Missing link dinosaur nests-bird nests discovery

This video from Canada says about itself:

First feathered dinosaur from North America introduced by Darla Zelenitsky

26 October 2012

Canadian researchers discover fossils of first feathered dinosaurs from North America.

From Science magazine:

Missing link between dinosaur nests and bird nests

By Sid Perkins

25 November 2015 2:00 pm

The links between dinosaurs and birds keep getting stronger: skeletal structures, feathers—and now nests. Whereas some dinosaurs buried their eggs crocodile-style, a new analysis suggests that other dinosaurs built open nests on the ground, foreshadowing the nests of birds.

Interpreting the fossil record is always tough, but analyzing trace fossils such as nests is especially daunting. Those structures, and the materials used to make them, usually aren’t preserved, says Darla Zelenitsky, a paleobiologist at the University of Calgary in Canada. When paleontologists do find a nestlike structure that includes material such as sticks or other vegetation, the question arises: Was this stuff part of the original nest, or just carried there with the sediment that buried the nest and helped preserve it?

To gain insight into dinosaur nesting habits, Zelenitsky and her colleagues studied the most durable parts of nests—the eggs themselves. (Being largely made of the mineral calcium carbonate, they’ve got a head start on fossilization and are sometimes incredibly well preserved.) In particular, the team looked at the size and arrangement of small pores in the ancient shells, because those details are telling in modern creatures.

In crocodiles’ buried nests, the heat needed to incubate the eggs comes from decomposition of overlying organic matter or the sunlight absorbed by the soil. Plus, in buried nests airflow is somewhat limited, thus requiring eggs to be relatively porous to help increase the flow of oxygen into and carbon dioxide out of the eggs. But birds that brood in open nests can get by laying eggs with fewer or smaller pores.

So the team compared the porosity of eggshells from 29 species of dinosaurs (including large, long-necked herbivores called sauropods; bipedal meat-eaters called theropods; and duck-billed dinosaurs) with that of shells from 127 living species of birds and crocodiles.

Most of the dinosaur eggs were highly porous, suggesting that they buried their eggs to incubate them, the researchers report online today in PLOS ONE. But some of the dinosaur species in one group—a subset of well-evolved theropods considered to be the closest relatives of modern-day birds—laid low-porosity eggs, which suggests they incubated their eggs in open nests.

“This is a well done paper; the results make a lot of sense,” says Luis Chiappe, a vertebrate paleontologist at the Natural History Museum of Los Angeles County in California. The findings, he says, line up other studies suggesting that some birdlike dinosaurs were warm-blooded, which would have enabled them to incubate eggs in an open nest rather than depend on rotting vegetation or sunlight. Chiappe adds that the trend toward open nests could have allowed some dinosaurs to take another step toward birdlike nesting by moving their nests into the trees.

But considering only two types of nests—open versus buried—may be too simplistic, suggests Anthony Martin, a paleontologist at Emory University in Atlanta. Some dinosaurs—like a few of today’s birds—may have nested in burrows, which could have offered the stable temperature and protection from predators of a buried nest but resulted in low-porosity shells. Also, covered nests come in different types: Loose vegetation piled atop a buried nest can have a lot of airflow through it, allowing eggs to have relatively small pores, whereas eggs buried in soil or similar materials might not breathe as well and thus require larger pores, he notes. Nevertheless, Martin adds, the team’s study “is a good first start toward answering the question about what early dinosaur nests looked like.”

See also here.

The findings were published online on Nov. 25 2015 in the journal PLOS ONE.

Giraffe ancestry, new research

This video is about giraffes in Africa.

From Science journal:

Odd creature was ancient ancestor of today’s giraffes

By Sid Perkins

24 November 2015 7:15 pm

A distant relative of today’s giraffes was a bit of an odd creature: It was about the size of a bull moose, but it had a long neck that could stretch both up to eat tree leaves and down to eat grass. That’s the conclusion of the first comprehensive analysis of a complete set of fossilized neck bones from the animal, known as Samotherium major. Samotherium, which lived in the open woodlands of Eurasia about 7 million years ago, had a neck about 1 meter long—about half the length of that of today’s giraffes. (And like the vast majority of mammals, from tiny mice to towering giraffes, it had seven neck vertebrae.)

