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Dacentrurus

Tuesday, March 28, 2017

Dacentrurus by Oscar Sanisidro

Dacentrurus (meaning “tail full of points”), originally known as Omosaurus, was a large stegosaur of the Late Jurassic Period (154 – 150 mya) of Europe. Its type species, Omosaurus armatus, was named in 1875, based on a skeleton found in England. In 1902 the genus was renamed into Dacentrurus because the name Omosaurus had already been used for a crocodilian. After 1875, half a dozen other species would be named but perhaps only Dacentrurus armatus is valid.

Finds of this animal have been limited and much of its appearance is uncertain. It was a heavily built quadrupedal herbivore, adorned with plates and spikes.

Dacentrurus by Prehistoric Wildlife

Dacentrurus was a large stegosaurid. Some specimens have been estimated to reach lengths between 7–8 m (23–26 ft) and to weigh up to 5 t (5.5 short tons). Many books claim that Dacentrurus was a small stegosaur, when in fact finds such as a 1.5 metres (4.9 ft) wide pelvis indicate that Dacentrurus was among the largest of them. For a stegosaur the gut was especially broad, and a massive rump is also indicated by exceptionally wide dorsal vertebrae centra. The hindlimb was rather short, but the forelimb relatively long, largely because of a long lower arm.

Although Dacentrurus is considered to have the same proportions as Stegosaurus, its plate and spike configuration is known to be rather different, as it probably had both two rows of small plates on its neck and two rows of longer spikes along its tail. The holotype specimen of Dacentrurus armatus contained a small blunt asymmetrical neck plate and also included a tail spike which could have been part of a thagomizer. The tail spike had sharp cutting edges on its front and rear side.

Dacentrurus has sometimes been portrayed with a spike growing near the shoulder, similarly to a Kentrosaurus. Whether this portrayal is accurate or not is not yet determined.

Dacentrurus armatus reconstruction at the Natural History Museum in London, UK. Photo by Emőke Dénes

Due to the fact it represented the best known stegosaurian species from Europe, most stegosaur discoveries in this area were referred to Dacentrurus. This included finds in Wiltshire and Dorset in southern England (among them a vertebra ascribed to D. armatus in Weymouth), fossils from France and Spain and five more historically recent skeletons from Portugal. Most of these finds were fragmentary in nature; the only more complete skeletons were the holotypes of D. armatus and D. lennieri. .

1.Dacentrurus 2.Lexovisaurus 3.Huayangosaurus 4.Wuerhosaurus 5.Gigantspinosaurus – by Kawasaki Satoshi

 ‬Study of late Jurassic ecosystems in North America has brought the strong suggestion that stegosaurs regularly came into conflict with theropod dinosaurs like Allosaurus.‭ ‬This predator/prey interaction may have also happened in late Jurassic Europe,‭ ‬although most of the large theropods such as Dubreuillosaurus and Poekilopleuron are so far only known from earlier in the Jurassic.

The Origin of Tetrapods

Tuesday, March 28, 2017

The Origin of Tetrapods

The word “tetrapod” means “four feet” and includes all species alive today that have four feet — but this group also includes many animals that don’t have four feet. That’s because the group includes all the organisms (living and extinct) that descended from the last common ancestor of amphibians, reptiles, and mammals. So, for example, the ichthyosaur, an extinct swimming reptile, is a tetrapod even though it did not use its limbs to walk on land. So is the snake, even though it has no limbs. And birds and humans are tetrapods even though they only walk on two legs. All these animals are tetrapods because they descend from the tetrapod ancestor described above, even if they have secondarily lost their “four feet.”

Tetrapod evolution

Tetrapods evolved from a finned organism that lived in the water. However, this ancestor was not like most of the fish we are familiar with today. Most animals we call fishes today are ray-finned fishes, the group nearest the root of this evogram. Ray-finned fishes comprise some 25,000 living species, far more than all the other vertebrates combined. They have fin rays — that is, a system of often branching bony rays (called lepidotrichia) that emanate from the base of the fin.

In contrast, the other animals in the evogram — coelacanths, lungfishes, all the other extinct animals, plus tetrapods (represented by Charles Darwin) — have what we call “fleshy fins” or “lobe fins.” That is, their limbs are covered by muscle and skin. Some, such as coelacanths, retain lepidotrichia at the ends of these fleshy limbs, but in most fleshy-finned animals these have been lost.

The common ancestor of all those different organisms (ray-fins, coelacanths, lungfishes, tetrapods, etc.) was neither a lobe-fin nor a ray-fin. This ancient vertebrate lineage had fins (with lepidotrichia), scales, gills, and lived in the water. Yet they also had air bladders (air-filled sacs) connected to the back of their throats that could be used for breathing air (i.e., as lungs) or for buoyancy control. The air bladders of many ray-fins no longer connect to their throats, and so they are not able to breathe air. In these ray-fins, the air bladder is used mainly for buoyancy control and is known as a swim bladder. By contrast, tetrapods have taken an alternative route: they have lost the buoyancy control function of their air bladders, and instead this organ been elaborated to form the lungs that we all use to get around on land.

