Dinosaurs – Species Encycolpedia

Meet Patagotitan, the Biggest Dinosaur Ever Found

Wednesday, August 9, 2017

Meet Patagotitan, the Biggest Dinosaur Ever Found

A dinosaur that walked the Earth 100 million years ago but wasn’t discovered until 2012 was actually the largest to ever exist, according to a new study. The plant-eating behemoth averaged 122 feet long and weighed 76 tons.

The long-necked dinosaur was discovered by a shepherd in the Argentinian desert province of Chubut in 2012, after he noticed the tip of a large fossil bone sticking out of a rock.

Patagotitan size compared to a human

But the finding turned out to be more than just a big bone. In fact, it was an enormous discovery – on more than one level.

Scientists soon realized that a new species of dinosaur had been unearthed, and it was so big that its femur alone measured 7.8 feet (2.37 meters) in length.

The dinosaur – which scientists say was the biggest of a group of large dinosaur called titanosaurs – has now been officially named ‘Patagotitan mayorum’ after the Patagonia region where it was found and the Greek word ‘titan,’ which means ‘large.’

“There was one small part of the family that went crazy on size,” said Diego Pol of the Egidio Feruglio paleontology museum in Argentina, a co-author of a study which analyzed six fossils of the species, as quoted by AP.

The P. mayorum has now been given the award of largest dinosaur ever to walk the Earth, averaging a length of 122 feet (37 meters) and height of 20 feet (six meters) at the shoulders. It weighed around 76 tons (69 metric tons).

In short, the dinosaur was as heavy as a space shuttle or a Boeing 737.

Patagotitan reconstruction by Jorge Gonzalez

Those numbers make the Tyrannosaurus Rex and other meat-eaters “look like dwarfs when you put them against one of these giant titanosaurs,” Pol said.

But despite their intimidating size, Pol believes the vegetarian P. mayorum was a gentle giant.

“I don’t think they were scary at all,” he said. “They were probably massive big slow-moving animals.”

“Getting up. Walking around. Trying to run. It’s really challenging for large animals,” he added.

Researchers aren’t quite clear on how the species became so big, but study co-author José Luis Carballido, from the Museum of Palaeontology Egidio Feruglio in Argentina, believes part of it had to do with available food.

“We do not know yet why we have such drastic change in body mass at this time here in Patagonia. There are some major events that are occurring at this time relating to weather and plant availability. Titanosaurs were herbivores, so certainly they had the food they needed, and plants are directly constrained by the weather. Probably the weather helped [cultivate] a particular group of plants living in Patagonia,” Carballido told Newsweek, adding that giant titanosaurs are thought to have only lived in Patagonia.

He went on to state that the P. mayorum, like other herbivores, likely grew to be very large so it could better avoid being attacked by predators.

“The bigger it was, the less predators will try to attack it,” he said.

A cast of the dinosaur’s skeleton is on display at the American Museum of National History in New York. However, it’s so big that its head sticks out into a hallway.

Reconstructed skeleton and fossils on display at the American Museum of Natural History, New York

Despite its impressive size, Carballido believes an even larger dinosaur could have walked the Earth, but it probably wasn’t much bigger than the P. mayorum.

“There could be [bigger], but probably we are pretty close to the size limit,” he said.

Prior to the discovery of the P. mayorum, scientists believed the title of world’s biggest dinosaur belonged to the Argentinosaurus, another titanosaur.

The study conducted by Pol and Carballido was published in the journal Proceedings of the Royal Society B: Biological Sciences on Tuesday.

Thyreophora: The Armored Dinosaurs

Wednesday, August 9, 2017

Thyreophora: The Armored Dinosaurs

The Thyreophora are a group of small to quite large armored plant-eating dinosaurs. The most familiar are Stegosaurus and Ankylosaurus, though there were many others. Ornithopods are one of three major groups of Ornithischia, or “bird-hipped” dinosaurs.

