Unusual carnivorous dinosaur described


This video says about itself:

13 July 2016

A newly discovered meat-eating dinosaur that prowled Argentina 90 million years ago would have had a hard time using strong-arm tactics against its prey. That’s because the beast, though a fearsome hunter, possessed a pitifully puny pair of arms.

Scientists said on Wednesday they have unearthed fossils in northern Patagonia of a two-legged, up to 26-foot-long (8-meters-long) predator called Gualicho shinyae with arms only about 2 feet (60 cm) long, akin to a human child’s.

The fossils of Gualicho, named after an evil spirit feared by Patagonia’s indigenous Tehuelche people, were discovered in Argentina’s Rio Negro Province.

Gualicho and other carnivorous dinosaurs like Tyrannosaurus rex are part of a group called theropods that included Earth’s largest-ever land predators. But a curious thing happened during their many millions of years of evolution. For some, as they acquired huge body size and massive skulls, their arms and their number of fingers shrank.

From the Christian Science Monitor in the USA:

T. rex wasn’t the only one with those strange little arms

Paleontologists discover a new dinosaur with T. rex-like arms, but it’s not a tyrannosaur.

By Eva Botkin-Kowacki, Staff writer

July 13, 2016

Quick! Make like a T. rex.

What is the first step to mimicking the famous, fearsome dinosaur? After roaring, a person probably pulls both arms in, contorting them to make them tiny relative to the rest of the body, mashing the five fingers together to have just two digits on each hand. One of the most characteristic features of the iconic tyrant lizard dinosaur is its strange, seemingly uselessly small forelimbs.

But Tyrannosaurus rex wasn’t the only two-legged carnivorous dinosaur to sport such teeny, two-fingered arms.

“Theropods in general do this quite often,” Lindsay Zanno, head of the Paleontology Research Lab at the North Carolina Museum of Natural Sciences, tells The Christian Science Monitor in a phone interview. “There are a lot of different groups of theropods that tend to reduce the size of their hands and their arms or change the way that they’re used.”

And another one is joining the bunch.

Gualicho shinyae, discovered in Argentina in 2007, is named and described in a paper published Wednesday in the journal PLOS ONE.

This new dinosaur’s “arms are short – about 2 ft long – which is less than the length of the thigh bone, and they have weak muscle attachments and poorly developed articulations indicating they had little strength,” Peter Makovicky, associate curator of dinosaurs at the Field Museum of Natural History in Chicago who co-led the team that discovered Gualicho, describes in an email to the Monitor.

The fingers on the 90-million-year-old fossil are similar to those of tyrannosaurs. The thumb has a large claw while the second finger is more slender. A third finger has become so reduced that it is just a tiny bone in the flesh of the animal’s hand. …

Gualicho has weak little arms with just two functional fingers like T. rex, but the similarities pretty much stop there.

“This animal has a kind of mosaic of features. There are aspects of its skeleton that show some affinities with some groups of dinosaurs and some affinities with other groups of dinosaurs, although none of those are really tyrannosaurs,” study co-author Nathan Smith, associate curator in the Dinosaur Institute at the Natural History Museum of Los Angeles County, tells the Monitor in a phone interview.

But the “oddball” dinosaur, as Dr. Smith describes it, could help researchers figure out why so many diverse theropod dinosaurs have evolved similar, reduced forelimbs. …

Some scientists have suggested that humongous predatory dinosaurs would have evolved smaller arms because their skulls were used more readily to wrangle prey, she says.

There seems to be a pattern among tyrannosaurs, for example, in which the arms became shorter and the fingers fewer as the animals’ skulls and bodies became larger over generations, says Stephen Brusatte, a paleontologist at the University of Edinburgh who was not part of the study, in an email to the Monitor. This would suggest that “the head was taking over many of the duties that the arms once had, like procuring and processing food.”

“Most theropods with reduced forelimbs, like tyrannosaurs, ceratosaurs, and carcharodontosaurs are clearly macropredators that rely on their massive skulls for hunting, so it seems likely that the same was true of Gualicho,” Makovicky says.

These diverse dinosaurs were likely under similar evolutionary pressures that lead to similarly reduced forelimbs. The feature would have evolved independently in the different groups, in a process called convergent evolution. …

The mosaic features of Gualicho “makes figuring out the evolutionary placement of this animal a little difficult,” Smith says.

Weighing an estimated 1,000 pounds, Gualicho appears to fit into the family neovenatoridae, a large-bodied branch of carnivorous theropod dinosaurs, Smith says, but it also seems to bear the closest resemblance to Deltadromeus, a large theropod from Africa.

