New species of dinosaur discovered after lying misidentified in fossil vaults for 30 years

A PhD student of the University of the Witwatersrand, South Africa, has discovered a new dinosaur species in the University’s vaults, after it has been laying misidentified in a collection for 30 years.

The team of scientists, led by PhD Student Kimberley Chapelle, recognised that the dinosaur was not only a new species of sauropodomorph, but an entirely new genus. The specimen has now been named Ngwevu intloko which means “grey skull” in the Xhosa language, chosen to honour South Africa’s heritage. She was joined in the research by her PhD supervisors: Prof Jonah Choiniere (Wits), Dr Jennifer Botha (National Museum Bloemfontein), and Professor Paul Barrett (Natural History Museum, London). Together, Kimberley and these world-leading researchers have been improving knowledge of South African palaeontology for the last six years. The dinosaur has been described in the academic journal, PeerJ.

Professor Paul Barrett, Chapelle’s PhS supervisor and researcher at the Natural History Museum in the UK explains, “This is a new dinosaur that has been hiding in plain sight.” “The specimen has been in the collections in Johannesburg for about 30 years, and lots of other scientists have already looked at it. But they all thought that it was simply an odd example of Massospondylus.”

Massospondylus was one of the first dinosaurs to reign at the start of the Jurassic period. Regularly found throughout southern Africa, these animals belonged to a group called the sauropodomorphs and eventually gave rise to the sauropods, a group containing the Natural History Museum’s iconic dinosaur cast Dippy. Researchers are now starting to look closer at many of the supposed Massospondylus specimens, believing there to be much more variation than first thought.

Kimberley Chapelle explains why the team were able to confirm that this specimen was a new species, “In order to be certain that a fossil belongs to a new species, it is crucial to rule out the possibility that it is a younger or older version of an already existing species. This is a difficult task to accomplish with fossils because it is rare to have a complete age series of fossils from a single species. Luckily, the most common South African dinosaur Massospondylus has specimens ranging from embryo to adult. Based on this, we were able to rule out age as a possible explanation for the differences we observed in the specimen now named Ngwevu intloko.”

The new dinosaur has been described from a single fairly complete specimen with a remarkably well-preserved skull. The new dinosaur was bipedal with a fairly chunky body, a long slender neck and a small, boxy head. It would have measured three metres from the tip of its snout to the end of its tail and was likely an omnivore, feeding on both plants and small animals.

The findings will help scientists better understand the transition between the Triassic and Jurassic period, around 200 million years ago. Known as a time of mass extinction it now seems that more complex ecosystems were flourishing in the earliest Jurassic than previously thought.

“This new species is interesting,” says Prof Barrett, “because we thought previously that there was really only one type of sauropodomorph living in South Africa at this time. We now know there were actually six or seven of these dinosaurs in this area, as well as variety of other dinosaurs from less common groups. It means that their ecology was much more complex than we used to think. Some of these other sauropodomorphs were like Massospondylus, but a few were close to the origins of true sauropods, if not true sauropods themselves.”

This work shows the value of revisiting specimens in museum collections, as many news species are probably sitting unnoticed in cabinets around the world.


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A voracious Cambrian predator, Cambroraster, is a new species from the Burgess Shale

Palaeontologists at the Royal Ontario Museum and University of Toronto have uncovered fossils of a large new predatory species in half-a-billion-year-old rocks from Kootenay National Park in the Canadian Rockies. This new species has rake-like claws and a pineapple-slice-shaped mouth at the front of an enormous head, and it sheds light on the diversity of the earliest relatives of insects, crabs, spiders, and their kin. The findings were announced July 31, 2019, in a study published in Proceedings of the Royal Society B.

Reaching up to a foot in length, the new species, named Cambroraster falcatus, comes from the famous 506-million-year-old Burgess Shale. “Its size would have been even more impressive at the time it was alive, as most animals living during the Cambrian Period were smaller than your little finger,” said Joe Moysiuk, a graduate student based at the Royal Ontario Museum who led the study as part of his PhD research in Ecology & Evolutionary Biology at the University of Toronto. Cambrorasterwas a distant cousin of the iconic Anomalocaris, the top predator living in the seas at that time, but it seems to have been feeding in a radically different way,” continued Moysiuk.

