Dinosaurs: General name for two extinct orders of reptiles from the Mesozoic era: Saurischia and Ornithischia.Fossils: Remains, impressions, or traces of animals or plants of past geological times which have been preserved in the earth's crust.Paleontology: The study of early forms of life through fossil remains.Alligators and Crocodiles: Large, long-tailed reptiles, including caimans, of the order Loricata.Reptiles: Cold-blooded, air-breathing VERTEBRATES belonging to the class Reptilia, usually covered with external scales or bony plates.Skeleton: The rigid framework of connected bones that gives form to the body, protects and supports its soft organs and tissues, and provides attachments for MUSCLES.Anatomy, Comparative: The comparative study of animal structure with regard to homologous organs or parts. (Stedman, 25th ed)Extinction, Biological: The ceasing of existence of a species or taxonomic groups of organisms.Biological Evolution: The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.Geological Processes: Events and activities of the Earth and its structures.Skull: The SKELETON of the HEAD including the FACIAL BONES and the bones enclosing the BRAIN.Body Size: The physical measurements of a body.Birds: Warm-blooded VERTEBRATES possessing FEATHERS and belonging to the class Aves.Struthioniformes: An order of flightless birds comprising the ostriches, which naturally inhabit open, low rainfall areas of Africa.Carnivory: The consumption of animal flesh.MontanaEgg Shell: A hard or leathery calciferous exterior covering of an egg.Feathers: Flat keratinous structures found on the skin surface of birds. Feathers are made partly of a hollow shaft fringed with barbs. They constitute the plumage.Tooth: One of a set of bone-like structures in the mouth used for biting and chewing.Geological Phenomena: The inanimate matter of Earth, the structures and properties of this matter, and the processes that affect it.Geology: The science of the earth and other celestial bodies and their history as recorded in the rocks. It includes the study of geologic processes of an area such as rock formations, weathering and erosion, and sedimentation. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Bone and Bones: A specialized CONNECTIVE TISSUE that is the main constituent of the SKELETON. The principle cellular component of bone is comprised of OSTEOBLASTS; OSTEOCYTES; and OSTEOCLASTS, while FIBRILLAR COLLAGENS and hydroxyapatite crystals form the BONE MATRIX.Paleodontology: The study of the teeth of early forms of life through fossil remains.Humerus: Bone in humans and primates extending from the SHOULDER JOINT to the ELBOW JOINT.HornsEncyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Deltoid Muscle: Thick triangular muscle in the SHOULDER whose function is to abduct, flex, and extend the arm. It is a common site of INTRAMUSCULAR INJECTIONS.Earthquakes: Sudden slips on a fault, and the resulting ground shaking and radiated seismic energy caused by the slips, or by volcanic or magmatic activity, or other sudden stress changes in the earth. Faults are fractures along which the blocks of EARTH crust on either side have moved relative to one another parallel to the fracture.Volcanic Eruptions: The ash, dust, gases, and lava released by volcanic explosion. The gases are volatile matter composed principally of about 90% water vapor, and carbon dioxide, sulfur dioxide, hydrogen, carbon monoxide, and nitrogen. The ash or dust is pyroclastic ejecta and lava is molten extrusive material consisting mainly of magnesium silicate. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Book Reviews as Topic: Critical analyses of books or other monographic works.Book ReviewsBooksEctoparasitic Infestations: Infestations by PARASITES which live on, or burrow into, the surface of their host's EPIDERMIS. Most ectoparasites are ARTHROPODS.Achievement: Success in bringing an effort to the desired end; the degree or level of success attained in some specified area (esp. scholastic) or in general.Seychelles: A group of Indian Ocean Islands, east of Tanzania. Their capital is Victoria. They were first claimed by the French in 1744 but taken by the English in 1794 and made a dependency of MAURITIUS in 1810. They became a crown colony in 1903 and a republic within the Commonwealth in 1976. They were named for the French finance minister, Jean Moreau de Sechelles, but respelled by the English in 1794. (From Webster's New Geographical Dictionary, 1988, p1102 & Room, Brewer's Dictionary of Names, 1992, p496)Writing: The act or practice of literary composition, the occupation of writer, or producing or engaging in literary work as a profession.Educational Status: Educational attainment or level of education of individuals.LizardsBones of Upper Extremity: The bones of the upper and lower ARM. They include the CLAVICLE and SCAPULA.Rationalization: A defense mechanism operating unconsciously, in which the individual attempts to justify or make consciously tolerable, by plausible means, feelings, behavior, and motives that would otherwise be intolerable.Journal Impact Factor: A quantitative measure of the frequency on average with which articles in a journal have been cited in a given period of time.Australia: The smallest continent and an independent country, comprising six states and two territories. Its capital is Canberra.Western Australia: A state in western Australia. Its capital is Perth. It was first visited by the Dutch in 1616 but the English took possession in 1791 and permanent colonization began in 1829. It was a penal settlement 1850-1888, became part of the colonial government in 1886, and was granted self government in 1890. (From Webster's New Geographical Dictionary, 1988, p1329)WingHoof and Claw: Highly keratinized processes that are sharp and curved, or flat with pointed margins. They are found especially at the end of the limbs in certain animals.ChicagoFoot: The distal extremity of the leg in vertebrates, consisting of the tarsus (ANKLE); METATARSUS; phalanges; and the soft tissues surrounding these bones.Toes: Any one of five terminal digits of the vertebrate FOOT.Foot Diseases: Anatomical and functional disorders affecting the foot.Thumb: The first digit on the radial side of the hand which in humans lies opposite the other four.Copyright: It is a form of protection provided by law. In the United States this protection is granted to authors of original works of authorship, including literary, dramatic, musical, artistic, and certain other intellectual works. This protection is available to both published and unpublished works. (from Circular of the United States Copyright Office, 6/30/2008)Editorial Policies: The guidelines and policy statements set forth by the editor(s) or editorial board of a publication.