But could a South American dinosaur be closely related to an African one?

Possibly. Scientists have previously noted a lot of similarities between dinosaurs unearthed in the Kem Kem Beds on the border of Morocco and Algeria, where Deltadromeus has been found, and the Huincul Formation in Argentina, where Guialicho was discovered, Smith says. “So it may not be surprising that these two carnivorous dinosaurs are close relatives.”

And at the time when Guialicho roamed the Earth, the two continents had only recently, geologically speaking, begun to separate as the supercontinent Gondwana broke up.

‘Meteorite killed not only dinosaurs, also most mammals’


This video says about itself:

The Day the Mesozoic Died: The Asteroid That Killed the DinosaursHHMI BioInteractive Video

26 August 2014

Ever wonder why the dinosaurs disappeared? HHMI BioInteractive investigates the cause of the mass extinction at the end of the Cretaceous period—and the clues come from paleontology, chemistry, physics, and biology.

This three-act film tells the story of the extraordinary detective work that solved one of the greatest scientific mysteries of all time. Explore the fossil evidence of these prehistoric animals, and other organisms that went extinct, through this lively educational video.

From daily The Independent in Britain today:

Prehistoric asteroid wiped out nearly all mammals as well as dinosaurs, research suggests

‘More data shows the extinction was more severe than previously believed’

Jack Hardy

Nearly every species of mammal was eradicated by the prehistoric asteroid which wiped out the dinosaurs, research suggests.

Around 93% of mammal species were made extinct by the strike, which took place in the Cretaceous period, more than 66 million years ago.

Examination of fossil records by scientists from the University of Bath determined that the asteroid’s impact had been much more severe than previously thought.

Past estimates have been much lower because some of the rarer species that were killed left a smaller fossil record, researchers said.

The University of Bath’s Dr Nick Longrich said: “The species that are most vulnerable to extinction are the rare ones, and because they are rare, their fossils are less likely to be found.

“The species that tend to survive are more common, so we tend to find them.

“The fossil record is biased in favour of the species that survived. As bad as things looked before, including more data shows the extinction was more severe than previously believed.”

It was also found the asteroid’s catastrophic effect for life on Earth was mitigated by species recovering rapidly.

Within 300,000 years, the number of species on the planet was double the amount that had existed before the mass extinction.

Due to the lack of sustenance resulting from the widespread destruction of vegetation and animals, it is thought that the largest living animal during the period would have been about the size of a cat.

Dr Longrich added: “Because mammals did so well after the extinction, we have tended to assume that it didn’t hit them as hard.

“However, our analysis shows that the mammals were hit harder than most groups of animals, such as lizards, turtles, crocodilians, but they proved to be far more adaptable in the aftermath.

“It wasn’t low extinction rates, but the ability to recover and adapt in the aftermath that led the mammals to take over.”

Researchers analysed all known mammal species in North America from the end of the Cretaceous period to draw their conclusions.

The findings were published in the Journal of Evolutionary Biology.

Horned dinosaur discovery in Utah, USA


This video from the USA says about itself:

New big-nosed, horned-face dinosaur discovered in Utah

July 18, 2013

Researchers in Utah announced they had discovered a new dinosaur on Thursday. Known as Nasutoceratops, or ‘big-nose horned face’, it is unusual in its oversized nose and exceptionally long, curved horns over the eyes and its low, narrow blade-like horn above the nose.

Scientists said Nasutoceratops was a herbivore and would have fed on plants in its tropical, swampy surroundings. The fifteen foot-long beast is a smaller cousin of the Triceratops. The fossilized remains were found in 2006 in the Grand Staircase-Escalante National Monument near the border with Arizona. Nasutoceratops is one of several species that have been found in this region of North America.

That was two years ago. And now …

By Lee Speigel in the USA:

New Horned Dinosaur Species Unearthed In Utah

The two-ton plant-eater Machairoceratops cronusi had four horns and lived 77 million years ago.

05/18/2016 07:53 pm ET

A new species of horned dinosaur has been unearthed by scientists in southern Utah.

Remains of the animal, named Machairoceratops cronusi, suggest it was about 26 feet long, weighed two tons and ate plants. The first traces were found a decade ago in an area rich with the remains of centrosaurines — large-bodied, plant-eating dinosaurs that roamed North America and Asia 77 million years ago, during the Late Cretaceous period.

