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<p> This research project seeks to deconstruct the history of the horse in the Americas and its relationship with the Indigenous Peoples of these same lands. Although Western academia admits that the horse originated in the Americas, it claims that the horse became extinct in these continents during the Last Glacial Maximum (between roughly 13,000 and 11,000 years ago). This version of &ldquo;history&rdquo; credits Spanish conquistadors and other early European explorers with reintroducing the horse to the Americas and to her Indigenous Peoples. However, many Native Nations state that &ldquo;they always had the horse&rdquo; and that they had well established horse cultures long before the arrival of the Spanish. To date, &ldquo;history&rdquo; has been written by Western academia to reflect a Eurocentric and colonial paradigm. The traditional knowledge (TK) of the Indigenous Peoples of the Americas, and any information that is contrary to the accepted Western academic view, has been generally disregarded, purposefully excluded, or reconfigured to fit the accepted academic paradigm. Although mainstream academia and Western science have not given this Native TK credence to date, this research project shows that there is no reason&mdash;scientific or otherwise&mdash;that this traditional Native claim should not be considered true. The results of this thesis conclude that the Indigenous horse of the Americas survived the &ldquo;Ice Age&rdquo; and the original Peoples of these continents had a relationship with them from Pleistocene times to the time of &ldquo;First-Contact.&rdquo; In this investigation, Critical Indigenous Research Methodologies (CIRM) and Grounded Theory (GT) are utilized in tandem to deconstruct the history of the horse in the Americas and reconstruct it to include cross-cultural translation, the TK of many Indigenous Peoples, Western scientific evidence, and historical records. This dissertation suggests that the latest technology combined with guidance and information from our Indigenous Peoples has the power to reconstruct the history of the horse in the Americas in a way that is unbiased and accurate. This will open new avenues of possibility for academia as a whole, as well as strengthen both Native and non-Native communities.</p>

<p> Measurement of bioturbation reflects physical and biological processes operating over time and can be used to reveal information about paleo-environments. The purpose of this study was to determine the intensity of bioturbation in Triassic Moenkopi Formation at Hurricane Mesa in Southwestern Utah. This formation is interpreted as having been deposited mostly in large ancient river channels, tidal flats, delta and shallow marine environments. Five stratigraphic sections measured in the Virgin Limestone Member provided the basis for this study. Detailed descriptions and quantification of bioturbation were recorded in each of the sections. Similar treatment was given to additional study sites in the rest of the formation, above the Virgin Limestone. Treatments on selected samples were implemented to better reveal evidence of bioturbation. In these treatments samples were coated with water or oil, etched with HCL and viewed under blacklight. Integrating the results of the treatments with x-ray diffraction and petrographic analysis suggest that there was minimal bioturbation. These findings are consistent with more rapid deposition than previously reported by other researchers.</p>

Gorgonopsia represent a group of specialised carnivorous therapsids that filled the role of apex predator during the Late Permian of Gondwana. Skull size in the Gorgonopsia ranges from that of a cat, to larger than any extant, terrestrial predator. Despite this degree of size variation, the observed morphological variation in the skull is relatively conservative. This study set out to better understand the extent of size and morphological variation among species attributed to the South African genus, Aelurognathus, with the aim of possibly refining the taxonomy of the genus. Aelurognathus was chosen, as it contains the largest number of described specimens (16) of any of the Rubidgeinid genera. Previous work has led to numerous revisions to the taxonomic assignment of each specimen, at both the generic and specific levels. All available specimens were studied and morphological differences at both the intraspecific and interspecific levels noted. Morphological variations allowed for the division of the six previously recognised species into three morphotaxa based on the character state of the preparietal and the extent of contact by the frontal on the supraorbital margin. Both characters have been shown to vary among individuals of extant taxa. Taking this into account, a hypothesis that all 16 specimens represent a single taxon, exhibiting a high degree of morphological variation, was tested using allometric techniques. Linear measurements of the skull were selected, such that variation in skull size and shape was accounted for in all dimensions. Results of the bivariate analyses showed a high level of correlation with the bivariate fitted lines plotted, supporting the single taxon hypothesis. While Aelurognathus has previously been divided into six species, using morphological characters, this study has shown that the characters used in the past have been unreliable. As such it is proposed that all species attributed to Aelurognathus be synonymised with the type, Aelurognathus tigriceps.

