious black holes reside), will regulate the star formation processes in their host galaxy.

Now, in a new study published in the journal Monthly Notices of the Royal Astronomical Society, researchers believe that they’ve found the reason why maturing galaxies seem to “switch off” star formation all together.

“When you look into the past history of the universe, you see these galaxies building stars,” said Tobias Marriage, of Johns Hopkins University and co-lead author of the study. “At some point, they stop forming stars and the question is: Why? Basically, these active black holes give a reason for why stars stop forming in the universe.”

Marriage and his colleagues used an established method for studying large clusters of galaxies and applying it to single galaxies. By doing this, they discovered that supermassive black holes are driving “radio-frequency feedback,” which is heating up the galaxies, preventing interstellar gases from cooling, clumping and forming new stars.

In short, massive black holes, at a certain age, act like a switch and are snuffing out star formation before it can even take hold.

Normally, the Sunyaev–Zel’dovich (SZ) effect signature is used to study how the primordial cosmic microwave background radiation (the ‘echo’ of the Big Bang) interacts with the electrons inside interstellar gases locked in clusters of hundreds of galaxies. But for the first time, this method has been down-scaled to gauge the interstellar environment of single galaxies.

“The SZ is usually used to study clusters of hundreds of galaxies but the galaxies we’re looking for are much smaller and have just a companion or two,” said Megan Gralla, also of Johns Hopkins.

“What we’re doing is asking a different question than what has been previously asked,” Gralla said. “We’re using a technique that’s been around for some time and that researchers have been very successful with, and we’re using it to answer a totally different question in a totally different subfield of astronomy.”

So, while studying the SZ effect signature in galaxies, the researchers found that all the galaxies displaying radio-frequency feedback coincided with galaxies that also lacked signs of star formation. It just so happened that these particular galaxies were large and mature elliptical galaxies, where their heated interstellar gas was prevented from cooling down.

“If gas is kept hot, it can’t collapse,” said Marriage. If the gas cannot collapse, no new stars can form.

Read more at Discovery News

Oct 20, 2014

Puppy-Sized Spider Romps in Rainforest

Piotr Naskrecki was taking a nighttime walk in a rainforest in Guyana, when he heard rustling as if something were creeping underfoot. When he turned on his flashlight, he expected to see a small mammal, such as a possum or a rat.

"When I turned on the light, I couldn't quite understand what I was seeing," said Naskrecki, an entomologist and photographer at Harvard University's Museum of Comparative Zoology.

A moment later, he realized he was looking not at a brown, furry mammal, but an enormous, puppy-size spider.

Known as the South American Goliath birdeater (Theraphosa blondi), the colossal arachnid is the world's largest spider, according to Guinness World Records. Its leg span can reach up to a foot (30 centimeters), or about the size of "a child's forearm," with a body the size of "a large fist," Naskrecki told Live Science. And the spider can weigh more than 6 oz. (170 grams) — about as much as a young puppy, the scientist wrote on his blog.

Some sources say the giant huntsman spider, which has a larger leg span, is bigger than the birdeater. But the huntsman is much more delicate than the hefty birdeater — comparing the two would be "like comparing a giraffe to an elephant," Naskrecki said.

The birdeater's enormous size is evident from the sounds it makes. "Its feet have hardened tips and claws that produce a very distinct, clicking sound, not unlike that of a horse's hooves hitting the ground," he wrote, but "not as loud."

When Naskrecki approached the imposing creature in the rainforest, it would rub its hind legs against its abdomen. At first, the scientist thought the behavior was "cute," he said, but then he realized the spider was sending out a cloud of hairs with microscopic barbs on them. When these hairs get in the eyes or other mucous membranes, they are "extremely painful and itchy," and can stay there for days, he said.

But its prickly hairs aren't the birdeater's only line of defense; it also sports a pair of 2-inch-long (5 centimeters) fangs. Although the spider's bite is venomous, it's not deadly to humans. But it would still be extremely painful, "like driving a nail through your hand," Naskrecki said.

And the eight-legged beast has a third defense mechanism up its hairy sleeve. The hairs on the front of the spider's body have tiny hooks and barbs that make a hissing sound when they rub against each other, "sort of like pulling Velcro apart," Naskrecki said.

Yet despite all that, the spider doesn't pose a threat to humans. Even if it bites you, "a chicken can probably do more damage," Naskrecki said.

Despite its name, the birdeater doesn't usually eat birds, although it is certainly capable of killing small mammals. "They will essentially attack anything that they encounter," Naskrecki said.

