A regional study has been carried out within the Eastern Venezuela Basin and its offshore continuation to the Orinoco Delta and the Barbados Accretionary Complex. The Eastern Venezuela Basin and its offshore continuation is a Neogene foredeep superimposed on a Mesozoic passive margin. The Cretaceous to Paleocene of Eastern Venezuela is best subdivided into five second order transgressive-regressive cycles bounded by a 131 Ma (basal Cretaceous) sequence boundary, four maximum flooding surfaces with the inferred age of lower Aptian (111 Ma), upper Albian (98 Ma), middle Cenomanian (95 Ma), middle Turonian (91.5 Ma) and an upper Paleocene sequence boundary (58.5 Ma). An upper Paleocene to Eocene second-order cycle (58.5 Ma-36 Ma) is followed by the Oligocene which is subdivided into two third-order cycles bounded respectively by 36 Ma, 30 Ma and 25.5 Ma sequence boundaries. An uppermost Oligocene to lower Miocene (25.5 Ma) basal foredeep unconformity is associated with the sudden deepening of the passive margin in response to the emplacement of the Serrania del Interior. The Neogene of the Eastern Venezuela foredeep consists of three second-order sequences defined by 25.5 Ma, 16.5 Ma and 10.5 Ma boundaries. In the offshore an upper Miocene (5.5 Ma) unconformity is associated with deeply incised submarine canyons. Sixteen third-order sequence boundaries are recognized and correlated over the region.

The Ediacara Biota is a distinct group of soft-bodied organisms that flourished in late Precambrian (Ediacaran) oceans. The succession at Mistaken Point, Newfoundland, contains the most extensive collection of Ediacaran fronds in the world, with hundreds of complete specimens spanning at least 10 million years. The goals of the completed thesis were to investigate the growth strategies, preservational biases, function, and taxonomy of Ediacaran fronds through the use of qualitative morphological descriptions and quantitative morphometrics. Several of these mathematical techniques had not been previously applied to the Ediacara Biota, and strengthen traditional descriptive techniques through mathematical scrutiny. The second chapter applies standard biometric and principal components analyses to the cosmopolitan frond Charniodiscus from Newfoundland, which allowed for rigorous definition of two new closely related species that evolved differently shaped petalodiums to extract nutrients from different levels in the water column. The third chapter utilizes "landmark morphometrics" to interpret the original 3D shape of Charnia. These techniques suggest that traditional descriptions of Ediacaran fronds as sheet-like organisms are incorrect, and are a direct result of preservational processes. It was demonstrated that branch rigidity is species specific, resulting in the description of a new species of ancestral Charnia. The fourth chapter describes a new species of multifoliate rangeomorph frond that was preserved in four unique taphonomic settings. Only through comparison of specimens from all four preservational regimes was it possible to reconstruct the original morphology of this frond, and isolate taphonomically based features from true morphological characters. The final chapter reviews the biological significance of the frond morphoshape, and proposes that the present emphasis on overall shape in Ediacaran taxonomy is inherently flawed. It is recommended that a new system be erected to classify Ediacaran fronds based on branching architecture, as frond morphology most likely represents a common need to extract nutrients from the water column, and therefore represents a shared ecology, not ancestry. / Thesis (Ph.D, Geological Sciences & Geological Engineering) -- Queen's University, 2007-10-09 15:06:08.885

No description available.

Modern archosaurs have extensive pneumatic invasions derived from nasal and tympanic sinuses. These are present in many fossil archosaurs, but their evolutionary history has yet to be clarified. A full description of the cranial pneumaticity of a well-preserved ornithomimid theropod is presented to help clarify the evolution of this soft tissue using CT scan data and 3D reconstruction. The cranial sinuses of Ornithomimus edmontonicus represent nearly all cranial sinuses of birds and add new information to the range of that of ornithomimids. Phylogenetic comparisons of cranial pneumaticity across theropods with emphasis on O. edmontonicus imply a novel homology between the jugal fossa or recess of non-avian theropods and the suborbital diverticulum of birds. Comparisons also establish the presence of an avian-like nasal sinus morphology at Neotetanurae and tympanic sinus morphology at Coelurosauria. / Les archosauriens modernes ont des invasions pneumatiques extensives dérivées de leurs sinus nasales et tympaniques. Ils sont présents dans de nombreux fossiles d’archosauriens, mais l’histoire de leur évolution demeure incertaine. Une description complète de la pneumaticité crâniens d’un théropode ornithomimidé bien préservé aide à clarifier l’évolution de ces tissues mous à l’aide de donnés d’un scanneur CT et de la reconstruction 3D. Les sinus crâniennes de Omithomimus edmontonicus représentent presque tous les sinus crâniens des oiseaux et rajoutent de nouvelles informations en ce qui à trait aux ornithomimidés. Les comparaisons phylogénétiques de la pneumaticité crânienne à travers les théropodes avec une emphase sur O. edmontonicus suggèrent une nouvelle homologie de la jugal fossa ou la dépression des théropodes non-aviaires et le diverticulum sous-orbital des oiseaux. Les comparaisons permettent aussi d’établir la présence de sinus nasals à morphologie aviaire au Neotetanurae et de sinus à morphologie tympanique au Coelurosauria.

