Skipping evolution: Some kangaroos didn't hop

Extinct kangaroos used alternative methods to their famous hop according to comprehensive analysis from University of Bristol and the University of Uppsala scientists.

Although hopping is regarded as a pinnacle of kangaroo evolution, the researchers highlight that other kinds of large kangaroos, in the not too distant past, likely moved in different ways such as striding on two legs or traversing on all fours.

In the review, published in Alcheringa: An Australasian Journal of Palaeontology, the team shows that there are other ways to be an evolutionary successful large kangaroo and that large-bodied kangaroo weren't only specialised in endurance-hopping.

The review is an extensive discussion of the fossil evidence of the locomotion of kangaroos and their relatives (including wallabies, tree-kangaroos, rat-kangaroos, etc.) over the last 25 million years, and presents new analyses of limb bone and ankle bone metric data that add weight to previous locomotor hypotheses.

Together they indicated that the higher speed-endurance hopping, typical of modern large-bodied kangaroos, was probably rare or absent in all but a few large-bodied lineages, including the direct ancestors of modern large kangaroos like red and grey kangaroos. However, the diversity of kangaroo gaits disappeared with the Late Pleistocene extinctions of larger animals (in Australia as well as on other continents).

While almost all kangaroos today, small and large, use hopping gaits to some extent, the fossil record reveals that the locomotory capabilities of some extinct kangaroos were comparatively diverse.

The earliest recognized late Oligocene-middle Miocene (25to 15 million years ago) basal types of kangaroos most likely employed quadrupedal bounding, climbing and slower speed hopping as their primary modes of locomotion. (All kangaroos today use quadrupedal locomotion at slow speeds, which manifests as pentapedal locomotion -- using the tail as a fifth limb -- in larger species.) Yet, all these early forms were small-bodied, below 12kg, with larger bodied kangaroos over 20kg not appearing until the late Miocene (around 10 million years ago), coinciding with increasing aridity and the spread of openly vegetated habitats.

Hopping is functionally problematic at larger body sizes. Consequently, some members of the later kangaroo radiation achieved a more specialized anatomy for efficient higher-speed hopping at body sizes over 35kg. Modern large kangaroos are spectacular hoppers but none today are over 100kg (most individuals under 70 kg) and many extinct forms were well above this size and physically too big to hop.

Lead author Professor Christine Janis from Bristol's School of Earth Sciences said: "We want people to appreciate that large kangaroos were much more diverse as recently as 50 thousand years ago, which may also mean that the habitat in Australia then was rather different from today.

"In fact, modern large hopping kangaroos are the exception in kangaroo evolution."

While hopping apparently originated early in kangaroo evolution, in small-bodied forms, with the emergence of larger-sized kangaroos in the late Miocene there were several different options: to become more specialized for large-bodied endurance hopping, as in the ancestors of modern kangaroos, or to adopt other forms of locomotion at higher speeds, as in two main extinct lineages. The protemnodons (so-called 'giant wallabies', closely related to modern large kangaroos) likely relied upon a more quadrupedal type of locomotion most of the time, and rarely hopped. The sthenurine short-faced kangaroos, a lineage that split from all modern kangaroos around 15 million years ago, apparently adopted bipedal striding at all speeds.

The new data presented on the length of the tibia (shin bone) and calcaneum (ankle bone) reinforce these earlier hypotheses of locomotor differences from modern kangaroos in these two extinct groups. Co-author Adrian O'Driscoll, a former Master's student in the Palaeobiology program at Bristol and now a PhD student at the University of York made this contribution. He explained: "Especially supported by this new data is the notion of bipedal striding rather than hopping in the sthenurines, as their calcanea lack the anatomy (a long calcaneal heel) that would help resist rotational forces at the ankle experienced during hopping, and suggests a more-erect limb posture rather than the crouched posture essential for hopping."

Professor Janis concluded: "The assumption that increasing continent-wide aridity after the end of the Miocene selectively favoured hopping kangaroos is overly simplistic. Hopping is only one of many gait modes employed by kangaroos both in the past and today, and the fast endurance hopping of modern kangaroos should not be regarded as some "evolutionary pinnacle'.

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Scientists develop new index based on functional morphology to understand how ancestors of modern birds used their wings

Scientists at Nagoya University in Japan have developed an index to estimate how a bird uses its wings for flight or other locomotion by measuring the strength of the coracoid bone and the animal's body mass. It should improve our understanding of how extinct animals used their wings and the different patterns of wing-propelled locomotion that emerged as birds evolved. Their findings were published in the Journal of Anatomy.

The presence of a wing alone does not tell us whether an animal can fly. For example, penguins evolved wings to propel them through water whereas feathered dinosaurs may have used their wings for other purposes, such as thermoregulation and intraspecific display. Therefore, to better understand how animals evolved the ability to fly, an index must take into account both the presence of wings and the ability to perform powerful wing-beats.

"We wanted to create a new index because people think that if an animal has wings, then it can fly," said the study's second author, Assistant Professor Shin-ichi Fujiwara. "But this is not always true. An animal can also use its wings for other purposes, such as thermal insulation in flightless animals. Our research team focused on how changes in skeletal morphology can lead to changes in locomotion. Subsequently, these changes can lead to major ecological transitions such as a shift in lifestyle from a terrestrial environment to an aerial, aquatic, arboreal, or subterranean environment. The origin of flight in birds has been an important topic in this field. We, therefore, needed to develop an alternative index, based on biomechanics, to determine the flapping ability of birds and which we could also use to measure skeletal remains."

To create this index, the researchers used the avian coracoid bone. The coracoid bone acts as a strut to prevent the thoracic skeleton from deforming when an animal's powerful flight muscles, which connect the wings to the sternum, contract. Doctoral student Takumi Akeda of the Department of Earth and Planetary Sciences, Graduate School of Environmental Studies, at Nagoya University, and Fujiwara of the Nagoya University Museum, measured the size of a cross section of the coracoid bone in relation to the body mass of 220 bird specimens. Their sample of 209 species included extinct birds such as the dodo and the great auk.

The researchers then divided the birds into four groups based on how they used their wings. These groups were those that used flapping flight (e.g., pigeons); those that used wing-propelled diving (e.g., penguins); those that were flightless with no flapping ability (e.g., ostriches); and those that used thermal and dynamic soaring (e.g., albatrosses and vultures). Based on the strength of the coracoid bone and flapping ability, the researchers could create a new index to analyze flight patterns.

They found that the strength of the coracoid in relation to body mass may reflect the force exerted by the flight muscles, which counteract the lifting force on the wings. This helps to estimate how a bird uses propulsion. Soaring birds had increased coracoid strength, probably to enable them to withstand the greater bending forces caused by the contraction of the flapping muscles. In contrast, non-flapping birds had lower coracoid strength. These findings show that coracoid strength in relation to body mass reflects the lifting force on the wings, therefore, it is a useful tool for reconstructing the type of propulsion used by the animal.

Akeda and Fujiwara's index should allow future researchers to assess the flight styles and flapping abilities of not only extinct birds but also other flying animals, including the Pteranodon and Quetzalcoatlus of "Jurassic World" fame. The index could also allow them to estimate the origin of flight in winged theropods, the ancestors of birds.

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Learning about the first animals on Earth from life at the poles

The amazing survival strategies of polar marine creatures might help to explain how the first animals on Earth could have evolved earlier than the oldest fossils suggest according to new research. These first, simple and now extinct, animals might have lived through some of the most extreme, cold and icy periods the world has ever seen. The study is published in the journal Global Change Biology, published this week (12 October 2022).

The fossil record places the earliest animal life on Earth at 572-602 million years ago, just as the world came out of a huge ice age, whilst molecular studies suggest an earlier origin, up to 850 million years ago. If correct, this means that animals must have survived during a time influenced by multiple global ice ages, when the whole or large parts of the planet were encased in ice (snowball and slushball Earths), far bigger than any seen since. If animal life did arise before, or during, these extreme glacial periods it would have faced conditions like modern marine habitats found in Antarctica and the Arctic today, and required similar survival strategies.