The name Cambroraster refers to the remarkable claws of this animal, which bear a parallel series of outgrowths, looking like forward-directed rakes. “We think Cambroraster may have used these claws to sift through sediment, trapping buried prey in the net-like array of hooked spines,” added Jean-Bernard Caron, Moysiuk’s supervisor and the Richard M. Ivey Curator of Invertebrate Palaeontology at the Royal Ontario Museum.

With the interspace between the spines on the claws at typically less than a millimeter, this would have enabled Cambroraster to feed on very small organisms, although larger prey could also likely be captured, and ingested into the circular tooth-lined mouth. This specialized mouth apparatus is the namesake of the extinct group Radiodonta, which includes both Cambroraster and Anomalocaris. Radiodonta is considered to be one of the earliest offshoots of the arthropod lineage (today including all animals with an exoskeleton, a segmented body and jointed limbs).

The second part of the species name falcatus was given in tribute to another of Cambroraster‘s distinctive features: the large shield-like carapace covering its head, which is shaped like the Millennium Falcon spaceship from the Star Wars films. “With its broad head carapace with deep notches accommodating the upward facing eyes, Cambroraster resembles modern living bottom-dwelling animals like horseshoe crabs. This represents a remarkable case of evolutionary convergence in these radiodonts,” Moysiuk explained. Such convergence is likely reflective of a similar environment and mode of life — like modern horseshoe crabs, Cambroraster may have used its carapace to plough through sediment as it fed.

Perhaps even more astonishing is the large number of specimens recovered. “The sheer abundance of this animal is extraordinary,” added Dr. Caron, who is also an Assistant Professor in Ecology & Evolutionary Biology and Earth Sciences at the University of Toronto, and the leader of the field expeditions that unearthed the new fossils. “Over the past few summers we found hundreds of specimens, sometimes with dozens of individuals covering single rock slabs.”

Based on over a hundred exceptionally well-preserved fossils now housed at the Museum, researchers were able to reconstruct Cambroraster in unprecedented detail, revealing characteristics that had not been seen before in related species.

“The radiodont fossil record is very sparse; typically, we only find scattered bits and pieces. The large number of parts and unusually complete fossils preserved at the same place are a real coup, as they help us to better understand what these animals looked like and how they lived,” said Dr. Caron. “We are really excited about this discovery. Cambroraster clearly illustrates that predation was a big deal at that time with many kinds of surprising morphological adaptations.”

Fossils from the Cambrian period, particularly from sites like the Burgess Shale, record a dramatic “explosion” of biodiversity at this time, culminating in the evolution of most of the major groups of animals that survive today. But, the story has far more intricacy than a straight line leading from simple ancestors to the vast diversity of modern species. “Far from being primitive, radiodonts show us that at the very outset of complex ecosystems on Earth, early representatives of the arthropod lineage rapidly radiated to play a wide array of ecological roles,” remarked Moysiuk.

The fossils were found at several sites in the Marble Canyon area in Kootenay National Park, British Columbia, which have been discovered by ROM-led field teams since 2012, with some of the key specimens unearthed just last summer. These sites are about 40 kilometers away from the original Burgess Shale fossil site in Yoho National Park that was first discovered in 1909. What is also exciting for researchers is the realization that there is a large new area in northern Kootenay National Park worth scientific exploration, holding the potential for the discovery of many more new species.

The Burgess Shale fossil sites are located within Yoho and Kootenay National Parks and are managed by Parks Canada. Parks Canada is proud to work with leading scientific researchers to expand our knowledge and understanding of this key period of earth history and to share these sites with the world through award-winning guided hikes. The Burgess Shale was designated a UNESCO World Heritage Site in 1980 due to its outstanding universal value, and is now part of the larger Canadian Rocky Mountain Parks World Heritage Site.

