Tag Archives: fossils

Fossil Friday: Italy’s largest discovery of dinosaurs is a herd of 11 specimens

Every once in a while, paleontologists make some breathtaking discoveries. Recently, it was the turn of Italian paleontologists to do so, and a new paper reports on the remarkable finding: a herd of 11 fossilized dinosaurs, including the largest and most complete such reptile to ever be discovered in the country.

The fossilized skeleton of ‘Bruno’. Image credits Alfio A. Chiarenza et al., (2021), Nature Scientific Reports.

Italy isn’t known as a hotbed of dinosaur fossils. There have been a handful of discoveries here, most of them in the last 30 years or so. By and large, however, Italian dinosaur hunters generally look to places outside of their motherland when searching for fossils.

But a new paper comes to show that there are still hidden paleontological gems to be found in Italy. The fossilized herd was unearthed at the Villaggio del Pescatore site, a protected area in Italy that has yielded dinosaur fossils in the past, as well.

An impressive haul

“Italy is not known for dinosaurs and, although we had a few lucky strikes in the past, now we have a whole herd at one dinosaur site,” said Federico Fanti, a professor at the University of Bologna and corresponding author of the paper describing the findings.

Villaggio del Pescatore is the site of a former limestone quarry close to the city of Trieste. Back in 1996, an almost complete dinosaur skeleton was unearthed here, initially believed to have belonged to a “dwarf species”, which paleontologists named “Antonio” at the time. However, the new discovery calls into question the assumption that it belonged to a dwarf species.

The freshly-discovered herd consists of 11 specimens of hadrosaurids of the species Tethyshadros insularis. These dinosaurs lived some 80 million years ago and could reach up to five meters (around 16 feet) in length. The herd includes the largest and most complete dinosaur skeleton ever recovered from Italy, an individual christened “Bruno”. Beyond how spectacular the find itself is, it also helped paleontologists better identify the species of Antonio.

Unlike previously believed, Antonio was not a dwarf dinosaur, but rather a juvenile — most likely a member of the same herd unearthed now.

Geology and geographic context of Villaggio del Pescatore (VdP). The star symbol marks the relative position in the paleogeography of the Tethys (c) where VdP most likely originated. Image credits Alfio A. Chiarenza et al., (2021), Nature Scientific Reports.

“Bruno is the biggest and oldest of the group, and the most complete dinosaur skeleton ever found in Italy,” said Fanti.

“We knew there were dinosaurs at the site after the discovery of Antonio, but up until now nobody actually checked to see how many. What we have now are multiple bones belonging to the same herd.”

Around the time these dinosaurs were alive, the site at Villaggio del Pescatore was very close to water, being on the shoreline of the ancient layout of the Mediterranean sea. The discovery of fish, crocodiles, flying reptiles, and small shrimp alongside the dinosaur herd provides further evidence of this.

“This is super cool as we can figure out the kind of environment the dinosaurs lived and died in,” added Fanti. “During that period, the area was very close to the shoreline in a tropical, warm and humid environment capable of feeding herds of dinosaurs.”

The site is still closed to the public, but paleontologists hope to make at least part of it open to visitation in the future. Until then, fossil aficionados can see some of the fossils recovered so far at the site at the Civic Museum of Natural History in Trieste.

The paper “An Italian dinosaur Lagerstätte reveals the tempo and mode of hadrosauriform body size evolution” has been published in the journal Nature Scientific Reports.

Fossil(ish) Friday: Minnesotans want the Giant Beaver to be their new state fossil

The people of Minnesota have just elected their new state fossil: it’s going to be a Giant Beaver (Castoroides ohioensis). Hopefully.

The specimen that the Museum enrolled in the voting competition.

Don’t you just love democracy at work? The Minnesota Science Museum certainly does. They’ve asked the people “what should our state fossil be?” using the magic of the Internet, and the people have answered. A Wednesday post on the Museum’s page together with a live broadcast revealed that the vote went to a Giant Beaver specimen in their collection.

All that’s left now is to make it official.

Big Beaver

“Thank you for voting for our state fossil! What comes next, you ask? We’ll bring your massive mammal candidate to the legislature!”

The Science Museum of Minnesota offered the public a chance to vote which among nine specimens (we’ll see them in a bit) in its collection should come to represent the state as its state fossil. The Giant Beaver received 11,000 votes. It outdid other iconic species such as the crow shark, trilobite, and scimitar-toothed cat. Overall, a landslide win — it gained around 25% of all the votes cast in the competition.

So what exactly were Giant Beavers? Unsurprisingly, they were giant relatives of today’s beavers. Outwardly and in behavior, they resembled the dam-building mammals we all know and love; they had buck teeth and an aquatic lifestyle.

But there were some differences as well: Giant Beavers grew to around 200 pounds and could reach between 1.9 m and 2.2 m (6.2 ft to 7.2 ft) in length. They lived between 2.58 million years and 10,150 years ago, during a geological Epoch known as the Pleistocene.

In many ways, they looked like oversized versions of the beavers that inhabit Minnesota to this day, although their hind legs were much shorter with bigger feet relative to their body proportions. Their teeth were much larger, although proportional to their bigger bodies, but with a rough, striated enamel texture; modern beavers have smooth-textured enamel protecting their teeth. Judging from their skulls, however, we’re pretty confident that Giant Beavers had a smaller brain volume relative to their body, meaning they were probably not quite as smart as modern beavers and had less sophisticated interactions with their environment.

The genus Castoroides was first described from a specimen found in the USA in Ohio (hence its scientific name ‘ohioensis’). All known specimens have been unearthed from the USA and Canada. They’re generally clustered around the midwestern United States in states near the Great Lakes, particularly Illinois and Indiana. However, their habitat certainly ranged between today’s Alaska, Canada, and Florida, as Castoroides specimens have been found at these sites.

“Pretty impressive right? There’s beavers still throughout Minnesota today, they’re an important part of the ecosystems here. A lot of people have seen them, and learned to love these little toothy critters, so why wouldn’t you love an even larger version of that?” said Alex Hastings, the museum’s chair of paleontology, during the livestream on Wednesday.

The specimen that won this competition was found at a site near St. Paul, Minnesota. The museum will present the fossil alongside the results of the vote to lawmakers, who will get to decide if the Giant Beaver should become the state’s first official fossil. Minnesota is one of only seven states that have yet to designate an official fossil; the others are Arkansas, Hawaii, Indiana, Iowa, New Hampshire, and Rhode Island. The Giant Beaver almost became Minnesota’s official fossil back in 1988, but the measure failed in the legislature. Fingers crossed it makes it this time!

The museum also put up some cool and actually damn funny YouTube videos for each of the contenders, which you can see on their individual voting pages; they’re still up, even if the voting is closed. I will put up links to the individual pages or directly to their YouTube shorts for your convenience (the ones here are for the Giant Beaver).

Go give them a subscribe and some likes if you’re on YouTube, it really helps them out, and they really deserve it. I wish Netflix had content as good as this.

But we’re all here for fossils, and every runner-up in this competition is definitely deserving of some of our love.

Endoceras.

These squid-like creatures were among the largest animals alive during their time (during the Ordovician Period around 450 million years ago) and sported 10 arms. This specimen at the Science Museum of Minnesota was found by a local collector. Individual page and YouTube link.

Stromatolite.

Stromatolites have the honor of being the oldest fossils in Minnesota. They do look unassuming, but that comes down to their history. These clumpy fossils were formed almost 2 billion years ago by photosynthesizing bacteria. What you’re seeing here are the fossils of the first oxygen-producing organisms on Earth. They started the trend that led all the way to us breathing oxygen today. Individual page and YouTube link.

Squalicorax (Crow Shark).

