Academic literature on the topic 'Dinosaurs'

Dinosaur museums aspire to communicate authenticity to their visitors by displaying 'authentic dinosaurs' or what they perceive as 'authentic representations' of dinosaurs. The museums do this by employing a varied arsenal of objects, from bones still embedded in the rocks in which they were found to mounted skeletons, murals and computer-controlled life-size models. These same museums however, neglect to explicitly define what authenticity is, and fail to specify the criteria by which this quality might be defined.;Two distinct perspectives were revealed while exploring the vocabulary of authenticity and adapting it to the case of dinosaurs and museums: the museum's perspective and that of the visitor. This work focuses on the museum's perspective, one, which exists in a combination of needs, obligations, restraints, beliefs, and demands, some of which derive from forces within the museums while others are a reflection of influences from outside.;Using museum visits and written sources, mainly the ephemera produced by museums, this work demonstrates how the notion of authenticity is constructed by museums. The concept of authenticity and its theoretical understanding was examined in the museums context as well as in the often parallel worlds of private collectors, commercial manufacturers, the movie industry, and other agents of popular culture.;A considerable variety of techniques and materials have been used to create a sense of the dinosaur but in variable degrees the sense of authenticity they generate is governed by the following four criteria; Composition , Provenance, (degree of) Intervention and (scientific) Accuracy. Most of these are fairly static criteria; only a notion of scientific accuracy changes rapidly over time as a result of new knowledge superseding old, and old knowledge being perceived as inaccurate (wrong).

El registre geològic i paleontològic del Campanià i Maastrichtià del sud-oest europeu ofereix una de les millors oportunitats per estudiar els darrers 15 milions d’anys abans de l’extinció del Cretaci-Paleogen més enllà del registre de Nord Amèrica. En aquesta tesi doctoral s’ha estudiat i caracteritzat el registre de dinosaures i els seus paleoambients associats, i s’han datat successions sedimentàries mitjançant magnetostratigrafia amb l’objectiu d’aprofundir en el coneixement sobre les darreres comunitats de dinosaures de l’illa Ibero-Armoricana de l’Arxipèlag europeu. Els treballs integrats realitzats a la part mesozoica del Grup Tremp (Conca sud-pirinenca) inclouen l’estudi de les petjades de l’icnogènere Hadrosauropodus, associat a dinosaures hadrosaures. Aquestes empremtes són molt abundants en les planes costaneres fluvials del Maastrichtià superior. A més de l’ambient fluvial, els hadrosaures també van colonitzar l’ecosistema costaner (per exemple llacunes), tal com mostra el jaciment de L’Espinau, entre d’altres localitats. Per contra, els sauròpodes van ser dominants en els ambients costaners i continentals de la regió durant el Campanià i el Maastrichtià inferior, tot i que van persistir fins el Maastrichtià terminal tal i com evidencia el seu registre osteològic, oològic i de petjades, incloent-hi impressions de pell. Amb tot, les seves restes fòssils són molt més escasses que les d’hadrosaure en aquesta edat. La successió faunística de dinosaures del sud-oest europeu s’ha millorat gràcies a 1) la millora del coneixement sobre la distribució paleoambiental dels diferents grups, 2) la integració del registre paleontològic de de l’Alta Vall de l’Aude, una important zona fossilífera del nord dels Pirineus, gràcies al seu estudi magnetostratigràfic, 3) la millora de la calibració del sector Isona del sinclinal de Tremp, a la banda sud dels Pirineus, i 4) la integració de dades provinents del registre campano-maastrichtià de la resta d’àrees fossilíferes de França, Espanya i Portugal (Provença i Ibèria). Amb la millora de les datacions, s’ha pogut desenvolupar un nou model de canvi faunístic de dinosaures durant el Maastrichtià. Enlloc d’un reemplaçament ràpid de faunes herbívores dominades per sauròpodes cap a comunitats dominades per hadrosaures concentrat al voltant del límit entre el Maastrichtià inferior i el superior, les noves dades d’aquesta tesi mostren que les extincions i noves aparicions de clades no van coincidir en el temps. Ans al contrari, el reemplaçament faunístic entre grups de dinosaures va durar uns dos milions d’anys a la regió, existint un període de coexistència entre formes antigues i els nous habitants de l’illa Ibero-Armoricana. El canvi faunístic no es va produir com a conseqüència d’esdeveniments climàtics concrets, sinó per successives migracions durant episodes de trencament de barreres geogràfiques a Europa.