Over millions of years, the expansion and contraction of the ice sheets during cold and warm periods has driven the evolution of Antarctica's thousands of unique animals and plant species. The same could be true for the evolution of animal life on Earth. Whilst to humans the polar regions seem like the most hostile environments to life, they are the perfect place to study the past and the potential for life in the universe beyond our planet, such as on icy moons like Europa.

Marine biologist and lead author, Dr Huw Griffiths of British Antarctic Survey (BAS), says:

"This work highlights how some animals in the polar regions are incredibly adapted to life in and around the ice, and how much they can teach us about the evolution and survival of life in the past or even on other planets.

"Whether it is animals living upside down on the underside of ice instead of the seafloor, sponges living hundreds of kilometres under thick floating ice shelves, organisms that are adapted to live in seawater colder than ?2°C, or whole communities existing in the darkness on food sources that don't require sunlight, Antarctic and Arctic life thrives in conditions that would kill humans and most other animals. But these cold and icy conditions help to drive ocean circulation, carry oxygen into the ocean depths and make these places more suitable for life."

Floating ice covers more than 19 million km2 of the seas around Antarctica and 15 million km2 of the Arctic Ocean during winter. Under possibly the most extreme snowball Earth, lasting 50 to 60 million years during the Cryogenian period (720 to 635?million years ago), the whole world (510 million km²) is believed to have been entombed in ice around a kilometre thick, but there is some evidence that this ice was thin enough at the equator to allow marine algae to survive.

"The fact that there is this huge difference in the timing of the dawn of animal life between the known fossil record and molecular clocks means that there are huge uncertainties about how and where animals evolved" says co-author Dr Emily Mitchell, palaeontologist and ecologist at the University of Cambridge. "But if animals did evolve before or during these global ice ages, they would have to contend with extreme environmental pressures, but ones that may have helped to force life to become more complex to survive."

"Just like in Antarctica during the Last Glacial Maximum (33-14 thousand years ago), the huge amounts of advancing ice would have bulldozed the shallows, making them inhospitable to life, destroying fossil evidence and forcing creatures into the deep sea. This makes the chances of finding fossils from these times less likely and sheltered areas and the deep sea the safest places for life to evolve."

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Newly identified fossil insect used 360-degree vision and sticky feet to find and snare its meals

With bulging eyes, an elongated mouth and feet that oozed resin, a fossil insect identified by Oregon State University research is so different from anything alive today that it needed to be placed in its own, extinct family.

George Poinar Jr., professor emeritus in the OSU College of Science, named the insect Palaeotanyrhina exophthalma in a paper published in BioOne Complete. Encased in 100-million-year-old amber from Burma, P. exophthalma is a member of the Hemiptera order -- a "true bug," Poinar said.

"It is a small predator that used its protruding eyes to locate insect prey," said Poinar, an international expert in using plant and animal life forms preserved in amber to learn about the biology and ecology of the distant past.

More than 80,000 species including cicadas, aphids, planthoppers, leafhoppers, bed bugs and shield bugs comprise the order of Hemiptera, an ancient Greek word meaning half-winged. True bugs' size varies widely, from as small as 1 millimeter to as large as 15 centimeters, but they all have a similar arrangement of sucking mouthparts.

P. exophthalma has a body length of just over 5 millimeters. It shares some features with members of the Reduvoidea superfamily, which includes the assassin bug and the kissing bug, but its long labium (lower mouth), its head shape and its forewing veins disqualify it from placement in any modern Reduvoidea family, Poinar said.

Thus he assigned it to a new, extinct family: Palaeotanyrhinidae.

"Its eyes provided a clear, 360-degree view of its habitat so it could see prey that might appear from any side," Poinar said.

It reminded Poinar of the phrase, "Big brother is always watching you," from George Orwell's novel "1984" in which security cameras followed individuals' every movement.

The other strange feature on this fossil is an extended sheath on the final leg segment of the front tarsus, he added.

"That sheath was filled with a resinous substance," Poinar said. "The sticky substance was produced by dermal glands and helped the insect grasp potential prey."

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What did Megalodon eat? Anything it wanted -- including other predators.

New Princeton research shows that prehistoric megatooth sharks -- the biggest sharks that ever lived -- were apex predators at the highest level ever measured.

Megatooth sharks get their name from their massive teeth, which can each be bigger than a human hand. The group includes Megalodon, the largest shark that ever lived, as well as several related species.

While sharks of one kind or another have existed since long before the dinosaurs -- for more than 400 million years -- these megatooth sharks evolved after the dinosaurs went extinct and ruled the seas until just 3 million years ago.

"We're used to thinking of the largest species -- blue whales, whale sharks, even elephants and diplodocuses -- as filter feeders or herbivores, not predators," said Emma Kast, a 2019 Ph.D. graduate in geosciences who is the first author on a new study in the current issue of Science Advances. "But Megalodon and the other megatooth sharks were genuinely enormous carnivores that ate other predators, and Meg went extinct only a few million years ago."

Her adviser Danny Sigman, Princeton's Dusenbury Professor of Geological and Geophysical Sciences, added, "If Megalodon existed in the modern ocean, it would thoroughly change humans' interaction with the marine environment."

A team of Princeton researchers has now discovered clear evidence that Megalodon and some of its ancestors were at the very highest rung of the prehistoric food chain -- what scientists call the highest "trophic level." Indeed, their trophic signature is so high that they must have eaten other predators and predators-of-predators in a complicated food web, say the researchers.

"Ocean food webs do tend to be longer than the grass-deer-wolf food chain of land animals, because you start with such small organisms," said Kast, now at the University of Cambridge, who wrote the first iteration of this research as a chapter in her dissertation. "To reach the trophic levels we're measuring in these megatooth sharks, we don't just need to add one trophic level -- one apex predator on top of the marine food chain -- we need to add several onto the top the modern marine food web."

Megalodon has been conservatively estimated at 15 meters long -- 50 feet -- while modern great white sharks typically top out around five meters (15 feet).

To reach their conclusions about the prehistoric marine food web, Kast, Sigman and their colleagues used a novel technique to measure the nitrogen isotopes in the sharks' teeth. Ecologists have long known that the more nitrogen-15 an organism has, the higher its trophic level, but scientists have never before been able to measure the tiny amounts of nitrogen preserved in the enamel layer of these extinct predators' teeth.

"We have a series of shark teeth from different time periods, and we were able to trace their trophic level versus their size," said Zixuan (Crystal) Rao, a graduate student in Sigman's research group and a co-author on the current paper.

One way to tuck in an extra trophic level or two is cannibalism, and several lines of evidence point to that in both megatooth sharks and other prehistoric marine predators.

The nitrogen time machine

Without a time machine, there's no easy way to recreate the food webs of extinct creatures; very few bones have survived with teeth marks that say, "I was chewed on by a massive shark."

Fortunately, Sigman and his team have spent decades developing other methods, based on the knowledge that the nitrogen isotope levels in a creature's cells reveal whether it is at the top, middle or bottom of a food chain.

"The whole direction of my research team is to look for chemically fresh, but physically protected, organic matter -- including nitrogen -- in organisms from the distant geologic past," said Sigman.

A few plants, algae and other species at the bottom of the food web have mastered the knack of turning nitrogen from the air or water into nitrogen in their tissues. Organisms that eat them then incorporate that nitrogen into their own bodies, and critically, they preferentially excrete (sometimes via urine) more of nitrogen's lighter isotope, N-14, than its heavier cousin, N-15.

In other words, N-15 builds up, relative to N-14, as you climb up the food chain.

Other researchers have used this approach on creatures from the recent past -- the most recent 10-15 thousand years -- but there hasn't been enough nitrogen left in older animals to measure, until now.

Why? Soft tissue like muscles and skin are hardly ever preserved. To complicate matters, sharks don't have bones -- their skeletons are made of cartilage.

But sharks do have one golden ticket into the fossil record: teeth. Teeth are more easily preserved than bones because they are encased in enamel, a rock-hard material that is virtually immune to most decomposing bacteria.

"Teeth are designed to be chemically and physically resistant so they can survive in the very chemically reactive environment of the mouth and break apart food that can have hard parts," Sigman explained. And in addition, sharks aren't limited to the 30 or so pearly whites that humans have. They are constantly growing and losing teeth -- modern sand sharks lose a tooth every day of their decades-long lives, on average -- which means that every shark produces thousands of teeth over its lifetime.

