Dinosaur age shark teeth discovery in Dutch Maastricht


Cretaceous fossil shark's tooth from the Dutch Maastricht ENCI quarry, photo by Frans Frenken

This photo by Frans Frenken shows a Cretaceous fossil shark‘s tooth from the Dutch Maastricht ENCI quarry.

Translated from Dutch ANP news agency today:

Old shark teeth in Limburg ENCI quarry

Five teeth of an extinct mackerel shark were found in the ENCI quarry in Maastricht. According to conservation organisation Natuurmonumenten the animal was about 4 to 5 meters long. It lived about 66 to 68 million years ago.

Just before the Cretaceous-Tertiary extinction event which killed the dinosaurs and many other animals.

South Limburg was then a shallow subtropical inland sea.

Mackerel shark

The triangular teeth are about 2.5 centimeters. The mackerel shark used to eat sea turtles, fish and other animals. The first tooth was accidentally found during a guided tour of Natuurmonumenten volunteers on 17 November. On December 1 someone else found four more shark teeth.

The ENCI quarry has been used since 1926 to extract limestone. That stopped this year. The area is now being transformed into a nature and recreation area, to be opened in 2020. In the limestone layers in the quarry are many remains of prehistoric animals, such as sea urchins, corals, cephalopods and seashells.

Fossils

Fossils are often found in the ENCI quarry, such as sea urchins, but also a gigantic dinosaur age marine predator, a mosasaur.

This dinosaur age shark species is called Squalicorax pristodontus.

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Megaraptor carnivorous dinosaur, video


This 9 December 2018 video says about itself:

Megaraptor || The Beast With Massive Claws

Megaraptor (“giant thief”) is a genus of large theropod dinosaur that lived in the Turonian to Coniacian ages of the Late Cretaceous (93.5 – 85.8 million years ago).

Its fossils have been discovered in the Patagonian Portezuelo Formation of Argentina. Initially thought to have been a giant dromaeosaur-like coelurosaur, more recent research has placed it as either a basal tyrannosauroid or a basal coelurosaur.

In 2010, Gregory S. Paul estimated its length at 8 meters (26 ft), its weight at 1 tone (2,200 lb). The hands were unusually elongated; bearing sickle-shaped claws even more recurved than those of spinosaurids. It had a 14 to 16 inch claw that was one each hand—on what would be this creature’s thumb. Claws that were probably used to slash at its prey.

This dinosaur was bipedal, meaning that it ran on two legs—much like a tyrannosaur. It was a dinosaur that was evidently built to be lean and fast, and could probably run at a speed of around 31 miles per hour.

… A juvenile specimen described in 2014 has provided more evidence towards Megaraptor being a primitive tyrannosauroid. It could probably hunt down and kill just about any dinosaur during the Cretaceous Period, and if it hunted in packs—like some paleontologists believe—then this dinosaur would have been even more fearsome.

Birds survived dinosaurs, other birds extinct with them


A reconstruction of Mirarce eatoni perched on the horns of the ceratopsian dinosaur Utahceratops gettyi. Image credit: Brian Engh, dontmesswithdinosaurs.com

From the University of California – Berkeley in the USA:

Rare fossil bird deepens mystery of avian extinctions

Most complete North American enantiornithine fossil was aerodynamic equal of modern birds

November 13, 2018

Summary: Today’s birds descend from a small number of bird species living before the dinosaur extinction. Some of the birds that went extinct, the enantiornithines, were actually more common than and out-competed modern bird ancestors. Analysis of a newly described fossil, the most complete known from the Americas, demonstrates, too, that the enantiornithines were as agile and strong in flight as the ancestors of modern birds. Why, then, did enantiornithines die out and modern birds flourish?

During the late Cretaceous period, more than 65 million years ago, birds belonging to hundreds of different species flitted around the dinosaurs and through the forests as abundantly as they flit about our woods and fields today.

But after the cataclysm that wiped out most of the dinosaurs, only one group of birds remained: the ancestors of the birds we see today. Why did only one family survive the mass extinction?

A newly described fossil from one of those extinct bird groups, cousins of today’s birds, deepens that mystery.