When we get past coelacanths and lungfishes on the evogram, we find a series of fossil forms that lived between about 390 and 360 million years ago during the Devonian Period. During this interval, this lineage of fleshy-finned organisms moved from the water to the land. Many parts of the skeleton changed as new innovations that permitted life on land evolved.

For example, the ancestors at the base of this evogram lived fully in the water and had skulls that were tall and narrow, with eyes facing sideways and forwards. This allowed them to look around in their watery environments for predators and prey. However, as ancestors of the first tetrapods began to live in shallower waters, their skulls evolved to be flatter, with eyes on the tops of their heads. This probably allowed them to look up to spot food. Then, as tetrapods finally moved fully onto land and away from the water, many lineages once again evolved skulls that were tall and narrow, with eyes facing sideways and forwards, allowing them to look around their terrestrial environments for predators and prey.

As lineages moved into shallower water and onto land, the vertebral column gradually evolved as well. You may have noticed that fishes have no necks. Their heads are simply connected to their shoulders, and their individual vertebrae look quite similar to one another, all the way down the body. Mobile necks allow land animals to look down to see the things on the ground that they might want to eat. In shallow water dwellers and land dwellers, the first neck vertebra evolved different shapes, which allowed the animals to move their heads up and down. Eventually, the second neck vertebra evolved as well, allowing them to move their heads left and right. Later tetrapods evolved necks with seven or more vertebrae, some long and some short, permitting even more mobility.

The vertebrae you are probably most familiar with (like our own!) consist of a spool-like centrum, which connects in front and back with other centra. On top of the centra are vertebral spines and arches to which muscle segments attach, and lateral to the centra are the ribs; these anchor muscles that flex as the animals move. Fishes swim with simple lateral motions, so their arches are relatively straight and needle-like, and so are their ribs. When you eat fish and pick out the bones, these are mostly what you’re finding. Because fishes live in the water, gravity is not a big problem for them. But on land, a quadruped with a backbone between forelimbs and hindlimbs faces the same problems as a bridge designer: sag. As the fleshy-finned organisms began to venture onto land, they evolved a series of interlocking articulations on each vertebra, which helped them overcome sag and hold the backbone straight with minimal muscular effort.

Vertebra shape and connections in the early tetrapod Acanthostega.

 

One element of the human vertebral column.

The connection between the pelvis and hindlimbs in early tetrapods is a prime example of exaptation. We call this fused connection the sacrum. It is extremely useful for terrestrial organisms because it allows them to use their hindlimbs efficiently for locomotion on land. Since the aquatic ancestors of fishes and tetrapods had no such connection, one might guess that this feature first evolved serving the function of enabling terrestrial locomotion. However, the earliest form of this connection (as seen in Acanthostega) evolved while these tetrapod precursors were still living in the water. Based on current evidence, Acanthostega appears to have been fully aquatic, so this connection likely evolved to function in something other than terrestrial locomotion. Only later, as tetrapod ancestors moved onto land, was this trait co-opted for terrestrial support — and as it was, additional vertebrae were fused in the same way, providing further support.

As the limbs and their connections to the rest of the skeleton evolved, limb bones took on distinct roles and many bones were lost. The humerus and the femur were already connected to two outer bones (the radius and ulna in the forelimb, the tibia and fibula in the hindlimb). This is something that evolved about 30 million years before vertebrates came onto land. However, muscular connections between these bones began to change on the road to land and allowed the limbs to be used for terrestrial locomotion. The ankle was originally composed of many small bones arranged in two rows, but gradually many of these small bones were lost. The first animals to get close to walking on land had eight digits on each limb. Over time, some of these digits were lost, leading to animals with seven digits, then six, and then five, which is the common condition now seen in living tetrapods.

As these animals evolved to live on land, other changes in the rest of their bodies evolved. Many would eventually lose their gills, which only work well for getting oxygen when wet, and their tail fins got smaller. Similarly they lost the lateral line system, a network of vibration-sensitive canals along the skull and jaw, which doesn’t work out of water.

The environments of the animals shown in this evogram also changed through time. In fact, if you were to venture back to Arizona at the beginning of the “Age of Dinosaurs” in the Triassic Period, some 225 million years ago, you would find ray-fins, coelacanths, and lungfishes living in the marshes, streams, and temporary ponds of that day, along with freshwater sharks. So the habitats that these animals occupy today are not necessarily the ones in which they have always lived, or in which they originally evolved. It is still unclear exactly where the transition from water to land took place ecologically. Paleontologists have discovered fossils involved in this transition preserved from freshwater, brackish, and marine habitats. Regardless of where the transition occurred, eventually early ancestors of the first tetrapods came up onto land — although not all stayed. Some, like the whales, made the transition back into the water.