Thyreophora Miscellany by PaleoGuy

The earliest Thyreophoran was Scutellosaurus, a slender-tailed beast known from the earliest Jurassic of western North America, and is among the earliest known Ornithischians. It is among the smallest of the armored dinosaurs, and grew to only one and one-half meters long. Like its kin, it had armor plates set into the skin of its back, though these were not as large as in later Thyreophorans.

The next known Thyreophoran is Scelidosaurus, which lived in western Europe a little over 180 million years ago. This dinosaur grew to about four meters long and a little over a meter tall, walking on all four legs. Like later armored dinos, it had spikes along its back, and hoof-like claws. Though this is a very important dinosaur for understanding the evolution of this group, it was not discovered until 1980!


The remaining Thyreophorans consist of two major groups: the Stegosauria and the Ankylosauria. The stegosaurids had two rows of spikes or plates runnning along their backs and tails. They were most diverse in the late Jurassic, though the genus Dravidosaurus lived in southern India in the late Cretaceous, when the group went extinct. Stegosaurids are known from most of the globe.

The other group, the Ankylosauria, had more extensive armoring, and often whole patches of external bone were fused into plates. Early in the Cretaceous, most of these belonged to the Nodosaurid subgroup (though one genus, Sarcolestes, is known from the Jurassic). In the later Cretaceous, most are Ankylosaurids, distinguished by their broad heads, spikes extending from the backs of their skulls, and heavy club-like tails. It is generally believed that the club could be used as a defensive weapon against predators.

Source: NatGeo.com

Top 10 T. Rex Discoveries

Sunday, August 6, 2017

New computer modeling claims that the T. rex wouldn't have been able to run due to its size and weight (Credit: Elenarts/Depositphotos)

The Tyrannosaurus family, of which the most famous species is T. rex, were among the last dinosaurs to appear on the planet, around 80 million years ago. These large carnivorous theropods were only on the planet for a relatively short time, but they had a huge impact on our understanding of dinosaurs – partly because more specimens exist from these final stages than any earlier time in history.


10 They Had Lips

T. rex may not have been so toothy. A new study suggests that the ferocious dinosaur might have had lips that completely covered its pearly daggers. Sadly, this could one day remove the popular image showing off the permanent croc-like grin.

The Cretaceous predator’s fearsome fangs had a thin coating of enamel. To avoid decay, especially when it is this fragile, enamel must remain moist. Today’s larger lizards support this face-changing theory. Land-dwelling species, like the Komodo dragon, all have enclosed teeth.

Their lip-lacking brethren, such as crocodiles, live in water, so they don’t need the extra moisture. Since T. rex scared everything on land, not water, it’s plausible that they also needed lips to keep those 10–15–centimeter (4–6 in) snappers in peak condition.


9 They Ran In Packs

This is one moment in time that you don’t want to go back to. In western Canada, researchers found the tracks of three tyrannosaurs moving together. While they didn’t find a trail of destruction, interesting behaviors and hints about the dinosaurs themselves were uncovered.

These were life-scarred, successful adults. The trio clearly knew how to survive in a dinosaur-eat-dinosaur world. All three were about 30 years old, a grand age for T. rex. Skin imprints were still visible from the well-preserved tracks and even showed the severed claw from one T. rex‘s left foot.

They walked side by side but kept well out of each other’s reach. The 70-million-year old spoor is the first discovery of a stretch of T. rex tracks as well as the best evidence that the beasts did form herds.


8 Teenage Terrors

There’s a reason why the Canadian Three kept their distance from each other. From an early age, T. rex kids locked in vicious battles with each other. An adolescent fossil called “Jane,” although her gender is unknown, was bitten to the bone by another testy teen.

Her snout and upper jaw suffered a serious attack that broke her nose. The scrap was with a peer of similar age since her own teeth fit the shape and size of the scars. When Jane was about 12, she died. By then, her snout had already healed, although it was somewhat flattened. This means that the fight occurred when she was years younger.

At 12, Jane was already a tool of terror. Tiny compared to an adult T. rex, she measured 7 meters (22 ft) long and almost 2.5 meters (8 ft) at the hip. The youngster weighed a hefty 680 kilograms (1,500 lb).