The origin of birds is one of the major evolutionary events in vertebrate history. The transition from non-avian to avian theropod dinosaurs encompass the origin of powered flight, a suite of musculoskeletal adaptations for powered flight, and early radiation of one of the most taxonomically and ecologically diverse groups of vertebrates today. In this thesis I will examine four separate but interrelated aspects of the non-avian to avian theropod transition and comment on how my findings shape our view of the origin of birds and powered flight in vertebrates and the tempo and mode of a macroevolutionary transition.The first chapter of my thesis is a detailed examination of character change in the forelimb and pectoral girdle of Theropoda including the non-avian to avian transition. This work focuses on both the placement and magnitude of character change along the phylogenetic backbone from early theropods through to birds. Across these phylogenetic permutations, three nodes repeatedly showed significant increased levels of evolutionary change: Tetanurae, Paraves, and Ornithothoraces. Notably Aves itself did not have above average evolutionary change and in most permutations had little to no character change in the forelimb at this node. This punctuated signal and the lack of forelimb skeletal evolution at Aves supports the hypothesis that the basic composition of the avian wing was in place before the origin of birds, and that other factors had a significant role in the transition from non-volant to volant locomotion. Chapter two is a re-description and re-analysis of a small feathered maniraptoran for the Jehol Biota Yixianosaurus longimanus. The phylogenetic analysis suggests that Yixianosaurus shares a basal position within Maniraptora, near Coelurus and Therizinosauria. This re-description was incorporated into a larger study of the proposed ecological niches selection of Jehol theropods based on the linear bone measurements and morphology of the forelimb skeleton. This work adds to our understanding of the evolution of Maniraptora by further refining the evolutionary characters and trends at its origins and suggests more accurate functional characters and paleoecolgical reconstructions for some advanced maniraptorans. The third section of my thesis is a test of the arboreal origin of birds theory and an examination of the paleoecological setting for the origin of the avian flight stroke. This work presents the traditional "tree's down" versus "ground up" debate on the origin of flight in a testable framework. This work demonstrates that all non-avian theropods and Archaeopteryx group closer to terrestrial cursors than any climbing lineage. It also highlights the differences between post-Archaeopteryx basal birds, which are generally accepted to have had the ability to actively fly, and non-avian theropods in regards to arboreal adaptations. Basal birds cluster closer to modern perching birds whereas all non-avian theropods cluster with strictly terrestrial avians, such as ratites. This work strongly suggests that theropods were not arboreal until after the origin of both birds and flight, and places the origin of the avian flight stroke in a terrestrial context. The final chapter examines the effects of allometry on the theropod appendicular skeleton. Through the use of snout to vent length as a size proxy, a common approach in extant vertebrates, both the absolute and relative scaling of limb elements are studied. Using nodal reconstructions on trees encompassing 6 distinct phylogenetic hypotheses, the purported trend of maniraptoran theropod's elongating their forelimb beyond those expected by commensurate size reduction are tested. The results suggest that non-paravian theropods have no signal of forelimb enlargement beyond that expected through allometry. Furthermore this study suggests that avians have shorter than expected hindlimb lengths, which conflates the signal of forelimb enlargement