In Late Devonian vertebrate speciation, descendants of pelagic lobe-finned fish — like Eusthenopteron — exhibited a sequence of adaptations: *Panderichthys, suited to muddy shallows *Tiktaalik with limb-like fins that could take it onto land *Early tetrapods in weed-filled swamps, such as: **Acanthostega, which had feet with eight digits **Ichthyostega with limbs Descendants also included pelagic lobe-finned fish such as coelacanth species.

Original article published on http://evolution.berkeley.edu

Torvosaurus

Sunday, March 26, 2017

Torvosaurus - Discovery Channel

Torvosaurus is a genus of carnivorous megalosaurid theropod dinosaurs that lived approximately 153 to 148 million years ago during the later part of the Jurassic Period in what is now Colorado and Portugal. It contains two currently recognized species, Torvosaurus tanneri and Torvosaurus gurneyi.

In 1979 the type species Torvosaurus tanneri was named: it was a large, heavily built, bipedal carnivore, that could grow to a length of about 10 m (33 ft). T. tanneri was among the largest carnivores of its time, together with Epanterias and Saurophaganax (which could be both synonyms of Allosaurus). Specimens referred to Torvosaurus gurneyi were initially claimed to be up to eleven metres long, but later shown to be smaller. Based on bone morphology Torvosaurus is thought to have had short but very powerful arms.

The genus name Torvosaurus derives from the Latin word torvus, meaning “savage”, and the Greek word sauros (σαυρος), meaning “lizard”. The specific name tanneri, is named after first counselor in the First Presidency of The Church of Jesus Christ of Latter-day Saints Nathan Eldon Tanner. Torvosaurus gurneyi is dedicated to the paleoartist James Gurney, creator of the Dinotopia series of books. Torvosaurus was described and named by Peter M. Galton and James A. Jensen in 1979 and the type species is Torvosaurus tanneri.

Torvosaurus vs ‘Edmarka’ by EoFauna

Fossilized remains of Torvosaurus have been found in North America and Portugal. In 1971, Vivian Jones, of Delta, Colorado (USA), in the Calico Gulch Quarry in Moffat County, discovered a single gigantic thumb claw of a theropod. This was shown to James Alvin Jensen, a collector working for Brigham Young University. In an effort to discover comparable fossils, Vivian’s husband Daniel Eddie Jones directed Jensen to the Dry Mesa Quarry, where abundant gigantic theropod bones, together with Supersaurus remains, proved present in rocks of the Morrison Formation. From 1972 onwards the site was excavated by Jensen and Kenneth Stadtman. The genus and the type species T. tanneri were named and described in 1979 by Peter Malcolm Galton and Jensen. In 1985 Jensen could report a considerable amount of additional material, among it the first skull elements. The fossils from Colorado were further described by Brooks Britt in 1991.

This is the main lobby of the Museum of Ancient Life at Thanksgiving Point in Lehi, Utah, U.S.A. It displays a depiction of a Torvosaurus dinosaur skeleton pursuing a herd of Othnielosaurus. Author leon7

Torvosaurus was a very large predator, with an estimated maximum body length of 10 metres (33 ft) and mass of 3.6–4.5 tonnes (4–5 short tons) for both T. tanneri and T. gurneyi, making Torvosaurus among the largest carnivores of the Jurassic. Claims have been made indicating even larger sizes. The synonymous Edmarka rex was named thus because it was assumed to rival Tyrannosaurus rex in length and weight. Likewise “Brontoraptor” was supposed to be a torvosaur of gigantic size. The T. gurneyi specimens from Portugal initially prompted larger size estimates to be made. In 2006 a lower end of a thighbone, specimen ML 632, was referred to Torvosaurus sp. and later to T. gurneyi. This specimen was initially stated to indicate a length of 11 m (36 ft). Applying the extrapolation method of J.F. Anderson, correlating mammal weights to their femur circumference, resulted in a weight of 1930 kilogrammes. However, revised estimates performed in 2014 suggested a slightly smaller total body size for this specimen, of about 10 m (33 ft). Among the differentiating features between T. gurneyi and T. tanneri are the number of teeth and size and shape of mouth. While the upper jaw of T. tanneri has more than 11 teeth, that of T. gurneyi has less.