An extinct species that lived during the Cretaceous Period, 90 to 100 million years ago, the Crow Shark prowled the seas as dinosaurs roamed the Earth. Judging by the serrations on its teeth, this shark used to punch high above its weight — and tooth marks found on the bones of fish, dinosaurs, marine reptiles, and even some flying reptiles tell us that it did so with frightening enthusiasm. Individual page and YouTube link.

Dikelocephalus minnesotensis (Trilobite).

Trilobites… were sea bugs. A great, very diverse family of sea bugs who lived during the Cambrian Period, between 492 and 487 million years ago. This particular species got its name for being discovered near Stillwater, Minnesota, and that specimen is now housed at the Smithsonian National Museum of Natural History. Individual page and YouTube link.

Bison antiquus.

A relatively young contender, this bison native to Minnesota lived between 60,000 and 4,270 years ago, making the transition from the Late Pleistocene to the Holocene Epoch (the one we’re currently in right now). This species eventually gave rise to the bison we all know. They were probably larger than modern bison, however. Individual page and YouTube link.

Homotherium serum (Scimitar Toothed Cat).

A large predator that stalked the tundras of Minnesota some 27,000 years ago during the Pleistocene Epoch. It had somewhat smaller canines than the infamous saber toothed cat, but more muscular shoulders and arms. Individual page and YouTube link.

Terminonaris robusta.

An extinct (and much bigger) relative of the modern crocodile that lived between 90 and 100 million years ago during the Cretaceous Period. Like modern crocs, it was very toothy and not afraid to bite. Individual page and YouTube link.

Mammuthus columbi.

The Columbian Mammoths lived during the Pleistocene Epoch, between 2 million and 12,000 years ago. They’re one species that are well represented in the state of Minnesota, as the tundra landscapes present here at that time were an ideal stomping ground for these huge beasts. This particular tusk belongs to the Lyle Mammoth which was discovered in the state and is now on display at the Science Museum of Minnesota. Individual page and YouTube link.

All images in this post are courtesy of the Science Museum of Minnesota.

The oldest animal life on Earth was discovered in Canada: 890 million years old

A Canadian paleontologist may have found the earliest evidence of life on Earth — and it’s much older than we thought.

a. and b. show the fossils that Turner believes show evidence of sponge life; compared with the spongin skeleton of a modern sponge, shown in c. Image credit: Turner, 2021, Nature CC by 4.0

Life as we know it took a pretty funky turn around 541 million years ago. That’s when a period called the Cambrian emerged, and with it, the so-called Cambrian explosion ushered in practically all major groups of animals. It lasted for about 25 million years and resulted in the divergence of life as we know it.

Before the Cambrian explosion, life on Earth was simple and small. It was composed either of individual cells, or of microscopic, multicellular organisms — or at least so we thought.

Scientists have found some evidence of animal life existing before the Cambrian. In particular, some sponges (immobile aquatic animals) seem to have emerged before the Cambrian. But how long before it?

According to a recent study, the first sponges emerged a whopping 350 million years before the Cambrian — or 890 million years ago.

“If I’m right, animals emerged long, long before the first appearance of traditional animal fossils,” study author Elizabeth Turner told Nature. “That would mean there’s a deep back history of animals that just didn’t get preserved very well.”

The fossils discovered by Turner, from a remote area of northwestern Canada accessible only by helicopter, resemble some modern sponges known as keratose demosponges. The researchers dated the layer of rocks in which the sponge fossils were found, a solid analysis tool that leaves little room for question regarding the fossils’ age. The identification as sponges also seems pretty clear.

“This organic skeleton is very characteristic [of sponge fossils],” explained geobiologist Joachim Reitner, who reviewed Turner’s study ahead of publication. “[T]here are not known comparable structures.”

But a finding that would force us to reconsider the evolution of life on Earth won’t happen easily, and Turner’s peers are rightfully raising all sorts of questions regarding the fossils. Some point out that the findings may not be fossils at all (but rather other structures), while others are focusing on another question: if life emerged a few hundred million years before the Cambrian, why haven’t we found any fossils of it until this?

Ultimately, if the finding is confirmed, it will help us understand the evolution of life on Earth.

“We are animals,” Turner said. “And we have a big brain, and we’re capable of wondering about stuff, and we wonder how we came to be. 

“What happened before, and what was it like? How did it begin?” she said. “This is really digging into that. I’m shaking up the apple cart.”  

The study has been published in Nature.

Hallett Cove’s fossil secrets are now accessible through virtual reality

Filled with fossils and traces of glacial activity, the Hallett Cove Conservation Park in Australia is one of the best-known geological sites in the land down under. Now, thanks to virtual reality technology, visitors from around the world can explore its fossilized landscape in a new gamified VR experience.

Credit Dietmar Down Under. Flickr (CC BY 2.0)

The project, “Beyond the Ice,” was developed by the University of South Australia’s Project LIVE team in partnership with Framework VR and the Australian Institute of Mining and Metallurgy (AusIMM). It aims to reveal, in spectacular 3D detail, the hidden stories behind Hallett cove.

Accessible through a VR headset, the online experience lets you visit 17 different geological sites of Hallett Cove. It uses 3D models obtained created with data from drone surveys, 360-degree panoramas, and “walk-through” footage that helps identify fossils, draw outlines of rock folds, and measure glacial grooves.

Beyond the Ice is freely available online and can be used from anywhere in the world, which might come handy with tourism being limited due to the coronavirus pandemic. The users are guided by a virtual robot and can do quizzes, collect 3D pet rocks, and even uncover hidden Easter eggs.

“Unlike many VR experiences, this is a lot more than some pretty pictures and 3D models thrown together that don’t really offer much as a learning exercise. It was designed as an interactive, gamified experience that engages people in science by challenging them to unlock the geological secrets of Hallett Cove,” Tom Raimondo, project leader, said in a press release.

Leaving aside its broad novelty and appeal, the project also offers important educational aspects, particularly as an authentic supplement to fieldwork. Raimondo said that through this virtual reality tour students can repeat, reflect, on and extend their field skills across different locations.

Preserved by nature in an ancient valley for hundreds of millions of years, the landscape at Hallett Cove paints an incredible picture of Australia’s past, including an ice age at the South Pole, the rise of the Mt Lofty Ranges, and the breakup of the supercontinent Gondwana.

More than 1,700 Aboriginal artifacts have been found on Hallett Cove. Its outstanding glacial pavements along the northern cliff tops are recognized as the best record of Permian glaciation in Australia and have international significance. The area is a popular tourist destination in Australia.

“Not only does virtual reality provide a flexible way to engage the next generation of science students, it also lets us adapt the program to suit different audiences, different skill levels and different field locations, so it’s a really fantastic step forward in online and immersive learning,” said Raimondo.

Amber fossils reveal the true colors of 99-million-year-old insects

Researchers have discovered the true colors of a group of fossilized insects, trapped in amber approximately 99 million years ago in Myanmar. The ancient insects include cuckoo wasps, soldier flies, and beetles, all bursting in metallic blue, purple, and green colors.

Comparisons between original and altered metallic colors in cleptine wasps. Credit: NIGPAS.

Nature is very visually rich but fossils rarely retain evidence of an organism’s original color. Nevertheless, paleontologists are now finding ways of teasing out colors from well-preserved fossils, whether they be dinosaurs and flying reptiles or ancient snakes and mammals.

Knowing the color of extinct species is actually very important, as it can tell researchers many things about the behavior of the animals. Colors could have been used to attract mates or warn off predators or even help with temperature regulation, for example. Knowing more about them can also help researchers know more about ecosystems and environments.

For the new study, a research team from the Nanjing Institute of Geology and Palaeontology of the Chinese Academy of Sciences (NIGPAS) looked at 35 individual amber samples with fantastically preserved insects trapped inside. The fossils were found in an amber mine in northern Myanmar.