7 The Gender Breakthrough

Paleontologists still struggle to separate the girls from the boys. Even species with frills, horns, plates, and spikes possess no clear gender traits, appearing for some reason to be identical.

Enter MOR 1125. The dull-sounding tag is attached to groundbreaking tyrannosaur remains—a definite female. Molecular biologists found a way to identify dino moms at least, all thanks to MOR 1125.

Her thighbone held evidence that she was pregnant at the time of her death. A special tissue was found inside, named medullary bone. In modern birds, it’s as good as a positive pregnancy test.

The scientists subjected the tissue to a multitude of tests to rule out a disease and succeeded. The tissue matched medullary bone both chemically and structurally. The discovery proves that, similar to birds, a sharp rise in estrogen laid down true medullary bone in pregnant dinosaurs.


T. Rex Was On The Menu

The scary interspecies violence didn’t end with breaking each other’s noses. If the meat was available and T. rex was hungry, dinner was served—even if it meant crunching on cousin Bob.

The prehistoric predator needed a lot of meat to survive. Their fossilized poop contained half-digested bones and flesh, indicating a fast metabolism and perhaps quick tummy rumbles urging the dinosaur toward the next meal.

Scientific circles have known for a while that T. rex was a cannibal. Separate discoveries of tyrannosaur bones, carrying the trademark serrated teeth damage, show that they did indeed feed on each other. Researchers are unsure whether T. rex cannibalized their own by deliberately killing them or scavenging on the already dead. Most likely both.


5 Tooth Folds

Anyone can see that tyrannosaur snappers belong in a slasher movie. Their blood-splattered purpose is hard to overlook. But the deadly bite didn’t just come from the obvious. T. rex‘s teeth were also built for killing on the inside.

Each tooth was serrated like a steak knife. These enamel points touched within what was first mistaken for cracks caused by high-impact grabbing and tearing. A fresh study determined that the “cracks” weren’t feeding damage but an internal type of fold.

Running deep into the tooth, the folds kept it sharp and stable, minimizing the chances of getting knocked out by feisty prey. This dental structure is unique to T. rex and other carnivorous theropods. The ability to hang onto highly effective fangs could be the reason that these dinosaurs successfully walked the planet as the largest meat eaters ever.



In 1988, paleontologist Robert Bakker declared a T. rex–type skull to be a new species, Nanotyrannus. Compared to the robust head of a tyrannosaur, the Cleveland Museum fossil was infinitely smaller, narrower, and had more teeth.

But was it really a dainty family member or a baby T. rex?

Few believed that T. rex could change so drastically while growing, and so the debate raged for years. In 2001, the most intact juvenile T. rex to date was discovered in Montana.

It was none other than Jane, which we discussed above. The half-grown dinosaur was the missing middle child that connected the Cleveland skull to her own breed. She possessed the jawbone gaps once thought to be unique to little Nano.

Nanotyrannus was made obsolete. But in its place, researchers now know that T. rex did indeed switch its looks big time during the different stages of its growth.


3 Intelligence Made Them Apex Predators

Another gap existed in the T. rex time line, in this case within its evolution. Ironically, it also involves a smaller tyrannosaur. This one was a family member—an ancestor called Timurlengia euotica.

Previously, experts couldn’t understand how the earliest horse-sized forerunners developed into the most feared apex predator that would eventually weigh over seven tons. Timurlengia may be the answer. Its braincase indicates a math-nerd intelligence and could prove that smarts, not monstrous size, was behind T. rex‘s rise to dominance.

The tyrannosaur group played second fiddle for millions of years to larger carnivores. They only rose to the top of the food chain when T. rex‘s competition mysteriously went extinct.

When the apex predator position became available, they already possessed the intelligence and sharp senses to beat other takers. Interestingly, their famous bulk only evolved later, near the end of the dinosaur age.


2 Decapitation Specialists

Researchers were intrigued by Triceratops‘ neck frills that revealed an unknown behavior from T. rex. Fang marks matched the predator biting and even pulling on the frills.

