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Marine fossil sheds light on arthropod evolution – Earth.com

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By investigating a cache of fossils containing the brain and nervous system of a 500-million-year-old marine predator from the Burgess Shale (a fossil deposit in the Canadian Rocky Mountains) called Stanleycaris, a team of researchers led by the Royal Ontario Museum (ROM) has managed to shed more light on the evolution of the arthropod brain, vision, and head structure.

Stanleycaris belongs to an ancient, extinct offshoot of the arthropod evolutionary tree called Radiodonta, which was distantly related to modern insects and spiders. With large compound eyes, a fierce circular mouth lined with teeth, frontal claws with an impressive array of spines, and a flexible, segmented body with several swimming flaps along its sides, Stanleycaris was most likely a feared marine predator that fed upon a large variety of sea-bottom dwellers.

The fossils discovered in the Burgess Shale contained extremely well-preserved remains of this prehistoric animal’s brain and nervous system. “While fossilized brains from the Cambrian Period aren’t new, this discovery stands out for the astonishing quality of preservation and the large number of specimens,” said study lead author Joseph Moysiuk, a doctoral student in Ecology and Evolutionary Biology at the University of Toronto. “We can even make out fine details such as visual processing centers serving the large eyes and traces of nerves entering the appendages. The details are so clear it’s as if we were looking at an animal that died yesterday.”

The fossils revealed that the brain of Stanleycaris consisted of two segments, the protocerebrum and the deutocerebrum, which were connected with the eyes and frontal claws, respectively. “We conclude that a two-segmented head and brain has deep roots in the arthropod lineage and that its evolution likely preceded the three-segmented brain that characterizes all living members of this diverse animal phylum,” Moysiuk explained.

In modern arthropods such as insects, the brain consists of three segments – the protocerebrum, the deutocerebrum, and the tritocerebrum. While the absence of one of these segments in Stanleycaris may not seem a fundamental game-changer, this discovery has in fact radical scientific implications. Since repeated copies of many arthropod organs can be found in their segmented bodies, clarifying how segments line up among different species is fundamental to understanding how these structures diversified during evolution. “These fossils are like a Rosetta Stone, helping to link traits in radiodonts and other early fossil arthropods with their counterparts in surviving groups,” said Moysiuk.

Moreover, the fact that this animal possessed a huge third eye at the front of its head shows that the earliest arthropods had already evolved a variety of complex visual systems like many of their modern counterparts, according to study senior author Jean-Bernard Caron, a curator of Invertebrate Paleontology at ROM. “Since most radiodonts are only known from scattered bits and pieces, this discovery is a crucial jump forward in understanding what they looked like and how they lived,” he concluded.

The study is published in the journal Current Biology

By Andrei Ionescu, Earth.com Staff Writer  

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Move over, Stegosaurus, there’s a new armored dino in town – Popular Science

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Paleontologists in southern Argentina have recently discovered an adorable, five-foot-long armored dinosaur. The Jakapil kaniukura roamed the Earth during the hot and humid Cretaceous period roughly between 145.5 and 65.5 million years ago, and weighed 9 to 15 pounds–the size of the average domestic cat. 

The tiny dino’s fossilized remains were dug up during multiple digs over the over the past 10 years near a dam in Patagonia’s Río Negro province. The province is home to the La Buitrera palaeontological zone, a region well-known for the discovery of three complete southern raptors (Unenlagia) skeletons, herbivorous terrestrial crocodiles, the oldest found chelid turtles, and more.

Jakapil is part of the Thyreophoran dinosaur group that lived from the Jurassic period to the early Cretaceous period whose name means “shield bearer.” This feisty-looking group includes the bony backed, spiky tailed Stegosaurus and the tank-like Ankylosaurus. Like its prickly cousins, Jakapil had built in physical defenses, with rows of bony oval-shaped armor along its neck, back, and down to its tail.

[Related: This fossilized butthole gives us a rare window into dinosaur sex.]

“It bears unusual anatomical features showing that several traits traditionally associated with the heavy Cretaceous thyreophorans did not occur universally,” wrote the study’s authors, Facundo J. Riguetti, Sebastián Apesteguía, and Xabier Pereda-Suberbiola. “Jakapil also shows that early thyreophorans had a much broader geographic distribution than previously thought.”

The team published their findings in the journal Scientific Reports on August 11th. They first discovered Jakapil’s partial skeleton alongside 15 tooth fragments, which revealed that jakapil’s teeth were leaf-shaped like a modern-day iguana’s. 

According to lead paleontologist Sebastián Apesteguía, Jakapil marks the first-of-its-kind discovery of an armored dinosaur from the Cretaceous in South America. It also resembles a more primitive form of thyreophoran dinosaur that lived in the area significantly earlier. 

“Thyreophorans originated about 200 million years ago and rapidly evolved into various species distributed throughout the world,” Riguetti, first author of the work and a Conicet doctoral fellow at the Center for Biomedical, Environmental and Diagnostic Studies at Maimónides University said in a release. “However,of these early thyreophorans, the lineage represented by ‘Jakapil’ was the only one that lasted until at least 100 million years ago.”

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Full moon may hinder most anticipated meteor shower of the year – DiscoverWestman.com

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This weekend is the peak of Perseid’s meteor shower, one of the best-known and largest celestial events that can be seen from Earth.

Throughout the past couple of days, meteors have been visible to on-lookers and will get an even better view during the event’s peak on Friday night.

