Dinosaur Articles 1999


Baby Tyrannosaurus Rex discovered

The pelvic bone of the skeleton pokes through

December 1, 1999 - BBC

A gangly, 500 kilogram baby with massive bone-crushing teeth has been discovered in South Dakota, the first almost complete fossil skeleton of a juvenile Tyrannosaurus rex.

Mr Bakker estimates the skeleton could be up to 90% complete. It was found last year by a team led by a private Houston palaeontologist, Mike Harrell, who died recently.

Mr Bakker believes the dinosaur died about 66 million years ago. The animal probably weighed about a quarter "as much as Dad," he said. This would be between 550 and 680 kilograms (1,200 to 1,500 pounds) and it measured about seven metres from the tip of its tail to the snout.

It is clearly a juvenile because of some unfused backbone vertebrae, he said. The specimen shows that juvenile T. rex was "quite gangly, particularly long in the shin and ankle".

But "the jaws are 100% adult," armed with "massive bone-crushing teeth." That suggests it ate an adult diet, even though it does not appear strong enough to wrestle large prey to the ground said Mr Bakker. It appears that its parents would have captured the baby's prey.

Until now, scientists had never found a complete "or even a good skeleton" of a juvenile T. rex. But tyrannosaur expert Thomas Holtz, of the University of Maryland, noted that fairly complete skeletons have been found for juveniles of other tyrannosaurs.

Nonetheless, Dr Holtz said the find "would indeed be a big deal."

The finding will help scientists understand the life cycle of the enormous dinosaur, such as its growth patterns.

The dinosaur is still encased in rock but is now at a laboratory, where its bones are being painstakingly exposed. Ron Frithiof who owns the lab is an amateur fossil-hunter and a rancher near San Antonio and was a part of the team that unearthed the baby T. rex.


'Striking' dinosaurs found in Sahara

Jobaria: Long-necked and broad-toothed

Two new dinosaur species have been discovered. The creatures are both sauropods - the group of giant plant-eaters that includes the well-known Diplodocus and Brachiosaurus.

One of the newly-discovered species, Jobaria tiguidensis, is a long-necked, broad-toothed creature that is "strikingly primitive" for a sauropod that appeared quite late - about 130 to 140 million years ago - in dinosaur history.

The team endured intense heat during the dig

November 11, 1999

An adult Jobaria would have weighed about 20 tonnes and grown to a length of 20 metres (65 feet).

University of Chicago palaeontologist Paul Sereno, whose team dug the creature out of the Sahara desert in the Republic of Niger, said the fossilised bones represent a particularly fine dinosaur specimen.

"With 95% of its skeleton preserved, the new species stands as the most complete long-necked dinosaur ever discovered from the Cretaceous period," he said.

Flash flood

Jobaria refers to "Jobar," a creature in the legends of the local Tuareg nomads; tiguidensis refers to a cliff near to where Paul Sereno and his colleagues made their discovery.

The desert we know today would not have existed in Jobaria's day - the animal would have populated an area covered by open forests and broad rivers.

An artist's impression of Jobaria

The team recovered a range of fossils from both juveniles and adults, which suggests Jobaria roamed in herds of mixed age. It looks as though the dinosaurs may have been caught in an ancient flash flood and buried quickly.

However, some may have died at the hands of the chief meat-eating dinosaur of the time, Afrovenator, an eight-metre (27-foot) long predator previously discovered in the same area by Sereno's team. Tooth marks are present on the ribs of one of the juvenile skeletons.

Ancient lineage

The team think Jobaria probably represents an ancient sauropod lineage that survived and flourished only in Africa during the Cretaceous.

Unlike other Cretaceous sauropods, Jobaria has spoon-shaped teeth - well adapted for nipping the smaller branches of trees - and a relatively short neck composed of only 12 vertebrae. Jobaria's backbone and tail are also simple, compared with the complex vertebrae and whiplash tail of the older North American sauropods Diplodocus and Apatosaurus.

The other dinosaur announced by the team is one of the smallest sauropods ever found, with a maximum body length of about 15 metres (49 ft). The dinosaur has been given the name Nigersaurus taqueti. Despite its relatively small overall size, it still had a big mouth with over 600 teeth and an unusual snout.