Each prey fossil examined was determined to be dead at the time that T. rexappeared to develop a fascination with the bony appendages. Wondering why they would nibble on something that had no meat, scientists looked deeper. What they found was horrifying.

Adult T. rex had the habit of decapitating Triceratops. The nibble was more of a violent tugging so that T. rex could pull off the head of its prey.

Triceratops‘ neck muscle appeared to have been the sought-after delicacy, and the bony frill was in the way. There were also slash marks on the neck joints of several Triceratops, something only possible if the herbivore’s head had been torn off.


1 They Didn’t Roar

To discover what T. rex really sounded like, a study looked at the nearest thing to dinosaurs alive today. Examining how these so-called archosaurs—crocodiles and birds—vocalize, researchers concluded that bigger dinosaurs such as Tyrannosaurus didn’t perform theatrical bellows that shook the Earth.

If it was anything like its feathered descendants, it would not have had vocal cords but air sacs, perhaps even an avian syrinx. Without vocal cords, T. rexcouldn’t roar.

When feeling the need to communicate, T. rex would have inflated the sacs to produce noises without opening its jaws, just like some of the larger bird species do. The real sounds of the most well-known dinosaur would have been disappointing—closed-mouth booms and coos.


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Source: listverse.com, NatGeo.com

Trix, the T. rex

Sunday, August 6, 2017

Artist impression of T. rex Trix according to the latest scientific theories and showing her actual wounds. (Naturalis Biodiversity Center)

Trix is a Tyrannosaurus rex specimen excavated in 2013 in Montana, USA by a team of paleontologists from the Naturalis Biodiversity Center in Leiden in the Netherlands. It is the oldest known Tyrannosaurus specimen, with an age of more than thirty years, and has been considered the third most complete tyrannosaurus found, with between 75% to 80% of its bone volume recovered. The specimen was named Trix after the Dutch former Queen Beatrix and is the only Tyrannosaurus specimen on permanent exhibit in mainland Europe.

In 2012, Naturalis Biodiversity Center at Leiden, the largest natural history museum of the Netherlands, planned to open a new exhibition hall in 2017. In order to increase the structural number of visitors from 300,000 to 400,000 per annum, the management decided to try and procure an authentic Tyrannosaurus skeleton, preferably one excavated by the museum itself. In September 2012, a museum delegation travelled to the US to contact the Black Hills Institute, a company that had been involved in nine Tyrannosaurus excavations. As it happened, the BHI had just received a report from a farmer in Wyoming about a Tyrannosaurus discovery. Senior Naturalis paleontologist John Vos immediately visited the site and identified the remains as those of Tyrannosaurus. As it was late in the season, it was decided to postpone the excavation until the next Spring. In April and May 2013, the site was thoroughly excavated but apart from some foot bones, a skeleton proved to be absent. However, five Triceratops skeletons were present elsewhere on the farm land and procured by the museum for exhibition.

In the evening of 27 May 2013, Blaine Lunstad, an amateur paleontologist, with his wife Michele Lunstad who is of Dutch descent, stumbled upon some bones in the “East Pasture”, part of the land of farmer Lige M. Murray, fifty kilometres south of Jordan, Montana. Local fossil hunter Clayton “Dino Cowboy” Phipps confirmed that it was a tyrannosaur skeleton. Rumours of the find reached the BHI, which informed Naturalis. In August 2013, a team of paleontologists from the Naturalis Biodiversity Center, now headed by Anne Schulp, again travelled to the USA. From 29 August to 9 September they unearthed a big and remarkably complete Tyrannosaurus rex specimen. The fossil was found in the Hell Creek Formation. The pattern of geomagnetic reversal showed it had an age of at least 66.4 million years. The excellent preservation had been caused by the skeleton being surrounded by a three metres thick sandstone lens with a high chalk content, neutralizing damaging acids. The Black Hills Institute collaborated with the team in the excavation, which was also assisted by Phipps and the Lundstads. On 5 September, paleontologist Philip Manning of the University of Manchester performed a lidar-laserscan of the site surface to precisely determine the position of all bones.