Brief review of dinosaur studies and perspectives in Brazil. (1/401)

Dinosaur research is developing at very high rates around the world resulting in several new discoveries that are improving our understanding of this terrestrial reptilian clade. Except for the last couple years, the studies of Brazilian dinosaurs have not followed this expansive trend, despite the high potential of several dinosaur localities. So far there are only eight described taxa, four in the last year, representing theropod, sauropod, and one possible prosauropod taxa. Except for footprints, there are no records of ornithischian dinosaurs in the country what is at least partially explainable by the lack of continuous vertebrate fossil collecting program in the country. More funding is necessary to improve the research activities in this field.  (+info)

Dinosaurs, dragons, and dwarfs: the evolution of maximal body size. (2/401)

Among local faunas, the maximum body size and taxonomic affiliation of the top terrestrial vertebrate vary greatly. Does this variation reflect how food requirements differ between trophic levels (herbivores vs. carnivores) and with taxonomic affiliation (mammals and birds vs. reptiles)? We gathered data on the body size and food requirements of the top terrestrial herbivores and carnivores, over the past 65,000 years, from oceanic islands and continents. The body mass of the top species was found to increase with increasing land area, with a slope similar to that of the relation between body mass and home range area, suggesting that maximum body size is determined by the number of home ranges that can fit into a given land area. For a given land area, the body size of the top species decreased in the sequence: ectothermic herbivore > endothermic herbivore > ectothermic carnivore > endothermic carnivore. When we converted body mass to food requirements, the food consumption of a top herbivore was about 8 times that of a top carnivore, in accord with the factor expected from the trophic pyramid. Although top ectotherms were heavier than top endotherms at a given trophic level, lower metabolic rates per gram of body mass in ectotherms resulted in endotherms and ectotherms having the same food consumption. These patterns explain the size of the largest-ever extinct mammal, but the size of the largest dinosaurs exceeds that predicted from land areas and remains unexplained.  (+info)

Influence of rotational inertia on turning performance of theropod dinosaurs: clues from humans with increased rotational inertia. (3/401)