Theropod dinosaurs are an iconic and familiar group of extinct species that include predators such as Tyrannosaurus and Velociraptor, as well as an array of other Mesozoic taxa. Carnivorous theropods are the evolutionary ancestors of birds, and the evolutionary transition between theropods and birds is a textbook example of a major evolutionary transformation in the history of life. Despite a flurry of research on early birds and their dinosaurian relatives, however, several questions still remain. First, the anatomy of some major theropod groups has yet to be described in detail. Second, there is little consensus on the phylogenetic relationships of the basal members of a theropod subgroup called Coelurosauria: the clade of birds and their closest relatives (defined as all taxa closer to birds than to Allosaurus). Third, there has been little synthetic work on large-scale macroevolutionary patterns during theropod evolution. This dissertation includes three chapters that touches on these three major issues. Chapter 1 is a detailed description of the Late Cretaceous tyrannosaurid theropod Alioramus altai, based on its holotype specimen from the Tsaagan Khuushu locality in the Maastrichtian Nemegt Formation of Mongolia. This monographic description provides further evidence that Alioramus is an unusual long-snouted, gracile, and slender-limbed taxon with an unpredecented degree of cranial ornamentation among tyrannosaurids and an extremely pneumatized skeleton. Anatomical comparisons indicate that the long skull of Alioramus is an autapomorphic feature that is proportionally longer (relative to femur length) than in any other known tyrannosaurid specimen, including juveniles, and that Alioramus is morphologically distinctive relative to similarly-sized individuals of the contemporary and sympatric Tarbosaurus. The coexistence of the long-snouted Alioramus and robust and deep-snouted Tarbosaurus, which are found together at the Tsaagan Khuushu locality, demonstrate that multiple large tyrannosaurids were able to live in sympatry, likely because of niche partitioning due to differences in craniofacial morphology and functional behavior. Chapter 2 presents a comprehensive new phylogenetic analysis of coelurosaurian theropods, which is an updated version (and thus the latest iteration) of the long-standing Theropod Working Group (TWiG) analysis. The new analysis incoroporates a wealth of new taxa and character data into the TWiG matrix for the first time, most of which is relevant to basal (non-maniraptoran) coelurosaurs such as tyrannosauroids and ornithomimosaurs, which had previously been the subject of only cursory character and taxon sampling in TWiG studies. The full dataset was analyzed under parsimony, and the resulting phylogeny includes several well supported relationships and agrees with previous analyses in many aspects. As a result, it is argued that a consensus view of basal coelurosaurian relationships has emerged, including: 1) the monophyly of major subclades such as Tyrannosauroidea, Compsognathidae, and Ornithomimosauria; 2) the position of the singleton genera Bicentenaria, Zuolong, and Tugulusaurus near the base of Coelurosauria; 3) the placement of Tyrannosauroidea as the most basal major coelurosaurian subclade; 4) the inclusion of Guanlong, Dilong, and Proceratosaurus within Tyrannosauroidea; 5) the existence of a derived maniraptoran clade that includes alvarezsauroids, therizinosauroids, oviraptorosaurs, and paravians to the exclusion of ornithomimosaurs and tyrannosauroids. Remaining areas of uncertainty include the phylogenetic position of Compsognathidae and the singleton genus Ornitholestes, and relationships at the base of the Ornithomimosauria + Maniraptora clade and Maniraptora itself. The phylogeny indicates that much of the early history of Coelurosauria has yet to be sampled in the fossil record, that coelurosaurs originated at small body size, and that the evolution of the iconic Tyrannosaurus-like bauplan occurred only towards the end of the Cretaceous. Chapter 3 presents a geometric morphometric analysis that is used to study broad patterns in theropod skull shape variation and compare the distribution of taxa in cranial morphospace (form) to both phylogeny and quantitative metrics of biting behaviour (function). The analysis finds that theropod skulls primarily differ in relative anteroposterior length and snout depth and to a lesser extent in orbit size and depth of the cheek region, and that oviraptorosaurs deviate most strongly from the "typical" and ancestral theropod morphologies. Noncarnivorous taxa generally fall out in distinct regions of morphospace and exhibit greater overall disparity than carnivorous taxa, whereas large-bodied carnivores independently converge on the same region of morphospace. The distribution of taxa in morphospace is strongly correlated with phylogeny but only weakly correlated with functional biting behaviour. These results imply that phylogeny, not biting function, was the major determinant of theropod skull shape.

The interrelationship of the chondrichthyan subclasses is evaluated based on divergence in the nature of the suspensorium, the preorbital cranial anatomy, the distribution of major venous sinuses and localization of hematopoietic tissue. The anatomy of representative extant taxa was examined by radiography and/or dissection. Fossil selachians, paraselachians, and holocephalans of the Bear Gulch of Montana, U.S.A. (Mississippian, Namurian E2B) were studied for evidence of vascular pigmentation, suspensorium, and cranial, branchial, and pectoral anatomy. These studies validate the suspensorial condition of autodiastyly and suggest autodiastyly is a fundamental condition involved in the basic radiation of Chondrichthyes. The plesiomorphous condition of all gnathostomes is proposed to be sutodiastylic, with the hyoid arch modified for the support of an opercular covering. A precerebral fontanelle is primary within Chondrichthyes, being lost in Holocephali as cranial remodeling induces ethmoid canal formation. The holocephalan pattern of cranial vascularization is based on the more general selachian plan. Thus, given the formulation of a morphocline based on selachian, paraselachian, and holocephalan data, seemingly distinct selachian and holocephalan vascular elements are shown to be analogous. Similarly, the unique patterns of lymphomyeloid tissue distribution identified for each subclass may also be explained on the basis of general plan which has been subject to relocalization stresses. Finally, both the morphocline and a cladistical analysis of the data support a cochliodont ancestry for extant holocephalans.

acase@tulane.edu

Benthic foraminifers from the Concepcion and Encanto strata of southeastern Mexico, Isthmus of Tehuantepec, are identified and illustrated (by scanning electron and light photomicrographs). The ranges of key planktic foraminifers and calcareous nannoplankton indicate that the Concepcion and Encanto strata of the study area range from Neogene Zones 19 and 20 Blow (1969) and are lower Pliocene in age The study is based on eighty-two samples from 38 localities within a 600 sq. km. area that is centered around the town of Acayucan, Veracruz, in the western Salina Basin. A total of 214 species and subspecies of benthic foraminifers are identified and described from the Encanto and Concepcion strata. These deposits, traditionally subdivided into upper and lower Concepcion Formations and Encanto Formation by Mexican geologists, are not formations but biostratigraphic units Three assemblage zones, based on key benthic foraminifers, are proposed to define these units. The Encanto strata, with a middle to upper bathyal paleobathymetry, is represented by the Melonis affinis - Uvigerina hispida Assemblage Zone. This unit is overlain by the lower Concepcion beds represented by the Marginulinopsis hispaniolanus - Anomalinoides nucleatus Assemblage Zone (upper bathyal to outer neritic). The youngest unit, the upper Concepcion deposit, is defined by the Bolivina imporcata - Saracenaria nuttalli Assemblage Zone (outer neritic to middle neritic) / acase@tulane.edu

acase@tulane.edu