The amber is mid-Cretaceous, approximately 99 million years old, dating back to the golden age of dinosaurs,” said Cai Chenyan, the lead author, in a press release. “It is essentially resin produced by ancient coniferous trees that grew in a tropical rainforest environment. Animals and plants trapped in the thick resin got preserved, some with life-like fidelity.”

Colors in nature usually fall under three main categories: bioluminescence, pigments, and structural colors. The amber fossils found retained structural colors, which tend to be intense and rather eye-grabbing (including metallic colors) and are produced by microscopic light-scattering structures located on the heads, bodies, and limbs of animals.

The researchers polished the fossils using sandpaper and diatomite powder. Some pieces of amber were polished into very thin slices, making the insects clearly observable and the surrounding amber matrix almost transparent in bright light. The images included in the study were edited to adjust for brightness and contrast.

“The type of color preserved in the amber fossils is called structural color,” said Pan Yanhong, a co-author of the study, in a statement. “The surface nanostructure scatters light of specific wavelengths” which “produces very intense colors,” said Pan, adding that this “mechanism is responsible for many of the colors we know from our everyday lives.”

Diverse structural-colored insects in mid-Cretaceous amber from northern Myanmar. Credit: NIGPAS.

Among all the fossils, the cuckoo wasps were particularly stunning, with their heads, thorax, abdomen, and legs featuring hues of metallic blue-green, yellow-red, violet, and green. The color patterns were a close match to cuckoo wasps alive today, according to the research. Other standouts included blue and purple beetles and metallic dark-green soldier flies.

The researchers used electron microscopy to demonstrate that the amber fossils have a “well-preserved exoskeleton nanostructure that scatters light.”

“Our observations strongly suggest that the color preserved in some amber fossils may be the same as displayed by the insects when alive, some 99 million years ago,” wrote the authors in the study. “This is moreover corroborated by the fact that metallic blue-green coloration is frequently found in extant living cuckoo wasps.”

The study was published in the journal Proceedings of the Royal Society B.

Fossil Friday: teeny tiny T. rexes showcase the predator’s teenage years

New research found that two dinosaur skeletons believed to belong to a previously-unknown species were, in fact, immature tyrannosaurus rexes.

Back in the early 2000s, members from the Burpee Museum of Natural History in Rockford, Illinois collected two fossil skeletons from Carter County, Montana. These specimens, christened “Jane” and “Petey,” were about as tall as a draft horse and about two times as long. Their bones hinted at a predator species but, due to their size, it was believed we were looking at a diminutive relative of the species.

The skull of the juvenile T. rex, “Jane”
Image credits Scott A. Williams.

Now, new research shows that both Jane and Petey were, in fact, teenage tyrannosaurs, aged 13 and 15.

Terrible teens

“Historically, many museums would collect the biggest, most impressive fossils of a dinosaur species for display and ignore the others,” said Holly Woodward, a Ph.D. at Oklahoma State University Center for Health Sciences, who led the study.

“The problem is that those smaller fossils may be from younger animals. So, for a long while we’ve had large gaps in our understanding of how dinosaurs grew up, and T. rex is no exception.”

The team looked within the fossilized bones to determine the age at which these animals died. This technique is known as paleohistology and involves the analysis of bone microstructures of a particular specimen to determine how fast it grew and at what age it stopped. To do this, the team took thin slices from the leg bones of both specimens and investigated them at high magnification.

Cyclical growth marks resembling tree rings in a femur and tibia bone from the specimens.
Image credits Woodward et al., (2020), Science Advances.

Jane and Petey met their end at 13 and 15 years old, respectively, the team reports. Determining their age also helped clarify the issue of species as well. Previously, the fossils were believed to belong to a pygmy relative of the tyrannosaur known as Nanotyrannus.

The research does help us better understand the lives of these immense predators. Woodward points out that it took T. rex up to twenty years to reach adult size, and as such they probably experienced dramatic physical changes as they matured. She adds that Jane and Petey, being juveniles, were likely lightning-fast and used their sharp, blade-like teeth to tear flesh. Adults, on the other hand, were likely much more cumbersome and used their massive jaws to crack open bones through sheer force.

One interesting find the team made is that T. rex could work around periods with scarce food by simply not growing as much. When food became plentiful again, it would grow rapidly, they add.

“The spacing between annual growth rings record how much an individual grows from one year to the next. The spacing between the rings within Jane, Petey, and even older individuals is inconsistent — some years the spacing is close together, and other years it’s spread apart,” said Woodward.

Still, as evidenced by their growth spurts, even in early life T. rex was a formidable predator.

The paper “Growing up Tyrannosaurus rex: histology refutes pygmy ‘Nanotyrannus’ and supports ontogenetic niche partitioning in juvenile Tyrannosaurus” has been published in the journal Science Advances.

The best fossils may need oxygen — just a little — to form

We may have had a few bad assumptions about how fossils form, a new study suggests.

Image credits Aryok Mateus.

The prevailing wisdom among paleontologists today is that fossils form in the absence of oxygen. It isn’t a simple guess: some of the best-preserved fossils ever found formed in oxygen-poor conditions in ancient oceans.

However, new research from the University of Texas at Austin found that this assumption wasn’t wrong, but rather incomplete. Fossil formation is jump started in anoxic (‘without oxygen’) conditions, but oxygen is eventually required to complete the process.

Not too little, not too much

“The traditional thinking about these exceptionally preserved fossil sites is wrong,” said lead author Drew Muscente. “It is not the absence of oxygen that allows them to be preserved and fossilized. It is the presence of oxygen under the right circumstances.”

The best-preserved fossils tend to come from Lagerstätte (German for ‘storage place’), rare sedimentary deposits that make up an anoxic, relatively bacteria-free environment. The unique conditions in Lagerstätten support tissue conservation. Fossils in these structures can even preserve soft tissues like flesh or fur alongside hard tissues like bone. This makes them a unique (and uniquely valuable) window into ancient ecosystems.

The new paper examined the fossilization processes at an exceptional fossil site (Ya Ha Tinda Ranch in Canada’s Banff National Park). The site is known for its unique collection of delicate marine life from the Early Jurassic trapped in slabs of black shale. Lobsters have been found in very good condition here, as well as some vampire squids with ink sacks still intact, the team explains.

At the time these animals died (about 183 million years ago), the world’s ocean water had lower levels of oxygen than it does today, consistent with our understanding of fossilization processes. In order to determine whether the fossils started forming in an oxygen-deprived environment, the team analyzed their mineral makeup using a scanning electron microscope (different minerals form in different chemical conditions).

“When you look at lagerstätten, what’s so interesting about them is everybody is there,” said Jackson School undergraduate Brooke Bogan, paper co-author. “You get a more complete picture of the animal and the environment, and those living in it.”

“The cool thing about this work is that we can now understand the modes of formation of these different minerals as this organism fossilizes,” adds Rowan Martindale, Jackson School Assistant Professor and co-author. “A particular pathway can tell you about the oxygen conditions.”

The vast majority of the fossils analyzed were formed of apatite, a phosphate-based mineral. Most importantly, however, we know that apatite needs oxygen to form — so the fossils were at some point in their formation exposed to this gas. Factor in that animals need oxygen to live, and it becomes pretty obvious that at least some of it was floating around dissolved in the ancient ocean water. That being said, however, the team also found that the climatic conditions of a low-oxygen environment helped set the stage for fossilization once oxygen became available.

Periods of low ocean oxygen are linked to high global mean temperatures, which causes sea levels to rise (yes, what we’re causing today). Higher seas come into contact with fresh rocks on the coast and start eroding them, which generates a large influx of phosphate. But, if this low-oxygen state persists, this phosphate simply escapes the sediment (created by rock erosion) and dissolves into the water. The team explains that oxygen is needed to fix this phosphate in sediment, where it can take part in fossilization processes. Muscente said that the apatite fossils of Ya Ha Tinda point to this mechanism.