"When you look in the geologic record, one of the most abundant fossil types are shark teeth," said Sigman. "And within the teeth, there is a tiny amount of organic matter that was used to build the enamel of the teeth -- and is now trapped within that enamel."

Since shark teeth are so abundant and are preserved so well, the nitrogen signatures in enamel provide a way to measure status in the food web, whether the tooth fell from a shark's mouth millions of years ago or yesterday.

Even the largest tooth has only a thin casing of enamel, of which the nitrogen component is only a tiny trace. But Sigman's team has been developing more and more refined techniques for extracting and measuring these nitrogen isotope ratios, and with a little help from dentist drills, cleaning chemicals and microbes that ultimately convert the nitrogen from within the enamel into nitrous oxide, they're now able to precisely measure the N15-N14 ratio in these ancient teeth.

"We're a little bit like a brewery," he said. "We grow microbes and feed our samples to them. They produce nitrous oxide for us, and then we analyze the nitrous oxide they produced."

The analysis requires a custom-built, automated nitrous oxide preparation system that extracts, purifies, concentrates and delivers the gas to a specialized stable isotope ratio mass spectrometer.

"This has been a multiple-decades-long quest that I've been on, to develop a core method to measure these trace amounts of nitrogen," Sigman said. From microfossils in sediments, they moved on to other types of fossils, like corals, fish ear bones and shark teeth. "Next, we and our collaborators are applying this to mammalian teeth and dinosaur teeth."

A deep dive into the literature during lockdown

Early in the pandemic, while her friends were making sourdough starters and bingeing Netflix, Kast pored through the ecologic literature to look for nitrogen isotope measurements of modern marine animals.

"One of the cool things that Emma did was really dig into the literature -- all the data that's been published over decades -- and relate that to the fossil record," said Michael (Mick) Griffiths, a paleoclimatologist and geochemist at William Patterson University and a co-author on the paper.

As Kast quarantined at home, she painstakingly built up a record with more than 20,000 marine mammal individuals and more than 5,000 sharks. She wants to take things much further. "Our tool has the potential to decode ancient food webs; what we need now is samples," said Kast. "I'd love to find a museum or other archive with a snapshot of an ecosystem -- a collection of different kinds of fossils from one time and place, from forams near the very base of the food web, to otoliths -- inner ear bones -- from different kinds of fish, to teeth from marine mammals, plus shark teeth. We could do the same nitrogen isotope analysis and put together the whole story of an ancient ecosystem."

In addition to the literature search, their database includes their own samples of shark teeth. Co-author Kenshu Shimada of DePaul University connected with aquariums and museums, while co-authors Martin Becker of William Patterson University and Harry Maisch of Florida Gulf Coast University gathered megatooth specimens on the sea floor.

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A large predator from the Pyrenees

A fossilized lower jaw has led an international team of palaeontologists, headed by Bastien Mennecart from the Natural History Museum Basel, to discover a new species of predator that once lived in Europe. These large predators belong to a group of carnivores colloquially known as "bear dogs." They could weigh around 320 kilograms, appeared 36 million years ago before becoming extinct around 7.5 million years ago.

Palaeontologist Bastien Mennecart and his research group precisely described the fossilized lower jaw of a carnivore and discovered that it must be a specimen from a new species. The jawbone comes from 12.8 to 12 million-year-old marine deposits that were examined in the small community of Sallespisse in the Pyrénées-Atlantiques department of south western France.

The teeth of time

The jawbone was striking because of its teeth. Unlike the familiar amphicyonidae specimens, this animal has a unique fourth lower premolar. This tooth is particularly important for determining species and genera. Correspondingly, the lower jaw examined probably represents a new genus. It is called Tartarocyon. This name comes from Tartaro, a large, powerful, one-eyed giant from Basque mythology. The legend of Tartaro is also known in Béarn, the region where the lower jaw was found. Floréal Solé, a specialist in carnivorous mammals, Jean-François Lesport and Antoine Heitz from the Natural History Museum Basel chose the name of the new genus.

Dog-like predator

The fossilized lower jaw can be classified as belonging to predators that resembled a cross between a bear and a large dog, known as "bear dogs." Their scientific name is "Amphicyonidae." They belong to a group of carnivores such as dogs, cats, bears, seals and badgers. These predators were a widespread part of the European fauna of the Miocene (23 to 5.3 million years ago). They were very species-rich and diverse, weighing between 9 kg and 320 kg. Tarataroyon is estimated at 200 kg. The last European Amphicyonidae disappeared during the late Miocene 7.5 million years ago.

Key contemporary witnesses

Discoveries of fossilized terrestrial vertebrates that lived on the northern edge of the Pyrenees 13 to 11 million years ago are very rare. The discovery and description of the lower jaw is even more significant. That is because it offers the opportunity to explore the development of European "bear dogs" against the background of known environmental events at this time.

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Lost or extinct? Study finds the existence of more than 500 animal species remains uncertain

An international study provides the first global evaluation of all terrestrial vertebrate species that have not been declared extinct and identifies more than 500 species considered to be 'lost' -- those that haven't been seen by anyone in more than 50 years.

Researchers reviewed information on 32,802 species from the International Union for Conservation of Nature Red List of Threatened Species (IUCN Red List) and identified 562 lost species. Their findings appear in the journal Animal Conservation.

The IUCN Red List defines extinct as 'when there is no reasonable doubt the last individual of a species has died,' which can be challenging to verify. According to Simon Fraser University biodiversity professor and study co-author Arne Mooers, the Red List categorizes 75 of these 562 lost species as 'possibly extinct.' The researchers note the existence of many species with an uncertain conservation status may become increasingly problematic as the extinction crisis worsens and more species go missing.

A total of 311 terrestrial vertebrate species have been declared extinct since 1500, meaning 80 per cent more species are considered lost than have been declared extinct.

Reptiles led the way with 257 species considered lost, followed by 137 species of amphibians, 130 species of mammals and 38 species of birds. Most of these lost animals were last seen in megadiverse countries such as Indonesia (69 species), Mexico (33 species) and Brazil (29 species).

While not surprising, this concentration is important, according to researchers. "The fact most of these lost species are found in megadiverse tropical countries is worrying, given such countries are expected to experience the highest numbers of extinctions in the coming decades," says study lead author Tom Martin from the UK's Paignton Zoo.

Mooers, who anchored the study, says: "While theoretical estimates of ongoing 'extinction rates' are fine and good, looking hard for actual species seems better."

Gareth Bennett, an SFU undergraduate student who did much of the data combing, adds: "We hope this simple study will help make these lost species a focus in future searches."

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Earth's first giant

The two-meter skull of a newly discovered species of giant ichthyosaur, the earliest known, is shedding new light on the marine reptiles' rapid growth into behemoths of the Dinosaurian oceans, and helping us better understand the journey of modern cetaceans (whales and dolphins) to becoming the largest animals to ever inhabit the Earth.

While dinosaurs ruled the land, ichthyosaurs and other aquatic reptiles (that were emphatically not dinosaurs) ruled the waves, reaching similarly gargantuan sizes and species diversity. Evolving fins and hydrodynamic body-shapes seen in both fish and whales, ichthyosaurs swam the ancient oceans for nearly the entirety of the Age of Dinosaurs.

"Ichthyosaurs derive from an as yet unknown group of land-living reptiles and were air-breathing themselves," says lead author Dr. Martin Sander, paleontologist at the University of Bonn and Research Associate with the Dinosaur Institute at the Natural History Museum of Los Angeles County (NHM). "From the first skeleton discoveries in southern England and Germany over 250 years ago, these 'fish-saurians' were among the first large fossil reptiles known to science, long before the dinosaurs, and they have captured the popular imagination ever since."

Excavated from a rock unit called the Fossil Hill Member in the Augusta Mountains of Nevada, the well-preserved skull, along with part of the backbone, shoulder, and forefin, date back to the Middle Triassic (247.2-237 million years ago), representing the earliest case of an ichthyosaur reaching epic proportions. As big as a large sperm whale at more than 17 meters (55.78 feet) long, the newly named Cymbospondylus youngorum is the largest animal yet discovered from that time period, on land or in the sea. In fact, it was the first giant creature to ever inhabit the Earth that we know of.