Presentation of the Tyrannosaurus specimen RGM 792.000 in the 2016-2017 exposition “T. rex in town” of the Naturalis Biodiversity Center, Leiden, the Netherlands. Author: Rique

In May 2015, a CAT-scan of the skull was made in a large industrial scanner of the Fraunhofer Entwicklungszentrum Röntgentechnik of the Fraunhofer Institut at Fürth in Germany.

According to Peter Larson, director of the Black Hills Institute, Trix is the third most complete Tyrannosaurus found, after Sue and Stan. About half of the bones have been found. These represent between 75% and 80% of its bone volume. The main missing parts include the tip of the snout, the front lower jaws, at least seven vertebrae of the middle tail, the point of the tail, the right shoulder blade, the arms, the left hindlimb and the right foot. Parts never before discovered in a Tyrannosaurus fossil include a turbinal bone in the nasal cavity. A rare element present is the furcula and the stapes of the ear. There is some root damage from plant growth and some bones had been gnawed by scavengers. A smaller shed tooth was found, attributed to Nanotyrannus. Trix in 2016 was the most complete Tyrannosaurus specimen permanently exhibited outside of the USA. Tyrannosaurus skeletons part of the collection of the Natural History Museum, London, are more fragmentary.


For formal use, the BHI referred to the skeleton as the “Murray T. rex”. Because of her age, gender and face injuries, the tyrannosaurus was nicknamed “grandma pusface”. Naturalis preferred Grand Old Lady. Wim Pijbes, the director of the Amsterdam Rijksmuseum, called the skeleton “the Nightwatch of Natural History”. She has also been called the “Mona Lisa of Naturalis”, because of her enigmatic smile. Both Larson and the museum concluded it was “the most beautiful tyrannosaurus of the world”. Naturalis decided that the skeleton needed an official name, as all main exemplars of Tyrannosaurus possess. In the press, it was speculated it would be called “Michelle” after its discoverer, as had happened with many specimens. Naturalis asked the Dutch public to suggest a name. On 23 June 2016 it was announced that the name overwhelmingly chosen was “Trix”, as both an allusion to “T-rex” and former Queen Beatrix of the Netherlands. Trix thus became known as the “Queen of the Cretaceous”.

T. rex in Town is a temporary exhibit from September 10, 2016 to June 5, 2017 in the Naturalis Biodiversity Center in Leiden, The Netherlands.

 Source. Wikipedia.org


Sunday, August 6, 2017

Tarascosaurus salluvicus art by Sergey Krasovskiy. Stocktrek Images

Tarascosaurus (“Tarasque lizard”) is a genus of, perhaps abelisaurid, theropod dinosaur from Late Cretaceous of France.

After having in 1988 identified an upper jaw bone found near Pourcieux as belonging to a member of the Abelisauridae, French paleontologist Éric Buffetaut reviewed the known remains of larger theropods found in the Late Cretaceous of Europe concluding they all were of abelisaurid affinity. Most of these fossils, earlier named as Megalosaurus pannoniensisMegalosaurus hungaricus and Megalosaurus lonzeensis, he considered to be nomina dubia because of the paucity of the material. However, when in the collection of the University of Lyon he discovered some theropod bones once excavated by an unknown collector at the escarpment of the Lambeau de Beausset, Buffetaut and Jean Le Loeuff named and described these in 1991 as the type species Tarascosaurus salluvicus. The generic name is derived from the Tarasque or Tarasca, a devouring monster from Occitan and Spanish folklore. The specific name refers to the Salluvii, a Gallic tribe in Antiquity inhabiting the area near Marseilles.

Tarascosaurus salluvicus size comparison by MoriceMonkey93

The holotype PSL 330201 was found in the Fuvelian Beds, dating from the lower Campanian. It consists of the upper part of a thigh bone, 22 centimetres (8.7 in) long. PSL 330202, consisting of two dorsal vertebrae, was made a paratype; these bones may belong to the same individual. Referred was PSL 330203, a damaged tail vertebra. The femur, with an undamaged length estimated at 35 centimetres (14 in), indicates a body length of two and a half to three metres. Some fossils from Spain were also referred to the genus.