The discovery and study of Cambroraster will be profiled in the upcoming CBC’s The Nature of Things episode “First Animals” airing October 18, 2019 at 9 p.m. and on the free CBC Gem streaming service. These and other Burgess Shale specimens will be showcased in a brand-new gallery at the Royal Ontario Museum, the Willner Madge Gallery of the Dawn of Life, expected to open in 2021. Starting this summer, select specimens of Cambroraster will be put on display in the New Research case within the current temporary Willner Madge Gallery, Dawn of Life Preview exhibition.

Major funding support for the research and field work came from the Natural Sciences and Engineering Research Council of Canada (Discovery Grant #341944), the Royal Ontario Museum, the National Geographic Society (#9475-14), the Swedish Research Council (to Michael Streng), the National Science Foundation (NSF-EAR-1554897) and Pomona College (to Robert R. Gaines). Moysiuk’s PhD research is also supported by an NSERC Canada Graduate Scholarship (CGSM).


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Paleontology: New light on cichlid evolution in Africa

Cichlids (Cichlidae) are a group of small to medium-sized fish that are ubiquitous in freshwater habitats in the tropics. They are particularly notable in exhibiting a wide range of morphological and behavioral specializations, such as various modes of parental care, including mouthbrooding. Some species (mainly members of the genus Tilapia) have achieved fame as culinary delicacies and are of considerable economic significance. Cichlids have undergone rapid diversification in Africa, which is home to at least 1100 species. This process has been especially prominent in the Great Lakes in East Africa’s Rift Valley (Lakes Tanganyika, Malawi and Victoria), where it is referred to as the East African Radiation.

“Cichlid diversification in East Africa has become a central paradigm in evolutionary biology. As a consequence, dating the onset of the process and understanding the mechanisms that drive it are issues of great interest to evolutionary biologists and paleobiologists,” says LMU paleontologist Professor Bettina Reichenbacher, who is also member of the GeoBio-Center at LMU. Fossils from the area provide the sole source of direct evidence that would allow one to determine the timing and trace the course of lineage diversification within the group. However, the search for cichlid fossils has proven to be both arduous and extremely time- consuming. Indeed, only about 20 fossil species of cichlids from Africa have yet been formally described.

In a study that appears in the online journal Scientific Reports, a team of researchers led by Bettina Reichenbacher now describes a new fossil cichlid, which the authors assign to the new genus Oreochromimos. The name derives from the fact that the specimens, which the team discovered in Central Kenya, show similarities to members of the Tribe Oreochromini (hence the element ‘mimos’, meaning ‘mimic’, in the genus name), which are widely distributed in Africa today. “Determining whether or not the fossils could be assigned to any of the extant cichlid lineages was particularly challenging,” says Stefanie Penk, first author of the study and a doctoral student in Reichenbacher’s group. The difficulties are rooted in the great diversity of the modern cichlid fauna in Africa, and the fact that even distantly related species may be morphologically very similar to each other. “The architecture of the skeleton in cichlids is pretty conservative. All of them have a similar basic form, which undergoes very little change during speciation,” Reichenbacher explains. In collaboration with Dr. Ulrich K. Schliewen, co-author of the new paper, Curator of Fishes at the Bavarian State Collection for Zoology in Munich (SNSB-ZSM) and also a member of the GeoBio-Center at LMU, the team adopted the ‘best-fit approach’ to the classification of the fossil specimens. This requires comparison of the fossil material with all the relevant modern lineages of cichlids. In light of their contemporary diversity, that might seem an impossible task. But thanks to Schliewen’s knowledge — and the range of comparative material represented in the collection under his care — the strategy succeeded.