"The importance of the find was not immediately apparent," notes Dr. Sander, "because only a few vertebrae were exposed on the side of the canyon. However, the anatomy of the vertebrae suggested that the front end of the animal might still be hidden in the rocks. Then, one cold September day in 2011, the crew needed a warm-up and tested this suggestion by excavation, finding the skull, forelimbs, and chest region."

The new name for the species, C. youngorum, honors a happy coincidence, the sponsoring of the fieldwork by Great Basin Brewery of Reno, owned and operated by Tom and Bonda Young, the inventors of the locally famous Icky beer which features an ichthyosaur on its label.

In other mountain ranges of Nevada, paleontologists have been recovering fossils from the Fossil Hill Member's limestone, shale, and siltstone since 1902, opening a window into the Triassic. The mountains connect our present to ancient oceans and have produced many species of ammonites, shelled ancestors of modern cephalopods like cuttlefish and octopuses, as well as marine reptiles. All these animal specimens are collectively known as the Fossil Hill Fauna, representing many of C. youngorum's prey and competitors.

C. youngorum stalked the oceans some 246 million years ago, or only about three million years after the first ichthyosaurs got their fins wet, an amazingly short time to get this big. The elongated snout and conical teeth suggest that C. youngorum preyed on squid and fish, but its size meant that it could have hunted smaller and juvenile marine reptiles as well.

The giant predator probably had some hefty competition. Through sophisticated computational modeling, the authors examined the likely energy running through the Fossil Hill Fauna's food web, recreating the ancient environment through data, finding that marine food webs were able to support a few more colossal meat-eating ichthyosaurs. Ichthyosaurs of different sizes and survival strategies proliferated, comparable to modern cetaceans' -- from relatively small dolphins to massive filter-feeding baleen whales, and giant squid-hunting sperm whales.

Co-author and ecological modeler Dr. Eva Maria Griebeler from the University of Mainz in Germany notes, "due to their large size and resulting energy demands, the densities of the largest ichthyosaurs from the Fossil Hill Fauna including C. youngourum must have been substantially lower than suggested by our field census. The ecological functioning of this food web from ecological modeling was very exciting as modern highly productive primary producers were absent in Mesozoic food webs and were an important driver in the size evolution of whales."

Whales and ichthyosaurs share more than a size range. They have similar body plans, and both initially arose after mass extinctions. These similarities make them scientifically valuable for comparative study. The authors combined computer modeling and traditional paleontology to study how these marine animals reached record-setting sizes independently.

"One rather unique aspect of this project is the integrative nature of our approach. We first had to describe the anatomy of the giant skull in detail and determine how this animal is related to other ichthyosaurs," says senior author Dr. Lars Schmitz, Associate Professor of Biology at Scripps College and Dinosaur Institute Research Associate. "We did not stop there, as we wanted to understand the significance of the new discovery in the context of the large-scale evolutionary pattern of ichthyosaur and whale body sizes, and how the fossil ecosystem of the Fossil Hill Fauna may have functioned. Both the evolutionary and ecological analyses required a substantial amount of computation, ultimately leading to a confluence of modeling with traditional paleontology."

They found that while both cetaceans and ichthyosaurs evolved very large body sizes, their respective evolutionary trajectories toward gigantism were different. Ichthyosaurs had an initial boom in size, becoming giants early on in their evolutionary history, while whales took much longer to reach the outer limits of huge. They found a connection between large size and raptorial hunting -- think of a sperm whale diving down to hunt giant squid -- and a connection between large size and a loss of teeth -- think of the giant filter-feeding whales that are the largest animals ever to live on Earth.

Ichthyosaurs' initial foray into gigantism was likely thanks to the boom in ammonites and jawless eel-like conodonts filling the ecological void following the end-Permian mass extinction. While their evolutionary routes were different, both whales and ichthyosaurs relied on exploiting niches in the food chain to make it really big.

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Extinct reptile discovery reveals earliest origins of human teeth, study finds

A new extinct reptile species has shed light on how our earliest ancestors became top predators by modifying their teeth in response to environmental instability around 300 million years ago.

In findings published in Royal Society Open Science, researchers at the University of Bristol have discovered that this evolutionary adaptation laid the foundations for the incisor, canine and molar teeth that all mammals -- including humans -- possess today.

Shashajaia is one of the most primitive members of a group called the Sphenacodontoidea, which includes the famous sail-backed Dimetrodon, and mammal-like reptiles known as therapsids, which eventually evolved into mammals. It is remarkable for its age and anatomy, possessing a very unique set of teeth that set it apart from other synapsids -- meaning the animal lineage that mammals belong to -- of the time.

Dr Suresh Singh of the School of Earth Sciences explained: "The teeth show clear differentiation in shape between the front and back of the jaw, organised into distinct regions. This is the basic precursor of what mammals have today -- incisors and canines up front, with molars in the back. This is the oldest record of such teeth in our evolutionary tree."

The novel dentition of Shashajaia demonstratesthat large, canine-like differentiated teeth were present in synapsids by the Late Carboniferous period -- a time famous for giant insects and the global swampy rainforests that produced much of our coal deposits.

By analytically comparing the tooth variation observed in Shashajaia with other synapsids, the study suggests that distinctive, specialised teeth likely emerged in our synapsid ancestors as a predatory adaptation to help them catch prey at a time when global climate change approximately 300 million years ago saw once-prevalent Carboniferous wetlands replaced by more arid, seasonal environments. These new, more changeable conditions brought a change in the availability and diversity of prey.

Lead author Dr Adam Huttenlocker of the University of Southern California said: "Canine-like teeth in small sphenacodonts like Shashajaia might have facilitated a fast, raptorial bite in riparian habitats where a mix of terrestrial and semi-aquatic prey could be found in abundance."

The new reptile is one of the oldest synapsids. It was named "Shashajaia bermani," which translates as Berman's bear heart, to honour the 51-year career of veteran palaeontologist, Dr David Berman of the Carnegie Museum of Natural History, as well as the local Navajo people of the discovery site within the Bears Ears National Monument, Utah.

Dr Singh said: "The study is a testament to Dr Berman who originally discovered the fossil site in 1989, and his decades of work on synapsids and other early tetrapods from the Bears Ears region of Utah which helped to justify the Bears Ears National Monument in 2016."

The site is located within an area known as the Valley of the Gods and is of huge importance to palaeontologists.

Read more at Science Daily

Extinct swordfish-shaped marine reptile discovered

A team of international researchers from Canada, Colombia, and Germany has discovered a new marine reptile. The specimen, a stunningly preserved metre-long skull, is one of the last surviving ichthyosaurs -- ancient animals that look eerily like living swordfish.

"This animal evolved a unique dentition that allowed it to eat large prey," says Hans Larsson, Director of the Redpath Museum at McGill University. "Whereas other ichthyosaurs had small, equally sized teeth for feeding on small prey, this new species modified its tooth sizes and spacing to build an arsenal of teeth for dispatching large prey, like big fishes and other marine reptiles."

"We decided to name it Kyhytysuka which translates to 'the one that cuts with something sharp' in an indigenous language from the region in central Colombia where the fossil was found, to honour the ancient Muisca culture that existed there for millennia," says Dirley Cortes, a graduate student under the supervision of Hans Larsson and Carlos Jaramillo of the Smithsonian Tropical Research Institute.

The big picture of ichthyosaur evolution is clarified with this new species, the researchers say. "We compared this animal to other Jurassic and Cretaceous ichthyosaurs and were able to define a new type of ichthyosaurs," says Erin Maxwell of the State Natural History Museum of Stuttgart (a former graduate student of Hans Larsson's lab at McGill). "This shakes up the evolutionary tree of ichthyosaurs and lets us test new ideas of how they evolved."

According to the researchers, this species comes from an important transitional time during the Early Cretaceous period. At this time, the Earth was coming out of a relatively cool period, had rising sea levels, and the supercontinent Pangea was splitting into northern and southern landmasses. There was also a global extinction event at the end of the Jurassic that changed marine and terrestrial ecosystems. "Many classic Jurassic marine ecosystems of deep-water feeding ichthyosaurs, short-necked plesiosaurs, and marine-adapted crocodiles were succeeded by new lineages of long-necked plesiosaurs, sea turtles, large marine lizards called mosasaurs, and now this monster ichthyosaur" says Dirley Cortes.