The 75-million-year-old fossil, from a bird about the size of a turkey vulture, is the most complete skeleton discovered in North America of what are called enantiornithines (pronounced en-an-tea-or’-neth-eens), or opposite birds. Discovered in the Grand Staircase-Escalante area of Utah in 1992 by University of California, Berkeley, paleontologist Howard Hutchison, the fossil lay relatively untouched in University of California Museum of Paleontology at Berkeley until doctoral student Jessie Atterholt learned about it in 2009 and asked to study it.

Atterholt and Hutchison collaborated with Jingmai O’Conner, the leading expert on enantiornithines, to perform a detailed analysis of the fossil. Based on their study, enantiornithines in the late Cretaceous were the aerodynamic equals of the ancestors of today’s birds, able to fly strongly and agilely.

“We know that birds in the early Cretaceous, about 115 to 130 million years ago, were capable of flight but probably not as well adapted for it as modern birds”, said Atterholt, who is now an assistant professor and human anatomy instructor at the Western University of Health Sciences in Pomona, California. “What this new fossil shows is that enantiornithines, though totally separate from modern birds, evolved some of the same adaptations for highly refined, advanced flight styles.”

The fossil’s breast bone or sternum, where flight muscles attach, is more deeply keeled than other enantiornithines, implying a larger muscle and stronger flight more similar to modern birds. The wishbone is more V-shaped, like the wishbone of modern birds and unlike the U-shaped wishbone of earlier avians and their dinosaur ancestors. The wishbone or furcula is flexible and stores energy released during the wing stroke.

If enantiornithines in the late Cretaceous were just as advanced as modern birds, however, why did they die out with the dinosaurs while the ancestors of modern birds did not?

“This particular bird is about 75 million years old, about 10 million years before the die-off”, Atterholt said. “One of the really interesting and mysterious things about enantiornithines is that we find them throughout the Cretaceous, for roughly 100 million years of existence, and they were very successful. We find their fossils on every continent, all over the world, and their fossils are very, very common, in a lot of areas more common than the group that led to modern birds. And yet modern birds survived the extinction while enantiornithines go extinct.”

One recently proposed hypothesis argues that the enantiornithines were primarily forest dwellers, so that when forests went up in smoke after the asteroid strike that signaled the end of the Cretaceous — and the end of non-avian dinosaurs — the enantiornithines disappeared as well. Many enantiornithines have strong recurved claws ideal for perching and perhaps climbing, she said.

“I think it is a really interesting hypothesis and the best explanation I have heard so far,” Atterholt said. “But we need to do really rigorous studies of enantiornithines’ ecology, because right now that part of the puzzle is a little hand-wavey.”

Atterholt, Hutchison and O’Connor, who is at the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, China, published an analysis of the fossil today in the open-access journal PeerJ.

Theropod dinosaurs evolved into birds

All birds evolved from feathered theropods — the two-legged dinosaurs like T. rex — beginning about 150 million years ago, and developed into many lineages in the Cretaceous, between 146 and 65 million years ago.

Hutchison said that he came across the fossil eroding out of the ground in the rugged badlands of the Kaiparowits formation in the Grand Staircase-Escalante National Monument in Garfield County, Utah, just inside the boundary of the recently reduced monument. Having found bird fossils before, he recognized it as a late Cretaceous enantiornithine, and a rare one at that. Most birds from the Americas are from the late Cretaceous (100-66 million years ago) and known only from a single foot bone, often the metatarsus. This fossil was almost complete, missing only its head.

“In 1992, I was looking primarily for turtles“, Hutchison said. “But I pick up everything because I am interested in the total fauna. The other animals they occur with tell me more about the habitat.”

According to Hutchison, the area where the fossil was found dates from between 77 and 75 million years ago and was probably a major delta, like the Mississippi River delta, tropical and forested with lots of dinosaurs but also crocodiles, alligators, turtles and fish.

This 2016 video says about itself:

In this lecture we will summarize the Mesozoic birds that lived during the Cretaceous period and highlight the diversity of early birds.

The article about enantiornithines continues:

Unlike most bird fossils found outside America, in particular those from China, the fossil was not smashed flat. The classic early Cretaceous bird, Archaeopteryx, was flattened in sandstone, which preserved a beautiful panoply of feathers and the skeletal layout. Chinese enantiornithines, mostly from the early Cretaceous, are equally beautiful and smashed flatter than a pancake.

