Fossil oak tree relatives discovery in Argentina


This 2017 video is about Castanopsis trees.

From Penn State university in the USA:

Argentine fossils take oak and beech family history far into Southern Hemisphere

June 7, 2019

One of the world’s most important plant families has a history extending much farther south than any live or fossil specimen previously recorded, as shown by chinquapin fruit and leaf fossils unearthed in Patagonia, Argentina, according to researchers.

“The oak and beech family is recognized everywhere as one of the most important plant groups and has always been considered northern,” said Peter Wilf, professor of geosciences and associate in the Earth and Environmental Systems Institute, Penn State. “We’re adding a huge spatial dimension to the history of the Fagaceae family, and that’s exciting.” The plant family also includes chestnuts and the closely related chinquapins.

Common in the Northern Hemisphere and Asian tropics, Fagaceae cross the equator only in Southeast Asia, and even there just barely. The latest study, published today (June 7) in Science, extends the family’s biogeographical history and suggests a Gondwanan supercontinent legacy in Asian rainforests larger than previously thought.

The researchers first found fossils resembling some oak leaves, with straight secondary veins and one tooth per secondary vein, at Laguna del Hunco, Chubut province. The leaves comprise about 10 percent of the thousands of 52-million-year-old leaf fossils, representing almost 200 species, found at the site over two decades in a long-term project between Penn State, Cornell University and Museo Paleontológico Egidio Feruglio (MEF), Trelew, Argentina.

For years the researchers hesitated to classify the leaves, because paleobotanist Edward Berry had assigned similar fossils to another family, and any claim of Fagaceae at so remote a location would require much more supporting evidence.

Later, the team unearthed rare fruit fossils — two fruit clusters, one with more than 110 immature fruits — at the site and compared them to living relatives. They found that these were fossils of ancient Castanopsis, an Asian chinquapin that today dominates the biodiverse, lower elevation mountain rainforests of Southeast Asia.

“One of the first clues was a little lip where the fruit is splitting open,” Wilf said. “I recognized this lip as being similar to the fruit of the Japanese chinquapin. Then I realized there’s a nut inside.”

The nuts are fully encased in a scaly outer covering, or cupule, that splits open when the fruits mature. The cupules are arranged on a spike-like fruiting axis, and the young nuts retain delicate parts from their flowering stage. Their features are just like the living Castanopsis, Wilf said, and the fruits confirm that the leaves are Fagaceae.

“This is the first confirmed evidence that Fagaceae, considered restricted to the Northern Hemisphere, was in the Southern Hemisphere,” said Maria Gandolfo, associate professor, Cornell University. “This is remarkable and allows us to rethink the origins of the fossil flora.”

The fossils date to the early Eocene 52.2 million years ago. They are the only fossilized or living Fagaceae ever found south of the Malay Archipelago, the island chain just north of Australia.

During the globally warm early Eocene there was no polar ice, and South America, Antarctica and Australia had not completely separated, comprising the final stage of the Gondwanan supercontinent. The researchers think animals had helped disperse the chinquapin’s ancestors from North to South America at an earlier time. The plants thrived in the wet Patagonian rainforest, whose closest modern analog is the mountain rainforests of New Guinea.

“Before the current semi-desert conditions, trees covered Patagonia,” said Rubén Cúneo, director of MEF. “Changes in climatic conditions turned it into a shrubland, and the trees were displaced.”

The chinquapins may have also ranged into then-adjacent Antarctica and on to Australia, said Wilf. Castanopsis may have survived in Australia until the continent collided with Southeast Asia, where today chinquapins are keystone species, providing forest structure and food and habitat for birds, insects and mammals.

“We’re finding, in the same rocks as Castanopsis, fossils of many other plants that live with it today in New Guinea and elsewhere, including ferns, conifers and flowering plants,” said Wilf. “You can trace some of the associations with Castanopsis seen in Eocene Argentina to southern China and beyond.”

Today, Castanopsis plays an important role in intercepting year-round mountain precipitation that delivers clean water for drinking, fishing and agriculture to more than half a billion people and sustains diverse freshwater and coastal ecosystems. However, humans are clearing these rainforests for timber, development and crop cultivation, and modern climate change is increasing droughts and fire frequency.

“These plants are adaptable if given time and space,” Wilf said, adding Castanopsis’ trek from Patagonia to Southeast Asia occurred over millions of years and thousands of miles. “But the pace of change today is hundreds of times faster than in geologic time. The animals that depend on these plants are adaptable only to the extent that the plants are, and we are one of the animals that depend on this system. If we lose mountain rainforests, really fast we lose reliable water flows for agriculture, clean coral reefs offshore, biodiversity and much more.”