The spider hunts in leaf litter on the ground at night, so the chances of it encountering a bird are very small, he said. However, if it found a nest, it could easily kill the parents and the chicks, he said, adding that the spider species has also been known to puncture and drink bird eggs.

Read more at Discovery News

Earth's Magnetic Field Could Flip Within a Lifetime

A pilot looking down at her plane controls and realizing magnetic north is hovering somewhere over Antarctica may sound like a scene from a science-fiction movie, but new research suggests the idea isn't so far-fetched in the relatively near future.

A magnetic field shift is old news. Around 800,000 years ago, magnetic north hovered over Antarctica and reindeer lived in magnetic south. The poles have flipped several times throughout Earth's history. Scientists have estimated that a flip cycle starts with the magnetic field weakening over the span of a few thousand years, then the poles flip and the field springs back up to full strength again. However, a new study shows that the last time the Earth's poles flipped, it only took 100 years for the reversal to happen.

The Earth's magnetic field is in a weakening stage right now. Data collected this summer by a European Space Agency (ESA) satellite suggests the field is weakening 10 times faster than scientists originally thought. They predicted a flip could come within the next couple thousand years. It turns out that might be a very liberal estimate, scientists now say.

"We don't know whether the next reversal will occur as suddenly as this one did, but we also don't know that it won't," Paul Renne, director of the Geochronology Center at the University of California, Berkeley, said in a statement.

Geologists still are not sure what causes the planet's magnetic field to flip direction. Earth's iron core acts like a giant magnet and generates the magnetic field that envelops the planet. This helps protect against blasts of radiation that erupt from the sun and sometimes hurtle toward Earth. A weakening magnetic field could interrupt power grids and radio communication, and douse the planet in unusually high levels of radiation.

While the ESA satellite studied the magnetic field from above, Renne and a team of researchers studied it from below. The researchers dug through ancient lake sediments exposed at the base of the Apennine Mountains in Italy. Ash layers from long-ago volcanic eruptions are mixed into the sediment. The ash is made of magnetically sensitive minerals that hold traces of Earth's magnetic field lines, and the researchers were able to measure the direction the field was pointing.

Renne and colleagues then used a technique called argon-argon dating — which works because radioactive potassium-40 decays into argon-40 at a known rate — to determine the age of the rock sediment. The layers built up over a 10,000-year period, and the researchers could pinpoint where the poles flipped in the rock layers. The last flip happened around 786,000 years ago.

Sudden swap

The sediment layers also showed the magnetic field was unstable for about 6,000 years before the abrupt flip-flop. The period of instability included two low points in the field's strength, each of which lasted about 2,000 years.

Geologists don't know where the magnetic field is now in that reversal timescale or if this flip will even follow the same pattern as the last. The bottom line is that no one is sure when it's coming.

"We don't really know whether the next reversal is going to resemble the last one, so it's impossible to say whether we're just seeing the first of possibly several excursions (slight movements), or a true reversal," Renne told Live Science in an email.

Magnetic doomsday?

While a pole flip could cause a few technical issues, there's no need to panic. Scientists have combed the geological timeline for any evidence of catastrophes that might be related to a magnetic flip. They haven't found any.

The only havoc that a reversal would wreak is interference in the global electric grid. No direct evidence remains of past catastrophes triggered by a magnetic flip.

Read more at Discovery News

'Oldest Parisian': Neanderthal Fossil Suggests Hunting Injury

Three arm bones from a prehistoric individual, likely a Neanderthal, were uncovered in the Seine Valley of northern France, suggesting that Neanderthals had a temporary camp along the river 200,000 years ago.

The long left arm bones, dated at 200,000 years old, are the oldest human ancestor remains ever to be discovered in Tourville-la-Rivière, about 72 miles (116 kilometers) northwest of Paris. Fossils from this time period are rare, and may help fill in gaps about the evolution of humans and their close relatives, the researchers said.

"These are the oldest fossils found near Paris. It's the oldest Parisian, if you like," study researcher Bruno Maureille, at the Université de Bordeaux in Talence, France, told the BBC.

The bones, found in September 2010, consist of a humerus, radius and ulna from a left arm. Based on their size, the bones probably belonged to an adult or older adolescent, the researchers said.

The left humerus shows a curious injury that may indicate signs of muscle damage near the shoulder, possibly from doing a repetitive action, such as throwing or hammering, said study researcher Erik Trinkaus, a professor of anthropology at Washington University in St. Louis.

Trinkaus and his colleagues examined the humerus in detail, finding that it measures 9.1 inches (23.2 centimeters) and has a bony crest 1.6 inches (4 cm) long. Computer tomography scans suggest the crest may be evidence of an injury to the deltoid muscle at the owner's shoulder.