“On one hand, it’s great — you get the full skeleton most of the time, you get soft tissue preservation, including feathers. But it also means everything is crushed and deformed”, she said. “Not that our fossils have zero deformation, but overall most of the bones have really beautiful three-dimensional preservation, and just really, really great detail. We see places where muscles and tendons were attaching, all kinds of interesting stuff to anatomists.”

Once Hutchison prepared the fossils and placed them in the UC Museum of Paleontology collection, they drew the attention of a few budding and established paleontologists, but no one completed an analysis.

“The stuff is legendary. People in the vertebrate paleontology community have known about this thing forever and ever, and it just happened that everyone who was supposedly working on it got too busy and it fell by the wayside and just never happened”, Atterholt said. “I was honored and incredibly excited when Howard said that I could take on the project. I was over the moon.”

Her analysis showed that by the late Cretaceous, enantiornithines had evolved advanced adaptations for flying independent of today’s birds. In fact, they looked quite similar to modern birds: they were fully feathered and flew by flapping their wings like modern birds. The fossilized bird probably had teeth in the front of its beak and claws on its wings as well as feet. Some enantiornithines had prominent tail feathers that may have differed between male and female and been used for sexual display.

“It is quite likely that, if you saw one in real life and just glanced at it, you wouldn’t be able to distinguish it from a modern bird”, Atterholt said.

This fossil bird is also among the largest North American birds from the Cretaceous; most were the size of chickadees or crows.

“What is most exciting, however, are large patches on the forearm bones. These rough patches are quill knobs, and in modern birds they anchor the wing feathers to the skeleton to help strengthen them for active flight. This is the first discovery of quill knobs in any enantiornithine bird, which tells us that it was a very strong flier.”

Atterholt and her colleagues named the species Mirarce eatoni (meer-ark’-ee ee-tow’-nee). Mirarce combines the Latin word for wonderful, which pays homage to “the incredible, detailed, three-dimensional preservation of the fossil”, she said, with the mythical Greek character Arce, the winged messenger of the Titans. The species name honors Jeffrey Eaton, a paleontologist who for decades has worked on fossils from the Kaiparowits Formation. Eaton first enticed Hutchison to the area in search of turtles, and they were the first to report fossils from the area some 30 years ago.

Thousands of such fossils from the rocks of the Kaiparowits Formation, many of them dinosaurs, contributed to the establishment of the Grand Staircase-Escalante National Monument in 1996.

“This area contains one of the best Cretaceous fossil records in the entire world, underscoring the critical importance of protecting and preserving these parts of our natural heritage”, Atterholt said. “Reducing the size of the protected area puts some of our nation’s most valuable natural and scientific resources at risk.”

Hutchison’s field work was supported by the Annie M. Alexander endowment to the UCMP.

Ornithopod dinosaur teeth, new study


The skull of the holotype specimen of Changchunsaurus parvus (JLUM L0304-j-Zn2). Credit: Chen et al., 2018 CC-BY

From PLOS:

The teeth of Changchunsaurus: Rare insight into ornithopod dinosaur tooth evolution

Unexpected features in this dinosaur‘s teeth appear to represent early adaptations for herbivory

November 7, 2018

The teeth of Changchunsaurus parvus, a small herbivorous dinosaur from the Cretaceous of China, represent an important and poorly-known stage in the evolution of ornithopod dentition, according to a study released November 7, 2018 in the open-access journal PLOS ONE by Jun Chen of Jilin University in China and colleagues.

Ornithischian (“bird-hipped”) dinosaurs developed an incredible diversity of teeth, including the famously complex dental batteries of derived ornithopods, but little is known about how these intricate arrangements arose from the simple tooth arrangements of early dinosaurs. Changchunsaurus parvus belongs to an early branch at or near the origins of the ornithopods, and thus may provide insight into the ancestral state of ornithopod tooth development. In this study, Chen and colleagues took thin sections from five jaw bones of Changchunsaurus to investigate tooth composition as well as how the teeth are maintained throughout the life of the animal using histological techniques.