A unique glimpse of the past

Reichenbacher and colleagues recovered the Oreochromimosmaterial from a fossil-fish Lagerstätte in Kenya’s Tugen Hills, which lie within the Eastern Branch of the East African Rift System. This site provides a unique window into the region’s past. The volcanic and sedimentary rocks deposited here date back 5-20 million years. They were overlain by younger material and subsequently uplifted to altitudes of as much as 2000 m by tectonic forces. As a result, the fossil-bearing rocks exposed in the Tugen Hills are either inaccessible to exploration or have been lost to erosion in other parts of Africa. Consequently, the strata here contain a unique assemblage of fossils. Undoubtedly the best known finds so far excavated are the 6-million-year-old remains of a hominin species, which has been named Orrorin tugenensis (orrorin means ‘original man’ in the local language). But cichlid fossils are also among the paleontological treasures preserved in these sedimentary formations — and they are at the heart of Reichenbacher’s Kenya Project, which began in 2011. The material collected so far was recovered in cooperation with Kenya’s Egerton University, and is now on loan to LMU’s Department of Earth and Environmental Sciences for further study.

The Oreochromimos specimens are about 12.5 million years old, which makes this genus the oldest known fossil representative of the Tribe Oreochromini. It therefore qualifies as the oldest fossil clade yet assigned to the Haplotilapiini, the lineage which gave rise not only to most of the species that constitute the present-day diversity of African cichlids, but also to the East African Cichlid Radiation in the Great Lakes of the Rift Valley. With their use of an innovative approach to comparative systematics, the authors of the new study have provided a basis for the taxonomic assignment of future finds of fossil cichlid material. “With the aid of this dataset, it will be possible to classify fossil cichlids much more reliably than before and thus to shed new light on their evolutionary history,” says Bettina Reichenbacher.


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World’s smallest fossil monkey found in Amazon jungle

A team of Peruvian and American scientists have uncovered the 18-million-year-old remains of the smallest fossil monkey ever found.

A fossilized tooth found in Peru’s Amazon jungle has been identified as belonging to a new species of tiny monkey no heavier than a hamster.

The specimen is important because it helps bridge a 15-million-year gap in the fossil record for New World monkeys, says a team led by Duke University and the National University of Piura in Peru.

The new fossil was unearthed from an exposed river bank along the Río Alto Madre de Dios in southeastern Peru. There, researchers dug up chunks of sandstone and gravel, put them in bags, and hauled them away to be soaked in water and then strained through sieves to filter out the fossilized teeth, jaws, and bone fragments buried within.

The team searched through some 2,000 pounds of sediment containing hundreds of fossils of rodents, bats and other animals before they spotted the lone monkey tooth.

“Primate fossils are as rare as hen’s teeth,” said first author Richard Kay, a professor of evolutionary anthropology at Duke who has been doing paleontological research in South America for nearly four decades.

A single upper molar, the specimen was just “double the size of the head of a pin” and “could fall through a window screen,” Kay said.

Paleontologists can tell a lot from monkey teeth, particularly molars. Based on the tooth’s relative size and shape, the researchers think the animal likely dined on energy-rich fruits and insects, and weighed in at less than half a pound — only slightly heavier than a baseball. Some of South America’s larger monkeys, such as howlers and muriquis, can grow to 50 times that heft.

“It’s by far the smallest fossil monkey that’s ever been found worldwide,” Kay said. Only one monkey species alive today, the teacup-sized pygmy marmoset, is smaller, “but barely,” Kay said.

In a paper published online July 23 in the Journal of Human Evolution, the team dubbed the animal Parvimico materdei, or “tiny monkey from the Mother of God River.”

Now stored in the permanent collections of the Institute of Paleontology at Peru’s National University of Piura, the find is important because it’s one of the few clues scientists have from a key missing chapter in monkey evolution.

Monkeys are thought to have arrived in South America from Africa some 40 million years ago, quickly diversifying into the 150-plus New World species we know today, most of which inhabit the Amazon rainforest. Yet exactly how that process unfolded is a bit of a mystery, in large part because of a gap in the monkey fossil record between 13 and 31 million years ago with only a few fragments.

In that gap lies Parvimico. The new fossil dates back 17 to 19 million years, which puts it “smack dab in the time and place when we would have expected diversification to have occurred in the New World monkeys,” Kay said.

The team is currently on another fossil collecting expedition in the Peruvian Amazon that will wrap up in August, concentrating their efforts in remote river sites with 30-million-year-old sediments.

“If we find a primate there, that would really be pay dirt,” Kay said.