seen in this clade. / L'origine des oiseaux est l'un des événements majeurs dans l'histoire évolutive des vertébrés. La transition des dinosaures theropod en oiseaux comprends le vol d'origine alimenté, une suite d'adaptations musculo-squelettiques pour le vol motorisé, et le rayonnement au début d'un des groupes les plus taxonomiquement et écologiquement diversifié de vertébrés aujourd'hui. Ici, on examine quatre aspects distincts, mais interdépendants de la transition des theropodes non-aviaire en théropodes aviaire, et on commente sur la façon dont mes conclusions à façonner notre point de vue de l'origine des oiseaux et vol propulsé chez les vertébrés et le tempo et le mode d'une transition macroévolutifs. Le premier chapitre de ma thèse est un examen détaillé des changement de la ceinture pectorale de membres antérieurs dans les theropod y compris les membres transitoires non-aviaire - aviaire. Ce travail se concentre sur le placement et l'ampleur du changement de caractère le long du squelette phylogénétique à partir des theropods. Trois nœuds à plusieurs reprises montré des niveaux significativement accru de changements évolutifs: Tetanurae, Paraves et Ornithothoraces. Notamment Aves lui-même n'a pas supérieure à la moyenne des changements évolutifs. Ce signal ponctué et le manque d'évolution du squelette du membre antérieur au Aves soutient l'hypothèse que la composition de base de l'aile aviaire a été mis en place avant l'origine des oiseaux, et que d'autres facteurs ont un rôle important dans la transition de la non-volant au volant de locomotion.Le chapitre suivant est une re-description et ré-analyse d'une petite maniraptoran plumes pour le Jehol Biota Yixianosaurus longimanus. L'analyse phylogénétique suggère que Yixianosaurus part une position basale dans le groupe théropodes Maniraptora. Cette re-description a été incorporé dans une étude plus vaste de la sélection proposée niches écologiques des théropodes Jehol basé sur les mesures linéaires et la morphologie des os du squelette du membre antérieur. Ce travail ajoute à notre compréhension de l'évolution de la Maniraptora en affinant encore les caractères évolutifs et les tendances à sa base et suggère que plus précise des caractères fonctionnels et des reconstructions paleoecolgical pour certains maniraptorans avancés. La troisième section est un test de l'origine arboricole de la théorie des oiseaux et un examen de la mise en paléoécologie de l'origine de la course de vol aviaire. Ce travail présente le debat traditionnel «arbre bas» versus «zéro» sur l'origine de la fuite dans un cadre testables. Ce travail démontre que tous les théropodes non aviaires et de Archaeopteryx du groupe proche de curseurs terrestre que toute la lignée d'escalade. Il souligne également les différences entre le post-Archaeopteryx oiseaux basale, qui sont généralement acceptées d'avoir eu la possibilité de voler activement, et non aviaires théropodes en ce qui concerne les adaptations arboricoles. Les oiseaux basales pôle rapprochent les oiseaux modernes perchés alors que tous les théropodes non aviaires strictement terrestre, tels que les ratites. Ce travail suggère fortement que les théropodes ne sont pas arboricoles qu'après l'origine de deux oiseaux et le vol, et place l'origine de la course de vol aviaire dans un contexte terrestre. Le dernier chapitre examine les effets de l'allométrie du squelette appendiculaire théropodes. Grâce à l'utilisation de longueur museau-cloaque comme un proxy taille, une approche commune chez les vertébrés existantes, à la fois l'échelle absolue et relative des éléments du membre sont étudiées. Les résultats suggèrent que non paravian théropodes ont aucun signal de l'élargissement au-delà des membres antérieurs prévu par allométrie. En outre, cette étude suggère que aviaires sont plus courts que prévu longueurs membres postérieurs, qui assimile le signal de l'élargissement des membres antérieurs vus dans ce clade.