Among the notable features of Changchunsaurus dentition is a unique method of tooth replacement that allowed it to recycle teeth without disrupting the continuous shearing surface formed by its tooth rows. The authors also found that the teeth feature wavy enamel, a tissue type formerly thought to have evolved only in more derived ornithopods. The authors suspect these features may have arisen early on as this group of dinosaurs became specialized for herbivory.

Features of the jaws and teeth are often used to assess dinosaur phylogeny. In addition to investigating the evolution of ornithopod dentition, this study also identifies new dental traits that might help sort out ornithischian relationships in future analyses. But the authors note that this is only the first in-depth study at a dinosaur near the base of the ornithopod family tree, and that more studies on more dinosaurs will be needed to fill in the full picture of this group’s evolution.

Professor Chen Jun summarizes: “These tissue-level details of the teeth of Changchunsaurus tell us that their teeth were well-adapted to their abrasive, plant-based diets. Most surprisingly, the wavy enamel described here, presumably to make it more resistant to wear, was previously thought to be exclusive to their giant descendants, the duckbilled dinosaurs.”

New dinosaur species discovery in Argentina


Lavocatisaurus agrioensis, picture: Acta Palaeontologica Polonica

From AFP news agency today:

Paleontologists discover new sauropod species in Argentina

Buenos Aires: Buenos Aires (AFP) – A team of Spanish and Argentine paleontologists have discovered the remains of a dinosaur that lived 110 million years ago in the center of the country, the National University of La Matanza revealed Friday.

The remains came from three separate dinosaurs from the herbivorous group of sauropods, the best known of which are the Diplodocus and Brontosaurus. This new species has been named Lavocatisaurus agrioensis.

“We found most of the cranial bones: the snout, the jaws, a lot of teeth, also the bones that define the eye sockets for example and, in that way, we were able to create an almost complete reconstruction,” said Jose Luis Carballido, a researcher at the Egidio Feruglio museum and the national council of scientific investigations.

Parts of the neck, tail and back were also found.

“Not only is this the discovery of a new species in an area where you wouldn’t expect to find fossils, but the skull is almost complete”, added Carballido.

The remains belonged to an adult of around 12 meters (39 feet) in length, and two minors of around six to seven meters.

The paleontologists say the dinosaurs moved around in a group and died together.

“This discovery of an adult and two juveniles also signifies the first record of a group displacement among the rebbachisaurus dinosaurs”, said study lead author Jose Ignacio Canudo of Zaragoza University.

The area in which the fossils were found is unusual for dinosaurs as it would have been a desert with sporadic lakes in that era.

Sauropods were the biggest creatures ever to walk the planet. It is believed that Supersaurus could reach up 33-34 meters in length and Argentinosaurus might have weighed up to 120 tons.

They were herbivorous quadrupeds with long necks and tails, massive bodies and small heads.

But the discovery in Neuquen, published in the scientific journal Acta Palaeontologica Polonica, remains a huge surprise.

“While one can imagine that this group of sauropods could have adapted to move in more arid environments, with little vegetation, little humidity and little water, it’s an area in which you wouldn’t be looking for fossils”, said Carballido.

Dinosaur age beetle discovery in amber


This 31 October 2018 video is called Breaking News – A tiny beetle trapped in amber 99 million years ago.

From the Field Museum in the USA:

Tiny beetle trapped in amber might show how landmasses shifted

October 30, 2018

Summary: Scientists have discovered a tiny fossil beetle trapped in amber. It’s three millimeters long, and it has a flat body and giant feathery antennae that it would have used to navigate under tree bark. And, since it was found in amber from Asia but its closest relatives today live in South America, it hints at how landmasses have shifted over the past 100 million years.

In 2016, Shuhei Yamamoto obtained a penny-sized piece of Burmese amber from Hukawng Valley in northern Myanmar, near China’s southern border. He had a hunch that the three-millimeter insect trapped inside the amber could help to show why our world today looks the way it does.

After carefully cutting and polishing the amber, Yamamoto determined that the insect, smaller than the phone-end of an iPhone charger, was a new species to science. The beetle, which lived 99 million years ago, is a relative of insects alive today that live under tree bark, and it’s giving scientists hints about how Earth’s landmasses were arranged millions of years ago.

