Rareresource: November 2008

Sunday, November 30, 2008

No. Dinosaurs are a group of ancient reptiles that had a set of particular skeletal features. The hips, hind legs, and ankles were specialized and allowed the legs to move directly under the body, rather than extending out from the side of the body as in modern lizards. This arrangement enabled dinosaurs to bring their knees and ankles directly below their hips and provided the necessary attachments for very strong leg muscles. Dinosaur skeletons were well designed for supporting a large body, for standing erect (upright), and for running. The front legs were adapted for grasping prey, for supporting weight, or for walking and running. The skulls of dinosaurs were designed for maximum strength, for minimum weight, and (in some cases) for grasping, holding, or tearing at prey. These skeletal features separated dinosaurs from other ancient reptiles such as Dimetrodon, the plesiosaurs, and pterosaurs. Fossil mammals, like mammoths and "saber-toothed tigers" (e.g., Smilodon), are also often incorrectly called dinosaurs.

For More News: URL:https://pubs.usgs.gov/gip/dinosaurs/all.html

Thursday, November 27, 2008

More about dinosaurs

Your local museums, public libraries, and bookstores are good places to start. Some national monuments (Dinosaur National Monument, UT and CO), national parks (Petrified Forest National Park, AZ), and state parks (for example, Dinosaur Valley State Park, TX) have outstanding displays. State geological surveys also have or can provide information on nearby dinosaur exhibits. The references below will help you get started; they provided some of the information for this pamphlet.

Dodson, P., and Dawson, S.D., 1991, Making the fossil record of dinosaurs: Modern Geology, vol. 16, p. 3-15. Farlow, J.O., 1993, The dinosaurs of Dinosaur Valley State Park -- Somervell County, Texas: Texas Parks and Wildlife Department, Austin, 31 p. Glut, D.F., 1982, The New Dinosaur Dictionary: Secaucus. Citadel Press, 288 p. Lambert, D., and the Diagram Group, 1990, Dinosaur Data Book: New York, Avon Books, 320 p. Marsh, O.C., 1896, The dinosaurs of North America: U.S. Geological Survey, Sixteenth Annual Report, part I, p. 131-414. Norman, D., 1985, Illustrated Encyclopedia of Dinosaurs: New York, Crescent Books, 208 p. Russell, D.A., 1989, An Odyssey in Time, the Dinosaurs of North America: Minocqua, North Word Press, 220 p. Thulborn, T., 1990, Dinosaus Tracks: London, Chapman and Hall, 410 p. Weishampel, D.B., Dodson, P., and Osmolska, H., 1990, The Dinosauria: Berkeley, University of California Press, 733 p.
For More News: URL:https://pubs.usgs.gov/gip/dinosaurs/moreinfo.html

Wednesday, November 26, 2008

Food of Dinosaurs

Some dinosaurs ate lizards, turtles, eggs, or early mammals. Some hunted other dinosaurs or scavenged dead animals. Most, however, ate plants (but not grass, which hadn't evolved yet). Rocks that contains dinosaur bones also contain fossil pollen and spores that indicate hundreds to thousands of types of plants existed during the Mesozoic Era. Many of these plants had edible leaves, including evergreen conifers (pine trees, redwoods, and their relatives), ferns, mosses, horsetail rushes, cycads, ginkos, and in the latter part of the dinosaur age flowering (fruiting) plants. Although the exact time of origin for flowering plants is still uncertain, the last of the dinosaurs certainly had fruit available to eat.

For More News: URL:https://pubs.usgs.gov/gip/dinosaurs/food.html

Dinosaurs Colors

Direct fossil evidence for dinosaur skin color is unknown. Paleontologists think that some dinosaurs likely had protective coloration, such as pale undersides to reduce shadows, irregular color patterns ("camouflage") to make them less visible in vegetation, and so on. Those dinosaurs that had enough armor, such as the stegosaurs and ceratopsians, may not have needed protective coloration but may have been brightly colored as a warning to predators or as a display for finding a mate. Most dinosaurs probably were as brightly colored as modern lizards, snakes, or birds.

For more news: https://pubs.usgs.gov/gip/dinosaurs/color.html

Origin of avian genome size and structure in non-avian dinosaurs.

Avian genomes are small and streamlined compared with those of other amniotes by virtue of having fewer repetitive elements and less non-coding DNA. This condition has been suggested to represent a key adaptation for flight in birds, by reducing the metabolic costs associated with having large genome and cell sizes. However, the evolution of genome architecture in birds, or any other lineage, is difficult to study because genomic information is often absent for long extinct relatives. Here we use a novel bayesian comparative method to show that bone cell size correlates well with genome size in extant vertebrates, and hence use this relationship to estimate the genome sizes of 31 species of extinct dinosaur, including several species of extinct birds.

Our results indicate that the small genomes typically associated with avian flight evolved in the saurischian dinosaur lineage between 230 and 250 million years ago, long before this lineage gave rise to the first birds. By comparison, ornithischian dinosaurs are inferred to have had much larger genomes, which were probably typical for ancestral Dinosauria. Using comparative genomic data, we estimate that genome-wide interspersed mobile elements, a class of repetitive DNA, comprised 5-12% of the total genome size in the saurischian dinosaur lineage, but was 7-19% of total genome size in ornithischian dinosaurs, suggesting that repetitive elements became less active in the saurischian lineage. These genomic characteristics should be added to the list of attributes previously considered avian but now thought to have arisen in non-avian dinosaurs, such as feathers, pulmonary innovations, and parental care and nesting.

For more info: ncbi.nlm.nih.gov/pubmed/17344851

Thursday, November 13, 2008

dinosaurs live

Paleontologists now have evidence that dinosaurs lived on all of the continents. At the beginning of the age of dinosaurs (during the Triassic Period, about 230 million years ago) the continents we now know were arranged together as a single supercontinent called Pangea. During the 165 million years of dinosaur existence this supercontinent slowly broke apart. Its pieces then spread across the globe into a nearly modern arrangement by a process called plate tectonics. Volcanoes, earthquakes, mountain building, and sea-floor spreading are all part of plate tectonics, and this process is still changing our modern Earth.

Wednesday, November 5, 2008

The colour and skin of dinosaurs

We know something about the scaly skin because there are fossil examples of the imprints of the skin in ancient mud. However the colours have not been preserved. The pictures in books showing colours are just the guesses of artists and are based upon what sort of environments the dinosaurs may have lived in.

Tuesday, November 4, 2008

Platypterygius

Platypterygius was a large ichthyosaur (not a dinosaur) which grew to 6 or 7 metres long. It inhabited the inland sea between 110 and 100 million years ago. Fossils of this animal are amongst the most common of the large marine reptiles found in Queensland. Platypterygius was a fast and agile swimmer. It swam by moving its tail from side to side and steered with paddles or fins. It gave birth to live young. It would have eaten squid, fish and ammonites. The fossil remains of a hatching and its mother were discovered in Queensland in 1988. The name Platypterygius means broad-fin.