September 5, 2014

Paleontologists have unearthed fossils in the Patagonian Desert in Argentina that represent the most complete giant dinosaur ever discovered, the journal Scientific Reports announced today. According to Kenneth Lacovara of Drexel University in Philadelphia, his team has uncovered 70 percent of the key bones needed to fully describe the creature, one of a group of dinosaurs known as sauropods. Sauropods were immense, long-necked, plant-eating dinos that were the most massive beasts ever to roam the surface of Earth. The scientists estimate that the newly found sauropod measured 85 feet (26 meters) in length and weighed approximately 60 tons (54 metric tons).

Seismosaurus, the huge sauropod depicted in this illustration, was one of the largest dinosaurs that ever lived. Scientists believe it measured about 150 feet (45 meters) in length. The giant fossil Dreadnoughtus recently found in Argentina may not have been as large as Seismosaurus. But, the recently found skeleton of Dreadnoughtus is the most complete ever discovered for the sauropods, and it will allow scientists to learn much about how these giant dinosaurs moved and lived. ( World Book illustrations by Tim Hayward, Bernard Thornton Artists)

Lacovara and his team named the 77-million-year-old fossil Dreadnoughtus schrani after the massive battleships introduced at the turn of the last century. “Dreadnoughtus was huge, and in its environment there would have been nothing that could have preyed on it; it was essentially impervious to attack,” explained Lacovara. “And that evoked in my mind those turn-of-the-last-century battleships—the first really big steel battleships—that were also impervious to attack from the other ships that existed at that time. So, what better name than ‘dread nought’—’fears nothing’.”

The Dreadnought battleship was introduced by the British Navy in 1906. The first modern battleship, the Dreadnought was more powerfully armed and more heavily armored than any earlier warship.  On the seas, it “feared nothing.” (World Book illustrations by George Suyeoka)

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May 19, 2014

Fossils from a massive dinosaur that was longer than two tractor-trailer trucks parked end-to-end and weighed more than 14 African elephants have been unearthed in the Patagonia region of Argentina. The 95-million-year-old fossils were found near La Fletcha, about 800 miles (1,300 kilometers) south of Buenos Aires, the capital. The yet-unnamed dinosaur may have been the biggest of the big–a new species of titanosaurus, the largest of the gigantic, long-necked dinosaurs called sauropods.

Sauropods walked on four stout, strong legs, much like those of an elephant. Nearly all sauropods had a long neck, a small head, a long tail, and a huge, deep chest and stomach region. Sauropods were the largest plant-eaters, feeding on the leaves of tall shrubs and of such trees as conifers. During the Cretaceous Period, they declined in importance in the Northern Hemisphere. But they remained the dominant plant-eaters in what are now South America, India, and Africa. Other supersized saurpods include Seismosaurus and Supersaurus.

A new sauropod discovered in Argentina may have been larger than Supersaurus (above), one of the largest dinosaurs to ever walk on Earth. (World Book illustration by John Francis, Bernard Thornton Artists)

The newly discovered sauropod was an estimated 130 feet (40 meters) long, weighed 88 short tons (80 metric tons), and stood 65 feet (20 meters) tall at the hips.  (By way of comparison, Tyrannosaurus rex was about 40 feet (12 meters) long, weighed about 7 short tons (6.3 metric tons), and stood about 12 feet (3.7 meters) high at the hips.)

The Argentine and Spanish paleontologists who excavated the fossils based their estimates of its gargantuan size on the largest of the thigh bones found. About 150 bones from at least seven individual dinosaurs have been found at the site. They include 10 vertebrae (bones of the spine) from the torso, 40 vertebrae from the tail, parts of the neck, and complete legs. Scientists cannot yet say with certainty that the newly discovered sauropod is the largest dinosaur–and, therefore, the largest animal–to ever walk Earth. Fossil skeletons from sauropods are generally incomplete. In addition, sauropod tails, which accounted for much of the dinosaurs’ length, are particularly rare.

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• Paleontology (2003) (a Back in Time article)
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February 13, 2014

The discovery of a site in Canada containing hundreds of ancient fossils is being heralded as one of the most important discoveries in paleontology in the past 100 years. The huge fossil site, located in Marble Canyon in Kootenay National Park in southeastern British Columbia, contains hundreds of magnificently preserved fossils of early animals from the Cambrian, a period in Earth’s history that lasted from about 543 million to 490 million years ago. So far, scientists have found the fossils of more than 50 invertebrate (animals without backbones) species, about a dozen of which have never been seen before. The site rivals the famous Burgess Shale formation, a 505 million-year-old site discovered in 1909 in Yoho National Park about 26 miles (42 kilometers) northwest of Marble Canyon. For now, the exact location of the fossil deposit is being kept secret to protect the delicate fossils from collectors. The Marble Canyon site was discovered in 2012 by scientists fromt the Royal Ontario Museum, the Universities of Toronto and Saskatchewan in Canada, Pomona College in California, and Uppsala University in Sweden.