Some scientists have long presumed today’s giraffe (Giraffa camelopardalis), which includes a handful of subspecies scattered throughout sub-Saharan Africa, evolved from an animal that looked like its close cousin the okapi (Okapia johnstoni), which lives in the tropical forests of central Africa. The team’s analyses of bones from all three animals bolster that notion—and not just because the neck bones are of a length between the giraffe’s and the okapi’s. For example, ridges and other features that are prominent on the okapi’s neck bones and missing entirely on the giraffe’s are typically present but smaller on Samotherium’s, the researchers report online today in Royal Society Open Science.

See also here.

Dinosaur-age haramiyids, mammals or reptiles?

This video from the USA says about itself:

High-tech analysis of proto-mammal fossil clarifies the mammalian family tree

16 November 2015

3D Reconstruction of the jaw of Haramiyavia, one of the earliest known proto-mammals, clarifies the debate over when mammals evolved. The study, published in the Proceedings of the National Academy of Sciences on Nov 16, 2015, confirms previous suggestions that mammal diversification occurred in the Jurassic around 175 million years ago—more than 30 million years after Haramiyavia and other forerunners to mammals diversified in the Triassic.

From the New York Times in the USA:

Jawbone in Rock May Clear Up a Mammal Family Mystery


NOV. 16, 2015

With technologies like CT scans and 3-D printing, a team of scientists reported on Monday that it had solved a mystery about the family tree of mammals that started with a single tooth a century and a half ago.

The tooth, found in Germany in 1847, was tiny and distinctive in shape — not quite reptile, not quite mammal. More fossils of that kind were found around Europe, but always just single teeth. Scientists named this group of animals haramiyids — Arabic for “trickster.”

The teeth were embedded in rocks as old as 210 million years, an era in which ancestors of the first mammals were evolving.

“These were some of the most enigmatic fossils for years,” said Neil H. Shubin, a professor of organismal biology and anatomy at the University of Chicago. “People didn’t know what they were at all.”

In the late 1980s, Dr. Shubin, then a graduate student, was part of a team led by Farish Jenkins, a Harvard paleontologist, that searched for fossils in East Greenland. “You’re looking for tiny teeth in this vast Arctic landscape,” Dr. Shubin said. “The words ‘needle in a haystack’ seem very appropriate.”

The researchers found one particularly intriguing specimen, which they named Haramiyavia. “Avia” is Latin for “grandmother” — this was the grandmother of the trickster.

After a couple of years of meticulously clearing away much of the limestone surrounding the fossil, they reported on part of the Haramiyavia jawbone, revealing that the animal was indeed a proto-mammal.

What was unclear was whether Haramiyavia was a direct part of the family tree of mammals — that would push the emergence of mammals back to more than 200 million years ago — or an evolutionary branch that split off before common ancestors of mammals emerged, the view of paleontologists who believe that the first mammals evolved 170 million to 160 million years ago.

About two years ago, Dr. Shubin decided to re-examine the slab of Greenland limestone that enveloped the Haramiyavia fossil. “We knew that there were more bones in the rock,” he said.

Clearing away more limestone would jeopardize the fragile fossil. Instead, Dr. Shubin and his colleagues placed it in CT scanners and saw a mostly complete jawbone and many of the teeth.

“This kind of work used to be unimaginable,” said Zhe-Xi Luo, another University of Chicago paleontologist who joined Dr. Shubin on the new analysis.

Their conclusion: Haramiyavia, and thus all haramiyids, were not mammals, but belonged to a more ancestral side branch.

The crucial evidence they cite, reported Monday in the Proceedings of the National Academy of Sciences, is a trough in the lower jaw of Haramiyavia. In mammals, the trough is absent, because two bones connected to the trough migrated to the middle ear to form part of the three-bone hearing mechanism. (Birds and reptiles have only one bone in their middle ears.)

“This thing had a very primitive ear,” Dr. Shubin said. “That is the piece that is sort of the smoking gun.”

From the scans of the jaw and the teeth, the researchers created three-dimensional enlargements of the fossils, studying them like puzzle pieces to see how they fit together. Haramiyavia, a few inches long and rodentlike in appearance, ate plants by grinding leaves between broad teeth.

One argument that haramiyids were mammals was the similarity of the teeth to those of later animals known as multituberculates that were unquestionably mammals. But Dr. Shubin said the explanation instead was that the similar tooth characteristics evolved independently.

Timothy Rowe, a professor of geology at the University of Texas at Austin who was not involved in the new research, praised the work. “They really stepped out and squeezed every last bit of information that they could from these fossils,” he said. “What a relief after all these years to see a very compelling case made for exactly where haramiyids fit on the family tree.”

