Monday, September 24, 2012

Flight Dynamics of Giant Pterosaurs Explained

Researchers Propose that Quetzalcoatlus Used Cretaceous Runways to Take Off and Land

Scientists from the Museum of Texas Tech University have used computer modelling to assess how the last of the Pterosaurs (flying reptiles) took to the air. Pterosaurs, evolved during the Triassic and they went onto dominate the skies for much of the Mesozoic, until the emergence of the Aves (birds). The very last types of flying reptile were giants, creatures like Hatzegopteryx thambema from Europe and Quetzalcoatlus northropi whose fossils have been found in the Big Bend National Park of Texas. These Pterosaurs were members of the Azhdarchidae and some of these animals were the largest flying creatures known to science with wingspans in excess of ten metres reported. Quetzalcoatlus, for example, had a wingspan greater than that of an American F-16 jet fighter. Seeing this huge animal, many times bigger than the largest birds today, soaring overhead would have been a truly memorable sight. However, how such large and heavy creatures took to the air has puzzled palaeontologists ever since the first fossils of these giant Pterosaurs were discovered.

Creating a Model of Flying Reptile Flight

One University of Texas academic, Sankar Chatterjee (Horn Professor of Geosciences and Curator of the Palaeontology Department at the University's Museum), has suggested that these enormous creatures needed down-sloping runways to enable them to take off. The scientist presented a paper detailing his work on the aerodynamics of Azhdarchidae Pterosaurs at the recent annual meeting of the Geological Society of America in Charlotte (North Carolina).

After a careful, three-dimensional study of Azhdarchid fossils, Professor Chatterjee and his colleagues developed a computer simulation that showed how such an ungainly looking animal would have used a run up in order to gain momentum before finally being able to achieve lift off. Landing would also have been very tricky for these animals, which some palaeontologists estimate may have weighed more than two hundred kilogrammes. When coming into land, the large wings would have acted like giant air brakes, and the Pterosaur would effectively "stall" before touchdown with its hind legs contacting the ground first and then the front of the body and the large head would pitch forward and a quadrupedal stance would be adopted as the flying reptile came to a halt.

Commenting on his research, Professor Chatterjee stated that Azhdarchid Pterosaurs had a similar lifestyle to the modern-day frigate bird or albatross. They could spend a long time in the air with the minimum of effort. However, when it comes to landing and taking off, Pterosaurs would have been very awkward and ungainly. Launching from a cliff top would have been ideal, but where fossils of the Quetzalcoatlus have been found in Texas, these represent non-marine sediments, there were no sea cliffs for these creatures to use. To become airborne a Quetzalcoatlus would have to find a sloping area such as a river bank, a downward slope of just ten degrees would have been adequate. By running, first on all fours and then on two legs, speed could be built up and enough momentum generated to take off. These Pterosaurs needed plenty of room, they needed an area to taxi.

Did Flying Reptiles "Vault" into the Air?

In 2010, a study published in the open access and on line journal "Public Library of Science" proposed that the largest of the Pterosaurs launched themselves into the air by using their strong leg and arm muscles to "vault" upwards. This work was conducted by researchers based at the University of Portsmouth (England). Professor Chatterjee and his colleagues do not agree with these earlier findings. They postulate that such a method of taking to the air may be proven in small bats, but when it comes to a two hundred kilogramme Pterosaur with a wingspan in excess of ten metres; this method of becoming airborne is simply not viable.

Relying on Thermals to Stay Aloft

The Texas based team report that once animals got to a certain size they would not have had the strength and power required to vault into the air. They contend that the only way these large flying reptiles could get airborne would be by taking a long run up, preferably into the wind along a downward sloping bank or similar stretch of ground. Starting on all fours, the animal would quickly switch to a bipedal stance and build up running speed, then just like a modern-day hang glider, it would launch itself into the air, pick up a thermal and rapidly gain height.

Reaching Air Speeds of Over Thirty-Five Miles per Hour

The computer model suggests that these animals could not beat their wings very rapidly. With a high-aspect-ratio wing, similar to that observed today with modern petrels and albatrosses, the Azhdarchid Pterosaurs would rely on thermals and air currents to keep them aloft with the minimum of effort. The animals would have been vulnerable and ungainly on the ground but once in the air they could soar for hours. Professor Chatterjee and his team have suggested that such creatures could attain air speeds in excess of 36 mph (58 kmh).

These enormous creatures, some of which stood taller than a giraffe, were aerial masters, the very last of their kind. Pterosaurs died out at the end of the Cretaceous some sixty-five million years ago. All we have now are their amazing fossils that can be studied so that we can understand how these creatures were able to fly.