“This is a very rare find”, Yamamoto said, a Field Museum researcher and lead author of a paper in the Journal of Systematic Palaeontology describing the new species. The fossil beetle is one of the oldest known members of its family — its name, Propiestus archaicus, refers to the fact that it’s an ancient relative of the flat rove beetles in the Piestus genus today which now dominates the South America.

While dinosaurs roamed much of Earth 99 million years ago during the Late Cretaceous era, Propiestus, with its flattened body and short legs, was busy conquering smaller turf underneath the bark of rotting trees. Its long, slender antennae were the clear giveaway to Yamamoto that Propiestus lived in this environment — similar to today’s flat rove beetles.

“The antennae probably had a highly sensitive ability as a sensory organ”, Yamamoto said. Smaller hair-like structures attached perpendicular to the antennae would have increased its ability to feel out its surroundings. “There wouldn’t have been a lot of space available in the beetle’s habitat, so it was important to be able to detect everything”, he explains.

Propiestus is just one of the hundreds of thousands of Burmese amber inclusions — another word for the objects trapped inside the amber — that scientists have extensively researched over the last 15 years. Many small insects that lived during the Cretaceous era met their maker at the hands of tree sap that engulfed the bugs and hardened into amber. The bugs trapped inside fossilized and remained frozen for millions of years, unaffected by the passage of time. The hardened amber, covered by soil, decayed leaves, and other organic material, eventually blended in with its surroundings.

Because of this, amber in nature doesn’t look like it does in jewelry — in fact, it doesn’t look like anything special at all. The small clumps of unpolished amber look like rocks, meaning only those experienced in amber identification, mostly local miners, are able to find them.

After miners extract the amber, the clumps are either sold into the jewelry trade or to scientists like Yamamoto to study the inclusions. For Yamamoto’s piece of amber, he used sandpaper to carefully polish the amber just enough to make Propiestus clearly visible.

“It was very exciting, because the cutting process is very sensitive,” Yamamoto said. “If you cut too fast or apply too much pressure, you destroy the inclusion inside very quickly.”

Once the amber was polished, the beetle was clearly visible, enabling Yamamoto and his colleagues to study the beetle and determine its closest living relatives. Propiestus’s flat rove beetle cousins alive today are found mostly in South America, with the exception of one species in Southern Arizona. Myanmar, where Propiestus was found, is literally on the other side of the globe from these places. But it hasn’t always been that way.

Millions of years ago, Myanmar and South America were actually quite close to each other, all fused together as part of the megacontinent Gondwanaland, which formed when the earlier megacontinent Pangea broke apart. Gondwanaland itself eventually broke apart, helping to form the continents we recognize on a map today.

Scientists have a clear sense of which of today’s continents and subcontinents would have comprised Gondwanaland and which would have made up its sister continent, Laurasia. However, the detailed timing and pattern of Gondwanaland’s split into smaller continents is disputable. Searching for supporting or contrasting evidence means analyzing fossils, some as small as Propiestus, to compare their similarities to other organisms discovered across the globe that might have inhabited the same space long ago.

“Like koalas and kangaroos today, certain animals that we think lived in Gondwanaland are only found in one part of the world. Although Propiestus went extinct long ago, our finding probably shows some amazing connections between the Southern Hemisphere and Myanmar”, Yamamoto said. “Our finding fits well with the hypothesis that, unlike today, Myanmar was once located in the Southern Hemisphere.”

Many inclusions in Burmese amber that have been researched in the last 15 years, including Propiestus, show signs that show traits in common with insects from Gondwanaland. By studying these tiny creatures trapped in amber, we’re finding answers to the questions surrounding Earth’s structure and the life it supported millions of years ago.

“This fossil helps us understand life in the Mesozoic era”, he said. “We need to think about everything from that time, both big and small.”

How Tyrannosaurus rex hunted armoured dinosaurs


This 30 October 2018 video says about itself:

How T-Rex Preyed on Armored Dinosaurs

The biting force of T-Rex was around 400,000 pounds per square inch – the strongest bite of any animal to walk the earth. This enabled it to prey on large, often well-armored giants like Triceratops.