The turning agility of theropod dinosaurs may have been severely limited by the large rotational inertia of their horizontal trunks and tails. Bodies with mass distributed far from the axis of rotation have much greater rotational inertia than bodies with the same mass distributed close to the axis of rotation. In this study, we increased the rotational inertia about the vertical axis of human subjects 9.2-fold, to match our estimate for theropods the size of humans, and measured the ability of the subjects to turn. To determine the effect of the increased rotational inertia on maximum turning capability, five subjects jumped vertically while attempting to rotate as far as possible about their vertical axis. This test resulted in a decrease in the average angle turned to 20 % of the control value. We also tested the ability of nine subjects to run as rapidly as possible through a tight slalom course of six 90 degrees turns. When the subjects ran with the 9.2-fold greater rotational inertia, the average velocity through the course decreased to 77% of the control velocity. When the subjects ran the same course but were constrained as to where they placed their feet, the average velocity through the course decreased to 65 % of the control velocity. These results are consistent with the hypothesis that rotational inertia may have limited the turning performance of theropods. They also indicate that the effect of rotational inertia on turning performance is dependent on the type of turning behavior. Characters such as retroverted pubes, reduced tail length, decreased body size, pneumatic vertebrae and the absence of teeth reduced rotational inertia in derived theropods and probably, therefore, improved their turning agility. To reduce rotational inertia, theropods may have run with an arched back and tail, an S-curved neck and forelimbs held backwards against the body.  (+info)

An analysis of dinosaurian biogeography: evidence for the existence of vicariance and dispersal patterns caused by geological events. (4/401)

As the supercontinent Pangaea fragmented during the Mesozoic era, dinosaur faunas were divided into isolated populations living on separate continents. It has been predicted, therefore, that dinosaur distributions should display a branching ('vicariance') pattern that corresponds with the sequence and timing of continental break-up. Several recent studies, however, minimize the importance of plate tectonics and instead suggest that dispersal and regional extinction were the main controls on dinosaur biogeography. Here, in order to test the vicariance hypothesis, we apply a cladistic biogeographical method to a large dataset on dinosaur relationships and distributions. We also introduce a methodological refinement termed 'time-slicing', which is shown to be a key step in the detection of ancient biogeographical patterns. These analyses reveal biogeographical patterns that closely correlate with palaeogeography. The results provide the first statistically robust evidence that, from Middle Jurassic to mid-Cretaceous times, tectonic events had a major role in determining where and when particular dinosaur groups flourished. The fact that evolutionary trees for extinct organisms preserve such distribution patterns opens up a new and fruitful direction for palaeobiogeographical research.  (+info)

Ascent of dinosaurs linked to an iridium anomaly at the Triassic-Jurassic boundary. (5/401)

Analysis of tetrapod footprints and skeletal material from more than 70 localities in eastern North America shows that large theropod dinosaurs appeared less than 10,000 years after the Triassic-Jurassic boundary and less than 30,000 years after the last Triassic taxa, synchronous with a terrestrial mass extinction. This extraordinary turnover is associated with an iridium anomaly (up to 285 parts per trillion, with an average maximum of 141 parts per trillion) and a fern spore spike, suggesting that a bolide impact was the cause. Eastern North American dinosaurian diversity reached a stable maximum less than 100,000 years after the boundary, marking the establishment of dinosaur-dominated communities that prevailed for the next 135 million years.  (+info)

A genus-level supertree of the Dinosauria. (6/401)

One of the ultimate aims of systematics is the reconstruction of the tree of life. This is a huge undertaking that is inhibited by the existence of a computational limit to the inclusiveness of phylogenetic analyses. Supertree methods have been developed to overcome, or at least to go around this problem by combining smaller, partially overlapping cladograms. Here, we present a very inclusive generic-level supertree of Dinosauria (covering a total of 277 genera), which is remarkably well resolved and provides some clarity in many contentious areas of dinosaur systematics.  (+info)