In 2003 Oliver Rauhut concluded that Tarascosaurus itself was also a nomen dubium because the material was not diagnostic.

Tarascosaurus was placed in the Abelisauridae in 1991. It was then seen as the only known abelisaurid from the Northern Hemisphere apart from Betasuchus of the Maastrichtian of the Netherlands. However, in 2003 Ronan Allain et al. concluded that the type lacked any uniquely abelisaurid traits.

Source: Wikipedia.org, NatGeo


Thursday, August 3, 2017

Dreadnoughtus illustration by Jennifer Hall

Dreadnoughtus is a genus of giant titanosaurian sauropod dinosaur containing a single species, Dreadnoughtus schraniD. schrani is known from two partial skeletons discovered in Upper Cretaceous (Campanian-Maastrichtian; 84–66 Ma) rocks of the Cerro Fortaleza Formation in Santa Cruz Province, Argentina. It is one of the largest of all known terrestrial vertebrates, possessing the greatest mass of any land animal that can be calculated with reasonable certainty. D. schrani is known from a more complete skeleton than any other gigantic titanosaurian.

Dreadnoughtus means “fearing nothing.” It’s a fitting name for the largest dinosaur ever discovered. The beast measures 26 metres from nose to tail and weighs 59,300 kg (about the weight of 12 African elephants).

Based on a cladistic analysis, Dreadnoughtus schrani appears to be a “derived” basal titanosaur that is not quite a lithostrotian. Lacovara et al. (2014) note that because of the wide array of relatively “advanced” and “primitive” features in the skeleton of Dreadnoughtus schrani and the current instability of titanosaurian interrelationships, future analyses may find widely differing positions for it within Titanosauria.

The illustration below compares the size of Dreadnoughtus to a moose, an African elephant, other dinosaurs and a Boeing airplane.

Dreadnaughtus size comparison

Why name it “Dreadnoughtus”?

Dr. Kenneth Lacovara of Drexel University, the paleontologist who discovered the massive beast, decided to name the dinosaur after the early 20th century dreadnought battleships. Nothing stood in the way of those seafaring monsters. Look at the size of them:

Dreadnought Battleship

How was Dreadnoughtus discovered?

In 2005, Dr. Lacovara found a small collection of bones in South Patagonia, Argentina.

Patagonia, Argentina

Over the next four years, he and his team, plus Argentinian experts, excavated more than 100 bone fragments. (The bones were well-preserved as the dinosaur seemingly drowned in quicksand.) For the first time ever, paleontologists are able to examine an almost complete dinosaur skeleton.

Dr. Lacovara and his team scanned the bones to make a computerized reconstruction of how Dreadnoughtus looked and moved. They also are using 3D printers to print out models of the bones. One of the most amazing discoveries is that Dreadnoughtus hadn’t finished growing! Who knows how big it would have gotten?

Dr. Lacovara published his research on September 4, 2014, in the Scientific Reports journal, almost ten years after his first discovery.

Source Wikipedia.org, NatGeo.com


Thursday, August 3, 2017

©Michael Skrepnick dinosaursinart.com

Monolophosaurus (meaning “single-crested lizard”) is a genus of tetanuran theropod dinosaur from the Middle Jurassic Shishugou Formation in what is now Xinjiang, China. It was named for the single crest on top of its skull. Monolophosaurus was a mid sized carnosaurian carnivore at about 5 metres long.

Monolophosaurus mounted skeleton in Japan

A nearly complete skeleton of a theropod new to science was discovered by a Canadian-Chinese expedition in 1981. The fossil was unearthed until 1984. In 1987, before description in the scientific literature, it was referred to in the press as Jiangjunmiaosaurus, an invalid nomen nudum. In 1992 it was mentioned by Dong Zhiming as Monolophosaurus jiangjunmiaoi, and in 1993 by Wayne Grady as Monolophosaurus dongi. These latter names also lacked a description and therefore were nomina nuda as well.

