Evolution of Diplodocid Sauropod dinosaurs with emphasis on specimens from Howe Ranch, Wyoming (USA)

Diplodocidae are among the best known sauropod dinosaurs. Several species were described in the late 1800s or early 1900s. Since then, numerous additional specimens were recovered in the USA, Tanzania, Portugal, as well as possibly Spain, England, and Asia. To date, the clade includes about 12 to 15 different species, some of them with questionable taxonomic status (e.g. ‘Diplodocus’ hayi or Dyslocosaurus polyonychius). However, intrageneric relationships of the multi-species, iconic genera Apatosaurus and Diplodocus are still poorly known. The way to resolve this issue is a specimen-based phylogenetic analysis, which was done for Apatosaurus, but is here performed for the first time for the entire clade of Diplodocidae. New material from different localities and stratigraphic levels on the Howe Ranch (Shell,Wyoming, USA) sheds additional light on the evolution of Diplodocidae. Three new specimens are described herein, considerably increasing our knowledge of the anatomy of the group. The new specimens (SMA 0004, SMA 0011, and SMA 0087) represent two, to possibly three new diplodocid species. They preserve material from all parts of the skeleton, including two nearly complete skulls, as well as fairly complete manus and pedes, material which is generally rare in diplodocids. Thereby, they considerably increase anatomical overlap between the sometimes fragmentary holotype specimens of the earlier described diplodocid species, allowing for significant results in a specimenbased phylogenetic analysis. Furthermore, clavicles and interclavicles are identified, the latter for the first time in dinosaurs. Their presence seems restricted to early sauropods, flagellicaudatans, and early Macronaria, and might thus be a retained plesiomorphy, with the loss of these bones being synapomorphic for Titanosauriformes and possibly Rebbachisauridae. The new material allows to test previous hypotheses of diplodocid phylogeny. In order to do so, any type specimen previously proposed to belong to Diplodocidae was included in the study, as are relatively complete referred specimens, in order to increase the degree of overlapping material. For specimens subsequently suggested to be non-diplodocid sauropods, their hypothesized sister taxa were included as outgroups. The current phylogenetic analysis thus includes 76 operational taxonomic units, 45 of which belong to Diplodocidae. The specimens were scored for 477 morphological characters, representing one of the most extensive phylogenetic analyses done within sauropod dinosaurs. The resulting cladogram recovers the classical arrangement of diplodocid relationships. Basing on a newly developed numerical approach to reduce subjectivity in the decision of specific or generic separation, species that have historically been included into well-known genera like Apatosaurus or Diplodocus, were detected to be actually generically different. Thereby, the famous genus Brontosaurus is resuscitated, and evidence further suggests that also Elosaurus parvus (previously referred to Apatosaurus) or ‘Diplodocus’ hayi represent unique genera. The study increases our knowledge about individual variation, and helps to decide how to score multi-species genera. Such a specimen-based phylogenetic analysis thus proves a valuable tool to validate historic species in sauropods, and in paleontology as a whole.

Paleobiology and skeletochronology of Jurassic dinosaurs: implications from the histology and oxygen isotope compositions of bones

Fossil biogenic phosphate of fast-growing primary bone tissue of dinosaurs can preserve a histologic and isotopic time-series of annual seasonality in temperature variations, similar to tooth enamel and other accretionary skeletal phases such as corals or wood. On two bone fragments from sympatric dinosaurs with different histologic patterns of bone growth, high-resolution oxygen isotope profiles were analyzed along the radial direction of bone growth. The investigated specimens are from the Jurassic Shishugou Formation in the Junggar Basin, NW China and have distinct patterns of compositional variation. A fibrolamellar dinosaur bone with multiple lines of arrested growth (LAGs) and periodic growth cycles of decreasing bone laminae thickness displays a cyclic intra-bone variation in delta(18)O values of about 2parts per thousand corresponding with the LAGs. These growth cycles in fast-growing fibrolamellar bone provide evidence for seasonal growth of dinosaurs in lower latitudes ( similar to 45degreesN), possibly influenced by a monsoon-type paleoclimate. Seasonal changes in temperature and water supply are consistent with the oxygen isotope composition measured in dinosaur bone phosphate as well as with growth rings in contemporaneous fossil conifer wood from the same locality. In contrast, a plexiform sympatric sauropod bone displays continuous growth, free of LAGs and has a lower intra-bone variation of less than or equal to 0.8parts per thousand. Differences in bone histology are also reflected in the oxygen isotopic composition and its intra-bone variability, indicating different physiological responses to external climatic stress between sympatric dinosaur species. Seasonal intra-bone oxygen isotope variations combined with bone histology may thus yield new insights into species-specific response to climatic stress and its influence on dinosaur growth, formation of growth marks, growth rates, as welt as dinosaur thermophysiology. (C) 2004 Elsevier B.V All rights reserved.