<br>The terrestrial Campanian/Maastrichtian geological and paleontological record from southwestern Europe is one of the best outside North America to study the last 15 milion years previous to the Cretaceous-Paleogene mass extinction. The narrative of the last dinosaur communities from the Ibero-Armorican Island (European Archipelago) is addressed by studying their occurrences, associated paleoenvironments and magnetostratigraphic dating. Such integrated works in the Mesozoic portion of the Tremp Group (South-Pyrenean Basin) includes the study of footprints of the ichnogenus Hadrosauropodus, linked to hadrosaur dinosaurs. These tracks are abundant in the fluvial coastal plains of the upper Maastrichtian. In addition to the fluvial ecosystem, hadrosaurs also colonized the coastal environment (e.g. lagoons), as reveals the L’Espinau site (amongst other localities). In contrast, sauropods were dominant in the Campanian and the lower Maastrichtian coastal and inland environments of the region, but were still present in those settings until the uppermost Maastrichtian, as evidenced by bones, eggshell and tracks, and skin impressions. However, their remains were much scarcer than those of hadrosaurs at this age. The dinosaur faunal succession of southwestern Europe has been improved by means of: 1) habitat understanding, 2) dating and integrating the Aude record (northern Pyrenees), 3) improving of the age calibration of the Isona sector (southern Pyrenees), and 4) integrationg of the Campanian-Maastrichtian dinosaur fossil record from the rest of France, Spain and Portugal (Provence and Iberian areas). Dating refinements permit a new model for the Maastrichtian dinosaur faunal succession. Instead of a rapid faunal shift from titanosaurian-dominated herbivorous assemblages to hadrosaur-dominated communities around the early-late Maastrichtian boundary, the achieved data show that the extinction of major clades and the apparition of new ones took place diachronously and was not time coincident. On the contrary, a coexistence period of about two milion years between older and newer Ibero-Armorican dinosaur inhabitants have been identified. This dinosaur turnover was not the response to environmental changes, but probably to faunal migration episodes after geographical barriers disappeared.

La present tesi presenta un estudi de les petjades tridàctiles de dinosaure a partir d’una perspectiva morfològica que representa una nova visió i aproximació a la icnologia clàssica. S’han analitzat en profunditat els mecanismes que principalment controlen i afecten la morfologia de les petjades durant la seva formació, amb l’objectiu final d’aportar dades àmplies i quantitatives per discutir el fonament principal de la variació morfològica registrada en petjades individuals, rastres i conjunts de rastres. El compendi d’aquesta tesi recull sis estudis diferents de diversos marcs geogràfics (España, Portugal, Marroc i Suïssa) i geològics (del Juràssic Mitjà a l’actualitat) i la proposta d’un enfocament preliminar en un experiment controlat de laboratori. Aquest experiment pretén extrapolar i determinar tots els paràmetres (contingut d’aigua, propietats i composició del substrat, mida de gra, porositat) que intervenen en el procés de formació d’una petjada en substrats heterogenis durant la penetració mecànica d’un motlle de peu de voltor (capítol 10). Per aquesta tesi la conca de Cameros (Nord-oest d’Espanya) ofereix dos escenaris diferents del Cretaci Inferior: la reinterpretació d’un rastre llarg d’ornitòpode sobre un substrat homogeni al jaciment amb petjades de Barranco de La Canal (capítol 5), i el nou estudi de quatre rastres inèdits de teròpodes creuant-se en un substrate heterogeni al jaciment de petjades d’El Frontal (capítol 9). La localitat de la conca de l’Argana (Marroc) ha proporcionat observacions neoicnològiques que es consideren importants a l’hora d’identificar interpretaciones errònies d’icnopatologies i superfícies en pendent en el registre fòssil (capítol 8). Aquestes localitats mostren diferents patrons de variació morfològica intrarastre definits com alternat, el qual depèn de la dinàmica de les extremitats i l’anatomia del peu de l’animal productor; i continu, el qual depèn de la consistència del substrat al llarg de la superfície on es produeixen les petjades. La conca lusitana (centre-oest de Portugal) conté la localitat ja coneguda però inèdita del Juràssic Mitjà de Vale de Meios, l’estudi