During the Cambrian Period, the region lay at the bottom of a shallow ocean. Fine-grained mud that accumulated over time preserved in exquisite detail the soft-bodied invertebrates that lived and died in this ocean over millions of years, giving paleontologists an excellent view of their anatomy. Many of the animals can be identified as types of worms and arthropods (animals with jointed legs). Among them are trilobites, an extinct group of arthropods related to modern crabs and lobsters. Some of the fossil animals appear similar to invertebrates alive today, while other are unique and are new to science.

A mold preserved the three-dimensional form of a trilobite after its body decayed. ((c) Sinclair Stammers, Science Photo Library; Photo Researchers)

The Cambrian Period was an important time in the history of life on Earth. Many major types of animals first appear in fossils from the early Cambrian Period. Scientists often refer to this sudden, dramatic increase in the variety of animal fossils as the Cambrian Explosion. During the Cambrian Explosion, animals evolved (developed gradually) into many new forms and spread throughout Earth’s oceans. They also began interacting with one another and their environment in more complex ways. Animals began eating other animals, growing skeletons for protection, and burrowing into sea-floor sediments for food and shelter.

The fossils unearthed from the Marble Canyon site will help researchers better understand the conditions of the marine ecosystem that spurred the rapid diversification of animal forms during the Cambrian Period. For example, some of the invertebrate species found at Marble Canyon are also known from fossil sites in Asia about the same age. This indicates that some species had spread throughout the world, while others may have been limited to particular habitats.

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May 30, 2013

A newly described 160 million-year-old fossil from China is now the leading contender for the title of the world’s earliest bird. The fossil, given the scientific name Aurornis xui (meaning dawn bird), was described in the online edition of the journal Nature by a team led by paleontologist Pascal Godefroit of the Royal Belgian Institute of Natural Sciences in Brussels, Belgium. The scientists claim not only that Aurornis is the world’s oldest bird, but also that their discovery ends the debate about whether another famous fossil, the feathered Archaeopteryx, shared a perch on the bird family tree.

The remains of feathers and birdlike wings are clearly visible in the fossil of Archaeopteryx. This animal had a crow-sized body and lived about 150 million years ago, near the end of the Jurassic Period. (© Sally A. Morgan, Ecoscene/Corbis)

The nearly complete Aurornis fossil, encased in sedimentary (layered) rock, was unearthed by a farmer in the Liaoning Province of northeastern China some time ago. A local fossil dealer sold the specimen to the nearby Yizhou Fossil and Geology Park museum, where it was stored. In 2012, Godefroit and his team examine the specimen. They were able to confirm that the fossil came from the Tiaojishan Formation, a region famous for having produced many fossils of feathered dinosaurs and early birds. They dated the sedimentary rock that encased the fossil to about 160 million years ago. Clear impressions of downy feathers along the tail, arms, legs, neck, and chest of Aurornis suggested the creature was capable of gliding but lacked larger feathers necessary for true flight.

During the Jurassic Period, from about 200 million to 145 million years ago, some meat-eating dinosaurs began evolving birdlike skeletons and sprouting feathers on their bodies. One group of these creatures eventually split off to become birds, although researchers have long debated which one it was and when it actually happened.

Godefroit and his team compared almost 1,000 anatomical features of Aurornis with those of about 100 other dinosaurs and birds. These comparisons allowed them to construct a computer-generated cladogram, a kind of family tree illustrating how the species are related to one another. The resulting cladogram placed Aurornis at the very base of the family tree of modern birds. Combined with the early date for this fossil, the analysis makes Aurornis the oldest known bird by a margin of about 10 million years.

Scientists have long regarded Archaeopteryx, a feathered animal that lived about 150 million years ago near the end of the Jurassic Period, as the oldest example of a bird in the fossil record. First discovered in the Solnhofen limestone beds in Bavaria, Germany, in 1861, this crow-sized creature had a skeleton closely resembling that of a small dinosaur. However, it also had fully developed feathers and birdlike wings. As a result, Archaeopteryx has traditionally been classified as a bird. However, some paleontologists disagree with that conclusion. They argue that Archaeopteryx and similar fossils belonged to a side branch of feathered dinosaurs that separated from the main line leading to birds. However, this new analysis of Aurornis places Archaeopteryx firmly back on the bird line.

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April 5, 2012

Scientists announced the discovery of fossils of a large feathered dinosaur in China on April 4. The dinosaur is far larger than other feathered dinosaurs scientists have discovered in recent years. Paleontologists at the Chinese Academy of Sciences in Beijing, the capital, have named the new species Yutyrannus huali–”beautiful feathered tyrant”–because it is similar in size and shape to Tyrannosaurus rex. The Yutyrannus huali was 29 feet (9 meters) long and weighed more than 3,000 pounds (1,400 kilograms).

Three complete specimens–dating from the early Cretaceous Period, 125 million years ago–were found in a small quarry in Liaoning Province in northeast China. They were discovered alongside the fossilized remains of a sauropod, which suggests that they may have been stalking the sauropod when all four were killed. This led the scientists to theorize that Yutyrannus huali may have hunted in packs.

The dinosaur was too large to fly, and its feathers were hairlike filaments rather than flight feathers. The feathers probably served as insulation to keep the dinosaur warm.

“To have a complete skeleton with all the beautiful feathers preserved is a big discovery,” noted Professor Xu Xing, the lead author of the study.

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