Torvosaurus and Miragaia by Davide Bonadonna

Evolution Of Dinosaurs: Faster Than Previously Believed

Sunday, March 26, 2017

Honey, who shrunk the dinosaurs? Study traces dinosaur evolution into early birds

Dinosaurs were in decline for tens of millions of years before the Earth was struck by an asteroid, ending their dominion over the planet. What was killing off dinosaurs near the end of their reign?

Scientists previously thought that dinosaurs evolved from their smaller ancestors over a period of at least 10 million years but findings of a new study suggest that the evolution occurred in less than five million years.

For the new study published in the Proceedings of the National Academy of Sciences on Dec. 7, 2015 Randall Irmis, from the Natural History Museum, and colleagues used radioactive isotope measurements for dating the zircon crystals that were found in the sediments of the Chañares Formation, which is known for its fossils of early dinosaur relatives.

The analysis revealed that the formation is between 234 million and 236 million years old from the Late Triassic period, which means that the fossils of the dinosaur’s reptile predecessors, the early dinosauromorphs, that were sandwiched in the rock layers are of the same age.

The early dinosauromorphs were like the dinosaurs sans some key features such as the former having a ball-and-socket hip that rotates easily and an additional vertebra at the end of their spine.

FOSSIL BED Early dinosaur ancestors like the pair on the right were thought to evolve around 10 million years before dinosaurs. But new dating of fossil layers in Argentina cuts that time in half, to about 5 million years. IMAGE COURTESY OF VICTOR LESHYK

Scientists have already studied dinosauromorphs but there were uncertainties about their age since biostratigraphy, the technique used to date their fossils, were not as accurate as other dating methods such as the one employed in the new study.

The findings provided evidence that the early dinosauromorphs lived between five to 10 million years earlier than previously believed revamping the long held timeline of the early dinosauromorphs evolving into dinosaurs. The study likewise offered proof that the dinosaurs evolved much faster than previously thought.

“We constrain the rate of dinosaur origins, demonstrating their relatively rapid origin in a less than 5-Ma interval, thus halving the temporal gap between assemblages containing only dinosaur precursors and those with early dinosaurs,” Irmis and colleagues wrote.

The researchers said that although the dinosaurs may have evolved rapidly, the prehistoric animals appear to have dominated paleo-Earth in a smooth and gradual manner.  It took quite a while for the  prehistoric giants to spread globally as it took them millions of year after their origin to gradually dominate the mid to high-latitude regions of the Earth.

“You don’t seem to see dinosaurs showing up and immediately taking over,” Irmis said. “It really emphasizes that there wasn’t much special about the first dinosaurs. They were pretty similar to their early dinosauromorph relatives and probably doing very similar things.”

Source: www.techtimes.com

Jaws to Ears in the Ancestors of Mammals

Sunday, March 26, 2017

Ancestors of Mammals

All the animals you see on this evogram are synapsids, the group that gave rise to the mammals. Sometimes synapsids are called “mammal-like reptiles;” however, that is misleading because synapsids are not reptiles. Synapsids and reptiles are two distinct groups of amniotes, animals that produce young that are enveloped with a membrane called an amnion that prevents desiccation. All reptiles (including birds) have eggs with amniotic membranes (which some lay and others retain inside their bodies until hatching). And of course all mammals (the clade of synapsids still alive today) reproduce using an amnion, and those that lay eggs (e.g., the platypus and echidna) produce amniotic eggs.

Mammal evogram

Like birds, crocodiles, turtles, snakes, lizards, amphibians, and most fishes, the earliest synapsids had a bone in the back of the skull on either side called the quadrate that made the connection with the lower jaw via a bone called the articular. But mammals today, including humans, use two different bones, called the squamosal and the dentary, to make this connection. How did this new jawbone configuration evolve?

For reasons we don’t fully understand, several lineages of synapsids — including the one that would eventually give rise to the mammals — began to evolve changes in the jaw joint. Originally the quadrate and articular bones formed the jaw joint, but these synapsids (e.g., Probainognathus) evolved a second pair of bones involved in the jaw articulation. The squamosal bone was positioned alongside the quadrate in the upper jaw, and the dentary was positioned alongside the articular in the lower jaw.

Skull of Probainognathus, an early synapsid.

This unusual paired condition did not last long, though. Soon, the quadrate and articular lost their function in jaw articulation and even their position in the jaw as they evolved. They became increasingly smaller and eventually migrated into the ear region, where they became the “hammer” and “anvil” of the ear. So, over time, the synapsids’ quadrate-articular jaw joint (which the rest of the tetrapods possess) was replaced by a dentary-squamosal joint (which all living mammals possess), while the quadrate and articular migrated, shrank, and became part of the complex of middle ear bones.

Evolution of the jaw joint in synapsids. Abbreviations used: a-articular, d-dentary, q-quadrate, s-squamosal.