Other authors include Jean-Nöel Martinez and Luis Angel Valdivia of the National University of Piura, Lauren Gonzales of the University of South Carolina, Wout Salenbien and Paul Baker of Duke’s Nicholas School of the Environment, Siobhán Cooke of the Johns Hopkins University School of Medicine, and Catherine Rigsby of East Carolina University.

This research was supported by the National Science Foundation (EAR 1338694, DDIG 0726134) and the National Geographic Society (Young Explorers Grant 9920-16 and Waitt Grant W449-16).


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Oldest completely preserved lily discovered

Botanist Dr. Clement Coiffard of the Museum für Naturkunde Berlin discovered the oldest, completely preserved lily in the research collection: Cratolirion bognerianum was found in calcareous sediments of a former freshwater lake in Crato in northeastern Brazil. With an age of about 115 million years, Cratolirion is one of the oldest known monocotyledonous plants. These include orchids, sweet grasses, lilies and lilies of the valley.

Cratolirion is extraordinarily well preserved, with all roots, the flower and even the individual cells are fossilised. With a length of almost 40 centimetres, the specimen is not only extremely huge, but also shows almost all the typical characteristics of monocotyledonous plants, including parallel-veined, narrow leaves with a leaf sheath, a fibrous root system and triple flowers.

However, it was not trivial to examine the fossilised object, as it consisted of iron oxides associated with the stone. In order to see details here, Coiffard collaborated with the HZB physicist Dr. Nikolay Kardjilov, who is an expert in 3D analysis with X-rays and neutrons. At the HZB he also built up a 3D computed x-ray tomography and refined the data analysis in such a way that hardly any disturbing artefacts arise during the investigation of large, flat objects. This made it possible to analyse the details of the inflorescence hidden in the stone. A colour coding in the CT scan makes these details visible: the main axis is marked in turquoise, the supporting leaves in dark green, the pistils in light green and the remains of the actual petals can still be seen in orange.

Many early dicotyledonous flowering plants have already been described from the same sediments of the former freshwater lake in Crato. These include water lilies, aron rods, drought-resistant magnolias and relatives of pepper and laurel. In contrast to other flowering plants of the same age from the USA, Portugal, China and Argentina, the flowering plants of the Crato-Flora are unusually diverse. This could be due to the fact that Lake Crato was in the lower latitudes, but all other fossils of early flowering plants come from the middle latitudes.

From this newly described plant Cratolirion bognerianum and the species of Crato flora mentioned above, it can be deduced that the tropical flowering plants were already very diverse. “It is probable that flowering plants originated in the tropics, but only very few fossils have been described to date,” explains Coiffard. This study thus provides new insights into the role of the tropics in the development of early flowering plants and their rise to global supremacy.


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Bird with unusually long toes found fossilized in amber

Meet the ancient bird that had toes longer than its lower legs. Researchers have discovered a bird foot from 99 million years ago preserved in amber that had a hyper-elongated third toe. The study, published in the journal Current Biology on July 11, suggests that this bird might have used its toes to hook food out of tree trucks. This is the first time such a foot structure has been observed in birds, either extinct or living.

“I was very surprised when I saw the amber,” says first author Lida Xing at China University of Geosciences (Beijing). “It shows that ancient birds were way more diverse than we thought. They had evolved many different features to adapt to their environments.”

To study the Cretaceous period fossil, Xing and his colleagues scanned the amber with micro-CT and created a 3D reconstruction of the foot. They found that the bird’s third toe, measuring 9.8 millimeters, is 41 percent longer than its second toe and 20 percent longer than its tarsometatarsus, which is a bone in the lower legs of birds. The team compared the ratios with those of 20 other extinct birds from the same era and 62 living birds. No bird has a foot that resembles this one.

The researchers named it Elektorornis chenguangi. Elektorornis means “amber bird,” and it belongs to a group of extinct birds called Enantiornithes, the most abundant type of bird known from the Mesozoic era. It is thought that Enantiornithines became extinct during the Cretaceous-Paleogene extinction event about 66 million years ago, along with dinosaurs. They have no living descendants.