Everything Dinosaur is a company run by parents, teachers and real dinosaur experts. It specialises in developing educational dinosaur toys, models, clothing and games and strives to help young people learn more about science through their fascination with prehistoric animals. Many of the items featured on the Everything Dinosaur website Everything Dinosaur have been designed and tested by the teachers and real dinosaur experts in the company.

Our aim is to help young people learn more about Earth sciences through their fascination with dinosaurs and other prehistoric animals. Team members are happy to provide advice and support supplying free quizzes, drawing materials, puzzles, games even recipes for dinosaur themed biscuits and birthday cakes. With something like 900 products on line including dinosaur party supplies, Everything Dinosaur has built up a strong reputation assisting parents, guardians and fellow teachers, helping young people to learn more about science through creative play.

Monday, September 17, 2012

Predator/Prey Relationships in Miocene Spain

Joint American and Spanish Team Study Teeth to find out what Sabre-Toothed Cats Ate

A ratio of Carbon 12 to Carbon 13 isotopes preserved in the fossilised teeth of apex predators and herbivores that lived over nine million years ago has provided a joint American and Spanish research team with an insight into how food chains worked in the latter part of the Miocene epoch. The study, the academic paper having been published in the scientific journal "The Proceedings of the Royal Society of Biology", focused on the diets of the top, predatory mammals and attempted to establish how large carnivores such as Sabre-Toothed Cats and Bear Dogs (Amphicyonids) were able to live in the same habitats without necessarily competing for the same food resources.

Miocene Fossil Locations of Central Spain

Palaeontologists from the Museo Nacional de Ciencias Naturales (Madrid) and the University of Michigan (United States) studied the fossilised teeth of specimens of animals that had been found at a number of fossil dig sites at Cerro de los Batallones, just 25 miles south-west of Madrid. A substantial number of vertebrate skeletons have been discovered in this area, two dig sites are particularly rich in predator fossil bones. Scientists suspect these sites represent "natural predator traps", a herbivore may have become stuck fast in mud and this then attracted a number of carnivores and scavengers to the location hoping to feed on the hapless plant-eater. The meat-eaters soon became stuck too, and the rising pile of corpses would have attracted more and more predators, thus the number of carnivore fossil specimens found at such sites are far in excess of the number of herbivore fossil specimens found. Fossils found include those of hyenas, martens and skunks.

Two Types Sabre-Toothed Cat Studied

The researchers studied two species of Sabre-Tooth Cat, Promegantereon ogygia, about the size of an African Leopard (Panthero pardus pardus) and the much larger and heavier Machairodus aphanistus, which was about the size of an extant African Lion (Panthero leo). It is quite common to hear people describe Sabre-Toothed Cats as "Sabre-Toothed Tigers", this is an inaccurate description, as although Sabre-Tooths do belong to the same taxonomic family as today's "Big Cats" - Felidae, Sabre-Tooth Cats are not closely related to Tigers.

The Fearsome Bear Dogs

The other type of apex predator the research team studied was the Bear Dog known as Magericyon anceps. Bear Dogs are neither Bears or Dogs but seem to be distantly related to both types of carnivore, sharing a common Vulpavine ancestor. M. anceps was a particularly large and powerful example of the Mid to Late Miocene Bear Dogs, large specimens could weigh over 200 kilogrammes and would have stood over a metre high at the shoulder.

Apex Predators Co-existing

The study of the tooth isotopes revealed that the Sabre-Toothed Cats shared the same woodland habitat. The smaller Sabre-Tooth Cat species probably used the abundant cover to avoid encounters with M. aphanistus. Sabre-Toothed Cats have a different build when compared to modern cats. They are not built for speed but have immensely strong front legs and shoulders. Scientists have speculated that Sabre-Toothed Cats specialised in being ambush predators rather than pursuit predators, chasing after their prey. The woodland habitat would have been ideal for ambushing herbivores.

Sabre-Toothed Cats - Likely Ambush Hunters

Both species of Sabre-Toothed Cat showed no statistical differences in the ratio of Carbon 12 to Carbon 13 in their teeth samples. This means that they probably fed on similar prey animals that lived in the woodlands, but their body sizes probably meant that they targeted different sized prey. They may also have avoided direct competition by hunting at different times of the day. It has been speculated that Promegantereon ogygia may have hunted after dusk, or spent more time in the trees, so as to avoid the attentions of larger types of Sabre-Tooth Cat in the area. It seems that the members of the Machairodontinae living in the area that was to become central Spain preferred to eat primitive horses, animals that were not yet the highly efficient runners seen on race tracks today.