The individual may have gotten the injury from throwing a spear while hunting, even though all of the spears anthropologists have found from that time period are large and heavy, Trinkaus said.

If the injury is indicative of overuse from throwing, the newly found humerus would provide evidence that early humans and their relatives may have thrown spears 200,000 years ago, he said.

That interpretation is "controversial" but plausible, said Brian Richmond, a curator of anthropology at the American Museum of Natural History in New York, who was not involved in the study. "It looks like the bone kind of grew out [from the arm], probably from some damage where the muscle was attached to it," Richmond told Live Science.

It's unclear what caused the injury, but "they're arguing that this may be due to repetitive use, possibly throwing," Richmond said.

The guess isn't a bad one, he said. Humans are unusually good at throwing, whereas other animals, such as chimpanzees and apes, can't throw as accurately or as fast people can. "We seem to have an anatomy that's well designed for that," Richmond said. "And that anatomy probably goes back to as far as the Neanderthals."

Read more at Discovery News

New Book Explores the Building Blocks of Everything From Poison to Soap

Theodore Gray likes chemicals. “I’m not a shill for DOW, or Dupont, or anyone in the industry. I just think these things are cool, and are good to have around,” he said. His new book, Molecules, is dedicated to exploring chemistry’s building blocks on their own terms.

Molecules is the middle in a three book series about chemistry. It shares the same graphic style and tone as its predecessor, Elements, and according to Gray it was a lot harder to organize. In Elements, the table of contents mirrored the periodic table. But there was no methodical, objective way to cover the millions of molecules that exist in nature, so eventually he gave up and decided to write about whatever he found interesting.

That is how he ended up with a book that gives the same weight to explaining how molecules create color as it does to exploring the similarities of pepper and poison, and looks as just as deeply into artificial sweeteners as it does into opioid drugs. Speaking of drugs, Molecules rarely shies away from taboo topics, even though it’s targeted for classrooms. “I want to be able to talk about the chemistry of these interesting compounds without getting hung up on the controversies,” he said. Still, his publisher wasn’t comfortable with everything, and he had to make some compromises. “We had this absolutely gorgeous marijuana bud taking up a whole page, but we ended up taking it out.”

Of note is the book’s fuzzy, blue take on the classic stick-and-ball molecular model. These models, Gray says, do not represent the reality of molecules, but are merely convenient schematics. The blueish fuzz serves to remind readers that each molecule’s nuclei are vanishingly small, and if you could actually see them they would be blurred by a haze of unpredictable electrons.

Gray has a bachelor’s degree in chemistry, but got sidetracked from pursuing his PhD in the 1980s by an offer to co-found the computational software company Wolfram Research (You might be familiar with their knowledge engine, Wolfram Alpha). Between building that company and his career as an author, he won an Ig Nobel Prize for his hand made Periodic Table (really, it’s a wooden table), and for several years wrote a column for Popular Science.

Read more at Wired Science

Oct 19, 2014

Crystallizing the DNA nanotechnology dream

DNA has garnered attention for its potential as a programmable material platform that could spawn entire new and revolutionary nanodevices in computer science, microscopy, biology, and more. Researchers have been working to master the ability to coax DNA molecules to self assemble into the precise shapes and sizes needed in order to fully realize these nanotechnology dreams.

For the last 20 years, scientists have tried to design large DNA crystals with precisely prescribed depth and complex features -- a design quest just fulfilled by a team at Harvard's Wyss Institute for Biologically Inspired Engineering. The team built 32 DNA crystals with precisely-defined depth and an assortment of sophisticated three-dimensional (3D) features, an advance reported in Nature Chemistry.

The team used their "DNA-brick self-assembly" method, which was first unveiled in a 2012 Science publication when they created more than 100 3D complex nanostructures about the size of viruses. The newly-achieved periodic crystal structures are more than 1000 times larger than those discrete DNA brick structures, sizing up closer to a speck of dust, which is actually quite large in the world of DNA nanotechnology.

"We are very pleased that our DNA brick approach has solved this challenge," said senior author and Wyss Institute Core Faculty member Peng Yin, Ph.D., who is also an Associate Professor of Systems Biology at Harvard Medical School, "and we were actually surprised by how well it works."

Scientists have struggled to crystallize complex 3D DNA nanostructures using more conventional self-assembly methods. The risk of error tends to increase with the complexity of the structural repeating units and the size of the DNA crystal to be assembled.