Paper Dinosaurs : field notes as finds in Robert Kroetsch's Badlands

Des dinosaures sur papier : des notes « sur le terrain » comme on en trouve dans le Badlands de Robert Kroetsch passe en revue cette œuvre postmoderne de 1975 portant sur une expédition paléontologique fictive près de la rivière Red Deer, en Alberta, conformément à la récente tendance à exiger la vérification systématique des données à la base des récits métafictifs historiographiques dans la littérature canadienne-anglaise. Inspirée de l’exploration canonique qu’a effectuée John Livingston-Lowes des plus grands poèmes de Samuel Taylor Coleridge par le biais de la mine d’or du Gutch Memorandum Book dans The Road to Xanadu, cette thèse entreprend un nouveau type de recherche qui se démarque des archives conventionnelles et de la tradition documentaire. S’appuyant sur des documents holographes non publiés provenant de dépôts d’archives situés au Québec, en Ontario et en Alberta et écrits par des collecteurs, des géologues et des paléontologues de la Commission géologique du Canada, ainsi que sur des notes « sur le terrain », des notes de recherche et des journaux personnels écrits par Robert Kroetsch pendant la rédaction de son roman Badlands, cet examen critique révèle les strates sous-jacentes inédites d’une œuvre de fiction particulière. Dans pratiquement toute fouille paléontologique, le retrait de ce qui enveloppe un spécimen révèle souvent des données supplémentaires qui peuvent, si elles sont soigneusement interprétées, offrir des indices essentiels sur les environnements paléontologiques. Ainsi, un squelette de dinosaure est rarement retiré d’une carrière stérile dans son intégralité. Il en va de même pour toute recherche sur un processus littéraire. Aucun texte ne s’autosuffit. Comme Kroetsch s’est efforcé de produire son récit sous forme d’interrogation sur la création et la transmission des données historiques, particulièrement grâce à des notes « sur le terrain », une vaste étude de ce « terrain » comprenant des intertextes de l’Antiquité, des sciences, de l’Histoire, de l’histoire populaire, de récits de voyages et de la littérature canadienne et internationale est ici menée. On y fait librement référence à des périodes et à des auteurs très diversifiés, allant de Thomas Jefferson et des tombelles à Bruce Chatwin et sa peau de « brontosaure ». Évidemment, aucune entreprise interdisciplinaire du genre ne peut être exhaustive. Ce projet se veut plutôt une vitrine littéraire réunissant des curiosités autour d’une œuvre principale, soit le Badlands de Robert Kroetsch. Réduites à leur plus simple expression, les notes « sur le terrain » constituent des messages destinés à la postérité. En explorant trois thèmes principaux, cette thèse explique comment ces messages pourraient être transmis. « Saxa Loquuntur ! », ainsi intitulé en référence à l’analogie de Freud avec l’archéologie, traite des métaphores associées aux témoignages de la pierre ; « Good Jones » porte sur les façons dont la taxinomie peut combler le désir d’un chercheur d’os de ne pas tomber dans l’oubli ; « Box 16 » suit une piste documentaire en parcourant les écrits de Kroetsch pour reconstituer tant l’élaboration d’un roman que les notions de temps, d’espace et d’origine d’une œuvre littéraire.

Dangerous dinosaurs.

Descubre todo tipo de dinosaurios fantásticos, el duvetsaurus, el grumposaurus, el neversaurus, el binbagosaurus y muchos más.

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(1,2). 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(3,4). 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(5), pulmonary innovations 6, and parental care and nesting

Dinosaurs in decline tens of millions of years before their final extinction

Whether dinosaurs were in a long-term decline or whether they were reigning strong right up to their final disappearance at the Cretaceous–Paleogene (K-Pg) mass extinction event 66 Mya has been debated for decades with no clear resolution. The dispute has continued unresolved because of a lack of statistical rigor and appropriate evolutionary framework. Here, for the first time to our knowledge, we apply a Bayesian phylogenetic approach to model the evolutionary dynamics of speciation and extinction through time in Mesozoic dinosaurs, properly taking account of previously ignored statistical violations. We find overwhelming support for a long-term decline across all dinosaurs and within all three dinosaurian subclades (Ornithischia, Sauropodomorpha, and Theropoda), where speciation rate slowed down through time and was ultimately exceeded by extinction rate tens of millions of years before the K-Pg boundary. The only exceptions to this general pattern are the morphologically specialized herbivores, the Hadrosauriformes and Ceratopsidae, which show rapid species proliferations throughout the Late Cretaceous instead. Our results highlight that, despite some heterogeneity in speciation dynamics, dinosaurs showed a marked reduction in their ability to replace extinct species with new ones, making them vulnerable to extinction and unable to respond quickly to and recover from the final catastrophic event.