The researchers plan to continue their work by analyzing specimens from exceptional fossil sites in Germany and the United Kingdom that were preserved around the same time as the Ya Ha Tinda specimens and compare their fossilization histories.

The paper “Taphonomy of the lower Jurassic Konservat-Lagerstätte at Ya Ha Tinda (Alberta, Canada) and its significance for exceptional fossil preservation during oceanic anoxic events” has been published in the journal PALAIOS.

Fossils in La Brea Tar Pits redraw picture of saber-toothed cats

Usually described as fierce predators, saber-toothed cats are imagined as stalking the open savannah in pursuit of bison, horses and other grassland-dwelling prey. But a new study paints a much less fierce image of the now long-extinct animals.

Illustration depicting the hunting behavior of La Brea carnivores, including saber-toothed cats, dire wolves, and coyotes. Credit: Mauricio Antón.

A team of researchers led by Vanderbilt University’s Larisa DeSantis recovered fossils from the La Brea Tar Pits in California, which suggested that the up to 600-pound cat actually preferred hunting in the forest, were easy targets, including tapirs and deer, congregated. The work was published in the journal Current Biology.

Based on an analysis of more than 700 fossil teeth belonging to multiple prehistoric species, the findings contradict the idea that competition among carnivores drove saber-toothed cats and other megafauna to extinction some 10,000 to 12,000 years ago.

“The cats, including saber-toothed cats, American lions, and cougars, hunted prey that preferred forests, while it was the dire wolves that seemed to specialize on open-country feeders like bison and horses,” DeSantis explained. “While there may have been some overlap in what the dominant predators fed on, cats and dogs largely hunted differently from one another.

The scientists’ research pinpoints a different explanation for the giant cat’s demise, positing that factors, including climate change and an uptick in nearby human populations, which precipitated the species’ eventual extinction. Smaller predators such as coyotes, on the other hand, weathered harsh conditions.

DeSantis and her colleagues arrived at their conclusions by studying microscopic patterns of wear on fossil teeth, as well as the proportions of two carbon isotopes found within tooth enamel. These isotopes, passed along from plant-eating prey to carnivorous predators, identify victims’ preferred habitat as open versus forested environments.

The La Brea Tar Pits, bubbling pools of natural asphalt that attracted predators and prey alike, have yielded more than 3.5 million specimens representing some 600 species. Most of these unlucky animals were carnivores lured in by the carcasses of horses, bison, and camels already caught in the tar; rather than escaping with an easy meal, the predators soon found themselves similarly stuck.

La Brea Tar Pits. Credit: Flickr

Previous research had focused on carbon and nitrogen isotopes found within a bone protein called collagen. These analyses concluded that prehistoric predators from saber-toothed cats to dire wolves and American lions hunted in open environments, competing for the same limited pool of prey.

“When we look at the enamel, we get a totally different picture,” DeSantis said. “We find that the saber-tooth cats, American lions, and cougars are actually doing what cats typically do, which is hunting within forested ecosystems and using cover to potentially ambush their prey.

Nanotyrannus and the Skeptical Criteria for Species

The classification of varying species, even the very term species itself, has long been a puzzling element of taxonomic categorization. Pulled from the Latin phrase species (meaning “appearance”), the term, in regards to its scientific use, has more than two dozen different definitions.

Based on this information alone, we can see how precisely pinpointing what declares a specimen a specific species is not quite clear. It is, perhaps, unique to each individual case. Numerous factors need to be taken into account. When biologists examine an organism to see if it is identical to or distinct from another species, they analyze its attributes. In comparing it to other organisms, they look for common characteristics or reproduction compatibility, or the lack of either.

However, when studying the remains of organisms of eons past, definitively declaring a species can be more difficult. Take a look at the drawn-out Jane and Nanotyrranus dilemma, for example. More than 15 years ago now, a dinosaur skeleton was unearthed in Montana by a team from the Burpee Museum of Natural History from Rockford, Illinois. The remains were rather well-preserved. They belonged to a ferocious carnivore of the Cretaceous Period. But what kind of carnivore?

Skeleton of a T. Rex. Source: Wikipedia.

It was a tyrannosaurid. Well, that narrows it down a bit, kind of like narrowing one’s selection from mammals down to bears. We have eliminated countless possibilities, yet there are quite a few bear species to go through. Similarly, there is a variety of species of tyrannosaurids to compare the remains of one to.

It was 20 feet in length, 7 feet in height, and its gender was undetermined. Regardless of that trifling mystery, the tyrannosaurid was dubbed Jane. Paleontologists made their observations. But not all agreed on what the appropriate classification of this specimen should be. Some suggested it could be a Nanotyrannus, a species of dwarf tyrannosaurid, whereas others believed it to simply be a juvenile specimen of Tyrannosaurus rex.

Jane on Display at Burpee Museum. Credit: Wikimedia Commons.

The debate was on. Upon further research, the existence of Nanotyrannus has been a sketchy one, as far as some scientists are concerned. As Dougal Dixon puts it in his extensive World Encyclopedia of Dinosaurs and Prehistoric Creatures, “Some paleontologists regard Nanotyrannus as a juvenile specimen of something better known, or even a dwarf species of Albertosaurus or Gorgosaurus” (324)”, which are other tyrannosaurids.

Jane’s remains were not the first to be suggested to be those of Nanotyrannus. In 1942, David Dunkle found the skull of a carnivorous dinosaur which resembled that of Jane. Dunkle’s discovery was tagged “CMNH 7541.” After this, other paleontologists examined the fossil on numerous occasions. Each suggested it was a certain species of previously known tyrannosaurid, such as Albertosaurus. It would not be until the late 1980’s that the skull would be suggested to be something more.

Robert Bakker. Credit: Wikimedia Commons.

Robert Bakker. Credit: Wikimedia Commons.

Renowned modern paleontologist Robert T. Bakker and his associates took another look at CMNH 7541. This time though, the scientists were able to use a variety of advanced practices in their combing of the skull. One of these was the use of CAT scans. Bakker’s team ultimately determined it to be an utterly new species, calling it Nanotyrannus.

However, this skull, like the remains of Jane, has more recently fallen under scrutiny again. Some experts, such as Thomas Carr, have pointed to the presence of the factor of mere growth to explain the differences between “Nanotyrannus” and other tyrannosaurids. Carr and others have stated that the features of this supposed new species are different from those of its relatives only because the specimens of “Nanotyrannus” were juvenile examples of another species.

Once again, technology managed to come to the rescue. Fossilized bones carry LAG’s, lines of arrested growth. Like tree rings, these natural markings can allow us to better distinguish the age of a prehistoric creature. In order to detect the LAG’s, a tiny bit of practically weightless bone must be cut off. This is what was done with a segment of bone from Jane. (This could not be done with CMNH 7541 since a weightless fragment of bone cannot be extracted from the fossilized skull.)

Jane remains on display at the Burpee Museum. You can see the dinosaur in her museum habitat in this video I was able to shoot of Jane. It features some of the other skeletons on display at the Burpee Museum as well.

From the fragment taken from Jane, scientists concluded that Jane was merely a teenager, around 12 years old. With tyrannosaurs typically reaching adulthood around 20, Jane’s LAG’s showed the dinosaur was, in fact, a juvenile. Most now consider Jane simply a very well-preserved specimen of juvenile T. rex.

Despite the whole controversy over Jane’s identity, the existence of Nanotyrannus has not altogether been ruled out. This is just one example of the confusing, perpetually ongoing discussions regarding what classifies an organism under a certain species.

Millipede death-trail.