Only in recent years has it become apparent that several lineages of synapsids, including mammals, replaced their quadrate-articular jaw joint with a dentary-squamosal joint. We don’t fully understand why these changes happened. Some evidence suggests that the change in the quadrate-articular complex improved hearing. Other evidence suggests that these changes were a byproduct of early mammals’ increasing brain size. These ideas are not mutually exclusive, of course, and more research is needed. Whatever the functional advantages may have been, the pattern of evolution in these features clearly shows another example of exaptation: the incorporation of the dentary and squamosal bones into the jaw joint, originally alongside the quadrate and articular, eventually allowed the latter two bones to acquire a completely different function and to leave the jaw articulation altogether.

Source: evolution.berkeley.edu

Jurassic World and Indominus Rex

Saturday, March 25, 2017

Indominus Rex Attack!

What do you do when you want to boost visitor attendance to your dinosaur-dominated, Jurassic World theme park? Use DNA, from four different dinosaurs, and “in the Hammond lab” create something entirely new and fearsome.

Then … give the new creature a name which signifies its awesome power: Indominus rex. At least … that’s how the story theme works in the 2015 film “Jurassic World.”

So … let’s travel back in time, to the age of the dinosaurs, and meet the four interesting creatures whose DNA led to this new and ferocious predator:

If—contrary to plan—Indominus rex becomes a killing machine, we have to ask: Did she “inherit” that trait from her “ancestors?” Let’s examine the question, starting with Rugops (ROO-gops).

Rugops skull at the National Geographic Museum Spinosaurus Exhibit. Author Ryan Somma

What we know about this theropod, from a physical standpoint, comes from a single, nearly complete and fossilized skull. With its weak but gaping jaw and skull, Rugops—which means “wrinkle face”—is not a predator like the Cretaceous Period Spinosaurus.

Instead, Rugops is a natural-born scavenger, likely waiting in the wings for what’s left of a Spinosaurus-caught, Cretaceous-era fish known as Onchopristis. Living off the scraps of meals, killed by another creature, could be enough for a Rugops.

What does the DNA from Rugops contribute to Indominus rex ? Probably … a massive, gaping jaw. In other words … she isn’t getting the killer streak from Rugops.

How about Carnotaurus  (CAR-no-TOR-us), the “Meat Eating Bull?” 

Carnotaurus

This Late-Cretaceous theropod, measuring around 25 feet long, likely roamed the plains of South America. At least, that’s where palaeontologist Jose Bonaparte found amazingly in-tact fossilized remains—in Argentina—during 1985. Even its skull and skin impressions were visible once the creature’s skeleton was unearthed.

Those skin impressions have caused palaeontologists to believe that Carnotaurus had bumps across its body. It also had projections on its skull, resembling horns, which led to its “bull” name. It is this physical feature—the two horns—which Carnotaurus “passed-on” to Indomitus rex.

From whom did Indomitus rex inherit her size? Giganotosaurus  (jig-a-NOT-o-SOR-us) can take credit for that.

Giganotosaurus

This “Giant Southern Lizard” lived, in South America, during the Mid-Cretaceous period. Around 40-45 feet long, the Giganotosaurus  weighed around 8 tons and walked—upright—on two powerfully large legs. With its thin and pointed tail providing balance, the creature was likely able to make quick turns while running.

Because of its size, Giganotosaurus likely had no natural predators. Living before T. rex, it probably fed on herbivore dinosaurs. If so, it could have easily sliced through the flesh of its prey.

Because no complete skeleton of this creature has ever been found, paleontologists (and artists) can only speculate about this massive creature (including whether gigantic carnivores and herbivores lived at the same time.)

That leaves Majungasaurus (ma-JUNG-ah-SORE-us), the last of the four DNA-contributing dinosaurs. Once roaming Madagascar, in the late-Cretaceous period, this theropod likely contributed its teeth and lower torso to the lab-developed Indominus rex.

Fearsome teeth

We know about this predator from spectacular fossils located in the Berivotra area of northwest Madagascar. Long before lemurs lived on that island, Majungasaurus grew to around 21 feet in length. It is the best-known of the muscular abelisaurids (which dominated the southern hemisphere just as the tyrannosaurids dominated the northern hemisphere).

Majungasaurus had an unusual body. Its short-but-powerful hind legs were far different from its very small front “legs.” While paleontologists are not sure about the function of those forelimbs, there is little doubt about how a Majungasaurusused its sharp and knife-like teeth!

Plus … scientists believe this dinosaur may also have been … a cannibal. What is the evidence for that?

During 2003, in Madagascar, paleontologists found a fossilized tail bone from a Majungasaurus. That bone contains some interesting marks which paleontologists compared with the denticle spacings of Majungasaurus.

Guess what? They matched … almost exactly!