de la qual destaca per la importància d’haver analitzat tots els tipus de preservació de petjades a l’hora de reconèixer la morfologia mitjana i el fet que no s’hauria d’assumir que els icnotàxons de vertebrats estan restringits a edats i regions geogràfiques específiques (capítol 7). La plataforma carbonàtica del Jura (Nord-oest de Suïssa) conté sis localitats amb petjades del Juràssic Superior, que juntament amb 49 rastres i 397 petjades, aporten el nou i inèdit material per a la descripció d’una nova icnoespècie i la discussió de les variacions morfològiques de les petjades, introduint la possibilitat que les icnoassociacions clàssiques puguin ser el resultat de variants preservacionals del mateix animal productor (capítol 6). Aquests dos estudis mostren que quan es comparen múltiples rastres del mateix jaciment o icnoagrupacions, s’han de tenir en compte la diversitat taxonòmica i els canvis comportamentals juntament amb les condicions del substrat i la dinàmica de les extremitats de l’animal productor. Les tecnologies tridimensionals han estat la base i l’eina per a totes les anàlisis quantitatives que s’han realitzat. Els escàners LiDAR han estat sempre un complement a la fotogrametria de curt abast per tal d’aconseguir els majors detalls morfològics i aportar una quantificació sistemàtica i precisa de la variació morfològica de les petjades.<br>The study of tridactyl dinosaurs tracks from a morphological perspective is here presented in the form of a new look and approach to the classic ichnology. The mechanisms that mostly control and affect track morphology during its formation have been thoroughly analysed, so that the ultimate goal is to provide extensive quantitative data to discuss the main foundation of morphological variation registered in individual tracks, trackways and large sets of trackways. The compendium of this PhD collected six different studies from distinct geographical (Spain, Portugal, Morocco and Switzerland) and geological frames (from Middle Jurassic to present) and the proposal of a preliminary approach in a laboratory controlled-experiment. This experiment aims to extrapolate and determine all parameters (water content, substrate properties and composition, grain size, porosity) intervening in the track formation process on heterogeneous substrates during the mechanical indentation of a vulture foot cast (chapter 10). The Cameros basin (NW Spain) offered two Early Cretaceous different scenarios for this thesis, the re-interpretation of a long ornithopod trackway on homogeneous substrate at the Barranco de La Canal tracksite (chapter 5) and the new study of four previously unpublished theropod trackways inter-crossing a heterogeneous substrate at the El Frontal tracksite (chapter 9). The locality visited within the Argana basin (Morocco) provided neoichnological observations that are consider important for the identification of misinterpretations of ichnopathologies and sloping surfaces in the fossil record (chapter 8). These localities showed two different intra-trackway morphological variation patterns defined as alternate, which depends on the limb dynamics and foot anatomy of the trackmaker and continuous, which depends on the substrate consistency change along the tracking surface. The Lusitanian basin (Central-West Portugal) presented the previously known but unpublished Middle Jurassic quarry of Vale de Meios which underscores the importance of analyzing all types of track preservations in order to recognize the average morphology and that there should not be an assumption that vertebrate ichnotaxa are confined to specific ages or geographic regions (chapter 7). The Jura Carbonate platform (NW Switzerland) encompassed six Late Jurassic tracksites, which together with 49 trackways and 397 tracks provided the new and unpublished material for the description of a new ichnospecies and the discussion of track morphological variations, introducing the possibility that classic ichnoassociations might be the result of preservational variants of the same trackmaker (chapter 6). These two studies showed that when comparing multiple trackways on the same site or ichnoassemblage, taxonomical diversity and behavioural changes have to be considered together with substrate conditions and limb dynamics. Three-dimensional technologies have been the support and tool for all the quantitative analysis undertaken. LiDAR scans have been always complemented with a close range photogrammetry in order to give the highest morphological details and to provide a precise and systematic quantification of the track morphological variations recorded.