This study has implications for extinction in the face of climate change, according to Kevin Nixon, professor and L.H. Bailey Hortorium curator, Cornell University. He said Castanopsis went extinct in Patagonia due to a major extinction caused by the slow cooling and drying of the climate that occurred with the glaciation of Antarctica and the rise of the Andes.

“Those kinds of climate changes can have massive effects on biodiversity,” Nixon said. “The relevance of understanding this is we can start to look at extinction processes. The better we can understand what causes extinction, the better we can deal with it.”

The National Science Foundation, National Geographic Society and David and Lucile Packard Foundation funded this research.

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Mysterious Eocene crocodile, video


This 1 May 2019 video says about itself:

The Croc That Ran on Hooves

In the Eocene Epoch, there was a reptile that had teeth equipped for biting through flesh, its hind legs were a lot longer than its front legs and instead of claws, its toes were each capped with hooves. How did this living nightmare come to evolve?

This crocodile is called Boverisuchus.

Prehistoric school of fish discovered


PREHISTORIC SCHOOL: A shoal of extinct Erismatopterus levatus captured in a fossil that dates to the Eocene Epoch suggests that schooling behaviour in fish may have evolved tens of millions of years ago. Photo N. Mizumoto, S. Miyata and S.C. Pratt/Proceedings of the Royal Society B 2019

By Carolyn Wilke, 7:05pm, May 28, 2019:

A 50-million-year-old fossil captures a swimming school of fish

This snapshot in time reveals that fish may have coordinated their motion long ago

Fossilized fish captured mid-swim offer a rare glimpse into extinct animal behavior — and suggest that swimming in schools developed at least 50 million years ago.

A limestone shale slab from the Eocene Epoch reveals that extinct, thimble-sized fish called Erismatopterus levatus may have coordinated their motion similar to how fish in groups move today, researchers report May 29 in Proceedings of the Royal Society B.

The fossil captures a mass of 259 fish apparently swimming in the same direction. It’s unclear what killed the fish. But a suddenly collapsing sand dune, for example, could have buried them in place in a flash, knocking just a few askew in the process, the researchers suggest.

Analysis of the fish’s positions and orientations suggests they followed the same rules of “attraction” and “repulsion” that govern fish shoals today: The fish are repelled from their nearest neighbors to avoid collisions, but stick with the group by tracking with farther away fishes.

Because collective behavior is seen in so many animals, including the flocking of birds or swarming of insects, scientists believed such behavior evolved long ago. But there has been scant evidence in extinct species, says Nobuaki Mizumoto, a behavioral ecologist at Arizona State University in Tempe.

Mizumoto, whose research usually focuses on how termites build together, stumbled across the fish shoal fossil in a museum in Katsuyama, Japan in 2016. The fossil originally came from sediments in the Green River Formation, a geologic formation spanning what is now Colorado, Wyoming and Utah.

Ancient four-legged whale discovery in Peru


This 4 April 2019 video says about itself:

Four-legged whale ancestors reached South America in an otter-like swimming style

A four-legged whale from Peru indicates that early whales crossed the South Atlantic before 42.6 million years ago and may have propelled like otters: with a robust tail and webbed fingers on their long feet.

Production: Stéphane Van Israël, Royal Belgian Institute of Natural Sciences

From ScienceDaily:

Ancient, four-legged whale with otter-like features found along the coast of Peru

April 4, 2019

Cetaceans, the group including whales and dolphins, originated in south Asia more than 50 million years ago from a small, four-legged, hoofed ancestor. Now, researchers reporting the discovery of an ancient four-legged whale — found in 42.6-million-year-old marine sediments along the coast of Peru — have new insight into whales’ evolution and their dispersal to other parts of the world. The findings are reported in the journal Current Biology on April 4.

The presence of small hooves at the tip of the whale’s fingers and toes and its hip and limbs morphology all suggest that this whale could walk on land, according to the researchers. On the other hand, they say, anatomical features of the tail and feet, including long, likely webbed appendages, similar to an otter, indicate that it was a good swimmer too.

“This is the first indisputable record of a quadrupedal whale skeleton for the whole Pacific Ocean, probably the oldest for the Americas, and the most complete outside India and Pakistan”, says Olivier Lambert of the Royal Belgian Institute of Natural Sciences.

Some years ago, study co-author Mario Urbina of Museo de Historia Natural-UNMSM, Peru, discovered a promising area for digging fossils in the coastal desert of southern Peru, named Playa Media Luna. In 2011, an international team, including members from Peru, France, Italy, the Netherlands, and Belgium, organized a field expedition, during which they excavated the remains of an ancient whale they’ve since named Peregocetus pacificus. It means “the traveling whale that reached the Pacific.”

“When digging around the outcropping bones, we quickly realized that this was the skeleton of a quadrupedal whale, with both forelimbs and hind limbs,” Lambert says.