The DNA brick method uses short, synthetic strands of DNA that work like interlocking Lego® bricks to build complex structures. Structures are first designed using a computer model of a molecular cube, which becomes a master canvas. Each brick is added or removed independently from the 3D master canvas to arrive at the desired shape -- and then the design is put into action: the DNA strands that would match up to achieve the desired structure are mixed together and self assemble to achieve the designed crystal structures.

"Therein lies the key distinguishing feature of our design strategy -- its modularity," said co-lead author Yonggang Ke, Ph.D., formerly a Wyss Institute Postdoctoral Fellow and now an assistant professor at the Georgia Institute of Technology and Emory University. "The ability to simply add or remove pieces from the master canvas makes it easy to create virtually any design."

The modularity also makes it relatively easy to precisely define the crystal depth. "This is the first time anyone has demonstrated the ability to rationally design crystal depth with nanometer precision, up to 80 nm in this study," Ke said. In contrast, previous two-dimensional DNA lattices are typically single-layer structures with only 2 nm depth.

"DNA crystals are attractive for nanotechnology applications because they are comprised of repeating structural units that provide an ideal template for scalable design features," said co-lead author graduate student Luvena Ong.

Furthermore, as part of this study the team demonstrated the ability to position gold nanoparticles into prescribed 2D architectures less than two nanometers apart from each other along the crystal structure -- a critical feature for future quantum devices and a significant technical advance for their scalable production, said co-lead author Wei Sun, Ph.D., Wyss Institute Postdoctoral Fellow.

"My preconceived notions of the limitations of DNA have been consistently shattered by our new advances in DNA nanotechnology," said William Shih, Ph.D., who is co-author of the study and a Wyss Institute Founding Core Faculty member, as well as Associate Professor in the Department of Biological Chemistry and Molecular Pharmacology at Harvard Medical School and the Department of Cancer Biology at the Dana-Farber Cancer Institute. "DNA nanotechnology now makes it possible for us to assemble, in a programmable way, prescribed structures rivaling the complexity of many molecular machines we see in Nature."

Read more at Science Daily

First Sex Happened Between Square-Dancing Fish

The origin of mating via sexual intercourse has been pushed back nearly 100 million years to 430 million years ago when, according to a new study, an ancient type of fish engaged in copulation that resembled square dancing.

The remains of one such male, nicknamed “Big Boy,” include the earliest known sexual organ for any vertebrate (an animal with a backbone or spinal column). Big Boy and his mate -- both primitive jawed fish -- are described in the latest issue of the journal Nature.

Their sexual intercourse, the first to involve internal fertilization, explains why these fish had tiny arms.

“We have found large L-shaped bony claspers (penis-like organs) on the males, which were so large they could have only reached the female’s genital region if the fishes were lying side by side,” lead author John Long told Discovery News.

“The tiny arms, which were jointed in these fishes, would have probably interlocked to help the male position the clasper into position for mating, hence it looked a bit like they were doing a square dance.”

Long, a paleontologist at Flinders University, and his colleagues investigated fossils for the fish, known as “antiarch placoderms,” which are the earliest primitive jawed fishes. Remains suggest that the fish from the genus Microbrachius (meaning tiny arms) lived in ancient lakes of Scotland, as well as in parts of Estonia and China.

The researchers believe that animals in general first procreated by external fertilization, but that as antiarch placoderms evolved their jaws, they also evolved anatomy permitting internal fertilization: internal and external fertilization both come with benefits and drawbacks. Later bony fish lost this anatomy and ability.

The former, Long explained, requires more effort but protects young “from predation, allowing the mother to invest more time nurturing this young until they are ready to be born or hatch from large eggs.”

External fertilization, on the other hand, means the parents can produce numerous eggs, hoping that at least some will survive. He indicated that many fish in non-turbulent waters tend to reproduce this way, while some fish in fast-running streams tend to copulate, keeping their sperm and eggs inside their bodies, protecting them.

Long and his team now think that humans and all other vertebrates are distantly related to placoderms, since all share key traits in common: paired hind limbs; paired bony skull plates with sutures (a type of fibrous joint); similarly structured inner ears, jaws, teeth, and vertebrae; abdominal muscles; and, last but not least, sexual intercourse.

Co-author Zerina Johanson, a researcher at the Natural History Museum in London, said, “Now we know that internal fertilization is the general condition for placoderms and is the most primitive type of reproduction for vertebrates.”

Matt Friedman, a paleobiologist from the University of Oxford who did not work on the research, described the discovery as “nothing short of remarkable.”

“Claspers in these fishes demand one of two alternative, but equally provocative, scenarios: either an unprecedented loss of internal fertilization in vertebrates, or the coherence of the armored placoderms as a single branch in the tree of life,” Friedman said.

Read more at Discovery News