According to a scientific paper about the discovery in the PLOS ONE journal, “the specimen consists of two curved and elongate orbital horncores, … [and] a nearly complete, slightly deformed braincase.”  …

The new species was discovered by an international team of scientists conducting paleontological and geological surveys in the Grand Staircase-Escalante National Monument of southern Utah.

It can take years for this kind of discovery to find its way to the public.

“The first parts of the specimen were discovered on the surface in 2006, but the full excavation was completed over two additional field seasons (in 2007 and 2009). Then, the process of doing the careful laboratory preparation took another couple of years,” study co-author Patrick O’Connor, a professor of anatomical sciences at the Heritage College of Osteopathic Medicine, told HuffPost in an email.

Professional excavators and volunteers from Ohio University and the Natural History Museum of Utah helped the team unearth the horncores and various other skull pieces. …

“An effort like this underscores both the necessity and excitement of basic, exploratory science in order to better understand the history of the world around us,” O’Connor said in a statement.

“Even in a place like western North America, where intense work has been conducted over the past 150 years, we are still finding species new to science,” O’Connor added. …

As it turns out, Machairoceratops is one of two new horned dinosaurs announced on Wednesday. A second one, found in Montana 10 years ago by an amateur fossil collector, was finally identified. Its name is Spiclypeus shipporum, or spiked shield.

Eric Lund, a member of the Utah team that discovered Machairoceratops, remarked on the unrelated announcement horning in on his group’s news.

“It’s true,” Lund told HuffPost in an email. “Today is the day of new horned dinosaurs. Still very exciting for the world of paleontology.”

‘Dinosaur decline already before mass extinction’


This video from Britain says about itself:

Dinosaurs in decline BEFORE asteroid apocalypse

18 April 2016

Dinosaurs were already in an evolutionary decline tens of millions of years before the asteroid impact that finally wiped them out, scientists from the University of Reading and University of Bristol have found. Read more here.

Dr Manabu Sakamoto and Dr Chris Venditti, University of Reading, explain more.

This research was published on 18 April 2016 in the journal PNAS.

Filming took place in the Cole Museum of Zoology, University of Reading.

Asteroid animation courtesy of NASA.

See also here.

Pregnant tyrannosaur discovered?


This video says about itself

An excerpt from the “Clash of the Dinosaurs” series episode “Extreme Survivors” featuring the mighty TYRANNOSAURUS REX produced by Discovery Channel in 2009.

By Ed Mazza in the USA:

Science Answers An Age-Old Question: How Can You Spot A Pregnant T. rex?

“We know next to nothing about sex-linked traits in extinct dinosaurs.”

03/16/2016 05:31 am ET

Scientists have discovered what they believe is a pregnant Tyrannosaurus rex — and it might even still contain dino DNA.

Tests conducted on the fossilized femur of a 68-million-year-old T. rex revealed the presence of medullary bone, or a type of bone that forms only in female birds before or during egg-laying, according to a news release from North Carolina State University.

“It’s a dirty secret, but we know next to nothing about sex-linked traits in extinct dinosaurs,” Lindsay Zanno, assistant research professor of biological sciences at the university and co-author of the new study, said in the release.

“Dinosaurs weren’t shy about sexual signaling, all those bells and whistles, horns, crests, and frills, and yet we just haven’t had a reliable way to tell males from females,” Zanno said. “Just being able to identify a dinosaur definitively as a female opens up a whole new world of possibilities.”

N.C. state paleontologist Mary Schweitzer spotted what she believed to be the medullary bone in the T. rex sample in 2005.

“All the evidence we had at the time pointed to this tissue being medullary bone,” Schweitzer, who is lead author of the new study, said in the release. “But there are some bone diseases that occur in birds, like osteopetrosis, that can mimic the appearance of medullary bone under the microscope. So to be sure we needed to do chemical analysis of the tissue.”

The new study focused on that analysis, comparing the dino bones to the medullary tissue of ostriches and chickens.

It was a match.

One test looked for a substance called keratan sulfate, which is found in medullary bone but not other types of bone.

Scientists thought this substance might not survive the passage of millions of years, but it turns out it did.

And if that can still be detected, there may be hope that a sample of dino DNA is still waiting to be found.

“Yes, it’s possible,” Lindsay Zanno told Discovery News. “We have some evidence that fragments of DNA may be preserved in dinosaur fossils, but this remains to be tested further.”

Tyrannosaur relative, new discovery


This video says about itself:

Scientists Dicover Small T. Rex Ancestor

14 March 2016

Scientists announced Monday they have discovered a new, smaller ancestor to the T. rex. The Timurlengia euotica was roughly the size of a horse and posessed many of the same features as the T. rex.