Based on the fossil, the team estimates that the Elektorornis was smaller than a sparrow, and it was arboreal, meaning it spent most of its time in trees as opposed to on the ground or in water.

“Elongated toes are something you commonly see in arboreal animals because they need to be able to grip these branches and wrap their toes around them,” says co-author Jingmai O’Connor at the Chinese Academy of Sciences. “But this extreme difference in toe lengths, as far as we know, has never been seen before.”

The amber the foot was found in, measuring 3.5 centimeters long and weighing 5.5 grams, was discovered around 2014 in the Hukawng Valley of Myanmar. During the Mesozoic era, the valley was full of trees that produced resin, a gooey substance that oozes out of the tree bark. Plants and small animals, such as geckos and spiders, often get trapped in the resin and become fossilized with the amber after millions of years. Scientists have discovered many extinct animals, including the oldest known bee and a feathered dinosaur tail, in amber from this valley.

Xing obtained the amber from a local amber trader, who didn’t know what animal this weird foot belonged to.

“Some traders thought it’s a lizard foot, because lizards tend to have long toes,” Xing says. “Although I’ve never seen a bird claw that looks like this before, I know it’s a bird. Like most birds, this foot has four toes, while lizards have five.”

It remains unknown why the amber bird evolved such an unusual feature. The only known animal with disproportionally long digits is the aye-aye. The aye-aye is a lemur that uses its long middle fingers to fish larvae and insects out of tree trunks for food. Therefore, the researchers suggest Elektorornis might have used its toe for the same purpose.

“This is the best guess we have,” O’Connor says. “There is no bird with a similar morphology that could be considered a modern analog for this fossil bird. A lot of ancient birds were probably doing completely different things than living birds. This fossil exposes a different ecological niche that these early birds were experimenting as they evolved.”

Moving forward, the team hopes to extract the proteins and pigments from some feathers exposed on the surface of the amber. Xing says such data could help them better understand the bird’s adaptation to the environment, such as whether it had camouflage plumage.


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Bird three times larger than ostrich discovered in Crimean cave

A surprise discovery in a Crimean cave suggests that early Europeans lived alongside some of the largest ever known birds, according to new research published in the Journal of Vertebrate Paleontology.

It was previously thought that such gigantism in birds only ever existed on the islands of Madagascar and New Zealand as well as Australia. The newly-discovered specimen, discovered in the Taurida Cave on the northern coast of the Black Sea, suggests a bird as giant as the Madagascan elephant bird or New Zealand moa. It may have been a source of meat, bones, feathers and eggshell for early humans.

“When I first felt the weight of the bird whose thigh bone I was holding in my hand, I thought it must be a Malagasy elephant bird fossil because no birds of this size have ever been reported from Europe. However, the structure of the bone unexpectedly told a different story,” says lead author Dr Nikita Zelenkov from the Russian Academy of Sciences.

“We don’t have enough data yet to say whether it was most closely related to ostriches or to other birds, but we estimate it weighed about 450kg. This formidable weight is nearly double the largest moa, three times the largest living bird, the common ostrich, and nearly as much as an adult polar bear.”

It is the first time a bird of such size has been reported from anywhere in the northern hemisphere. Although the species was previously known, no one ever tried to calculate the size of this animal. The flightless bird, attributed to the species Pachystruthio dmanisensis, was probably at least 3.5 metres tall and would have towered above early humans. It may have been flightless but it was also fast.

While elephant birds were hampered by their great size when it came to speed, the femur of the current bird was relatively long and slim, suggesting it was a better runner. The femur is comparable to modern ostriches as well as smaller species of moa and terror birds. Speed may have been essential to the bird’s survival. Alongside its bones, palaeontologists found fossils of highly-specialised, massive carnivores from the Ice Age. They included giant cheetah, giant hyenas and sabre-toothed cats, which were able to prey on mammoths.

Other fossils discovered alongside the specimen, such as bison, help date it to 1.5 to 2 million years ago. A similar range of fossils was discovered at an archaeological site in the town of Dmanisi in Georgia, the oldest hominin site outside Africa. Although previously neglected by science, this suggests the giant bird may have been typical of the animals found at the time when the first hominins arrived in Europe. The authors suggest it reached the Black Sea region via the Southern Caucasus and Turkey.