Dr. Rowe said there was no longer evidence that the earliest divergence of mammals occurred during the Triassic Period more than 200 million years ago. “The oldest date that’s based on real evidence is 30 or 40 million years younger than that,” he said. “It helps more accurately calibrate the mammalian tree of life.”

Not everyone agrees. “It’s a very great work, but I don’t think I’m totally convinced that is the case,” said Jin Meng, the curator of fossil mammals at the American Museum of Natural History in New York.

Dr. Meng is a member of a team that in the last couple of years has described more recent species of haramiyids that lived in China about 160 million years ago. The well-preserved Chinese fossils, nearly complete, possessed the characteristics of true mammals, Dr. Meng and his colleagues said.

The mammalian characteristics include the absence of a jawbone trough, Dr. Meng said in an interview. “If we accept the conclusion of this study, many of those mammalian structures must have evolved independently,” he said. “I still think the other hypotheses remain alive.”

Fossil seal discovered in South America

Figure 6, from Valenzuela-Toro et al. (2015) shows the relative size of Australophoca changorum (number 12 in the figure) to other assemblages of fossil and living pinnipeds, from other places (based on latitude) and geologic times

This picture shows the relative size of newly discovered fossil seal Australophoca changorum (number 12 in the figure) to other fossil and living pinnipeds (seal relatives), from other places (based on latitude) and geologic times.

From Pyenson Lab:


by Ana Valenzuela-Toro

Australophoca, a new dwarf fossil seal from South America

Today, my South American colleagues and I announce the publication of a new species of fossil seal from the western coast of South America. The name of the new genus and species, Australophoca changorum, reflects its austral origin from Chile and Peru, and honors the Changos, a coastal tribe of indigenous people who lived in the Atacama (from northern Chile to southern Peru), and were short in stature. The description, published in Papers in Palaeontology, provides a scientific name for a dwarf species of true seal from the late Miocene Bahía Inglesa and Pisco formations of Chile and Peru, respectively. One of the paratype specimens that we identified was originally recovered from Cerro Ballena in the Atacama Region of Chile; the type specimen is USNM 438707.

This tiny fossil seal was smaller than a living harbor seal (Phoca vitulina), and ranks among the smallest true seals ever described, including both living and fossil ones. Interestingly, in the past ~11-3 million years, the western coast of South America seems to have been only occupied by true seals (or phocids), a fact that stands in stark difference to what we know about pinniped communities from other parts of the world, and other time[s] in the geologic record. This unusual feature of the pinniped community in western South America fits into a broader pattern of ecological turnover seen in the fossil record of marine consumers, including pinnipeds and seabirds, throughout the Southern Hemisphere, since the late Miocene.

New hadrosaur dinosaur discovery

This 13 November 2015 video is called New Duck-Billed Dinosaur found, Probrachylophosaurus – Should it be used in Jurassic World 2?

From Gizmodo.com in the USA:

This New Hadrosaur Species Is A Classic Missing Link

Kiona Smith-Strickland

11/15/15 7:06pm

A new dinosaur species sheds some light on how duck-billed dinosaurs got their crests. Paleontologists say Probrachylophosaurus bergei is a missing link between two other species, and it fills in vital pieces of the story of how crests evolved.

Probrachylophosaurus bergei is a hadrosaur, one of the large crested herbivores that roamed the Earth – mostly on their hind legs – during the late Cretaceous period. Hadrosaurs are best known for their duck-like bills and their frilled, crested skulls, and now scientists know a little more about how those distinctive crests evolved.

The fossils’ age put Probrachylophosaurus right in the middle of two hadrosaur species: the older Acristavus, which had no crest on its skull, and the more recent Brachylophosaurus, which had a large, well-developed crest. “So we would predict that its crest would be intermediate between these species. And it is,” said Elizabeth Freedman Fowler, the Montana State University paleontologist who unearthed the first Probrachylophosaurus fossils in 2007 and has studied them ever since.

81 million years ago, a hadrosaur called Acristavus roamed the Late Cretaceous coastal plain that is now Montana. Unlike its descendants, Acristavus had a flat skull with no sign of a crest – but by 79 million years ago, its descendants had evolved small, triangular crests that stuck up from their skulls just slightly, right above their eyes. Otherwise, their skulls weren’t very different from their ancestor, Acristavus. This small-crested species is now called Probrachylophosaurus.

By 77.5 million years ago, those small triangular crests had evolved further, into large, flat, paddle-shaped crests covering the back portion of the top of their skulls. Paleontologists now call these hadrosaurs Brachylophosaurus, and aside from the crests, their skulls are very similar to Acristavus and Probrachylophosaurus.