In 2006, Thomas Carr suggested that Guanlong, another theropod with a large, thin, and fenestrated midline crest and from the same formation, was in fact a subadult individual of Monolophosaurus. Usually Guanlong had been considered a proceratosaurid tyrannosauroid, but Carr had performed an analysis in which both specimens clustered and were allosauroids. More conservatively, in 2010 Gregory S. Paul renamed Guanlong into a Monolophosaurus species, Monolophosaurus wucaii, presuming the taxa might be sister species. In 2010, Brusatte e.a. rejected the identity, pointing out that the Guanlong holotype was actually a fully adult individual.

The type and only known individual has been estimated at five metres (16.4 ft). In 2010, Paul estimated the length at 5.5 metres, the weight at 475 kilogrammes.

Profile view of skull cast of Monolophosaurus

Several distinguishing traits have been established. The snout on its midline bears a large crest, the front of which is formed by the praemaxillae. It continues to behind over the nasals and lacrimals; its rear touches the frontals. The top of the crest runs parallel to the upper jaw edge. The ascending branches of the praemaxillae each have a forked rear. The side of the praemaxilla features a deep groove running from an opening in the ascending branch towards an opening below the nostril. Within the depression around the upper rear side of the nostril two pneumatic openings are present, of unequal size. The rear branch of the lacrimal, above the eye socket, has a distinctive hatchet-shaped process pointing upwards. The combined frontals are rectangular and elongated with a length:width ratio of 1.67.

Monolophosaurus was originally termed a “megalosaur” and has often since been suggested to be an allosauroid. Smith et alii(2007) was the first publication to find Monolophosaurus to be a non-neotetanuran tetanuran, by noting many characters previously thought to be exclusive of Allosauroidea to have a more wider distribution. Also, Zhao et alii in 2010 noted various primitive features of the skeleton suggesting that Monolophosaurus could be one of the most basal tetanuran dinosaurs instead. Benson (2008, 2010) placed Monolophosaurus in a clade with Chuandongocoelurus that is more basal than Megalosauridae and Spinosauridae in the Megalosauroidea. Later, Benson et alii (2010) found the Chuandongocoelurus/Monolophosaurus clade to be outside of Megalosauroidea and Neotetanurae, near the base of Tetanurae. A 2012 phylogeny found Monolophosaurus and Chuandongocoelurus, while not sister taxa, to form a group outside more derived groups at the base of Tetanurae.

Source: Wikipedia.org, NatGeo.com


Monday, July 31, 2017

Aucasaurus garridoi by Paleocolour

Aucasaurus was a genus of medium sized theropod dinosaur from Argentina that lived during the Santonian – Campanian stage of the Anacleto Formation. It was smaller than the related Carnotaurus, although more derived in some ways, such as its extremely reduced arms and almost total lack of fingers. The type skeleton is complete to the thirteenth caudal vertebra, and so is relatively well understood, and is the most complete abelisaurid yet described. However, the skull is damaged, causing some paleontologists to speculate that it was involved in a fight prior to death.

Aucasaurus garridoi scale diagram

Aucasaurus short, deep-snouted skull was not as short or as deep-snouted as that of Carnotaurus. Also, instead of horns, it had a pair of low ridges above each eye.

In 2010, Gregory S. Paul estimated its body length at 5.5 metres, its weight at 700 kilograms. In 2016, its length was estimated to be 6.1 metres (20 ft) in a comprehensive analysis of abelisaur size.

Aucasaurus small arms were also alike that of its horned relative, but were proportionally longer due to its small size, and the bones lacked the bony processes and some unusual proportions present in Carnotaurus. The hand of Aucasaurus was unusual: four metacarpals were present, but the first and fourth lacked fingers. The second and third had fingers, but they were quite short and had no claws.