Bear Dogs "Top Dog" on the Open Plains

The tests on the Bear Dog teeth showed a different ratio, indicating that a different type of prey was preferred by these carnivores. The Bear Dogs hunted animals that lived in more open, grassland habitats, they seem to have been better suited to pursuit predation, tackling herbivores that lived in open areas such as antelopes.

It seems that nine million years ago, a number of mammalian apex predators were able to co-exist in this part of Europe as they seem to have specialised in hunting different types of prey animal.

Providing an Insight into an Ancient Miocene Ecosystem

Commenting on the study one of the researchers stated that such investigations using isotope analysis of fossil teeth provided an insight into the diets of long extinct creatures. This in turn gave the palaeontologists an understanding of an ancient, long extinct ecosystem.

Everything Dinosaur is a company run by parents, teachers and real dinosaur experts. It specialises in developing educational dinosaur toys, models, clothing and games and strives to help young people learn more about science through their fascination with prehistoric animals. Many of the items featured on the Everything Dinosaur website Everything Dinosaur have been designed and tested by the teachers and real dinosaur experts in the company.

To learn more about the products and services we offer at Everything Dinosaur click on our website links.

Our aim is to help young people learn more about Earth sciences through their fascination with dinosaurs and other prehistoric animals. Team members are happy to provide advice and support supplying free quizzes, drawing materials, puzzles, games even recipes for dinosaur themed biscuits and birthday cakes. With something like 900 products on line including dinosaur party supplies, Everything Dinosaur has built up a strong reputation assisting parents, guardians and fellow teachers, helping young people to learn more about science through creative play.

Monday, September 10, 2012

New Super Predator from Africa - Sauroniops pachytholus

Sauroniops pachytholus - Palaeontologists turn to Tolkien to Name a New Dinosaur

A new super-sized meat-eating dinosaur has been named by a team of scientists after the evil Eye of Sauron from the Lord of the Rings books written by J. R. R. Tolkien. The inspiration for naming a new genus of organism can come from many things, but since this new predatory dinosaur is only known from a fragment of skull bone that was positioned directly above the eye socket (orbit) the name Sauroniops pachytholus seems entirely appropriate. The name means "thick domed eye of Sauron", in reference to the bump and thickened portion of the skull fragment studied.

The Kem Kem Formation of Morocco and Algeria represents a series of strata laid down in the Cretaceous (Albian to Cenomanian faunal stages), approximately 95 to 100 million years ago. The majority of the deposits represent an inter-tidal, estuarine environment, with wide lagoons, and broad, flat flood plains crossed by many rivers further inland. The environment supported and extensive and diverse flora and fauna, so rich in fact that this area probably supported the largest number of apex predators in any known Mesozoic habitat. A number of meat-eating dinosaurs have been associated with the Kem Kem Formation, most named from fragmentary fossil material just like Sauroniops. The list of predators reads like a "who's who" of Theropod dinosaurs - Carcharodontosaurus, Deltadromeus, Spinosaurus, Rugops and now the 13 metre long Sauroniops joins their ranks.

A Range of Theropods in the Fossil Record of Morocco

Palaeontologists had long suspected that there were other Theropod dinosaurs awaiting discovery from the sedimentary rocks of this region. The strata from south-west Morocco for example, had yielded a large number of fossilised Theropod teeth, these had yet to be assigned to any particular genus. One of the problems with the strata in this part of the world is that the fossils found within them are extremely fragmentary in nature. The action of river water and the tides has jumbled up and dis-articulated any fossil bones and teeth that have survived, the fossiliferous deposits have been described by palaeontologists as if all the fossils had been put into a blender, the blender turned on and the resulting mix re-deposited.

Identifying the New Dinosauria Genus

The age of the fossil bearing rocks of south-eastern Morocco is disputed, in the case of this new dinosaur genus, the exact age of the fossils appertaining to Sauroniops is further complicated as it is difficult to pinpoint exactly where this fossil material was found. A private collector purchased the fossil bone from a local fossil trader in Morocco, the trader stated that the fossil was purchased himself from local fossil hunters near to the small village of Taouz, which itself is located in a mountainous region close to the border with Algeria. The private collector later donated this specimen to a Museum located at Montevarchi in central Italy (Tuscany).