So … now you know the history of a 43-foot long, 18-foot high hybrid dinosaur called I. rex !

Jurassic World – Indominius Rex

Rugops

Saturday, March 25, 2017

Rugops - BBC

Rugops (meaning “wrinkle face”) is a genus of theropod dinosaur which inhabited what is now Africa approximately 95 million years ago (Cenomanian stage of the Late Cretaceous). The discovery of a Rugops skull in Niger in 2000 was a crucial breakthrough in the understanding of the evolution of theropods in that area, and demonstrates that this landmass was still united with Gondwana at that stage in history.

Rugops by Prehistoric Wildlife

Though known only from a skull, Rugops was estimated as being 6 metres (19.7 ft) long and 750 kilograms (1,650 lb) in weight based on comparisons with its relatives. Later estimates suggest a revised length of 4.4 metres (14.4 ft). The skull bore armour or scales, and other bones had many blood vessels, causing Paul Sereno, who led the team that discovered the fossil, to say, “It’s not the kind of head designed for fighting or bone-crushing”, suggesting that it may have been a scavenger. The skull also bears two rows of seven holes, each of unknown purpose, although Sereno has speculated that they may have anchored some kind of crest or horns.

Rugops skull at the National Geographic Museum Spinosaurus Exhibit. Author: Ryan Somma

Like other abelisaurs, Rugops probably had very short arms. These were probably useless in fighting. They may have only been balance tools, items to counterbalance the dinosaur’s head.

Holotype and only know specimen : MNN IGU1. A partial skull missing the posterior region, preserving the maxilla, frontals, lacrimals, prefrontals, nasals, parietal, and premaxillae. Full restored skull length is 31.5 centimeters, suggesting an animal significantly smaller than Majungasaurus crenatissimus, Aucasaurus garridoi, and Carnotaurus sastrei. Author: Crizz30

The type species is R. primus (meaning “first wrinkle-face”), discovered in the Cenomanian-age Echkar Formation. Rugopsis believed to be an abelisaurid, and is related to Majungasaurus.

‘Jurassic World’ Easter Eggs: 8 Hidden References To The ‘Jurassic Park’ Movies

Friday, March 24, 2017

Nedry’s Plan Goes Awry

Keep your eyes peeled in “Jurassic World” for these eight hidden references to the 1993 first movie:

1. That Music 
If you grew up with “Jurassic Park,” that inspirational John Williams score will bring back all the warm memories of the original. “Jurassic World” does the unforgettable theme justice and includes it in the movie several times, including the closing credits. Here, you can see Williams conducting the Boston Pops in the famous tune.

2. Jurassic Park Merchandise 
Lowry (Jake Johnson) is a Jurassic World employee with a morbid love of the park’s dark past. On the day everything goes awry, he is reprimanded by Claire (Bryce Dallas Howard) for wearing a Jurassic Park T-shirt to work.

A Jurassic Park board game (which has beautiful box art, by the way)

3. DNA Mascot 
Mr. DNA also makes a comeback as a mascot for safety and the cloning process in “Jurassic World.” Just as he did in 1993’s “Jurassic Park,” Mr. DNA can be found on the “Jurassic World” website explaining what the scientists do to create the dinosaurs for the park.

Jurassic Park – Mr. DNA Sequence

4. Abandoned Jurassic Park Building
When the two young boys, Grey (Ty Simpkins) and Zach (Nick Robinson), of “Jurassic World” veer off course and right into the path of Indominus Rex, they seek shelter in an abandoned building, which many will recognize as the old hub of Jurassic Park. Using the banner that falls at the end of “Jurassic Park” as a torch, the pair discover the painted walls of the original park building like abandoned cave paintings. Easter eggs abound in this scene.

5. Old School Wheels 
In their search for a way back to the civilized part of the island, the two boys find abandoned 1992 Jeep Wranglers from the original Jurassic Park. They manage a quick repair (the cars haven’t been started for more than 20 years) and it’s back to the temporary safety of Jurassic World.

Original Jurassic Park Jeep Front

6. Dilophosaurus! 
Remember when Nedry (“Seinfeld” actor Wayne Knight) tries to escape the park with dino DNA in “Jurassic Park”? This frilly fella shows up with poisonous spit and brings down the curtain for this bad guy.

Nedry’s Plan Goes Awry

7. InGen 
The cloning company founded by Dr. Hammond returns to the island after the death of its sitting CEO Simon Masrani (Irrfan Khan) in an effort to recapture its latest creation gone wild, Indominus Rex. Well, their return to the “Jurassic Park” series could have gone better (they’re never the heroes in the franchise). A bit more of an obscure Easter egg, but one that will be recognizable for fans of the franchise.