The team had to rely on a number of incomplete specimens to build up a picture of this creature.

The National Geographic Society has sponsored the dinosaur research which has been published in the journal Science. The society has made a full-size cast of an adult and a juvenile Jobaria for its Explorers Hall museum in Washington. The adult stands about 10-metres (32 ft) high.

An artist's impression of Jobaria


Biggest dinosaur identified

Diplodocus: Did the giant dinosaur have an even bigger cousin?

November 3, 1999 - AP

US palaeontologists believe they may have discovered the largest dinosaur ever to walk the Earth - it could have peered through a sixth-floor window with ease.

The colossal creature would have weighed 60 tonnes and stood 18 metres (60 feet) tall. This ground-shaking monster has been named Sauroposeidon, which means "earthquake god lizard".

The researchers from the University of Oklahoma think the Sauroposeidon had the longest neck in the fossil record.

Sauroposeidon towers over brachiosaurus which itself dwarfs man

"It's truly astonishing. It's arguably the largest creature ever to walk the earth," said Richard Cifelli.

Professor Cifelli led the team that examined bones unearthed in south-eastern Oklahoma in 1994. When they were first catalogued, he said he thought they might be the trunks of prehistoric trees.

But closer examination revealed that they belonged to a larger relative of the better-known Brachiosaurus, which could stretch its head up to 13.5 metres (45 feet). The diplodocus, often regarded as the biggest creature ever, reached 15m (50ft).

Each of the neck bones of the creature is about 120 centimetres (four feet) long.

"The neck on our creature is about a third longer than that of the Brachiosaurus," said team member Mathew Wedel. "It's a lot longer and a lot more specialised."

Like a giraffe - but bigger

Sauroposeidon was giraffe-like in shape, with a short body and long neck, but was 30 times larger than the largest giraffe ever known.

The massive load was made lighter by the bones being filled with tiny air cells, revealed by scanning the fossils at the university's hospital.

"No matter how small the dinosaur's brain was, just lifting it up was a challenge," Professor Cifelli said. "It's remarkable how large the bones are."

It would be very hard to imagine that a neck could get much longer and still function, he added.

"An old design"

"He's an old design. By this time, that body plan is just not working anymore. By the time this guy comes along, they are dying out in North America. He is pretty much the last of his kind."

Sauroposeidon lived about 110 million years ago. At that time, Sauroposeidon inhabited the delta of a massive river system. The Gulf of Mexico had swamped most of Texas, bringing the shoreline to Oklahoma.


New Dino Species Fill Gap

October 28, 1999 - ABC News

Four species of squat, plant-eating dinosaurs unearthed in Utah are filling a gap in the record of reptiles that roamed Earth 100 million to 120 million years ago.

The new dinosaurs - tank-like ankylosaurs and nodosaurs found at College of Eastern Utah digs - sport tough armor to protect them from predators like the utahraptor, a 7-foot-tall, 20-foot-long carnivore with 9-inch, razor-sharp claws.

"They had little, teeny, wedge-shaped heads and big, fat bodies like a short-legged cow with a crocodile tail," said paleontologist Don Burge, director of the CEU Prehistoric Museum in Price.

The dinosaurs, which were discovered over the last decade, were presented last week at the annual meeting of the Society for Vertebrate Paleontology.

Burge and CEU field party leader John Bird tried to show how the species differed from each other, with Burge comparing the presentation to a copyright or patent on the specimens. It gives them formal acceptance in the scientific community.

One of the new finds, Bilbeyhallorum, belongs to the family Ankylosauridae, which lacked spiny armor but had clublike tails.

The other three - Gastonia burgei, Animantarx ramaljonesi and an unnamed elephant-size dinosaur - had spiny armor but no tail clubs and belong to the family Nodosauridae.

The four species span a gap between the Jurassic Period, more than 147 million years ago, and the Late Cretaceous Period, about 70 million years ago.

Pelvic Bone Key to Gastonia

Gastonia burgei was found in the early 1990s by Rob Gaston, who uncovered a 2- to 3-foot-long bony plate from the dinosaur's pelvic area.

Other fossils were later uncovered by Gaston, Burge and Kirkland. To date, more than 1,300 remnants of the Gastonia burgei - named for Gaston and Burge - have been found.