Biomechanical comments about Triassic dinosaurs from Brazil

Triassic dinosaurs of Brazil are found in Santa Maria and Caturrita formations, Rio Grande do Sul state, Brazil. There are three species known from the Santa Maria Formation (Staurikosaurus pricei, Saturnalia tupiniquim and Pampadromaeus barberenai), and two from Caturrita Formation (Guaibasaurus candelariensis and Unaysaurus tolentinoi). These dinosaur materials are, for the most part, well preserved and allow for descriptions of musculature and biomechanical studies. The lateral rotation of the Saturnalia femur is corroborated through calculations of muscle moment arms. The enhanced supracetabular crest of Saturnalia, Guaibasaurus, Staurikosaurus, Herrerasaurus ischigualastensis, Efraasia minor and Chormogisaurus novasi suggests that basal dinosaurs may have maintained an inclination of the trunk at least 20º on the horizontal axis. The pectoral girdle articulation of basal sauropodomorphs (Saturnalia and Unaysaurus) was established using a new method, the Clavicular Ring, and the scapular blade remains near 60º on the horizontal axis. This is a plesiomorphic condition among sauropodomorphs and is also seen in the articulated plateosauridae Seitaad ruessi. The Brazilian basal dinosaurs were lightweight with a body mass estimated around 18.5 kg for Staurikosaurus, 6.5 kg for Saturnalia, and 17 kg for Guaibasaurus. Pampadromaeus probably weighed 2.5 kg, but measures of its femur are necessary to confirm this hypothesis. The Triassic dinosaurs from Brazil were diversified but shared some functional aspects that were important in an evolutionary context.

Incremental lines of von Ebner in dinosaurs and the assessment of tooth replacement rates using growth line counts

Dinosaur dentine exhibits growth lines that are tens of micrometers in width. These laminations are homologous to incremental lines of von Ebner found in extant mammal and crocodilian teeth (i.e., those of amniotes). The lines likely reflect daily dentine formation, and they were used to infer tooth development and replacement rates. In general, dinosaur tooth formation rates negatively correlated with tooth size. Theropod tooth replacement rates negatively correlated with tooth size, which was due to limitations in the dentine formation rates of their odontoblasts. Derived ceratopsian and hadrosaurian dinosaurs retained relatively rapid tooth replacement rates through ontogeny. The evolution of dental batteries in hadrosaurs and ceratopsians can be explained by dentine formation constraints and rapid tooth wear. In combination with counts of shed dinosaur teeth, tooth replacement rate data can be used to assess population demographics of Mesozoic ecosystems. Finally, it is of historic importance to note that Richard Owen appears to have been the first to observe incremental lines of von Ebner in dinosaurs more than 150 years ago.

A revision of the Ceratopsia or horned dinosaurs.

3 pt.3

Developing New Tourism Services: Dinosaurs a New Drive Tourism Resource for Remote Areas

This paper examines issues encountered when developing new tourism services generally, and specific aspects relating to the development of remote area dinosaur fossil fields for tourism. It studies two sites, one in the USA and one in Australia. Access to both sites is by minor roads, and both sites are characterised by long drives separating the sites from small communities that offer limited infrastructure and few other attractions for visitors. In both areas, however, tourism is seen as one of the few possible ways to sustain existing communities in the face of declining primary-industry-based employment. In general, tourists visiting these areas are on touring holidays of two weeks’ duration or more where the attraction is the general attributes of the region as well as to a lesser extent their interest in dinosaur fossils. These provide a potential resource for remote-region economic development through commodification as a new tourism attraction. Development of dinosaur fossil finds as a tourism resource is conceptualised here as new service development. Developing new tourism services, especially in remote regions, is challenging and has not been well examined in the tourism literature. The new service development process used in this case study first examines the characteristics of the existing tourists travelling through the region. The characteristics of a number of potential market segments currently interested in dinosaur fossils were then examined and contrasted with the existing market. This is conceptualised on a specialist-generalist spectrum of interest in fossils. A study of the tourist service features associated with dinosaur fossil tourism in remote regions of the USA was conducted, leading to the identification of a number of possible incremental development opportunities. The paper then takes a strategic approach to examining potential new tourism service development related to dinosaur fossils in remote regions of Queensland, Australia. In particular, it describes use of information about existing services in similar regions as the basis for ideas about development as well as comparison between existing and potential markets.

On the tracks of the earliest dinosaurs: implications for the hypothesis of dinosaurian monophyly

From the record of dinosaurian skeletal remains it has been inferred that the origin and initial diversification of dinosaurs were rapid events, occupying an interval of about 5 million years in the Late Triassic. By contrast numerous reports of dinosauroid tracks imply that the emergence of dinosaurs was a more protracted affair extending through much of the Early and Middle Triassic. This study finds no convincing evidence of dinosaur tracks before the late Ladinian. Each of the three dinosaurian clades - Theropoda, Sauropodomorpha, Ornithischia - produced a unique track morphotype that appears to be an independent modification of the chirotherioid pattern attributed to stem-group archosaurs (thecodontian reptiles). The existence of three divergent track morphotypes is consistent with the concept of dinosaurian polyphyly but can be reconciled with the hypothesis of dinosaurian monophyly only by invoking many and rapid reversals in the locomotor anatomy of early dinosaurs. The origin of dinosaurs was not the correlate or consequence of any single event or process, be it global change, competitive replacement, or opportunism in the wake of mass extinction. Instead the origin of dinosaurs is envisaged as a series of three cladogenetic events over an interval of at least 10 million years and possibly as much as 25 million years. This scenario of dinosaurian polyphyly is as well-supported by fossil evidence as is the currently favoured view of dinosaurian monophyly.