With the help of microfossils, the sediment layers where the skeleton was positioned were precisely dated to the middle Eocene, 42.6 million years ago. Anatomical details of the skeleton allowed them to infer that the animal was capable of maneuvering its large body (up to 4 meters long, tail included), both on land and in the water. For instance, features of the caudal vertebrae (in the tail) are reminiscent of those of beavers and otters, suggesting a significant contribution of the tail during swimming.

The geological age of the new four-limbed whale and its presence along the western coast of South America strongly support the hypothesis that early cetaceans reached the New World across the South Atlantic, from the western coast of Africa to South America, the researchers report. The whales would have been assisted in their travel by westward surface currents and by the fact that, at the time, the distance between the two continents was half what it is today. The researchers suggest that, only after having reached South America, the amphibious whales migrated northward, finally reaching North America.

The international team continues to study the remains of other whales and dolphins from Peru. “We will keep searching in localities with layers as ancient, and even more ancient, than the ones of Playa Media Luna, so older amphibious cetaceans may be discovered in the future,” Lambert says.

Fossil sharks, rays discovery in Madagascar


Eocene shark teeth from northwestern Madagascar. Credit: Samonds et al, 2019

From PLOS:

A rare assemblage of sharks and rays from nearshore environments of Eocene Madagascar

This finding, including one new shark species, fills a gap in the known marine record of Madagascar

February 27, 2019

Eocene-aged sediments of Madagascar contain a previously unknown fauna of sharks and rays, according to a study released February 27, 2019 in the open-access journal PLOS ONE by Karen Samonds of Northern Illinois University and colleagues. This newly-described fauna is the first report of sharks and rays of this age in Madagascar.

The Mahajanga basin of northwestern Madagascar yields abundant fossil remains of terrestrial and marine ecosystems, but little is known about fossil sharks and rays during the Eocene Epoch, 55-34 million years ago, in this region. This is in contrast to the numerous shark and ray faunas known from other Eocene sites around the globe, and to shark and ray ecosystems known from older and younger sediments in the Mahajanga basin.

In this study, Samonds and colleagues collected isolated teeth, dental plates, and stingray spines from ancient coastal sediments of the Ampazony and Katsepy regions of the basin, dated to the middle to late Eocene. They identified at least 10 species of sharks and rays, including one new species, Carcharhinus underwoodi. This is the oldest named species of Carcharhinus, a genus that has been globally distributed for the past 35 million years but is known only rarely from the Eocene.

Aside from the new species, the fauna of Eocene Madagascar shares many species with Eocene ecosystems across North Africa, suggesting these animals were widespread in southern seas at that time. On the other hand, the Madagascar fauna is uniquely lacking in sandsharks and dominated by eagle rays, indicating a somewhat unusual ecosystem, unsurprising given Madagascar’s long history of isolation. The authors caution that this study provides an incomplete picture given that they collected only fossils larger than 2 millimeters. They recommend that future studies target smaller material for a more complete view of the ancient ecosystem.

Oldest seed-eating perching bird discovered


This 7 February 2019 video is called Ancestor to modern day sparrows flew around 52 million years ago.

From the Field Museum in the USA:

Earliest known seed-eating perching bird discovered in Fossil Lake, Wyoming

February 7, 2019

Summary: The ‘perching birds‘, or passerines, are the most common birds in the world today — they include sparrows, robins, and finches. They used to be very rare. Scientists have just discovered some of the earliest relatives of the passerines, including a 52-million-year-old fossil with a thick, curved beak for eating seeds.

Most of the birds you’ve ever seen — sparrows, finches, robins, crows — have one crucial thing in common: they’re all what scientists refer to as perching birds, or “passerines”. The passerines make up about 6,500 of the 10,000 bird species alive today. But while they’re everywhere now, they were once rare, and scientists are still learning about their origins. In a new paper in Current Biology, researchers have announced the discovery of one of the earliest known passerine birds, from 52 million years ago.

“This is one of the earliest known perching birds. It’s fascinating because passerines today make up most of all bird species, but they were extremely rare back then. This particular piece is just exquisite,” says Field Museum Neguanee Distinguished Service Curator Lance Grande, an author of the paper. “It is a complete skeleton with the feathers still attached, which is extremely rare in the fossil record of birds.”

The paper describes two new fossil bird species — one from Germany that lived 47 million years ago, and another that lived in what’s now Wyoming 52 million years ago, a period known as the Early Eocene. The Wyoming bird, Eofringillirostrum boudreauxi, is the earliest example of a bird with a finch-like beak, similar to today’s sparrows and finches. This legacy is reflected in its name; Eofringilllirostrum means “dawn finch beak.” (Meanwhile, boudreauxi is a nod to Terry and Gail Boudreaux, longtime supporters of science at the Field Museum.)”