Small Piece of Skull Bone to Study

With just an isolated fragment of skull material measuring 18.5 centimetres in length to work with, a team of Italian scientists compared the shape and structure of this part of the skull (left frontal bone) with those of other meat-eating dinosaurs known from the Kem Kem Formation and concluded that this fragment (assigned the identification code of MPM 2594) was indeed attributable to a new type of carnivorous dinosaur. An academic paper has just been published in the scientific journal Acta Palaeontologica Polonica, some five years after the fossil was acquired by the private collector.

The "Eye of Sauron"

Based on comparisons with the skulls of other Theropods, the palaeontologists have estimated that Sauroniops may have been up to thirteen metres in length, establishing "the eye of Sauron" as one of the apex predators known from this part of the world. One of the lead authors of the scientific paper, Andrea Cau commented that with the frontal bone to study, the only part of this dinosaur known, it seemed appropriate to name the fearsome creature after the evil eye of Sauron from the J. R. R. Tolkien novels.

Given the paucity of the fossil material, it is extremely difficult to assign any further characteristics to this new dinosaur species, however, S. pachytholus has been tentatively assigned to the Carcharodontosauridae and placed close to Eocarcharia, which itself has been described from a maxilla and a parietal bone (skull bones found in the Sahara).

Evidence of Intra-specific Contests Amongst Theropods

The bump and raised portion of the skull has been seen in other Carcharodontids as well as Abelisaurids. The scientists have speculated that these animals had crests over their eyes which indicated that they were mature, breeding adults. These bumps and crests may have been brightly coloured and acted as signalling devices in non-verbal communication between members of the same species. It has even been suggested that these thickened portions of the skull evolved as a result of intra-specific competition. Animals of the same species competing with each other to win mates, social status, fight over the carcases of other dinosaurs and so on. Perhaps the Carcharodontids and their relatives were "head bumpers".

A Number of Predatory Dinosaurs in the Area

The palaeontologists have concluded that the environment in this part of north Africa during the Cretaceous must have been particularly favourable to herbivorous dinosaurs and other creatures that would have made up the food chain. It would have needed to be to support the number of large, predatory dinosaurs now known from this part of the world.

Monday, September 3, 2012

The Importance of 'Doing' Hands-On Science

What makes "difficult subjects", such as science, so difficult to teach and to learn? It could be that the concepts aren't quite as easy to learn via rote memorization or by simply reading about them in books. Based on how people learn, science is a subject that is best taught by using hands-on experimentation and relating it to the physical world around us.

Why Is Science So Hard?

Science often gets a bad rap as being one of those subjects we need to teach our kids - but since we don't understand it all that well ourselves, we dread teaching it and our kids can't get excited it about learning it, either.

And that's a real shame, because children love science before any formal schooling takes place. According to the National Academies Press book by John Bradsford, Ann Brown, and Rodney Cocking, How People Learn, gaining knowledge about science is a natural part of development, "Developmental researchers have shown that young children understand a great deal about basic principles of biology and physical causality, about number, narrative, and personal intent, and that these capabilities make it possible to create innovative curricula that introduce important concepts for advanced reasoning at early ages."

So we know that young kids can innately understand science... why do they have a difficult time learning it in school?

One problem is that homeschool teachers expect to be able to purchase a science textbook, open it up, and start teaching straight from its pages. This presents several problems, however. For one, it's boring. Kids don't get excited about seeing things on the pages of a book. For another, it's ineffective. This type of teaching promotes rote memorization. That's difficult for most of us because we have so much data in our brains already and years later, we usually forget most of that information because it's not tied to other, more important areas of our lives.

A Better Way To Teach Science

Fortunately, you don't have to thoroughly understand the topics you teach. What if you could learn along with your child? There is a way to do this, and it involves finding a curriculum that supports this type of study. It's referred to as "building block" methodology that introduces students to essential topics first, then builds on that foundation to introduce more and more complex topics. This logical progression allows students to begin understanding science at an early age and even learn college-level science by the time they are in middle school.

Not only should science education use a building block approach, it should serve as more of a guide rather than a listing of dry, hard facts. In order to help students come to the "right" conclusions, an effective science curriculum sets up the scenario, then allows students to explore the concepts in a hands-on manner. This occurs while connecting the new concepts to information they already know, thus allowing them to assimilate science in real life situations. In other words, students form a hypothesis based on science learning, then perform an experiment to prove or disprove the belief. This is how real scientists work and how kids are best able to understand real science.

When you are considering any homeschool science curriculum, look for a depth of understanding over a breadth of knowledge. It's not important to cram a bunch of science "facts" into a student's head; what is important is allowing him or her to explore and have fun with the process of science. Doing science rather than simply memorizing it is what results in true comprehension.