"We are discovering many new species in the rocks this new ichthyosaur comes from. We are testing the idea that this region and time in Colombia was an ancient biodiversity hotspot and are using the fossils to better understand the evolution of marine ecosystems during this transitional time," she adds. As next steps the researchers are continuing to explore the wealth of new fossils housed in the Centro de Investigaciones Paleontológicas of Villa de Leyva in Colombia. "This is where I grew up," says Cortes "and it is so rewarding to get to do research here too."

Read more at Science Daily

Henderson island fossils reveal new Polynesian sandpiper species

 Fossil bones collected in the early 1990s on Henderson Island, part of the Pitcairn Group, have revealed a new species of Polynesian sandpiper.

The Henderson Sandpiper, a small wading bird that has been extinct for centuries, is described in an article in the Zoological Journal of the Linnean Society published last week.

The newly-described bird is formally named Prosobonia sauli after Cook Islands-based ornithologist and conservationist Edward K Saul.

A team of researchers from New Zealand, Australia, Denmark, Switzerland, the Netherlands and China, led by Canterbury Museum Research Curator Natural History Dr Vanesa De Pietri, described the Henderson Sandpiper from 61 fossilised bones cared for by the Natural History Museum at Tring in England.

Canterbury Museum Visiting Researcher Dr Graham Wragg collected the bones from caves and overhangs on Henderson Island in 1991 and 1992 during the Sir Peter Scott Commemorative Expedition to the Pitcairn Islands.

Prosobonia sauli is the fifth known species of Polynesian sandpiper. All but one of the species, the endangered Tuamotu Sandpiper (Prosobonia parvirostris), are extinct.

"We think Prosobonia sauli probably went extinct soon after humans arrived on Henderson Island, which archaeologists estimate happened no earlier than the eleventh century," says Dr De Pietri.

"It's possible these humans brought with them the Polynesian rat, which Polynesian sandpiper populations are very vulnerable to."

DNA of the living Tuamotu Sandpiper and the extinct Tahiti Sandpiper (Prosobonia leucoptera), which is known only from a skin in the Naturalis Biodiversity Center in the Netherlands, was used to determine how Polynesian sandpipers are related to other wading birds.

"We found that Polynesian sandpipers are early-diverging members of a group that includes calidrine sandpipers and turnstones. They are unlike other sandpipers in that they are restricted to islands of the Pacific and do not migrate," says Dr De Pietri.

Comparisons with the other two extinct Polynesian sandpiper species, the Kiritimati Sandpiper (Prosobonia cancellata) and the Mo'orea Sandpiper (Prosobonia ellisi), are complicated. These birds are known only from illustrations primarily by William Wade Ellis, an artist and Surgeon's Mate on Captain James Cook's third expedition, who probably saw the birds alive in the 1770s.

Compared to the Tuamotu Sandpiper, its geographically closest cousin, the Henderson Sandpiper had longer legs and a wider, straighter bill, indicating how it foraged for food. It probably adapted to the habitats available on Henderson Island, which are different to those on other islands where Polynesian sandpipers were found.

Henderson Island is the largest island in the Pitcairn Group, in the middle of the South Pacific Ocean. It has been uninhabited since around the fifteenth century and was designated a World Heritage Site by the United Nations in 1988.

Dr Paul Scofield, Canterbury Museum Senior Curator Natural History and one of the study's co-authors, says Henderson Island is home to a number of unique species, a handful of which are landbirds like the Henderson Sandpiper.

"The island is really quite remarkable because every landbird species that lives there, or that we know used to live there, is not found anywhere else," he says.

Dr De Pietri says the study shows the need to protect the one remaining Polynesian sandpiper species, the Tuamotu Sandpiper.

"We know that just a few centuries ago there were at least five Polynesian sandpiper species scattered around the Pacific. Now there's only one, and its numbers are declining, so we need to ensure we look after the remaining populations."

Read more at Science Daily

Paleontologists uncover three new species of extinct walruses in Orange County, California

 Millions of years ago, in the warm Pacific Ocean off the coast of Southern California, walrus species without tusks lived abundantly.

But in a new study, Cal State Fullerton paleontologists have identified three new walrus species discovered in Orange County and one of the new species has "semi-tusks" -- or longer teeth.

The other two new species don't have tusks and all predate the evolution of the long iconic ivory tusks of the modern-day walrus, which lives in the frigid Arctic.

The researchers describe a total of 12 specimens of fossil walruses from Orange, Los Angeles and Santa Cruz counties, all estimated to be 5 to 10 million years old. The fossils represent five species, with two of the three new species represented by specimens of males, females and juveniles.

Their research, which gives insights on the dental and tusk evolution of the marine mammal, was published today in the Journal of Vertebrate Paleontology.

Geology graduate Jacob Biewer, and his research adviser James F. Parham, associate professor of geological sciences, are authors of the study, based on fossil skull specimens.

Parham and Biewer worked with Jorge Velez-Juarbe, an expert in marine mammals at the Natural History Museum of Los Angeles County, who is a co-author of the paper. Velez-Juarbe is a former postdoctoral scholar in Parham's lab and has collaborated on other CSUF fossil research projects. Parham is a research associate at the museum, which provides research opportunities for him and his students.

The researchers teamed to study and describe the anatomy of the specimens, most of which are part of the museum's collection.

"Orange County is the most important area for fossil walruses in the world," said Biewer, first author of the paper who conducted the research for his master's thesis. "This research shows how the walruses evolved with tusks."

Extinct Walrus Species Get Names

Today, there is only one walrus species and its scientific name is Odobenus.

For the new species found in Orange County, the researchers named the semi-tusked walrus, Osodobenus eodon, by combining the words Oso and Odobenus. Another is named Pontolis kohnoi in honor of Naoki Kohno, a fossil walrus researcher from Japan. Both of these fossils were discovered in the Irvine, Lake Forest and Mission Viejo areas.

Osodobenus eodon and Pontolis kohnoi are both from the same geological rock layer as the 2018 study by Parham and his students of another new genus and species of a tuskless walrus, Titanotaria orangensis, named after CSUF Titans. These fossils were found in the Oso Member of the Capistrano Formation, a geological formation near Lake Forest and Mission Viejo.

The third new walrus species, Pontolis barroni, was found in Aliso Viejo, near the 73 Toll Road. It is named after John Barron, a retired researcher from the U.S.Geological Survey and world expert on the rock layer where the specimens were found, Parham said.

Analysis of these specimens show that fossil walrus teeth are more variable and complex than previously considered. Most of the new specimens predate the evolution of tusks, Parham said.

"Osodobenus eodon is the most primitive walrus with tusk-like teeth," Parham said. "This new species demonstrates the important role of feeding ecology on the origin and early evolution of tusks."

Biewer explained that his work focused on getting a better understanding of the evolutionary history of the walrus in regards to its teeth.

"The importance of dental evolution is that it shows the variability within and across walrus species. Scientists assumed you could identify certain species just based on the teeth, but we show how even individuals of the same species could have variability in their dental setup," said Biewer, who earned a master's degree in geology in 2019.

"Additionally, everyone assumes that the tusks are the most important teeth in a walrus, but this research further emphasizes how tusks were a later addition to the history of walruses. The majority of walrus species were fish eaters and adapted to catching fish, rather than using suction feeding on mollusks like modern walruses."

Biewer, now a paleontologist in the Modesto area, also examined whether climate changes in the Pacific Ocean had an impact on ancient walruses. His work suggests that a rise in water temperature helped to boost nutrients and planktonic life, and played a role in the proliferation of walruses about 10 million years ago, which may have contributed to their diversity.

Background

For the fossil walrus research project, geology graduate Jacob Biewer spent hours in the lab measuring and describing the walrus bones.

"I sat many hours with a handy caliper taking notes on the lengths of teeth and width of skulls, among many other measurements," he said. "Describing bones is much more in depth and meticulous than it sounds. There are traits that the bones of each walrus species have -- the size, shape and number of teeth. I recorded how the bones are different from, or similar to, other extinct walrus species."