8. And T-Rex! 
From the iconic park logo to one of the final shots of Steven Spielberg’s 1993 movie, Tyrannosaurus Rex has been a major part of the “Jurassic” franchise. Its appearance in “Jurassic World” is the stuff of dinosaur fan fiction, but that didn’t stop the audience from cheering at the screening at an ending not too dissimilar from “Jurassic Park.”

Jurassic World ending – Trex roar footage

Sarcosuchus

Wednesday, March 22, 2017

Sarcosuchus by Frank Lode

Sarcosuchus (meaning “flesh crocodile”) is a genus of crocodyliform and distant relative of living crocodylians that lived 112 million years ago. It dates from the early Cretaceous Period of what is now Africa and South America and is one of the largest crocodile-like reptiles that ever lived. It was almost twice as long as the modern saltwater crocodile and weighed up to 8 tonnes.

S. imperator, Muséum national d’Histoire naturelle, Paris. Photo by Shadowgate

The first remains were discovered during several expeditions led by the French paleontologist Albert-Félix de Lapparent, spanning from 1946 to 1959, in the Sahara. These remains were fragments of the skull, vertebrae, teeth and scutes. In 1964, an almost complete skull was found in Niger by the French CEA, but it was not until 1997 and 2000 that most of its anatomy became known to science, when an expedition led by the American paleontologist Paul Sereno discovered six new specimens, including one with about half the skeleton intact and most of the spine.

Sarcosuchus was a giant relative of crocodiles, with fully grown individuals estimated to have reached up to 11–12 m (36–39 ft) in total length and 8 tonnes (8.8 short tons) in weight. It had somewhat telescoped eyes and a long snout comprising 75% of the length of the skull. There were 35 teeth in each side of the upper jaw, while in the lower jaw there were 31 teeth in each side. The upper jaw was also noticeably longer than the lower one leaving a gap between them when the jaws were shut, creating an overbite. In young individuals the shape of the snout resembled that of the living gharial but in fully grown individuals it became considerably broader.

Some of the extinct crocs

Bulla

At the end of its snout, Sarcosuchus presented an expansion, known as a bulla, which has been compared to the ghara seen in gharials. However, unlike the ghara, which is only found in male gharial, the bulla is present in all Sarcosuchus skulls that have been found so far, suggesting that it was not a sexually dimorphic trait. The purpose of this structure remains enigmatic. Opinions from researchers range from it being an olfactory enhancer to being connected to a vocalization device.

The Snout of Sarcosuchus Ended in a “Bulla”. Photo by LadyofHats

Osteoderms

The osteoderms, also known as dermal scutes, of Sarcosuchus were similar to those goniopholodids like Sunosuchus and Goniopholis, they formed an uninterrupted surface that started in the posterior part of the neck up to the middle of the tail like is seen in Araripesuchus and other basal crocodyliforms, different from the pattern seen in living crocodiles, which present discontinuity between the osteoderms of the neck and body.

Scutes of S. imperator. Photo by Ghedoghedo

Size

A common method to estimate the size of crocodiles and crocodile-like reptiles is the use of the length of the skull measured in the midline from the tip of the snout to the back of the skull table, since in living crocodilians there is a strong correlation between skull length and total body length in subadult and adult individuals irrespective of their sex, this method is preferred for Sarcosuchus due to the absence of a complete enough skeleton.

Sarcosuchus skull comparison

Two regression equations were used to estimate the size of S. imperator, they were created based on measurements gathered from 17 captive gharial individuals from northern India and from 28 wild saltwater crocodile individuals from northern Australia, both datasets supplemented by available measurements of individuals over 1.5 metres (4.9 ft) in length found in the literature. The largest known skull of S. imperator (the type specimen) is 1.6 m (5.2 ft) long, and it was estimated that the individual it belonged to had a total body length of 11.65 m (38.2 ft), its snout-vent length of 5.7 m (19 ft) was estimated using linear equations for the saltwater crocodile and in turn this measurement was used to estimate its body weight at 8 tonnes (8.8 short tons). This shows that Sarcosuchus was able to reach a maximum body size not only greater than previously estimated but also greater than that of the Miocene Rhamphosuchus, only the Late Cretaceous Deinosuchus and the Miocene Purussaurus may have achieved a comparable maximum body size.