The Sauropodomorpha represented a globally important clade of Mesozoic herbivores and included the largest terrestrial animals known to science. This makes them of great interest in understanding the fundamental constraints acting upon terrestrial life and the evolution of gigantism. However, sauropodomorph biology presents many problems, not least how they secured sufficient food intake to fuel their massive bodies. Herein, a combination of morphological description, 3D reconstruction of osteology and myology, biomechanical modelling, multivariate analysis and evolutionary modelling was performed in order to investigate the sauropodomorph feeding apparatus in more detail. This integrated approach pennitted intenogation of hypotheses that have linked the diversification and gigantism of sauropodomorphs with the evolution of herbivory in the clade. Results demonstrate that basal ('prosauropod') taxa are characterized by relatively gracile and mechanically inefficient skulls and mandibles, but are also highly disparatepotentially relating to variation along the omnivorylherbivory spectrum. A prominent functional shift towards increased cranial robusticity and jaw processing power is observed at the base of Sauropoda, coincident with the attainment of very large body size. This is consistent with a shift towards bulk-herb ivory, providing quantitative evidence for the hypothesised role of such an ecological shift as a driver of sauropodomorph gigantism. Shifts towards novel functional morphologies are also observed in some derived sauropod lineages. Although some similarities are acquired convergently by the derived diplodocoids and titanosaurs each clade remains highly disparate and they cannot be stereotyped as confonning to a common functional 'grade'. The high disparity present in sauropod craniodental systems would have suppOlied dietary niche partitioning between sympatric taxa. Still, despite these functional shifts overall disparity does not increase through the Mesozoic. Similarly, sauropodomorphs do not reoccupy small body sizes after the extinction of 'prosauropod' taxa, suggesting constraint to larger sizes as a result of specialisations of the sauropod bauplan towards gigantism.

This dissertation examines how the modern dinosaur—fully mounted, freestanding assemblages of vertebrate fossils such as we are accustomed to seeing at the natural history museum—came into being during the late 19th and early 20th century, focusing especially on the United States. But it is not just, or even primarily a history of vertebrate paleontology. Rather, I use dinosaurs as an opportunity to explore how science was embedded in broader changes that were happening at the time. In particular, I am interested in tracing how the culture of modern capitalism—the ideals, norms, and practices that governed matters of value and exchange—manifested itself in the way fossils were collected, studied, and put on display. During the second half of the 19th century, America experienced an extended period of remarkable economic growth. By the eve of WWI, it had emerged as the world’s largest producer of goods and services. At the same time, paleontologists were unearthing the fossil remains of marvelous creatures the likes of which no one had ever dreamed in the American west. The discovery of dinosaurs like Brontosaurus, Stegosaurus, Tyrannosaurus, and Triceratops prompted the nation’s wealthy elite to begin cultivating an intense interest in vertebrate paleontology. In part, this is because dinosaurs meshed well with a conventional narrative that celebrated American exceptionalism. Dinosaurs from the United States were widely heralded as having been larger, fiercer, and more abundant than their European counterparts. Not only that, but their origins in the deep past meant that dinosaurs were associated with evolutionary theory, including the conventional notion that struggle was at the root of progress. Finally, it did not hurt that America’s best fossils hailed from places like Colorado, Wyoming, and Utah. This is precisely where most of the raw materials consumed by factories could also be found. As they coalesced into a coherent social class, American capitalists began to patronize a number of elite cultural institutions. Just as Gilded Age entrepreneurs invested considerable resources in the acquisition of artworks, so too did they invest in natural history. However, whereas the acquisition of artworks functioned as a display of refined aesthetic sensibilities, the collection of natural history specimens primarily represented another form of social distinction, one that combined epistemic virtues like objectivity with older notions of good stewardship and civic munificence. Capitalists who had grown rich off of the exploitation of America’s natural resources turned to dinosaur paleontology as a form of cultural resource extraction.<br>History of Science

This thesis is centred around an anatomical study of the cranial osteology of the Mesozoic sphenodontidans, Asiacephalosaurus wangi, Rarojugalosaurus mcgilli, Dianosaurus petilus and Homoeosaurus maximiliani. The first two are newly discovered and have not been studied previously. The third, previously described only in a preliminary fashion, was misinterpreted as a protorosaur. Although many specimens of H. maximiliani have been described (Cocude-Michel, 1963; Faber, 1981) since the species was first named by Meyer (1845), the newly exposed dorsal part of the skull of a new specimen has provided many new cranial features. Consequently, it was necessary to examine, draw and describe all of these sphenodontidans. The descriptions are all original and present a virtually complete picture of the cranial osteology of these genera for the first time. In addition, the different patterns of the middle ear apparatus of the Sphenodontida and the functional problems of the temporal region in the Lepidosauria have been considered. Although use is made of the literature to obtain background data, the conclusions drawn are original unless explicitly stated otherwise. Finally, the detailed descriptions of the four genera have permitted a reassessment of the phylogeny of the Sphenodontida. After reviewing the literature, original conclusions are given.