“Prehistoric Pompeii” answers the question of when animals first moved on land

The discovery of a ‘prehistoric Pompeii’ is poised to rewrite what we knew about animals colonizing the land.

Millipede death-trail.

Close-up of a looping millipede death-trail.
Image credits Anthony Shillito.

A duo of geoscientists from the University of Cambridge reports that Ordovician strata in Borrowdale, a site in the Lake District area of England, don’t actually hold the earliest known animal footprints on dry land. In fact, the side bore witness to volcanic-ash-induced mass dying.

Ashes to ashes

Our best estimates of when animals first moved in on dry land come, unsurprisingly, from fossils. However, these aren’t your usual run of the mill fossils — rather, paleontologists rely on a special kind, known as trace fossils, for the job. These include the fossilized tracks, prints, slither marks, and all other manners of impressions left by ancient animals moving over soft ground. Places with significant such trace fossils are known as trackway sites.

Ordovician-era (about 455 million-year-old) strata in Borrowdale were believed to hold the earliest such trace fossils on dry land. This was actually pretty problematic, as it didn’t fit with the rest of the evidence. In all other known trackway sites, the earliest evidence of animals moving onto dry land comes from the Silurian period (cca. 420 million years ago)

Geoscientists Anthony P. Shillito and Neil S. Davies of the University of Cambridge studied the site in England and have finally managed to explain why. Trackways in the Borrowdale area haven’t captured animals living on land, they say — it shows a massive dying of millipede-like arthropods at the hands (particles?) of volcanic ash.

The fossilized tracks formed from volcanic ash settling underwater, the team explains, not within freshwater lakes or sub-aerial sands as previously believed. It “is actually a remarkable example of a ‘prehistoric Pompeii’,” says Shillito. In the course of their study, the team found 121 new millipede trackways, all within volcanic ash, with evidence for underwater or shoreline deposition.

Volcanic ash is particularly deadly for such animals — even modern arthropod communities, and particularly in water. The ash itself is made up of very small particles, ranging from under 2 mm to 1μm (a micron, or 1-millionth of a meter). These particles are also very hard — they’re basically ground volcanic glass. Because they’re so tiny, they can get inside anthropoids’ exoskeletons/shells and clump around soft tissue, especially breathing and digestive organs. Because they’re so hard and generally sharp, they wreak havoc on these organs, killing the animals via, quite literally, a thousand cuts.

Shillito and Davies noticed that most of the trails were extremely tightly looping — a feature which is commonly associated with “death dances” in modern and ancient arthropods, which first made them suspect they were looking at a massive dying rather than traditional trace fossils. This study, the authors say, overturns what is known about the earliest life on land and casts new light onto a key evolutionary event in the history of life on Earth.

“It reveals how even surprising events can be preserved in the ancient rock record, but — by removing the ‘earliest’ outlier of evidence — suggests that the invasion of the continents happened globally at the same time,” Shillito notes.

The paper “Death near the shoreline, not life on land: Ordovician arthropod trackways in the Borrowdale Volcanic Group, UK” has been published in the journal Geology.

Curiosity's crystals.

What Curiosity found on Mars are probably just crystals — not fossils

If you were excited about the signs of life reportedly spotted on Mars, it’s might be time to reign in your expectations. The tube-like structures identified by Curiosity were probably formed by geology, not biology, mission team members say.

Curiosity's crystals.

The troublesome structures captured by Curiosity on Jan. 2, 2018, using its Mars Hand Lens Imager. The tubular structures were likely created by crystalline growth, mission team members said.
Image credits NASA/JPL-Caltech/MSSS.

News that Curiosity stumbled upon fossilized traces of life took the Internet by storm a few days ago. And I get it — Mars is just so tantalizingly right for our first encounter with extraterrestrial life, no matter how dead the latter may be. The planet’s dry as a brick now, but we know it used to have water and a proper atmosphere. It’s relatively close-by, enough so that we actually stand a chance of getting there in the mid-future, but it’s still largely unexplored and mysterious as of now. I too, if I may use a cliche, want to believe.

NASA however, as they tend to do, comes to nip those hopes in the bud. The tubular structures spotted on Mars were probably formed by growing crystals, not burrowing creatures, members of the Curiosity mission said.

“When we looked at these things close up, they’re linear, but they’re not tubular in the sense of being cylinders; they’re actually quite angular,” said Ashwin Vasavada of NASA’s Jet Propulsion Laboratory in Pasadena, California.

“They have kind of a square or a parallelogram sort of cross section and form at angles to each other when there’s multiple of them together. And all of that’s pretty reminiscent of crystalline growth.”

The team suspects that the structures are either crystals or molds left in the rock when sediments hardened around pre-existing crystals. While that’s less exciting than finding life, it’s not an inconsequential find at all — both scenarios (the second one a bit more) would require quite a lot of liquid water, suggesting that the area Curiosity is roaming around right now was abundantly wet in Mars’ past. The whole area, a flank of the towering Mount Sharp, is pretty elevated as well — over 300 meters (1,000 feet) vertically above the rover’s initial landing site on Gale Crater.

Curiosity found ample evidence for the existence of a (now dry) groundwater network and an ancient lake-and-stream system on the crater’s floor and along the mountain’s lower slopes. The team is confident that evidence of Mars’ transition from a warm and wet world to the cold, dry place it is today remained locked in the mountain’s rocks. The rover is still to find that transition zone, however, and will continue its ascent until it does so.

Everything considered the chances that this will be our first taste of alien life look slim. It’s not impossible that the tubes are trace fossils of life on Mars, it’s just not very likely given what we know so far. And, as someone who’s gone fossil-hunting in the field, I can confirm that it’s really hard to distinguish trace fossils from weird, but random, shapes left over as geology does its stuff. So making a bullet-proof case that these really are fossils would be extremely difficult on Mars.

“We just, unfortunately, may not have the ability with Curiosity to tell that,” Vasavada said.

The rover has two instruments it can use to analyze the structures. The first is a laser-touting ChemCam, supplemented with the Alpha Particle X-Ray Spectrometer (APXS). These devices can be used to gauge the little tubes’ chemical make-up, but they’ve proven themselves difficult targets. The structures are only about 1 millimeter (0.04 inches) wide by 5 millimeters (0.2 inches) long. Still, Vasavada is confident we’ll have the results within the next week, and with them, we could get the answers we so crave.

Untill then, as the rover tweeted, science continues.

Infant skeleton sheds new light on early Native American populations

The remains of a six-week-old infant cast new light upon the Native American founding population.

Scientists divided the ancient American populations into two categories: the Southern and the Northern Native Americans. The two groups are related, but a link between them and an ancient Siberian population was missing, until now.

Pictures were taken at Upward Sun River site. Credit: Ben Potter

“It’s the first time that we have had direct genomic evidence that all Native Americans can be traced back to one source population, via a single, founding migration event.” said evolutionary geneticist Eske Willerslev from the University of Cambridge in the UK, the research team leader, in a press release.

Researchers named this population “Ancient Beringians” after Beringia, the land bridge that connected northeast Asia with northwestern North America, during the Pleistocene epoch — sometimes called the Ice Age.

Via Wikipedia

The girl was named Xach’itee’aanenh t’eede gaay, or Sunrise Child-girl, by the local Native community. Her skeleton was discovered at the Upward Sun River archaeological site in Alaska in 2013. Scientists say the child lived 11,500 years ago, long after the first wave of migration occurred, but her genome was consistently different from the two types of ancient Native Americans.

“The Ancient Beringians diversified from other Native Americans before any ancient or living Native American population sequenced to date. It’s basically a relict population of an ancestral group which was common to all Native Americans, so the sequenced genetic data gave us enormous potential in terms of answering questions relating to the early peopling of the Americas,” Eske Willerslev said.