Aucasaurus is known from finds in the Rio Colorado Formation, a Late Cretaceous formation in Argentina that has yielded many dinosaur fossils. Numerous sauropod eggs are also known from this deposit.

3D scan of the braincase Aucasaurus was closely related to Carnotaurus and they are united in the Carnotaurini.
Aucasaurus skeleton
Source: Wikipedia.org, NatGeo.com

Zhenyuanlong suni: A Newly Identified Species of Feathered Dinosaur

Tuesday, July 25, 2017


A newly identified species of feathered dinosaur – who has been unearthed in 2015 in China – is a close cousin of the Velociraptor, made famous by the Jurassic Park films.

It is the largest dinosaur ever to have been unearthed with a well-preserved set of bird-like wings, researchers said.

The dinosaur – dubbed Zhenyuanlong suni by researchers – grew to more than five feet in length, and had very short wings compared with other dinosaurs in the same family, consisting of multiple layers of large feathers.

The holotype of the large-bodied, short-armed Liaoning dromaeosaurid Zhenyuanlong suni gen et. sp. nov. (JPM-0008).

‘The movies have it wrong – this is what Velociraptor would have looked like too,’ said Dr Steve Brusatte, of Edinburgh University’s School of GeoSciences, who co-authored the study.

This latest discovery suggests that winged dinosaurs with larger and more complex feathers were more diverse than previously thought.

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T. rex Had Unique Serrated Teeth

Tuesday, July 25, 2017

If you want to know the secret behind the success of Tyrannosaurus rex and its meat-eating dinosaur cousins, look no further than their teeth.

Scientists in 2015 unveiled a comprehensive analysis of the teeth of the group of carnivorous dinosaurs called theropods, detailing a unique serrated structure that let them chomp efficiently through the flesh and bones of large prey.

Theropods included the largest land predators in Earth’s history. They first appeared about 200 million years ago and were the dominant terrestrial meat-eaters until the age of dinosaurs ended about 65 million years ago.

Tyrannosaurus rex tooth progression from the juvenile tinker

The study involving eight theropod species revealed their previously unknown tooth complexity. Internal dental tissues were arranged in a way that reinforced the strength and prolonged the life of teeth that were serrated like steak knives for easy dismembering of other dinosaurs.

University of Toronto Mississauga paleontologist Kirstin Brink said fossil evidence showed that T. rex’s teeth could crush bone. Its teeth have been found embedded in the bones of its prey and chunks of bone appear in its fossilized dung.

“But the serrations were most efficient for piercing flesh and gripping it while ripping off a chunk of meat, called the ‘puncture and pull’ feeding style,” Brink said.

The researchers analyzed slices from fossil teeth using a powerful microscope and a sophisticated device that revealed tooth chemical properties.

Bone crusher: The carnivorous group called theropods had serrated teeth like a steak knife that let them chomp efficiently through the flesh and bones of their prey. Pictured, a close-up of the structure of the teeth.

They studied teeth from: the early and relatively small Coelophysis; bird-like Troodon; large predators Allosaurus, Gorgosaurus, Daspletosaurus, Tyrannosaurus and Carcharodontosaurus; and big, semi-aquatic Spinosaurus.

The teeth of Tyrannosaurus and Carcharodontosaurus measured up to 9 inches (23 cm) long.

“In theropods, the serrations are larger and deeper than the superficial view suggests, making them stronger and longer lasting, less likely to get damaged or worn,” University of Toronto Mississauga paleontology professor Robert Reisz said.

Dinosaurs were able to continuously grow teeth throughout their lives. When a tooth was broken, another could replace it.

“It could take up to two years for a tooth to grow back in the big theropods like T. rex. Therefore, having specially reinforced teeth means less tooth breakage and less gaps in the jaw, leading to more efficient eating,” Brink said.

The Komodo dragon, a lizard up to 10 feet (3 meters) long from Indonesia, is the only living reptile with serrated teeth closely resembling those of theropods although these teeth evolved independently of those of the dinosaurs, Brink said.

The research appears in the journal Scientific Reports.

Source: SciFi.com