Maniraptoriformes, the speciose group of derived theropod dinosaurs that ultimately gave rise to modern birds, display a diverse and remarkable suite of skeletal adaptations. Apart from the evolution of flight, a large-scale change in dietary behavior appears to have been one of the main triggers for adaptations in the bauplan of these derived theropods. Amongst the different skeletal specialisations, partial or even complete edentulism and the development of keratinous beaks form a recurring and persistent trend in the transition from derived nonavian dinosaurs to birds. Therizinosauria is one of the most enigmatic and peculiar clades among Maniraptoriformes, exhibiting an unusual suite of characters, such as lanceolate teeth, a rostral rhamphotheca, long manual claws and a wide, opisthopubic pelvis. This specialised anatomy has been associated with a shift in dietary preferences and an adaptation to herbivory, making therizinosaurs prime candidates to assess the functional significance of these morphological characters. Centered on the skull of the therizinosaur Erlikosaurus andrewsi from the Upper Cretaceous of Mongolia, a wide range of computational techniques (including computed tomography, digital reconstruction and biomechanical modelling using finite element analysis) has been utilised in this thesis to investigate the skull form and function in therizinosaurs and to elucidate their palaeobiology. Evidence from hard- and soft tissue reconstructions of Erlilcosaurus andrewsi demonstrate that teeth had lost their importance and function in derived therizinosaurs. Rather a keratinous rhamphotheca was developed early in Therizinosauria to replace rostral teeth as a main device to procure and manipulate food. The results of a highly detailed biomechanical model of Erlikosaurus andrewsi further suggest that a keratinous rhamphotheca represent an evolutionary innovation developed early in the transition from non-avian dinosaurs to birds to enhance cranial stability, distinct to postulated mass-saving benefits associated with the origin of flight.

Southern Pyrenees has provided an abundant fossil record of dinosaur eggs and eggshells. Historically, the oofamily Megaloolithidae has shown its predominance over any other group of fossil eggs in this region. In addition, this oofamily is world-wide distributed being represented by, at least, four oogenus and 20 oospeices. Considering that the eggshell is a high stable structure, this number of Megaloolithus‘s oospecies is too high for such a relatively short time-interval (Campanian to Maastrichtian; less than 7 My). The structural characters used to define these oospecies are critically revised. As a consequence, three structural groups have been identified, and only ten oospecies have been considered valid. Four of those oospecies have been recognized in Southern Pyrenees: M. aureliensis, M. sirugei, M. mamillare and M. baghensis. The oogenus Cairanoolithus, historically included in Megaloolithidae oofamily, is reevaluated. All evidences suggest that this type of fossil egg is, definitively, different from any other Megaloolithus. Consequently, a new oofamily is erected (Cairanoolithidae oofam. nov), which emphasizes the singularity of cairanoolithid eggs. Phylogenetical analysis also suggests that the eggs of Cairanoolithidae oofam. nov. could be laid by ornithischian dinosaurs. New oological material is described here, including the first spheroolithid oospecies (Spheroolithus oosp. nov.) from the Upper Cretaceous of Europe. Several oospecies of Prismatoolithus (Prismatoolithus oosp. nov, Prismatoolithus cf. levis, Prismatoolithus oosp. indet.) and few eggshells of ratite-morphotype (cf. Ageroolithus fontllonguensis) have been identified. In addition, the great number of specimens attributed to Pseudogeckoolithus oogenus allows re-describing and re-assigning this ootaxon to Mesozoic lizards. The space-temporal variation of the oological diversity in the Southern Pyrenees could be a consequence of environmental changes during the end-Cretaceous or even due to preferences in the nesting-site of each group of dinosaurs. Finally, biostratigraphical studies based on the successions of megaloolithid oospecies have been performed in Coll de Nargó and Àger-Tremp basins, and the European Megaloolithus succession has been updated. As a result, three oozonones have been described: M. aureliensis + Cairanoolithus oozone dates the Late Campanian, M. siruguei oozone the Early Maastrichtian and M. mamillare + M. baghensis oozone the Late Maastrichtian.