Biewer, a paleontologist who lives in Modesto, noted that despite the pandemic, he and Parham worked on the scientific paper with 300 miles of social distancing.

Completing his first journal publication, based on his master's work, and conducting the research project helped him to understand scientific methods and techniques that he now uses in his career, where he monitors construction sites for paleontological resources. He also teaches undergraduate geology courses at Cal State Stanislaus, where he earned a bachelor's degree in geology, and is considering pursuing a doctorate.

Read more at Science Daily

Lost frogs rediscovered with environmental DNA

 Scientists have detected signs of a frog listed extinct and not seen since 1968, using an innovative technique to locate declining and missing species in two regions of Brazil.

The frog, Megaelosia bocainensis, was among seven total species -- including four other declining species, and two that had disappeared locally for many years -- that were detected. The findings appeared in a paper, "Lost and Found: Frogs in a Biodiversity Hotspot Rediscovered with Environmental DNA," published in August in Molecular Ecology.

Megaelosia bocainensis. A disappeared species from Parque Nacional da Serra da Bocaina, Brazil, known only from this museum specimen collected in 1968, and detected by eDNA surveys. In the study, the researchers collected and screened environmental DNA (eDNA) in the biodiverse Atlantic Coastal Forest and Cerrado grasslands of Brazil.

The eDNA technique offers a way to survey that can confirm the presence of species undetected by traditional methods, providing a tool for conservation scientists to evaluate the presence of threatened species, especially those with low population densities and those not seen in years.

After careful research to identify species at various levels of threat in these regions of Brazil, the researchers used the eDNA method to search for 30 target amphibian species in six localities where the frogs were known to previously live.

"Little bits of DNA in the environment don't tell us about how many individuals there are or whether those individuals are healthy, but it does tell us that the species is still present," said senior author Kelly Zamudio, the Goldwin Smith Professor of Ecology and Evolutionary Biology in the College of Arts and Sciences.

"This is one more kind of survey data, and for species that are declining or locally disappeared, it not only means they are there, but there's now the potential to study them in more detail," she said, noting that for many species, very little is known.

Around the world, conservationists have been challenged to keep pace with declining and disappearing amphibians. At the same time, living organisms leave DNA traces in the soil, water and air. Now, scientists are increasingly using highly sensitive sampling techniques to detect eDNA for conservation purposes.

In the study, the researchers targeted 13 frog species that have totally disappeared and are presumed extinct; 12 frogs that have disappeared locally but are still found in other parts of their range; and five species that were once very abundant and are still there but hard to find.

The researchers hiked into the sampling sites carrying battery packs, a shoebox-sized peristaltic pump and backpacks of sterile tubing. They used the pump and tubing to draw up to 60 liters of stream or pond water through a capsule fitted with a filter for capturing DNA. A buffer was then applied to stabilize and preserve the DNA on the filter.

Back in the lab, the researchers extracted the DNA, genetically sequenced it, weeded out genetic material from humans, pigs, chickens and other organisms until they could isolate all the frog DNA.

"Now you've got a subset of genetic sequences that we know only belong to frogs, and then it's step by step, going finer and finer, until you get to the genus and species you are looking for," Zamudio said.

Identifying M. bocainensis required clever detective work: The species disappeared long ago, and there were no tissues from which to extract DNA for comparison with the eDNA. But the researchers did have the sequences for all the sister species in the genus Megaelosia and they knew the ranges of the sister species and M. bocainensis.

"We know there's a Megaelosia there," Zamudio said, "we just don't know which one it is, but the only one that has ever been reported there historically is the one that went missing. Do we believe it? That's how far the analysis can take us."

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15-foot-long skeleton of extinct dolphin suggests parallel evolution among whales

A report in the journal Current Biology on July 9 offers a detailed description of the first nearly complete skeleton of an extinct large dolphin, discovered in what is now South Carolina. The 15-foot-long dolphin (Ankylorhiza tiedemani comb. n.) lived during the Oligocene -- about 25 million years ago -- and was previously known only from a partial rostrum (snout) fossil.

The researchers say that multiple lines of evidence -- from the skull anatomy and teeth, to the flipper and vertebral column -- show that this large dolphin (a toothed whale in the group Odontoceti) was a top predator in the community in which it lived. They say that many features of the dolphin's postcranial skeleton also imply that modern baleen whales and modern toothed whales must have evolved similar features independently, driven by parallel evolution in the very similar aquatic habitats in which they lived.

"The degree to which baleen whales and dolphins independently arrive at the same overall swimming adaptations, rather than these traits evolving once in the common ancestor of both groups, surprised us," says Robert Boessenecker of the College of Charleston in Charleston, South Carolina. "Some examples include the narrowing of the tail stock, increase in the number of tail vertebrae, and shortening of the humerus (upper arm bone) in the flipper.

"This is not apparent in different lineages of seals and sea lions, for example, which evolved into different modes of swimming and have very different looking postcranial skeletons," he adds. "It's as if the addition of extra finger bones in the flipper and the locking of the elbow joint has forced both major groups of cetaceans down a similar evolutionary pathway in terms of locomotion."

Though first discovered in the 1880s from a fragmentary skull during phosphate dredging of the Wando River, the first skeleton of Ankylorhiza was discovered in the 1970s by then Charleston Museum Natural History curator Albert Sanders. The nearly complete skeleton described in the new study was found in the 1990s. A commercial paleontologist by the name of Mark Havenstein found it during construction of a housing subdivision in South Carolina. It was subsequently donated to the Mace Brown Museum of Natural History, to allow for its study.

While there's much more to learn from this fossil specimen, the current findings reveal that Ankylorhiza was an ecological specialist. The researchers say the species was "very clearly preying upon large-bodied prey like a killer whale."

Another intriguing aspect, according to the researchers, is that Ankylorhiza is the first echolocating whale to become an apex predator. When Ankylorhiza became extinct by about 23 million years ago, they explain, killer sperm whales and the shark-toothed dolphin Squalodon evolved and reoccupied the niche within 5 million years. After the last killer sperm whales died out about 5 million years ago, the niche was left open until the ice ages, with the evolution of killer whales about 1 or 2 million years ago.

"Whales and dolphins have a complicated and long evolutionary history, and at a glance, you may not get that impression from modern species," Boessenecker says. "The fossil record has really cracked open this long, winding evolutionary path, and fossils like Ankylorhiza help illuminate how this happened."

Boessenecker notes that more fossils of Ankylorhiza are awaiting study, including a second species and fossils of Ankylorhiza juveniles that can offer insight into the dolphin's growth. He says that there's still much to learn from fossilized dolphins and baleen whales from South Carolina.

Read more at Science Daily

How birds evolved big brains

Common raven

An international team of evolutionary biologists and paleontologists have reconstructed the evolution of the avian brain using a massive dataset of brain volumes from dinosaurs, extinct birds like Archaeopteryx and the Great Auk, and modern birds.

The study, published online today in the journal Current Biology, reveals that prior to the mass extinction at the end of the Cretaceous Period, birds and non-avian dinosaurs had similar relative brain sizes. After the extinction, the brain-body scaling relationship shifted dramatically as some types of birds underwent an explosive radiation to re-occupy ecological space vacated by extinct groups.

"One of the big surprises was that selection for small body size turns out to be a major factor in the evolution of large-brained birds," says Dr. Daniel Ksepka, Curator of Science at the Bruce Museum and lead author of the study. "Many successful bird families evolved proportionally large brains by shrinking down to smaller body sizes while their brain sizes stayed close to those of their larger-bodied ancestors."

In order to understand how bird brains changed, a team of 37 scientists used CT scan data to create endocasts (models of the brain based on the shape of the skull cavity) of hundreds of birds and dinosaurs, which they combined with a large existing database of brain measurements from modern birds. They then analyzed brain-body allometry: the way brain size scales with body size.

"There is no clear line between the brains of advanced dinosaurs and primitive birds," notes co-author Dr. Amy Balanoff of Johns Hopkins University. "Birds like emus and pigeons have the same brains sizes you would expect for a theropod dinosaur of the same body size, and in fact some species like moa have smaller-than-expected brains."