The excavation site from Alaska. Credit: Ben Potter

This is the first ancient skeleton ever discovered in Alaska — acidic soils make bone tissue and DNA preservation very difficult.

“We were able to show that people probably entered Alaska before 20,000 years ago. It’s the first time that we have had direct genomic evidence that all Native Americans can be traced back to one source population, via a single, founding migration event.” said Professor Willerslev.

The Northern and the Southern branches are thought to have separated somewhere between 17,000-14,000 years ago. The two groups probably went separate ways as they passed through or around the Cordilleran and Laurentide ice sheets that covered present-day Canada and a part of northern United States.

Scientists believe that the Ancient Beringians were left behind the ice sheets and remained in Alaska. Next, the population was absorbed by other Native groups derived from the Northern branch, that migrated back after the ice had melted away.

“One significant aspect of this research is that some people have claimed the presence of humans in the Americas dates back earlier – to 30,000 years, 40,000 years, or even more. We cannot prove that those claims are not true, but what we are saying, is that if they are correct, they could not possibly have been the direct ancestors to contemporary Native Americans”, added Willerslev.

The paper was published in the Nature journal on the 3rd of January 2018.

 

The amazing Engare Sero footprints with the 'Mount of God' in the background. Credit: Liutkus-Pierce et al., 2016

Hundreds of prehistoric human footprints found near African volcano tell unique story

The amazing Engare Sero footprints with the 'Mount of God' in the background. Credit: Liutkus-Pierce et al., 2016

The amazing Engare Sero footprints with the ‘Mount of God’ in the background. Credit: Liutkus-Pierce et al., 2016

Right by the southern shore of a lake in Tanzania, only nine miles away from an active and menacing volcano which the locals call the ‘Mountain of God’, scientists have mde a monumental find. Etched and preserved in flood sediments were some 400 human footprints which are anywhere between 12,000 and 19,000 years old. No other site in the world has that many ancient human footprints and given their prehistoric age, the Lake Natron footprints might one day paint a unique story of how early humans lived and died together.

Prehistoric walk in the park

The site was found by a local a decade ago but it took a couple of years before paleontologists got on the line. When Cynthia Liutkus-Pierce, an Appalachian State University geologist, finally arrived at Lake Natron, thousands of miles away from home, she couldn’t resist shedding a tear.

“Human origins is a huge interest of mine: where we came from, and why we are who we are. It was definitely emotional to see our own history in this,” Liutkus-Pierce told National Geographic.

At first, they found some 50 footprints in the Engare Sero mud plains but later excavations revealed hundreds. These were of various shapes and sizes, some trailed straight to a finish line while others meandered.

“It’s a very complicated site,” says William Harcourt-Smith, a paleoanthropologist at the City University of New York and a member of Liutkus-Pierce’s team. “There’s one area where there are so many prints, we’ve nicknamed it the ‘dance hall,’ because I’ve never seen so many prints in one place. It’s completely nuts.”

Since only 60 miles away from Engare Sero scientists previously found 3.6-million-year-old footprints, likely made by hominid ancestor called Australopithecus afarensis, Liutkus-Pierce and colleagues presumed they were dealing with marking left by some ancestor. Much to their surprise, these were made by Homo sapiens.

We have much to owe for this treasure trove to the ‘Mountain of God’ volcano which looms over the Engare Sero flood plains. This bizarre volcano which sometimes spews thin, silvery lava, is a site of pilgrimage. It is because of some wandering pilgrims that the footprints were discovered in the first place — they literally retraced the steps of their ancestors and what a feeling it must have been when they learned the true nature of these prints which stretch over the area of a tennis court.

It was also the volcano’s ash combined with the wet ground that helped preserve the prints. Later the mud hardened and a flow of debris formed a time capsule that lasted for millennia.

Using the argon-argon dating technique, which measures the decay time of Argon-40 into Argon-39, the researchers found these ancient markings are at least 12,000 years old, as reported in Palaeogeography, Palaeoclimatology, Palaeoecology.

The next step is to identify each individual based on their markings. This will help document the whole social group. How many men, women, and children were there? How tall were they? How much did they weight? Did they run in terror or casually walked? There’s a great deal we can learn simply by studying the shape and texture of these imprints. Already, the team identified 24 distinct trackways or persons. They’ve also established for some of these individuals their age and gender, as well as walking patterns (walking or running).

 

World’s first mass extinction might have been caused by animals

The world’s first mass extinction might have been caused by animals called “ecosystem engineers,” a term that refers to organisms that create, modify or maintain habitats. In the case of the current study, the fossil evidence from Namibia suggests that newly evolved animals modified the environment so drastically that they drove older species to extinction.

Fossilized evidence of the relationship between Ediacarans and animals. Credit: Simon Darroch, Vanderbilt University

Fossilized evidence of the relationship between Ediacarans and animals. Credit: Simon Darroch, Vanderbilt University

Approximately 540 million years ago, the Earth experienced the end-Ediacaran extinction, the world’s first mass extinction. Ediacarans were the first multicellular organisms, which evolved from various types of single-celled organisms. Shaped like discs and tubes, they were largely immobile and inhabited marine environments.

After 60 million years of the Ediacarans spreading around the Earth, the world’s first animals – the metazoans – evolved. With the ability to move spontaneously and independently, animals burst onto the Earth in what is now known as the Cambrian explosion, a 25-million-year period when many of the modern animal families evolved.

“These new species were ‘ecological engineers’ who changed the environment in ways that made it more and more difficult for the Ediacarans to survive,” said Simon Darroch, assistant professor of earth and environmental sciences at Vanderbilt University and lead author of the study.

Previous research by Darroch and his team revealed communities of Ediacarans that appeared to be stressed. The fossils examined in the current paper represent a community of both Ediacarans and animals right before the Cambrian explosion, providing the best evidence thus far of the unique ecological association between these groups and highlighting the struggle of the Ediacarans as animals began to diversify.

“With this paper we’re narrowing in on causation; we’ve discovered some new fossil sites that preserve both Ediacara biota and animal fossils (both animal burrows – ‘trace fossils’ – and the remains of animals themselves) sharing the same communities, which lets us speculate about how these two very different groups of organisms interacted,” Darroch said.

Darroch also suggests that modern humans can learn from what is observed in the new fossil evidence given what is happening in the world today.

“The end-Ediacaran extinction shows that the evolution of new behaviors can fundamentally change the entire planet, and today we humans are the most powerful ‘ecosystems engineers’ ever known,” he said.

Journal Reference: A mixed Ediacaran-metazoan assemblage from the Zaris Sub-basin, Namibia. 4 July 2016. 10.1016/j.palaeo.2016.07.003

Treasure trove of Permian fossils discovered in Brazil

An international team of archaeologists unearthed a treasure trove of reptile and amphibian fossils in the Parnaiba Basin of north-eastern Brazil. The fossils are some 278 million years old, corresponding to the Permian period, when all the continents we know today were still fused together.

This illustration shows the two new amphibian species, T. anneae (left) and P. nazariensis (right), with one of the larger “rhinesuchidae” lurking in the background.
Image via bbc

Among the findings were two new species of “dvinosaurs,” ancient relatives of modern salamanders measuring about 40 centimeters in length, with preserved fangs and gills. South America’s oldest ever terrestrial reptile skeleton was also retrieved from the site.

Very little is currently known of the fauna and flora of the southern tropical regions of Pangaea during the Permian. Fossil finds for this period are exceedingly rare, and researchers are anxious to fill the gaps in the evolutionary history of the area. But it may be that this last fossil — of a lizard-like creature named Captorhinus aguti — that may be the crowning jewel of the site:

Previously only found in North America, discovering C. aguti here allows scientists to better understand the Permian era — up to now, it was described predominantly by North American and European fossils.