“Meteors are these tiny little pieces of space dust that crash into the earth and burn up, and when that happens we see them in the sky as a falling star or a shooting star,” says Scott Young, the Planetarium Astronomer at the Manitoba Museum. “The meteor is sort of the official name for those objects, and on any night you can probably see one or two of those if you’re lucky, but on certain nights of the year, the Earth goes through a big cloud of cosmic dust and when you get all that dust hitting the Earth all on the same night, you get lots of meteors. So we call that a meteor shower.”

Young also says that it won’t look as if thousands of stars are falling out of the sky, but rather it will be one star every minute instead of one a night.

“It always occurs every year around August 11-13, somewhere in that range because we’re going through the dust bunny left behind by a comet that crosses Earth’s orbit. Now, that doesn’t always mean that you will see all of those things hitting the Earth, and the timing might happen during the day for you. It might be cloudy, or like this year, close to the full moon. When the full moon is up, it makes it hard to see some of those fainter meteors that you would see.”

The best time to see any meteor shower is between midnight and dawn. According to Young, even with the bright light of the full moon on the same night as the peak time to see meteors, it is a strong enough shower that viewers will still be able to see shooting stars. 

“The official peak occurs after midnight, Friday night, so Saturday morning around 3:00 a.m. our time. But to be honest, it’s not a single-night event. It builds up over a previous couple of weeks and each night there’ll be more and more meteor showers until the peak and then after the peak, it fades away for a couple of weeks.”

The comet that causes the meteor shower is comet Swift–Tuttle, discovered by Lewis Swift and Horace Parnell Tuttle in 1862.

“Each meteor shower over the course of the year has its own source objects, most of them are comets and we know that when we get close to the comet’s orbit in our orbit, we’ll see this meteor shower. They’re actually named after the constellations in the sky where the meteors look like they’re coming from. When we’re looking at the sky, it seems that the meteors from the Perseid meteor shower will come from the constellation Perseus, which is rising in the northeastern part of the sky at this time of year. That doesn’t mean you have to know where Perseus is, the meteors can appear all over the sky.”

To get the best view of the meteor shower peak, Young suggests viewers go to a place where there are not a lot of lights and even “put your back towards any bright lights that are like the moon or city lights.” He also suggests putting the phone away, because the bright light will cause your eyes to need time to adjust to the dark sky and some of the dimmer shooting stars may be missed.

“This is one of those things where you have to unplug, disconnect and just lay out under the stars, relax and look up. it’s a great therapeutic way to connect with the sky.”

Normally on the peak day of the event, Young will go out with an all-sky camera and broadcast live on the Manitoba Museum’s Facebook and YouTube pages, but he says it always depends on the weather.

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Talk like you: Scientists discover why humans evolved to talk while other primates can’t – Euronews

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Why did humans evolve to talk, while monkeys were left to hoot, squeak and grunt to communicate?

The question has long puzzled scientists, who blamed our closest primate cousins’ inability to reproduce human speech sounds on their vocal anatomy.

Until now, researchers could not quite underpin what happened exactly during our evolution to make us able to speak while apes and monkeys can’t, given our vocal structures look almost identical to other primates.

Now, a new study published on Thursday in the journal Science claims to have the answer – and it’s not what anyone expected.

Analysing the phonal apparatus – the larynx – of 43 species of primates, a team of researchers based mainly in Japan found that all non-human primates – from orangutans to chimpanzees – had an additional feature in their throat that humans do not have.

Ability to speak and develop languages

While both humans and non-human primates produce sounds by forcing air through their larynges, causing folds of tissue to vibrate, monkeys and apes have an additional feature, a thin flap of tissue known as vocal membranes, or vocal lips.

Compared to apes and monkeys, humans were found to lack this anatomical vocal membrane – a small muscle just above the vocal cords – as well as balloon-like laryngeal structures called air sacs which apes and monkeys use to produce the loud calls and screams we’re not quite capable of.

According to the researchers, humans have lost this extra vocal tissue over time, somehow simplifying and stabilising the sounds coming out of our throat, and allowing us, in time, to develop the ability to speak – and eventually develop very complex sophisticated languages.

Monkeys and apes, on the other hand, maintained these vocal lips which don’t really allow them to control the inflection and register of their voice and produce stable, clear vocal fold vibrations.

“Paradoxically, the increased complexity of human spoken language thus followed simplification of our laryngeal anatomy,” says the study.

Communication through sign language

It’s unclear when humans lost these extra tissues still present in apes and monkeys and became able to speak, as the soft tissues in the larynx are not preserved in fossils, and researchers could only study living species.

We know that it must have happened sometime after the Homo Sapiens lineage split from the other primates, some 6-7 million years ago.

The fact that apes and monkeys haven’t developed the ability to speak like humans doesn’t mean that they are not able to clearly communicate with each other.

Though their vocal anatomy doesn’t allow them to form vowel sounds and proper words, non-human primates have a complex communication system based primarily on body language rather than oral sounds.

But monkeys and apes have also proven to be able to communicate with humans.

In the not-often-happy history of the interaction between non-human primates and humans, researchers have been able to teach apes and monkeys to communicate with people.

Koko the gorilla, for example, became famous for being able to use over 1,000 hand signs in sign language, while the bonobo Kanzi was reportedly able to communicate using a keyboard.

But when it comes to having a chat, monkeys and humans might never be able to share one.

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