The two groups of birds with truly exceptional brain sizes evolved relatively recently: parrots and corvids (crows, ravens, and kin). These birds show tremendous cognitive capacity, including the ability to use tools and language, and to remember human faces. The new study finds that parrots and crows exhibited very high rates of brain evolution that may have helped them achieve such high proportional brain sizes.

"Several groups of birds show above average rates of brain and body size evolution," remarks co-author Dr. N. Adam Smith of the Campbell Geology Museum at Clemson University. "But crows are really off the charts -- they outpaced all other birds. Our results suggest that calling someone 'bird-brained' is actually quite a compliment!"

Read more at Science Daily

Ancient teeth from Peru hint now-extinct monkeys crossed Atlantic from Africa

Marmoset. Ucayalipithecus perdita would have been very small, similar in size to a modern-day marmoset.

Four fossilized monkey teeth discovered deep in the Peruvian Amazon provide new evidence that more than one group of ancient primates journeyed across the Atlantic Ocean from Africa, according to new USC research just published in the journal Science.

The teeth are from a newly discovered species belonging to an extinct family of African primates known as parapithecids. Fossils discovered at the same site in Peru had earlier offered the first proof that South American monkeys evolved from African primates.

The monkeys are believed to have made the more than 900-mile trip on floating rafts of vegetation that broke off from coastlines, possibly during a storm.

"This is a completely unique discovery," said Erik Seiffert, the study's lead author and Professor of Clinical Integrative Anatomical Sciences at Keck School of Medicine of USC. "It shows that in addition to the New World monkeys and a group of rodents known as caviomorphs -- there is this third lineage of mammals that somehow made this very improbable transatlantic journey to get from Africa to South America."

Researchers have named the extinct monkey Ucayalipithecus perdita. The name comes from Ucayali, the area of the Peruvian Amazon where the teeth were found, pithikos, the Greek word for monkey and perdita, the Latin word for lost.

Ucayalipithecus perdita would have been very small, similar in size to a modern-day marmoset.

Dating the migration

Researchers believe the site in Ucayali where the teeth were found is from a geological epoch known as the Oligocene, which extended from about 34 million to 23 million years ago.

Based on the age of the site and the closeness of Ucayalipithecus to its fossil relatives from Egypt, researchers estimate the migration might have occurred around 34 million years ago.

"We're suggesting that this group might have made it over to South America right around what we call the Eocene-Oligocene Boundary, a time period between two geological epochs, when the Antarctic ice sheet started to build up and the sea level fell," said Seiffert. "That might have played a role in making it a bit easier for these primates to actually get across the Atlantic Ocean."

An improbable discovery

Two of the Ucayalipithecus perdita teeth were identified by Argentinean co-authors of the study in 2015 showing that New World monkeys had African forebears. When Seiffert was asked to help describe these specimens in 2016, he noticed the similarity of the two broken upper molars to an extinct 32 million-year-old parapithecid monkey species from Egypt he had studied previously.

An expedition to the Peruvian fossil site in 2016 led to the discovery of two more teeth belonging to this new species. The resemblance of these additional lower teeth to those of the Egyptian monkey teeth confirmed to Seiffert that Ucayalipithecus was descended from African ancestors.

"The thing that strikes me about this study more than any other I've been involved in is just how improbable all of it is," said Seiffert. "The fact that it's this remote site in the middle of nowhere, that the chances of finding these pieces is extremely small, to the fact that we're revealing this very improbable journey that was made by these early monkeys, it's all quite remarkable."

About this study

In addition to Seiffert, the study's other authors are Marcelo Tejedor and Nelson Novo from the Instituto Patagónico de Geología y Paleontología (CCT CONICET -- CENPAT); John G. Fleagle from the Department of Anatomical Sciences, Renaissance School of Medicine, Stony Brook University; Fanny Cornejo and Dorien de Vries from the Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University; Mariano Bond from CONICET, División Paleontología Vertebrados, Museo de Ciencias Naturales de La Plata and Kenneth E. Campbell Jr. from the Department of Vertebrate Zoology, Natural History Museum of Los Angeles County.

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Ancient Australia was home to strange marsupial giants, some weighing over 1,000 kg

Palorchestid marsupials, an extinct group of Australian megafauna, had strange bodies and lifestyles unlike any living species, according to a study released September 13, 2019 in the open-access journal PLOS ONE by Hazel Richards of Monash University, Australia and colleagues.

For most of the last 25 million years, eastern Australia was home to a now-extinct group of marsupials called palorchestids. These animals are well known for their large size, strange tapir-like skulls, and large claws, but so far there has been no detailed study of their limb morphology. In this study, Richards and colleagues examined more than 60 fossil specimens of palorchestids of varying geologic ages to characterize the function and evolution of their arms and legs.

Over the course of their evolution, palorchestids grew larger and stranger. Using limb proportions as a proxy for body size, these authors estimated that the latest and largest of the palorchestids may have weighed over 1,000kg. Furthermore, their forelimbs were extremely muscular and were likely adapted for grabbing or scraping at leaves and branches. Uniquely among known mammals, the elbow joints of the largest palorchestids appear to have been immobile and fixed at roughly a 100-degree angle, so that the arms served as permanently flexed food-gathering tools.

This study provides the first formal description of limb morphology in palorchestid marsupials and reveals a group of giant herbivores that probably filled a niche no longer occupied in modern Australian ecosystems. Fossil remains are still missing for certain parts of the palorchestid body, such as the shoulders and wrists, but the authors are hopeful that more material may be found in existing museum collections.

The authors add: "This study has allowed us for the first time to appreciate just how huge these mega-marsupial palorchestids were, while also providing the first comprehensive view of a strange limb anatomy unprecedented in the mammalian world. This research reveals yet more about the diversity of unique large marsupials that once roamed Australia not so long ago."

From Science Daily

New light shed on demise of two extinct New Zealand songbirds

They may not have been seen for the past 50 and 110 years, but an international study into their extinction has provided answers to how the world lost New Zealand's South Island kokako and huia.

Lead author Dr Nicolas Dussex, of the University of Otago, New Zealand, and Swedish Museum of Natural History, says the team set out to investigate if it was external (habitat loss, mammalian predators) or internal (demography, genetic effects) factors which led to their extinction.

Very little was known about the forest songbirds he describes as "iconic and somehow mysterious," which were last seen in 1960s and 1907 respectively, but recent advances in the extraction and analysis of ancient DNA provided the opportunity scientists needed to find out more.

The study, just published in Biology Letters, produced what Dr Dussex calls "very surprising" results.

The researchers mapped the birds' complete genomes and saw a response to ice age climate change many thousands of years ago, but no signs of genetic problems common in small populations such as inbreeding. This suggests a rapid population decline possibly caused by habitat loss and new predators introduced by the Europeans.

"Because even the earliest Polynesian settlers more than 700 years ago had a significant impact on forest cover, we would have expected huia and South Island kokako populations to have survived at small population sizes for centuries and thus to have experienced an increase in inbreeding.

"However, our data did not show evidence for inbreeding and indicated that the two species still had quite a bit of genetic diversity close to the time of extinction. This means that their extinction was most likely not driven by genetic effects and inbreeding, but that further habitat loss and introduction of mammalian predators by European must have triggered a rapid extinction," he says.

Dr Dussex says this is the first study to generate high-quality genomes from historical specimens of extinct New Zealand species.

"Using complete genomes allowed us to reconstruct the birds' population history, and, more importantly, to determine whether genetic effects could have contributed to their extinction.

"While we focused here on two extinct species, understanding the role of genetic effects in the extinction process is extremely relevant to the study of declining and inbred populations, such as the kakapo, saddleback, and kiwi. This knowledge can thus contribute the conservation and recovery of endangered species potentially exposed to negative genetic effects."

Co-author Dr Michael Knapp, of Otago's Department of Anatomy, says the team hopes its work will stimulate similar research in other extinct or endangered endemic species from New Zealand.

Read more at Science Daily

Do volcanoes or an asteroid deserve blame for dinosaur extinction?

Layered lava flows within the Wai Subgroup from near Ambenali Ghat, Western Ghats.