“This discovery is remarkable as most of what we understand about the evolution and adaptation of amphibians through time is based on animals located in Europe and North America,” said Dr Martha Richter from the Natural History Museum in London.

“Now that we know that their distant relatives inhabited a vast lake system in the tropical region of the super continent Pangaea… we can find out more about their abundance, paleontology, and how wide their distribution away from the equator was,” she concluded.

The researchers described one of the newly found fang-and-gill amphibian, dubbed Timona anneae, as being like a cross between a Mexican salamander and an eel.The other amphibian, Procuhy nazariensis, was probably closely related to it but fewer bones have been found and its anatomy remains unclear.

Both species appear to have spent their entire lives in the water.

The team also recovered skull remains belonging to another, much larger amphibian, part of the rhinesuchidae family described up to now in South African fossils. The animal was about as big as a medium-sized dog, scientist report.

The skull of Timonya anneae is just a few centimetres across.
Imaeg via bbc

This variety of fossils help researchers get an idea of how prehistoric animals dispersed and evolved.

“Fossils from classic areas in North America and Europe have been studied for over a century, but there are long-standing questions about how different animal groups dispersed to other areas,” said another of the paper’s authors, Dr Ken Angielczyk from the Field Museum in Chicago, US.

“Exploration in understudied areas, such as north-eastern Brazil, gives us a snapshot of life elsewhere that we can use for comparisons. In turn, we can see which animals were dispersing into new areas, particularly as an ice age was ending in the southern continents and environmental conditions were becoming more favorable for reptiles and amphibians.”

Challenging the “Out of Africa” theory, one tooth at a time

Recent fossils unearthed in the Chinese province of Daoxian come to unravel the story of humanity’s spread as we know it today. The find consists of 47 teeth, belonging to modern humans, but what’s really important is their age – they have been dated to 80,000 years ago. This number doesn’t fit with the “Out of Africa” migration theory, holding that humans originate and have spread from the horn of the continent all around the world. The theory as we know it can’t explain human presence in the area for another 20,000 years.

These 47 teeth, estimated to be between 80,000 and 120,000 years old, were found in a cave in Dao county, Hunan province in China.
Image via cnn

“We need to re-think our models. Maybe there was more than one Out of Africa migration” says Dr. María Martinón-Torres, UCL.

Evidence from several fields of science supports the dispersal of our species from Africa some 60,000 years ago. It is believed that a group of nomads crossed the Red Sea, by taking advantage of the Bab el Mandeb straits’ low water levels, and that from them, all non-African people today originate. But the excavations at Funyan Cave in Daoxian throw a wrench into the workings of this theory:

“It was very clear to us that these teeth belonged to modern humans [from their morphology]. What was a surprise was the date,” Dr María Martinón-Torres, from University College London (UCL), told BBC News. “All the fossils have been sealed in a calcitic floor, which is like a gravestone, sealing them off. So the teeth have to be older than that layer. Above that are stalagmites that have been dated using uranium series to 80,000 years.“

Everything under those stalagmites must be older than 80,000 years; the teeth could even be 125,000 years old, according to the researchers. Animal bones found with the teeth are also typical of the late Pleistocene, the same time period indicated by radioactive dating.

Now, these are not the first fossils of modern humans that predate the Out of Africa migration – some were found in Skhul and Qafzeh caves in Israel, for example. But due to their close proximity to the African continent, they were regarded as nothing more than a failed attempt at dispersal by groups of people who probably went extinct. But discovering modern fossils all the way in China is another thing entirely.

“Some researchers have proposed earlier dispersals in the past,” said Dr Martinón-Torres. “We really have to understand the fate of this migration. We need to find out whether it failed and they went extinct or they really did contribute to later people. Maybe we really are descendents of the dispersal 60,000 years ago – but we need to re-think our models. Maybe there was more than one Out of Africa migration.”

Professor Chris Stringer, working at London’s Natural History Museum, believes that the study will become a “game-changer” in finding out how modern humans spread around the world.

“Many workers (often including me) have argued that the early dispersal of modern humans from Africa into the Levant recorded by the fossils from Skhul and Qafzeh at about 120,000 years ago was essentially a failed dispersal which went little or no further than Israel.”

“However, the large sample of teeth from Daoxian seem unquestionably modern in their size and morphology, and they look to be well-dated by uranium-thorium methods to at least 80,000 years. At first sight this seems to be consistent with an early dispersal across southern Asia by a population resembling those known from Skhul and Qafzeh. But the Daoxian fossils resemble recent human teeth much more than they look like those from Skhul and Qafzeh, which retain more primitive traits. So either there must have been rapid evolution of the dentitions of a Skhul-Qafzeh type population in Asia by about 80,000 years, or the Daoxian teeth represent a hitherto-unsuspected early and separate dispersal of more modern-looking humans.”

Dr Pontus Skoglund, from the department of genetics at Harvard Medical School, told BBC News:

“The genetic evidence we have puts strong constraints on some aspects of human history, but less so on the timing of the out of Africa event.” Sais Dr. Pontus Skoglund. Most genetic reconstructions based on modern data relies on assumptions on the mutation rate, for which there are still some real uncertainties. In terms of direct genetic evidence, we already have a 45,000 year-old genome from Siberia (Ust Ishim) and a ~40,000 year old individual from Europe (Oase) that are consistent with being from now-mostly-extinct lineages. ”

“The conclusion is perhaps that the genetics does allow an 80,000 year old East Asian population to contribute some ancestry to present-day people, but I think not very much. It is a very interesting discovery that is hard to fit in our current thinking, but not impossible. We are just starting to cope with this data point.”

Dr Martinón-Torres said the study could also shed light on why it took Homo sapiens another 40,000 years to settle Europe. Perhaps it was Neanderthal presence that kept our species out of the western part of Eurasia, until their numbers started to dwindle; or, maybe it was the cold climate that kept us away.

Skoglund also noted that while modern humans occupied the warmer south of China 80,000 years ago, the colder regions of central and northern China appear to be settled by more primitive human groups who may have been Asian relatives of the Neanderthals.

The full study was published in the journal Nature.

Fossilized burrows thought to be left by Paleodictyon nodosum [souce: scitechdaily.com]

A primitive form of parenting possibly found in 540 million years old paleodictyon patterns

Paleodictyon is a mysterious fossil pattern found mainly in marine sediments thought to be specific of a certain paleo-depth range; it is a relatively widespread trace fossil – called this way because it is mainly accepted that it is created by a burrowing creature. Although it has been discovered since the dawn of geology and fossil hunting, no one was able to find sediments where you can also see the “architect” of such a symmetric creation – given that underwater honeybees are excluded.

Among his many other passions, Leonardo da Vinci collected and described fossils, including it seems, what later came to be known as Paleodictyon [from BIBLIOTECA LEONARDIANA, via Nature]

Among his many other passions, Leonardo da Vinci collected and described fossils, including it seems, what later came to be known as Paleodictyon [from BIBLIOTECA LEONARDIANA, via Nature]

A new study finds a special type of paleodictyon fossils in the limestone of Nevada and Mexico – one where clues to the elusive pattern may appear to be present. At least that is what the lead author proposes, Mark McMenamin, a paleontologist at Mount Holyoke College in South Hadley, Massachusetts.

Besides the fact that this new fossil may hint towards an explanation of a centuries’ old mystery, what is also interesting is the fossil’s age: about 540 million years – placing it in the early Cambrian – a period when modern multicellular life seemed to have emerged and diversified in a relatively brief period of geological time.

When examining the fossil, McMenamin noticed that some of the burrow swarms seemed to cut through organic pellets 250 to 500 micrometers in diameter — making the pellets too large to have been created by the creature that made the burrows.

“I noticed that the smaller micro-burrows tended to cluster in the center of the swarms,”says McMenamin.