"Gastonia is a marvelous creature," said Burge. "Imagine a horny toad blown up to 17 feet. He had shoulder spikes that resemble thorns on a rose but are over a foot long. On both sides of the tail and neck, it had rows of big plates that looked like the triangular dorsal fin on a great white shark. The tail could whip around and cut you bad."

In 1995, University of Utah radiation analyst Ramal Ray Jones, working with Burge and others, discovered the Animantarx ramaljonesi in Cedar Mountain rocks east of Castle Dale.

Rare Armadillo Cousin

The 12-foot-long dinosaur resembles an armadillo and has rowboat-shaped cups of armor. Fewer than 100 Animantarx fossils have been found.

The third dinosaur, tentatively named Bilbeyhallorum, was found two or three years ago by Vernal paleontologist Sue Anne Bilbey and her husband, Evan Hall, on a dig with Burge and Bird at a CEU quarry 20 miles southeast of Price.

It was reported to be 30 feet long, but Burge now believes it was 17 feet long. So far parts of a juvenile and two adults have been excavated.

The fourth, unnamed dinosaur was discovered in the same quarry last year by Bird and his crew.

"It's a monstrous thing," Burge said. He's as big as an elephant. The dinosaur weighed 4 to 5 tons and was 30 feet long. The armor looks like barnacles on a ship knobby things like on a crocodile head."


Fossil find in Italy gets to guts of dinosaur debate

Christian Science Monitor Service - January 23, 1999

110-million-year-old fossil from the south of Italy is giving scientists the fullest picture yet of why dinosaurs dominated animal life on Earth for eons.

For millions of years, predators like velociraptor and Tyrannosaurus rex ruled the Earth. Now, the Italian fossil - called a Rosetta stone of paleontology by some researchers - is yielding fresh insights into why the animals were such effective hunters. At the same time, the scientists responsible for one of the first detailed studies of the specimen say it throws doubt on a theory held by many paleontologists: that birds are the direct descendants of theropods such as velociraptors - the villains of "Jurassic Park."

"This is the most spectacular fossil ever found," says John Ruben, an Oregon State University zoologist who headed the U.S.-Italian team that examined the creature. Unlike most fossils, he explains, this one displays internal organs and even some muscle fibers, in addition to the creature's skeletal structure. Thus, he says, it's possible to study biological features that until now could only be inferred from bone structure.

The fossil was first reported last March in the journal Nature by Italian paleontologists Cristiano Dal Sasso and Marco Signore, who also took part in Ruben's study. It was discovered near Salerno, Italy, in the early 1980s by rockhound Giovanni Todesco, who thought the creature was a bird.

Years later, he saw the film "Jurassic Park." Its beaked velociraptors prompted him to take out his old find and give it a closer look. Suspecting it might be a small dinosaur, he turned it over to paleontologists, who immediately saw its significance. Indeed, the researchers say, the creature is similar to a velociraptor.

Last July, Oregon State's Ruben traveled to Salerno with graduate students Terry Jones and Nicholas Geist to examine the creature's fossilized internal organs to see what they would tell them about how it functioned. Their report appears in the latest edition of the journal Science.

One of the most striking features of the baby theropod, known as Scipionyx samniticus, was the body cavity's separation into two compartments - one for the heart and lungs, the other for the liver and digestive system.

Today, the researchers say, that kind of structure is seen only in animals that have active diaphragms to help move air into their lungs, such as mammals or crocodile-like reptiles.

Moreover, the placement of the lower organs and the structure of the pelvis suggested that S. samniticus's diaphragm was pumped with a piston-like motion similar to that of modern crocodilians.

With that kind of breathing apparatus, such dinosaurs were unlikely to be sluggish animals, according to Geist. Instead, he says, "what you have is a turbocharged reptile." Indeed, Ruben adds, the creature combined the best metabolic traits of cold-blooded animals and of warm-blooded animals. Like cold-blooded creatures, S. samniticus used very little energy when resting. But with the breathing mechanisms of warm-blooded creatures, it could use its reserves of stored energy to run down prey over fairly long distances.

Ruben says the dinosaur's metabolic traits were particularly well-suited to the climate of the times. Temperatures in that period were warmer than today, and there were little seasonal changes. Once the climate cooled and seasonal changes grew more extreme, S. samniticus would have had a difficult time adapting.