Based on new data published today in the journal Science, it seems increasingly likely that an asteroid or comet impact 66 million years ago reignited massive volcanic eruptions in India, half a world away from the impact site in the Caribbean Sea.

But it leaves unclear to what degree the two catastrophes contributed to the near-simultaneous mass extinction that killed off the dinosaurs and many other forms of life.

The research sheds light on huge lava flows that have erupted periodically over Earth's history, and how they have affected the atmosphere and altered the course of life on the planet.

In the study, University of California, Berkeley, scientists report the most precise and accurate dates yet for the intense volcanic eruptions in India that coincided with the worldwide extinction at the end of the Cretaceous Period, the so-called K-Pg boundary. The million-year sequence of eruptions spewed lava flows for distances of at least 500 kilometers across the Indian continent, creating the so-called Deccan Traps flood basalts that in some places are nearly 2 kilometers thick.

"Now that we have dated Deccan Traps lava flows in more and different locations, we see that the transition seems to be the same everywhere. I would say, with pretty high confidence, that the eruptions occurred within 50,000 years, and maybe 30,000 years, of the impact, which means they were synchronous within the margin of error," said Paul Renne, a professor-in-residence of earth and planetary science at UC Berkeley, director of the Berkeley Geochronology Center and senior author of the study, which will appear online Feb. 21. "That is an important validation of the hypothesis that the impact renewed lava flows."

The new dates also confirm earlier estimates that the lava flows continued for about a million years, but contain a surprise: three-quarters of the lava erupted after the impact. Previous studies suggested that about 80 percent of the lava erupted before the impact.

If most of the Deccan Traps lava had erupted before the impact, then gases emitted during the eruptions could have been the cause of global warming within the last 400,000 years of the Cretaceous Period, during which temperatures increased, on average, about 8 degrees Celsius (14.4 degrees Fahrenheit). During this period of warming, species would have evolved suited to hothouse conditions, only to be confronted by global cooling from the dust or by climate cooling gases caused by either the impact or the volcanos.

The cold would have been a shock from which most creatures would never have recovered, disappearing entirely from the fossil record: literally, a mass extinction.

But if most of the Deccan Traps lava emerged after the impact, this scenario needs rethinking.

"This changes our perspective on the role of the Deccan Traps in the K-Pg extinction," said first author Courtney Sprain, a former UC Berkeley doctoral student who is now a postdoc at the University of Liverpool in the United Kingdom. "Either the Deccan eruptions did not play a role -- which we think unlikely -- or a lot of climate-modifying gases were erupted during the lowest volume pulse of the eruptions."

The hypothesis that climate-altering volcanic gases leak out of underground magma chambers frequently, and not just during eruptions, is supported by evidence from present-day volcanos, such as those of the gas-spewing Mt. Etna in Italy and Popocatepetl in Mexico, the researchers said. Magma stewing below the surface is known to transmit gases to the atmosphere, even without eruptions.

"We are suggesting that it is very likely that a lot of the gases that come from magma systems precede eruptions; they don't necessarily correlate with eruptions," Renne said. In the case of the K-Pg extinction, the symptoms of significant climate change occurred before the peak in volcanic eruptions.

Flood basalts

Renne, Sprain and their colleagues are using a precise dating method, argon-argon dating, to determine when the impact occurred and when the Deccan Traps erupted to clarify the sequence of catastrophes at the end of the Cretaceous Period and beginning of the Tertiary Period -- the K-Pg boundary, formerly referred to as the K-T boundary.

In 2013, using rocks from Montana, they obtained the most precise date yet for the impact, and in 2018, they updated that to 66,052,000 years ago, give or take 8,000 years. Then, in 2015, they determined from a handful of samples in India that, in at least one spot, the peak of the Deccan Traps eruptions occurred within about 50,000 years of that date, which means, in geologic time, that the incidents were basically simultaneous.

Now, with three times more rock samples from areas covering more of the Deccan Traps, the researchers have established that the time of peak eruptions was the same across much of the Indian continent. This supports the group's hypothesis that the asteroid impact triggered super-earthquakes that caused a strong burst of volcanism in India, which is almost directly opposite the impact site, the Chicxulub crater in the Caribbean Sea.

Sprain and Renne argue that the coincident catastrophes likely delivered a one-two punch to life on Earth, but the details are unclear. Volcanic eruptions produce lots of gases, but some, like carbon dioxide and methane, warm the planet, while others, like sulfur aerosols, are cooling. The impact itself would have sent dust into the atmosphere that blocked sunlight and cooled the Earth, though no one knows for how long.

"Both the impact and Deccan volcanism can produce similar environmental effects, but these are occurring on vastly differing timescales," Sprain said. "Therefore, to understand how each agent contributed to the extinction event, assessing timing is key."

Which gases in the Deccan Traps are emitted when is a question that's hard to answer, because there are no flood basalt eruptions going on today, despite numerous ones in Earth's history. The most recent, near the Columbia River in the Pacific Northwest, dwindled 15 million years ago after 400,000 years of eruptions.

The paucity of information about flood basalts is one reason Renne and Sprain are interested in the Deccan Traps, which are still young enough to contain information about the sequence, effects and scale of the eruptions, and perhaps the cause.

"It makes we wonder whether we may see some external forcing mechanism, like the impact for the Deccan Traps, for other flood basalts that lead up to major peaks in eruptions, like the Columbia River basalts or the Siberian Traps," Renne said. "Could a major earthquake in nearby subduction zones or the accumulation of pressure due to rising magma unleash these major episodes in flood basalts?"

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Origins of giant extinct New Zealand bird traced to Africa

Adzebill skeleton on display in the Canterbury Museum, New Zealand. Among the giant bird's closest living relatives are the tiny flufftails from Madagascar and Africa.

Scientists have revealed the African origins of New Zealand's most mysterious giant flightless bird -- the now extinct adzebill -- showing that some of its closest living relatives are the pint-sized flufftails from Madagascar and Africa.

Led by the University of Adelaide, the research in the journal Diversity showed that among the closest living relatives of the New Zealand adzebills -- which weighed up to 19 kilograms -- are the tiny flufftails, which can weigh as little as 25 grams. The closeness of the relationship strongly suggests that the ancestors of the adzebills flew to New Zealand after it became physically isolated from other land.

This finding mirrors the close relationship between New Zealand's kiwi and the extinct Madagascan elephant birds, published by University of Adelaide researchers in 2014, hinting at an unappreciated biological connection between Madagascar and New Zealand.

Like the better-known moa, the two species of adzebill -- the North Island adzebill and South Island adzebill -disappeared following the arrival of early Maori in New Zealand, who hunted them and cleared their forest habitats. Unlike the moa, adzebills were predators and not herbivores.

"The adzebill were almost completely wingless and had an enormous reinforced skull and beak, almost like an axe, which is where they got their English name," says Alexander Boast, lead author and former Masters student at the University of Adelaide.

"If they hadn't gone extinct, they would be among the largest living birds."

A team of researchers from Australia, New Zealand, and the US analysed genetic data from the two adzebill species.

"A lot of past genetic research and publicity has focused on the moa, which we know were distant relatives of the ostrich, emu, and cassowary," says co-author Dr Kieren Mitchell, postdoctoral researcher at the University of Adelaide.

"But noone had analysed the genetics of the adzebill, despite a lot of debate about exactly what they were and where they came from."

"We know that adzebills have been in New Zealand for a relatively long time, since we previously discovered a 19 million-year-old adzebill fossil on the South Island," says co-author Associate Professor Trevor Worthy, a palaeontologist at Flinders University.

"A key question is whether they've been present since New Zealand broke away from the other fragments of the supercontinent Gondwana or whether their ancestors flew to New Zealand from elsewhere later on."

Researchers at both the University of Adelaide's Australian Centre for Ancient DNA and Curtin University's Ancient DNA Lab sequenced adzebill DNA from fragments of bone and eggshell. They compared this to DNA from living birds to discover the identity and origin of the adzebill.

"It's possible that ancient migration of birds between Madagascar and New Zealand may have occurred via Antarctica," says Dr Mitchell.

"Some coastal regions of the continent remained forested and ice free until as recently as 30 million years ago."

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