Fossilized burrows thought to be left by Paleodictyon nodosum [souce: scitechdaily.com]

Fossilized burrows thought to be left by Paleodictyon nodosum [souce: scitechdaily.com]

The paleontologist hypothesizes that some sort of adult animal laid down the organic pellets to form a nest around its eggs – and if these eggs were mostly made of soft material, which is the case for many animals – they failed to fossilize.  “The hatchlings then fed on organic matter in the pellets that had been broken down by bacteria,”he says. As they “ate their nest”, the hatchlings would have left that hexagonal burrowing pattern that we see fossilized today.

Although it all seems amazing, it is hard to irrevocably link such parenting behavior to this type of fossil. Gabriela Mangano, who studies Cambrian burrows at the University of Saskatchewan in Saskatoon, Canada says the idea certainly is spectacular, but for it to be true, it needs to rely on a more detailed morphological analysis.

Duncan McIlroy, a burrow specialist at the Memorial University of Newfoundland in St John’s says that in order to bring further evidence, one idea would be to create a 3D model of the rock containing the fossil, perhaps by making a section passing through its regions of interest: “I would look for a discrete structure as part of a large semi-permanent burrow system created by the adult,” he says.

Could Paleodictyon also be nests? “Sure they could be,” says McIlroy. “But it would be very difficult indeed to prove without finding one with associated eggs and juveniles.”
A few cases in which paleodictyon would not be related to this type of parenting would be, for example that the creatures making burrows would actually be preying on the hypothesized eggs. Or perhaps the small creatures would have nothing to do with the whole idea of nests and eggs, and it just came and drew it’s mysterious pattern in the sediment, years after such organic pellets existed. After all, what are a few years or even a decade when compared to the vast eons of geologic time ?
[Via Nature]

A Paleodictyon fossil from Austria [source: wiki]

A Paleodictyon fossil from Austria [source: wiki]

Raindrop imprints fossilized from 2.7 billion years ago in rock. (c) Sanjoy Som

Raindrops fossil 2.7-billion-year-old reveals secrets from Earth’s early atmosphere

Billions of years ago, the Earth was unrecognizable from the life supporting paradise it is today. Fossilized raindrops from some 2.7 billion years ago, conserved in time as rain dropped onto volcanic ash during an eruption, which eventually solidified into  rock known as tuff, has revealed some very interesting facts about Earth’s ancient atmosphere. The discovery will help scientists understand more about Earth’s early history and how it evolved in time, as well as aid research funneled towards finding life bearing exoplanets.

Raindrop imprints fossilized from 2.7 billion years ago in rock. (c) Sanjoy Som

Raindrop imprints fossilized from 2.7 billion years ago in rock. (c) Sanjoy Som

During this period, the sun burned as much as 30% less brighter. In those conditions, the Earth should have been covered in a thick layer of ice, however geologic evidence for rivers and ocean sediments testify otherwise. This is because, at the time, the planet had an atmosphere filled with greenhouse gases which warmed it – a thick haze filled with hydrocarbons which made the Earth resemble today’s Saturn’s moon Titan.

“Because the sun was so much fainter back then, if the atmosphere was the same as it is today the Earth should have been frozen,” says Sanjoy Som, a postdoctoral researcher at NASA’s Ames Research Center.

Scientists at University of Washington in Seattle scanned the raindrop craters engraved into the ancient rock sample with lasers, and compared them with similar marks left by raindrops in ash from present time. The sizes of raindrop impressions depend on their velocity, atmospheric pressure and the composition of the material into which they fall.

The maximum raindrop diameter is around 6.8 millimeters, anything larger breaks up in smaller droplets due to the laws of physics. Considering the same laws were in place billions of years ago, raindrops during the Archean period couldn’t have been larger than this either. After a careful analysis, the researchers concluded that Earth’s early atmosphere exerted at most twice as much pressure as the present day atmosphere. Most likely, it would have been similar to present day atmospheric pressure or as little as half present pressure.

The discovery and consequent research studying the raindrop fossils adds even more weight to the claim that Earth’s early atmosphere was covered in greenhouse gases, explaining the faint sun paradox from the time. Also, the finding could prove important in the search for life on planets orbiting other stars, called exoplanets. In all respects, ancient Earth was alien compared to present day, and studying its ancient history might hint scientists to what kind of planets might hold the potential for supporting life, even microbial.

“Setting limits on atmospheric pressure is the first step towards understanding what the atmospheric composition was then,” says Som. “Knowing this will double the known data points that we have for comparison to exoplanets that might support life.”

The scientists have reported their findings in the March 29 edition of the journal Nature.

[via Scientific American]

 

NASA slams alien life claims

Two days ago, the whole world was teeming with excitement, after some NASA researchers reported finding traces of alien life in meteorites; now, even their employer distances itself from them, and the whole scientific world seems to frown upon this work. However, in what is a very unusual move, NASA has denied any involvement with the paper, and even the Journal of Astrobiology refused to published the paper.

However, lead author Richard Hoover, engineer at NASA’s Marshall Space Flight Center in Huntsville, Alabama did publish his research in the online Journal of Cosmology, a publication which supports the idea that life came from outer space. Of course Fox News, in their usual and disturbing way, made big (and biased) news from this report, which led to NASA condemning the study; and it didn’t take long until other scientists followed too.

Paul Hertz, chief scientist of NASA’s science mission directorate issued a statement which left little to interpretation, stating that:

“NASA cannot stand behind or support a scientific claim unless it has been peer-reviewed or thoroughly examined by other qualified experts…. NASA was unaware of the recent submission of the paper to the Journal of Cosmology or of the paper’s subsequent publication.”

Now, the Journal of Cosmology is not your average publication; the 2 year publication claims to be peer reviewed, but this time, they published the report BEFORE having other peers review it, which is highly unprofessional and unethical. The journal was reported to be closed on Monday, being “killed by thieves and crooks” at the journal Science and other subscription-based periodicals. I’m not really sure at all what the situation is, but in this particular case, they messed up – if you want to ensure the accuracy of a publication, you have to peer review it before publishing it.

Biologists from all over the world have dashed and bashed the paper, claiming that other structures similar to those of the bacteria can easily be found in nature, and contamination cannot be ruled out either.

“Move along folks. There’s nothing to see here,” wrote Rosie Redfield, a microbiologist at the University of British Columbia,

Mister Hoover was unavailable for comments.

Picture source

Back when reptiles took on dry land

It was more than 300 million years ago that reptiles made tracks on earth. The exact moment when this happened is unknown, however; oh, and by exact moment, I’m talking about pinning it down to a couple million years (you gotta love geologists for their sense of time).

So, a discovery of fossilized footprints was recently made in the Bay of Fundy, New Brunswick, Canada. The track is 318 million years old, and it’s the oldest fossil found so far, so it’s probably very close to the “moment” I was mentioning above.

The footprints were discovered by Dr Howard Falcon-Lang of Royal Holloway, University of London. The results of his study, undertaken with Professor Mike Benton of the University of Bristol and Canadian colleagues, are published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.

It has long been suspected that it was reptiles and not their amphibian cousins that made this big leap, because amphibians need to return to the water in order to breed, while reptiles don’t. According to professor Benton:

“The footprints date from the Carboniferous Period when a single supercontinent (Pangaea) dominated the world. At first life was restricted to coastal swamps where lush rainforest existed, full of giant ferns and dragonflies. However, when reptiles came on the scene they pushed back the frontiers, conquering the dry continental interiors.”

Dr Falcon-Lang added: “The Bay of Fundy is such an amazing place to hunt for fossils. The sea-cliffs are rapidly eroding and each rock-fall reveals exciting new fossils. You just never know what will turn up next.”

So the Bay of Fundy, fossil hunting – on my to do list.