According to Ruben's team, the fossil's lungs and other features bear little resemblance to today's birds, leading the researchers to conclude that if birds did descend from dinosaurs, such ancestors would be unlike any known dinosaurs.

"My best guess is that, yes, there may be close relationships between birds and dinosaurs," Ruben says. But based on his study of S. samniticus, "we can't derive birds from any known theropods."

Yet others suggest that Ruben's conclusion fails to focus on the broader range of evidence supporting the link between birds and dinos we know. Birdlike features appear even in S. samniticus, they say - its breast bone, for example, or evidence of locations where birdlike air sacs invade the skeleton.

Rather than excluding known dinosaurs from the lineage of modern birds, S. samniticus may well represent one point in an evolutionary transition from piston-driven lung structures to a more birdlike breathing apparatus, says Jacques Gauthier, curator of the Peabody Museum of Natural History at Yale University.

"This is the beauty of the fossil record, to show us a world that no longer exists," he says. "It allows us to tease part traits and their sequence of acquisition."


Dinosaurs caught in their tracks

How a theropod would have left a deep track

Some dinosaurs moved their feet in much the same way as modern birds according to scientists who have studied 210-million-year-old fossilised footprints in Greenland.

The US researchers analysed the impressions preserved in the rock to model the operation of the creatures' lower limbs.

Their study, published in the journal Nature, will add to the debate about the evolution of birds and the idea that they are descended from theropods, the carnivorous dinosaurs that walked around on their hind legs.

The team from the Universities of Brown, Harvard and Pennsylvania even ran a turkey through wet soil to compare the marks left in mud by a modern ground-dwelling bird with those caught in the Greenlandic prints.

And although it did show up some significant differences in the position of the big toe, foot posture and leg movement, the scientists still believe in the evolutionary relationship between dinosaurs and birds.

"Living birds retain many features from their theropod ancestors, but hind limb anatomy and function did change," says lead scientist Stephen Gatesy, a Brown assistant professor of ecology and evolutionary biology. "Birds do not move exactly like 210-million-year-old dinosaurs, but they are the closest thing alive today."

Recorded in the Mud

The dinosaur tracks were found on exposed rock near the Fleming Fjords in eastern Greenland. When the therapods ran through this area it would have been more tropical than arctic and probably covered by a network of shallow lakes.

Where their feet landed on relatively firm ground, the therapods left three-toed impressions - the marks from joints and skin are clearly visible. Where the dinosaurs ran through sloppier muds, their feet sank deeper into the ground leaving behind unusually long, four-toed prints.

But whereas shallow prints reveal little about foot and leg movement, the deep "wounds" in the ground, the scientists realised, amounted to a three-dimensional recording of locomotor behaviour that could even tell them what the individual toes were doing.

In the tracks of both Triassic theropods and modern ground-dwelling birds, the foot plunges down and forward into the muck. The toes then collapse and come together as the foot is lifted up and forward.

Turkey experiment

Gatsey and his colleagues checked the comparison by running a modern turkey through sloppy mud and looking at its tracks.

"At first it was just a way of working out what was going on," Stephen Gatesy told BBC News Online. "Once we learned more, then it was obvious we could look for the subtleties of what is similar and what is different. We sent the turkey through various depths and various consistencies to see how the substrate properties might be affecting the tracks."

The study threw up several inconsistencies between birds and dinosaurs. The first toe - like our "big" toe - is reversed in most birds, allowing the foot to perch or grasp prey.

The deep Triassic prints bear an impression of the first toe that also points backwards, suggesting the existence of an as yet undiscovered theropod that could also perch.

However, the new research shows the backward pointing imprint is just an illusion created by the motion of the foot and the folding of the mud.

"The first toe doesn't have to be reversed, which is the way it would be if you read the print literally," Stephen Gatesy says. "We've learnt that the footprint can, in some ways, be deceiving - it can look more like a bird print than it actually should."

This revelation means an opposable first toe is likely to have evolved much later in history.

The study also suggests the theropods moved their hind legs about the hip, as in alligators. In contrast, walking birds primarily move by bending their knees, which raises the sole of the foot before it can leave a print.





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