The fossil birds’ finch-like, thick beaks hint at their diet. “These bills are particularly well-suited for consuming small, hard seeds,” says Daniel Ksepka, the paper’s lead author, curator at the Bruce Museum in Connecticut. Anyone with a birdfeeder knows that lots of birds are nuts for seeds, but seed-eating is a fairly recent biological phenomenon. “The earliest birds probably ate insects and fish, some may have been eating small lizards,” says Grande. “Until this discovery, we did not know much about the ecology of early passerines. E. boudreauxi gives us an important look at this.”

“We were able to show that a comparable diversity of bill types already developed in the Eocene in very early ancestors of passerines,” says co-author Gerald Mayr of the Senckenberg Research Institute in Frankfurt. “The great distance between the two fossil sites implies that these birds were widespread during the Eocene, while the scarcity of known fossils suggests a rather low number of individuals,” adds Ksepka.

While passerine birds were rare 52 million years ago, E. boudreauxi had the good luck to live and die near Fossil Lake, a site famous for perfect fossilization conditions.

“Fossil Lake is a really graphic picture of an entire community locked in stone — it has everything from fishes and crocs to insects, pollen, reptiles, birds, and early mammals,” says Grande. “We have spent so much time excavating this locality, that we have a record of even the very rare things.”

Grande notes that Fossil Lake provides a unique look at the ancient world — one of the most detailed pictures of life on Earth after the extinction of the dinosaurs (minus the birds) 65 million years ago. “Knowing what happened in the past gives us a better understanding of the present and may help us figure out where we are going for the future.”

With that in mind, Grande plans to continue his exploration of the locale. “I’ve been going to Fossil Lake every year for the last 35 years, and finding this bird is one of the reasons I keep going back. It’s so rich,” says Grande. “We keep finding things that no one’s ever seen before.”

Ancient baleen whale evolution, new research


This March 2014 video says about itself:

A prehistoric whale graveyard was discovered in a Chilean desert a few years ago, and no one could figure out how the whales all died together half a mile from the coast… until now. Anthony is here to tell you how something as small as algae might have killed dozens of whales at once.

From the University of Otago in New Zealand:

Piece to the puzzle of baleen whales’ evolution

January 22, 2019

An Otago researcher has added another piece to the puzzle of the evolution of modern baleen whales with a world-first study examining the teeth and enamel of baleen whales’ ancestors.

Modern baleen whales have no teeth when adults, instead they use large keratin plates called baleen to filter prey from large volumes of seawater. However, millions of years ago their ancestors had teeth as most mammals do.

Lead author of the research just published in the Journal of Mammalian Evolution, Dr Carolina Loch from the Faculty of Dentistry, explains scientists are still trying to understand how and why this process happened. The research she carried out together with colleagues from the National Scientific and Technical Research Council in Argentina, CONICET, and the Swedish Museum of Natural History has provided more information.

They studied details of the inside structure of the teeth of two fossil whales from around 35 million years ago. These teeth were collected in Antarctica by the Argentinian and Swedish study co-authors Monica Buono and Thomas Mörs. Because teeth are naturally heavily mineralised, they preserve well in the fossil record and can provide clues of how extinct animals lived.

“We looked at how the enamel — the hard outside cover of teeth — and dentine, the core ‘living’ part, were structured and how similar or different they were from teeth of living whales, other fossil whales and other mammals,” Dr Loch explains.

“Both fossil whales we analysed (basilosaurid and fossil mysticete) had a complex enamel layer with biomechanical structures that suggest they were capable of heavy shearing and processing of their prey”, she says.

The enamel layer of the fossil mysticete they studied was the thickest enamel layer ever observed among cetaceans, both extinct and living.

“This is quite puzzling; baleen whales’ ancestors had teeth with complex and thick enamel, but millions of years later the teeth were ‘lost’ and replaced with large keratin plates called baleen”, Dr Loch says.

Because of the rarity of the material examined, Dr Loch says it is quite significant that the researchers were able to study them.

“Scanning electron microscopy is considered a ‘destructive’ type of analysis because the specimens need to be cut, polished and gold coated. It is fantastic that some museum curators are open to facilitate this kind of research and allow us to unravel new and important information.”

The study of the structure of the enamel and dentine of animals, both fossil and living, is a strength of Dr Loch’s research programme. Last year, the University of Otago highlighted another of her projects examining bottlenose dolphin teeth to help understand coastal contamination.

She hopes to continue studying teeth to help learn about how past animals lived and interacted with the environment, showing the breadth of the multidisciplinary research carried out in the University’s Faculty of Dentistry.

“As more fossil whales and other mammals are discovered and described, there is more material to be studied. I will continue working in partnership with colleagues overseas and in New Zealand in order to add small pieces to this puzzle — one tooth at a time.”