A theropod tooth from the Late Triassic of southern Africa. (7/401)

An isolated, large recurved and finely serrated tooth found associated with the prosauropod Euskelosaurus fron the Late Triassic part of the Elliot Formation is described here. It is compared to the Triassic thecodonts and carnivorous dinosaurs and its possible affinity is discussed. The tooth possibly belongs to a basal theropod and shows some features similar to the allosauroids. This tooth is of significance, as dinosaur remains except for some footprints and trackways, are poorly known in the Late Triassic horizons of southern Africa.  (+info)

Recreating a functional ancestral archosaur visual pigment. (8/401)

The ancestors of the archosaurs, a major branch of the diapsid reptiles, originated more than 240 MYA near the dawn of the Triassic Period. We used maximum likelihood phylogenetic ancestral reconstruction methods and explored different models of evolution for inferring the amino acid sequence of a putative ancestral archosaur visual pigment. Three different types of maximum likelihood models were used: nucleotide-based, amino acid-based, and codon-based models. Where possible, within each type of model, likelihood ratio tests were used to determine which model best fit the data. Ancestral reconstructions of the ancestral archosaur node using the best-fitting models of each type were found to be in agreement, except for three amino acid residues at which one reconstruction differed from the other two. To determine if these ancestral pigments would be functionally active, the corresponding genes were chemically synthesized and then expressed in a mammalian cell line in tissue culture. The expressed artificial genes were all found to bind to 11-cis-retinal to yield stable photoactive pigments with lambda(max) values of about 508 nm, which is slightly redshifted relative to that of extant vertebrate pigments. The ancestral archosaur pigments also activated the retinal G protein transducin, as measured in a fluorescence assay. Our results show that ancestral genes from ancient organisms can be reconstructed de novo and tested for function using a combination of phylogenetic and biochemical methods.  (+info)