The body mass of the bird was reconstructed using calculations from several formulae, based on measurements from the femur bone. Applying these formulae, the body mass of the bird was estimated to be around 450kg. Such gigantism may have originally evolved in response to the environment, which was increasingly arid as the Pleistocene epoch approached. Animals with a larger body mass have lower metabolic demands and can therefore make use of less nutritious food growing in open steppes.

“The Taurida cave network was only discovered last summer when a new motorway was being built. Last year, mammoth remains were unearthed and there may be much more to that the site will teach us about Europe’s distant past,” says Zelenkov.


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Antarctic marine life recovery following the dinosaurs’ extinction

A new study shows how marine life around Antarctica returned after the extinction event that wiped out the dinosaurs.

A team led by British Antarctic Survey studied just under 3000 marine fossils collected from Antarctica to understand how life on the sea floor recovered after the Cretaceous-Paleogene (K-Pg) mass extinction 66 million years ago. They reveal it took one million years for the marine ecosystem to return to pre-extinction levels. The results are published today (19 June 2019) in the journal Palaeontology.

The K-Pg extinction wiped out around 60% of the marine species around Antarctica, and 75% of species around the world. Victims of the extinction included the dinosaurs and the ammonites. It was caused by the impact of a 10 km asteroid on the Yucatán Peninsula, Mexico, and occurred during a time period when the Earth was experiencing environmental instability from a major volcanic episode. Rapid climate change, global darkness, and the collapse of food chains affected life all over the globe.

The K-Pg extinction fundamentally changed the evolutionary history of life on Earth. Most groups of animals that dominate modern ecosystems today, such as mammals, can trace the roots of their current success back to the aftermath of this extinction event.

A team of scientists from British Antarctic Survey, the University of New Mexico and the Geological Survey of Denmark & Greenland show that in Antarctica, for over 320,000 years after the extinction, only burrowing clams and snails dominated the Antarctic sea floor environment. It then took up to one million years for the number of species to recover to pre-extinction levels.

Author Dr Rowan Whittle, a palaeontologist at British Antarctic Survey says:

“This study gives us further evidence of how rapid environmental change can affect the evolution of life. Our results show a clear link in the timing of animal recovery and the recovery of Earth systems.”

Author Dr James Witts, a palaeontologist at University of New Mexico says:

“Our discovery shows the effects of the K-Pg extinction were truly global, and that even Antarctic ecosystems, where animals were adapted to environmental changes at high latitudes like seasonal changes in light and food supply, were affected for hundreds of thousands of years after the extinction event.”


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Plate tectonics may have driven ‘Cambrian Explosion’

The quest to discover what drove one of the most important evolutionary events in the history of life on Earth has taken a new, fascinating twist.

A team of scientists have given a fresh insight into what may have driven the “Cambrian Explosion” — a period of rapid expansion of different forms of animal life that occurred over 500 million years ago.

While a number of theories have been put forward to explain this landmark period, the most credible is that it was fuelled by a significant rise in oxygen levels which allowed a wide variety of animals to thrive.

The new study suggests that such a rise in oxygen levels was the result of extraordinary changes in global plate tectonics.

During the formation of the supercontinent ‘Gondwana’, there was a major increase in continental arc volcanism — chains of volcanoes often thousands of miles long formed where continental and oceanic tectonic plates collided. This in turn led to increased ‘degassing’ of CO2 from ancient, subducted sedimentary rocks.

This, the team calculated, led to an increase in atmospheric CO2and warming of the planet, which in turn amplified the weathering of continental rocks, which supplied the nutrient phosphorus to the ocean to drive photosynthesis and oxygen production.

The study was led by Josh Williams, who began the research as an MSc student at the University of Exeter and is now studying for a PhD at the University of Edinburgh.

During his MSc project he used a sophisticated biogeochemical model to make the first quantification of changes in atmospheric oxygen levels just prior to this explosion of life.