Size commparison of a sarcosuchus to an argentinosaurus, BBC

Sarcosuchus is commonly classified as part of the clade Pholidosauridae, a group of crocodile-like reptiles (Crocodyliformes) related but outside Crocodylia (the clade containing living crocodiles, alligators and gharials). Within this group it is most closely related to the North American genus Terminonaris. Most members of Pholidosauridae had long, slender snouts and they all were aquatic, inhabiting several different environments, some forms are interpreted as marine, capable of tolerating saltwater while others, like Sarcosuchus, were freshwater forms, the most primitive members of the clade, however, were found in coastal settings, zones of mixing of freshwater and marine waters. Sarcosuchus stands out among pholidosaurids for being considered a generalist predator, different from most known members of the clade which were specialized piscivores

Habitat

The remains of S. imperator were found in a region of the Ténéré Desert named Gadoufaoua, more specifically in the Elrhaz Formation of the Tegama Group, dating from the late Aptian to the early Albian of the Early Cretaceous, approximately 112 million years ago. The stratigraphy of the region and the aquatic fauna that was found therein indicates that it was an inland fluvial environment, entirely freshwater in nature with a humid tropical climate. S. imperator shared the waters with the holostean fish Lepidotus and the coelacanth Mawsonia. The dinosaur fauna was represented by the iguanodontian Lurdusaurus, which was the most common dinosaur in the region, and its relative Ouranosaurus; there were also two sauropods, Nigersaurus and a currently unnamed sauropod while the theropod fauna included the spinosaurid Suchomimus, the carcharodontosaurid Eocarcharia and the abelisaurid Kryptops.

Sarcosuchus imperator vs Suchomimus by Raúl Martín

Meanwhile, S. hartti was found in the Reconcavo basin of Brazil, specifically in the Ilhas Formation of the Bahia series, it was a shallow lacustrine environment dating from the late Aptian, similar in age to the habitat of S. imperator, with similar aquatic fauna, including Lepidotus and two species of Mawsonia. The dinosaur fauna is of a very fragmentary nature and identification does not go beyond indeterminate theropod and iguanodontid remains.

Source: www.Wikipedia.org

Deinocheirus

Wednesday, March 22, 2017

Deinocheirus

Deinocheirus is a genus of large ornithomimosaur that lived during the Late Cretaceous around 70 million years ago. In 1965, a pair of large arms, shoulder girdles, and a few other bones of a new dinosaur were first discovered in the Nemegt Formation of Mongolia. In 1970, this specimen became the holotype of the only species within the genus, Deinocheirus mirificus; the genus name is Greek for “horrible hand”. No further remains were discovered for almost fifty years, and its nature remained a mystery. Two more complete specimens were described in 2014, which shed light on many aspects of the animal. Parts of these new specimens had been looted from Mongolia some years before, but were repatriated in 2014.

Deinocheirus size compared to a human by Matt Martyniuk

Deinocheirus was one of the most mysterious dinosaurs to have ever been found by paleontologists. It was originally found in 1965 in Southern Mongolia—actually, not the whole dinosaur was found but only its gigantic hands. And for the next 50 years, that is all that scientists would have of this elusive dinosaur. That is probably why its name means “terrible hand”.

Deinocheirus mirificus.  a, MPC-D 100/127. b, MPC-D 100/128. c, Composite reconstruction of MPC-D 100/127 with a simple proportional enlargement of MPC-D 100/128. Scale bar, 1 m. The human outline is 1.7 m tall.

When Deinocheirus was only known from the original forelimbs, its taxonomic relationship was difficult to determine, and several hypotheses were proposed. Osmólska and Roniewicz initially concluded that Deinocheirus did not belong in any already named theropod family, so they created a new, monotypic family Deinocheiridae, placed in the infraorder Carnosauria. This was due to the large size and thick-walled limb bones, but they also found some similarities with Ornithomimus, and, to a lesser extent, Allosaurus. In 1971, John Ostrom first proposed that Deinocheirus belonged with the Ornithomimosauria, while noting that it contained both ornithomimosaurian and non-ornithomimosaurian characters. In 1976, Rhinchen Barsbold named the order Deinocheirosauria, which was to include the supposedly related genera Deinocheirus and Therizinosaurus. A relationship between Deinocheirus and the long-armed therizinosaurs was supported by some later writers, but they are not considered to be closely related today.

Deinocheirus compared by Prehistoric Wildlife

Deinocheirus was around 30 feet long, almost 15 feet high and weighed about 6 tons. It was a bipedal dinosaur—from a species called Ornithomimids, which are sometimes called ‘ostrich dinosaurs’ and was the biggest of these dinosaurs. However, it probably didn’t move like an ostrich. Due to its large size and weight, it more than likely lumbered along and didn’t run very quickly. I

It is believed that this dinosaur was a scavenger of sorts. It is believed to have eaten a variety of different things such as fish, invertebrates, plants and maybe even insects. It probably didn’t hunt prey like a predator. However, an interesting fact about this dinosaur is that it was probably frequently hunted by tyrannosaurus dinosaurs, as bite marks on its skeleton would suggest.

Deinocheirus hands: Holotype specimen MPC-D 100/18 on exhibit in Barcelona. Photo by Jordi Payà

Source: www.Wikipedia.org, www.NatGeo.com

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