It’s a classic example of a “missing link” in a field where things seldom fall into place so neatly. “It is a perfect example of evolution within a single lineage of dinosaurs over millions of years,” said Freedman Fowler. She published her findings in the journal PLOS One.

Largest rats ever discovered in East Timor

Jaw bone of giant rat species discovered on East Timor, being compared with the same bone of a modern rat. (Photo : Stuart Hay, ANU)

From Science World Report:

Giant Rat Fossils Discovered, Largest To Have Existed

Rosanna Singh

Nov 06, 2015 01:23 PM EST

Archaeologists have discovered fossil remains of the world’s largest rat species in East Timor. The seven giant rat fossils were ten times the size of modern rats, according to the team of researchers from the Australian National University (ANU).

“They are what you would call mega-fauna. The biggest one is about five kilos, the size of a small dog,” said Dr Julien Louys, lead author of the study, in a news release. “Just to put that in perspective, a large modern rat would be about half a kilo.”

The researchers claimed that this species is considered to be the largest known rats to have ever lived. The researchers’ main objective in the study was to figure out what caused the rat species’ extinction. The study is a part of the Sunda to Sahul project, which is examining the earliest human movement through Southeast Asia.

ANU researchers found that the earliest evidence of humans in East Timor dates back to 46,000 years ago, leading them to believe that humans from that period lived with the rats.

“We know they’re eating the giant rats because we have found bones with cut and burn marks. The funny thing is that they are co-existing up until about a thousand years ago,” said Louys. “The reason we think they became extinct is because that was when metal tools started to be introduced in Timor, people could start to clear forests at a much larger scale.”

The researchers are hoping that they can find out when humans started inhibiting islands of Southeast Asia and how their activities impacted the ecosystem. The researchers believe that this information in turn can be used to create conservation practices.

“We’re trying to find the earliest human records as well as what was there before humans arrived,” said Louys. “Once we know what was there before humans got there, we see what type of impact they had.”

The findings of this study will be presented at the Meetings of the Society of Vertebrate Paleontology in Texas.

Frozen cave lion cubs discovery in Siberia

This video says about itself:

Extinct cave lions, almost perfectly preserved, discovered in Siberia

27 October 2015

The bodies of two extinct cave lion cubs from at least 10,000 years ago have been recovered in Russia’s Sakha Republic, almost perfectly preserved in permafrost, The Siberian Times reports.

From the Siberian Times in Russia:

WORLD EXCLUSIVE – Meet this extinct cave lion, at least 10,000 years old

By Anastasia Koryakina

26 October 2015

‘Sensational’ find of two cubs, the best preserved ever seen in the world, announced today.

The unprecedented discovery of the ancient predator was made this summer in the Sakha Republic, also known as Yakutia. The cave lions were almost perfectly preserved in permafrost and could be much older.

The Siberian Times is proud to be working with the Academy of Sciences of Yakutia which will introduce the cubs properly at a presentation to the Russian and international media in late November.

Along with the two lions, paleontologists will also show other Pleistocene animals preserved by ice in this vast region, the largest and coldest in the Russian Federation. Among these will be the famous woolly mammoth Yuka, the ‘Oimyakon‘ mammoth, the carcass of a Kolyma woolly rhinoceros, and Yukagir bison and horses.

The cave lions – Panthera spelaea (Goldfuss) – lived during Middle and Late Pleistocene times on the Eurasian continent, from the British Isles to Chukotka in the extreme east of Russia, and they also roamed Alaska and northwestern Canada. The extinct creatures were close relatives of modern Afro-Asiatic lions.

Finds of their remains are rare: today’s announcement about the existence of the pair is coupled with the confident claim that they are the best preserved ever unearthed in the world.

Full details will be given at the presentation in November, including the first results of research into the lions.

Previously, only fragments of carcasses, parts of skeletons and individual bones had been found. Until now, in Yakutia, only skulls, some teeth and bones were unearthed which has prevented scientists having more than an approximate image of the extinct creature.

Like other ancient animals, the cave lion became extinct: research on the two cubs could help to explain why they died out around 10,000 years ago, since the animal had few predators, was smaller than herbivores, and was not prone to getting bogged down in swamps, as did woolly mammoths and rhinos. One theory is a decline in deer and cave bears, their prey, caused their demise.

‘The find is sensational, no doubt,’ said a source close to the discovery. It is known the remains are free of dangerous infections such as anthrax following initial microbiological analysis, but no other significant details or pictures will be released before the presentation.

See also here.