Co-author and project supervisor Professor Tim Lenton, from the University of Exeter’s Global Systems Institute said: “One of the great dilemmas originally recognised by Darwin is why complex life, in the form of fossil animals, appeared so abruptly in what is now known as the Cambrian explosion.

“Many studies have suggested this was linked to a rise in oxygen levels — but without a clear cause for such a rise, or any attempt to quantify it.”

Not only did the model predict a marked rise in oxygen levels due to changes in plate tectonic activity, but that rise in oxygen — to about a quarter of the level in today’s atmosphere — crossed the critical levels estimated to be needed by the animals seen in the Cambrian explosion.

Williams added: “What is particularly compelling about this research is that not only does the model predict a rise in oxygen to levels estimated to be necessary to support the large, mobile, predatory animal life of the Cambrian, but the model predictions also show strong agreement with existing geochemical evidence.”

“It is remarkable to think that our oldest animal ancestors — and therefore all of us — may owe our existence, in part, to an unusual episode of plate tectonics over half a billion years ago” said Professor Lenton.


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Neanderthals and modern humans diverged at least 800,000 years ago, research on teeth shows

Neanderthals and modern humans diverged at least 800,000 years ago, substantially earlier than indicated by most DNA-based estimates, according to new research by a UCL academic.

The research, published in Science Advances, analysed dental evolutionary rates across different hominin species, focusing on early Neanderthals. It shows that the teeth of hominins from Sima de los Huesos, Spain — ancestors of the Neanderthals — diverged from the modern human lineage earlier than previously assumed.

Sima de los Huesos is a cave site in Atapuerca Mountains, Spain, where archaeologists have recovered fossils of almost 30 people. Previous studies date the site to around 430,000 years ago (Middle Pleistocene), making it one of the oldest and largest collections of human remains discovered to date.

Dr Aida Gomez-Robles (UCL Anthropology), said: “Any divergence time between Neanderthals and modern humans younger than 800,000 years ago would have entailed an unexpectedly fast dental evolution in the early Neanderthals from Sima de los Huesos.”

“There are different factors that could potentially explain these results, including strong selection to change the teeth of these hominins or their isolation from other Neanderthals found in mainland Europe. However, the simplest explanation is that the divergence between Neanderthals and modern humans was older than 800,000 years. This would make the evolutionary rates of the early Neanderthals from Sima de los Huesos roughly comparable to those found in other species.”

Modern humans share a common ancestor with Neanderthals, the extinct species that were our closest prehistoric relatives. However, the details on when and how they diverged are a matter of intense debate within the anthropological community.

Ancient DNA analyses have generally indicated that both lineages diverged around 300,000 to 500,000 years ago, which has strongly influenced the interpretation of the hominin fossil record.

This divergence time, however, is not compatible with the anatomical and genetic Neanderthal similarities observed in the hominins from Sima de los Huesos. The Sima fossils are considered likely Neanderthal ancestors based on both anatomical features and DNA analysis.

Dr Gomez-Robles said: “Sima de los Huesos hominins are characterised by very small posterior teeth (premolars and molars) that show multiple similarities with classic Neanderthals. It is likely that the small and Neanderthal-looking teeth of these hominins evolved from the larger and more primitive teeth present in the last common ancestor of Neanderthals and modern humans.”

Dental shape has evolved at very similar rates across all hominin species, including those with very expanded and very reduced teeth. This new study examined the time at which Neanderthals and modern humans should have diverged to make the evolutionary rate of the early Neanderthals from Sima de los Huesos similar to those observed in other hominins.

The research used quantitative data to measure the evolution of dental shape across hominin species assuming different divergent times between Neanderthals and modern humans, and accounting for the uncertainty about the evolutionary relationships between different hominin species.

“The Sima people’s teeth are very different from those that we would expect to find in their last common ancestral species with modern humans, suggesting that they evolved separately over a long period of time to develop such stark differences.”

The study has significant implications for the identification of Homo sapiens last common ancestral species with Neanderthals, as it allows ruling out all the groups postdating 800,000 year ago.


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