North of Grand Rapids, Manitoba, new exposures of a carbonate succession prompted study of the lithology and paleontology of the uppermost Ordovician along the northern edge of the Williston Basin in Manitoba. Modern concepts and approaches were applied in examining the sedimentary rocks and fossils, including X-ray diffraction, stable carbon and oxygen isotope analysis, and statistical algorithms. Nine lithofacies, representing a series of shallowing events, and environmentally significant subaerial exposure surfaces, were identified. The distribution and relative abundance of identified fossils were used to delineate faunal associations, which were examined in the context of the impending end-Ordovician mass extinction. Historically, the stratigraphy of the latest Ordovician has been problematic. Therefore, detailed examination of this succession aided in clarifying unit boundaries in the Stony Mountain and Stonewall formations. Study of this new succession contributed a wealth of information to the understanding of the uppermost Ordovician of Manitoba.

<p> In this study, I focus on the loss of species diversity&mdash;and therefore morphological diversity&mdash;within the Cimolodonta (Multituberculata) during the Cretaceous-Paleogene (K-Pg) extinction, followed by their recovery in the Puercan (earliest Paleogene). Teeth make up the majority of the cimolodontan fossil record, allowing inferences of dietary ecology, body size estimates, and phylogenetic proximity. I analyzed morphological disparity within the restricted phylogenetic framework of the Cimolodonta. I addressed 3 questions: 1) Did the conditions of the K-Pg extinction select for or against cimolodontan dental morphologies, if it was selective at all? 2) Do levels of cimolodontan morphological similarity return to pre-extinction levels in the Puercan? 3) Do the Puercan Cimolodonta recover morphology lost during the extinction, or do the Cimolodonta morphologically diverge from the pre-extinction morphospace? I used Euclidian inter-taxon distance measures derived from dental character data to perform a principal coordinates analysis (PCO), generating a multidimensional representation of morphological similarity. To assess the selectivity versus non-selectivity of cimolodontan extinction across the K-Pg boundary, I analyzed the axes of the morphospace for morphological character gradients. I tested for extinction selectivity to determine the probability of generating the survivor-specie morphospace by chance. These results indicate significant (P = 0.0006) selection affecting cimolodontan survival across the K-Pg extinction. Overall morphospace occupation changed significantly (P &lt; 0.015) in the Puercan as well. I attribute this change in morphospace occupation to the diversification of the Taeniolabididae and incomplete recovery of Late Cretaceous morphospace by the Puercan Cimolodonta. Vacancies in the Puercan cimolodontan morphospace may be a result of changes in available dietary resources, or competitive exclusion. The Taeniolabididae occupy a morphospace region distant from the remainder of the Puercan Cimolodonta, supporting independent studies suggesting they were an immigrant taxon rather than a product of rapid phenotypic divergence. My results indicate selection taking place over the K-Pg extinction for small body size within the Cimolodonta. I also find evidence of partial reoccupation of Late Cretaceous cimolodontan morphospace in the Puercan, indicating ecological niche recovery.</p>

<p> The Ordovician strata of the Lower Member of the Vinini Formation comprise a sequence of greenstone, sandstone, shale, and siltstone representing the prograding and retrograding of submarine fans along the continental margin. Although graptolites are normally preserved within shale beds in the Lower Member of the Vinini Formation, the greatest abundance of well preserved graptolites is found within the sandstone turbidite beds. These graptolites are uniquely preserved in full relief as opposed to being flattened on shale. It is interpreted based on fragmentation and species composition within the sandstone that the graptolites flourished in an upwelling zone on the continental margin and that as their remains accumulated on the underlying seafloor, were swept downslope in turbidity currents. </p><p> Graptolites were collected from 10 beds within the stratigraphic section and represent 33 taxa from 17 genera. There are no new taxa. All taxa are described, illustrated, and compared to other collections.</p>

Conodonts were extracted from three limestone units in westcentral Indiana: the Silverwood Limestone Member of the Staunton Formation; the Universal Limestone Member of the Dugger Formation; and from a new unit, the informally named Salt Creek limestone lens (Dagger Formation). Identified conodonts include: Adetognathus gigantus (Gunnell), 1933; Adetognathus lautus (Gunsell), 1933; Idiognathodus delicatus Gunnell, 1931; Idiognathodus sinuosis Ellison and Graves, 1941; Neognathodus bassleri bassleri (Harris and Hollingsworth), 1933; Spathognathodus coloradoensis Murray and Chronic, 1965; S athognathodus minutes Ellison, 1941; Spathognathodus orphanus Merrill, 1973; Streptognathodus holmesi Gunnell, 1933; and Streptognathodus minatus Gunnell, 1933.The presence of the genus Streptognathodus in the Salt Creek limestone lens supports the hypothesis that streptognathodid numbers increase in rocks of mid-Desmoinesian age or younger. The scarcity of conodonts in the Universal Limestone Member may ba attributed to storm-related deposition of unusually large quantities of carbonate sediments, effectively diluting the conodont population, followed by infaunal reworking of these sediments during a period of little or no deposition.The occurrence of conodonts establishes that the Silverwood limestone Member is early to middle Desmoinesian in age, the Universal Limestone Member is middle to late Desmoinesian in age, and that the newly discovered Salt Creek limestone lens is middle to late Desmoinesian in age.

<p> Abstract not available.</p>