  • Also, it's common to see dinosaur bones at a museum, but has anyone ever found a frozen piece of hide or meat in a glacier somewhere? (straightdope.com)
  • Florida State University paleobiologist Gregory M. Erickson sliced up some ancient dinosaur bones uncovered in China to help an international team of scientists identify a new genus and species. (fsu.edu)
  • The research team from the University of Southampton believe four bones found last year in the village of Shanklin, on the Isle of Wight, belong to a new species of theropod dinosaur, BBC News reported. (krmg.com)
  • According to a news release from the university, the team determined the bones were from the neck, back and tail of a new dinosaur "previously unknown to science. (krmg.com)
  • Now the dinosaurs appeared on the scene: They were warm-blooded like mammals, instead of fur they had scales (later feathers) and in addition they had an epochal innovation in their body plan: The dinosaurs had air sacs in their bones, so that they could inhale considerably more oxygen from the air than mammals could. (ddrheinrich.com)
  • What has been suspected for a long time has now been evidenced: Collagen in Tyrannosaurus Rex' fossilized bones (short form: T. Rex) was analyzed and it was proven that both T. Rex and the chicken belong to the same group of dinosaurs. (ddrheinrich.com)
  • Beginning in the 1960s and with the advent of the Dinosaur Renaissance, views of dinosaurs and their physiology have changed dramatically, including the discovery of feathered dinosaurs in Early Cretaceous age deposits in China, indicating that birds evolved from highly agile maniraptoran dinosaurs. (wikipedia.org)
  • These debates sparked interest in new methods for ascertaining the palaeobiology of extinct animals, such as bone histology, which have been successfully applied to determining the growth-rates of many dinosaurs. (wikipedia.org)
  • The Good Dinosaur" asks the question: What if the asteroid that forever changed life on Earth missed the planet completely and giant dinosaurs never became extinct? (i4u.com)
  • As Virginia's own "Jurassic Park," Dinosaur Land is doing its part to ensure that, although dinosaurs may be extinct, they will never be forgotten. (dinosaurland.com)
  • Despite these considerations, the image of dinosaurs as large reptiles had already taken root, and most aspects of their paleobiology were interpreted as being typically reptilian for the first half of the twentieth century. (wikipedia.org)
  • Their early work can be seen today in the Crystal Palace Dinosaurs, constructed in the 1850s, which present known dinosaurs as elephantine lizard-like reptiles. (wikipedia.org)
  • Today, it is generally thought that many or perhaps all dinosaurs had higher metabolic rates than living reptiles, but also that the situation is more complex and varied than Bakker originally proposed. (wikipedia.org)
  • Creationists also tend to have an early 20th century view of dinosaurs and thus see them as slow moving, cold-blooded reptiles that could be compared to dragons. (rationalwiki.org)
  • Dinosaurs (meaning "terrible lizards") are a varied group of Archosaur reptiles . (wikipedia.org)
  • They evolved - like the dinosaurs did as well - from reptiles and were biologically seen quite similar to the today's platypus - so they had fur, warm-blooded body temperature and probably they even laid eggs. (ddrheinrich.com)
  • Dinosaurs evolved within a single lineage of archosaurs 243-233 Ma (million years ago) from the Anisian to the Carnian ages, the latter part of the middle Triassic . (wikipedia.org)
  • The process leading up to the Dinosauromorpha and the first true dinosaurs can be followed through fossils of the early Archosaurs such as the Proterosuchidae , Erythrosuchidae and Euparkeria which have fossils dating back to 250 Ma, through mid-Triassic archosaurs such as Ticinosuchus 232-236 Ma. (wikipedia.org)
  • Dinosaurs appeared in the Upper Triassic , about 230 million years ago. (wikipedia.org)
  • However, when definite dinosaur fossils appear (early in the Upper Triassic), the group had already split into two great orders , the Saurischia , and the Ornithischia . (wikipedia.org)
  • Mammals were already present before dinosaurs had inhabited the earth, namely in that time of the so-called perm period. (ddrheinrich.com)
  • Suddenly all of the mammals apart from a few small forms died out and made way for the dinosaurs. (ddrheinrich.com)
  • Researchers say the identification of the oldest basal (primitive) tyrannosauroid yet will shed light on the early evolution and geographical distribution of its ancestors-small therapod dinosaurs known as coelurosaurs that were the closest relatives of modern-day birds. (fsu.edu)
  • Qijiang, China - Researchers from the University of Alberta have concluded that the fossil remains accidentally dug up in 2006 by local farmers seeking a prime fishing spot are that of a new dinosaur that measured up to 15 meters (~50 ft.) in length. (ecanadanow.com)
  • The earliest confirmed dinosaur fossils include saurischian ('lizard-hipped') dinosaurs Nyasasaurus 243 Ma, Saturnalia 225-232 Ma, Herrerasaurus 220-230 Ma, Staurikosaurus possibly 225-230 Ma, Eoraptor 220-230 Ma and Alwalkeria 220-230 Ma. (wikipedia.org)
  • My 6-year old daughter took me on a tour, telling which dinosaurs were vegetarians and which were meat eaters and describing each battle in detail. (dinosaurland.com)
  • For example, while smaller dinosaurs may have been true endotherms, the larger forms could have been inertial homeotherms, or that many dinosaurs could have had intermediate metabolic rates. (wikipedia.org)
  • Why would larger modern animals, such as elephants, survive but not the smaller dinosaurs? (rationalwiki.org)
  • Widely publicized research by Erickson-who also is known as an expert in dinosaur and crocodilian dentition, or bite force-has helped to generate interest in the sciences among young children, typically fascinated by animals such as dinosaurs and crocodiles. (fsu.edu)
  • Size comparison of many dromaeosaurids , a family of fully feathered dinosaurs that includes both Velociraptor and Deinonychus . (wikipedia.org)
  • According to the new classification, the original dinosaurs, arising 200 million years ago, were small, two-footed omnivorous animals with large grasping hands. (wikipedia.org)
  • But what has actually made dinosaurs so successful that they could dominate the earth for 200 million of years? (ddrheinrich.com)