By Jacqueline Howard, Senior Science Editor, The Huffington Post in the USA:

Meet T. Rex’s Fierce, Fleet-Footed Relative

The newly discovered species is being called a missing link.

03/14/2016 03:00 pm ET

Scientists have discovered a nimble, meat-eating dinosaur with blade-like teeth that fills an important gap in Tyrannosaurus rex’s family tree.

The newly named creature, Timurlengia euotica, sheds light on how a family of dinosaurs called tyrannosaurs advanced from being small predators to clever giants at the top of the food chain — within the span of about 70 million years.

The long-legged, 600-pound T. euotica lived some 90 million years ago. It was around this time that tyrannosaurs developed impressive cognitive abilities and sharp senses, such as the ability to detect low-frequency sounds, according to a study published Monday in the Proceedings of the National Academy of Sciences.

Soon after, tyrannosaurs began to get bigger. By the late Cretaceous period, massive tyrannosaur species would emerge, such as T. rex, which lived around 66 to 68 million years ago, said Dr. Hans-Dieter Sues, the chairman of the paleobiology department at the Smithsonian’s National Museum of Natural History and a co-author of the study.

“Timurlengia has already evolved the sophisticated senses and many bone features of T. rex but was a much smaller animal,” Sues said. “The new discovery fills in a multimillion-year gap in the evolution of one particularly successful group of dinosaurs.”

Sues and Dr. Alexander Averianov, a senior scientist at the Russian Academy of Sciences, unearthed the T. euotica fossils in the Kyzylkum Desert of Uzbekistan during a series of expeditions between 1997 and 2006.

Sues and an international team of paleontologists reanalyzed the remains and found that they belonged to a previously unknown species, T. euotica, which they determined was a relative but perhaps not an ancestor of T. rex.

“As few dinosaur fossils are known from 90 million-year-old rocks, we hoped to find fossils that would tell us something about dinosaur evolution at this point in time,” Sues said. “Still, Timurlengia showed unexpected features.”

To learn more about the species and its cognitive abilities, the researchers took CT scans of T. euotica‘s fossilized brain case and used that data to build a model of its brain.

They concluded that, even though T. euotica‘s skull was much smaller than that of T. rex, its brain and senses were highly developed.

“The ancestors of T. rex would have looked a whole lot like Timurlengia, a horse-sized hunter with a big brain and keen hearing that would put us to shame,” Dr. Steve Brusatte, a paleontologist at the University of Edinburgh in Scotland who led the new research, said in a statement. “Only after these ancestral tyrannosaurs evolved their clever brains and sharp senses did they grow into the colossal sizes of T. rex. Tyrannosaurs had to get smart before they got big.”

This new research is not only noteworthy for what it teaches us about the tyrannosaurs’ family tree, but also because it could provide clues about how dinosaurs evolved when faced with a changing environment, Sues said.

“Dinosaurs have been a huge evolutionary success since they first appeared about 230 millions year ago,” he said. “Learning about their evolutionary history and how they coped with environmental changes holds important lessons for the many changes seen in today’s world.”

Extremely big dinosaur discovery in Argentina


This 22 January 2016 Argentine TV video, in Spanish, is about the recent discovery of the Notocolossus gonzalezparejasi dinosaur.

From Nature:

A gigantic new dinosaur from Argentina and the evolution of the sauropod hind foot

18 January 2016

Abstract

Titanosauria is an exceptionally diverse, globally-distributed clade of sauropod dinosaurs that includes the largest known land animals. Knowledge of titanosaurian pedal structure is critical to understanding the stance and locomotion of these enormous herbivores and, by extension, gigantic terrestrial vertebrates as a whole. However, completely preserved pedes are extremely rare among Titanosauria, especially as regards the truly giant members of the group.

Here we describe Notocolossus gonzalezparejasi gen. et sp. nov. from the Upper Cretaceous of Mendoza Province, Argentina. With a powerfully-constructed humerus 1.76 m in length, Notocolossus is one of the largest known dinosaurs. Furthermore, the complete pes of the new taxon exhibits a strikingly compact, homogeneous metatarsus—seemingly adapted for bearing extraordinary weight—and truncated unguals, morphologies that are otherwise unknown in Sauropoda. The pes underwent a near-progressive reduction in the number of phalanges along the line to derived titanosaurs, eventually resulting in the reduced hind foot of these sauropods.

A Culture24 top ten of the best dinosaur museums and collections in the UK: here.