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Krey, Karl-Friedrich. "Untersuchungen zur Morphologie von dentofazialen und skelettalen Strukturen Erwachsener mit Methoden der geometrischen Morphometrie." Doctoral thesis, Universitätsbibliothek Leipzig, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-63908.
Full textAbstract:
Bibliographische Beschreibung:
Krey, Karl-Friedrich
Untersuchungen zur Morphologie von dentofazialen und skelettalen Strukturen Erwachsener mit Methoden der geometrischen Morphometrie
Universität Leipzig, Habilitation
251 S., 319 Lit.,109 Abb., 93 Tab.
Referat:
Die kieferorthopädische Diagnostik beruht neben der klinischen Untersuchung auf der metrischen Auswertung (Streckenmessungen, Winkelmessungen, Verhältniszahlen) von standardisierten extraoralen Fotos, Fernröntgenseitbildern und Modellen der Kiefer. Diese Verfahren werden denen der klassischen Morphometrie zugerechnet. In den letzen Jahren hat sich eine Vielfalt neuer Verfahren zur Analyse von biologischen Formen etabliert. Diese geometrische Morphometrie kann als Synthese multivariater statistischer Analysen kartesischer Koordinaten angesehen werden. Sie stellt eine effiziente, alle Eigenschaften von geometrischen Unterräumen abbildende Methode zur Beschreibung biologischer Formen unter Beibehaltung aller räumlichen Beziehungen dar.
In der vorliegenden Untersuchung wurden diese Methoden umfassend auf die Befunde von erwachsenen Kaukasiern angewendet. Es handelte sich dabei um 179 extraorale Fotos jeweils en face und im Profil, 463 Fernröntgenseitbilder und 242 Modelle kieferorthopädisch unbehandelter Erwachsener.
Ziel war es, mit den Methoden der geometrischen Morphometrie anhand dieser Befunde die Form, Größe und deren Variabilität in Abhängigkeit vom Geschlecht und Klassifikationen der klassischen Morphometrie zu beschreiben, und damit grundlegende Daten für die Etablierung dieser Verfahren in der Kieferorthopädie bereitzustellen.
Für die untersuchten dentofazialen Strukturen konnten mit sexuellem Dimorphismus einhergehende Größenunterschiede festgestellt und in Abhängigkeit von bestimmten skelettalen Konfigurationen erstmals differenziert und quantifiziert werden.
Die Betrachtung der Form des Gesichtes, repräsentiert durch die extraoralen Fotos, zeigte charakteristische geschlechtsspezifische Veränderungen sowie Eigenschaften, die nicht mit der Konfiguration der entsprechenden skelettalen Strukturen korrelierten. In der Analyse der Fernröntgenseitbilder konnten Veränderungen der vertikalen Dimension als ein für die Form bestimmender Faktor identifiziert werden. Auch für die untersuchten Modelle konnten in der Stichprobe die Varianz bestimmende Faktoren isoliert werden.
Der gewählte mathematisch-statistische Ansatz ermöglichte die Beschreibung unterschiedlicher (zwei- und dreidimensionaler) Strukturen mit einem einheitlichen Repertoire an Verfahren.
Es konnte gezeigt werden, dass die angewendeten Methoden in der Lage sind, die dentofaziale und skelettale Morphologie adäquat und vollständig numerisch und visuell zu beschreiben sowie klinisch relevante Fragestellungen zu beantworten.
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Plomp, Kimberly Anne. "Quantifying palaeopathology using geometric morphometrics." Thesis, Durham University, 2013. http://etheses.dur.ac.uk/6962/.
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Palaeopathology is the study of disease and injury in archaeological bone. Traditional methods rely heavily on macroscopic description which can have a high degree of subjectivity and error, as well as limiting the types of research questions possible. Geometric morphometrics are a suite of shape analysis techniques and provide an opportunity to investigate possible relationships between skeletal morphological variation and disease. This thesis aims to demonstrate the potential of applying these methods in palaeopathological research and the results illustrate the benefits of using quantifiable and objective shape analysis methods in palaeopathology. The first half of the thesis discusses the use of geometric morphometrics to investigate skeletal variation to identify possible aetiological factors in the development of Schmorl's nodes and osteoarthritis. There was a strong association found between vertebral morphology and Schmorl's nodes in the lower spine. These findings have great implications for both bioarchaeological interpretation and clinical understanding of the aetiology and pathogenesis of Schmorl's nodes. Joint morphology of the proximal ulna and distal humerus was found to have no identifiable relationship with osteoarthritis, indicating that joint morphology is not a predisposing factor in elbow osteoarthritis, nor does osteoarthritis deform the joints in a systematic manner. A tentative relationship between eburnation and knee joint morphology was identified, although these results need to be verified with future research. If the association can be supported, shape analyses may provide a way for clinicians to monitor the progression of the disease. Geometric morphometrics were also shown to objectively record pathological shape deformation resulting from leprosy and residual rickets. The ability to objectively describe lesions with quantified data will greatly strengthen palaeopathology by decreasing the subjectivity and error inherent in macroscopic based methods. This thesis represents promising groundwork for the incorporation of geometric morphometrics into palaeopathological research.
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Turner, Jennifer. "Wide-field anterior ocular surface morphometrics." Thesis, Cardiff University, 2011. http://orca.cf.ac.uk/25655/.
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The current understanding of anterior eye shape in humans is limited due to available technology and its accessibility. Accurate curvature metrics of specific areas of the peripheral cornea, corneo-limbal junction and anterior sclera have remained obscured by the limits of the palpebral aperture, since the upper and lower eyelids cover most of the vertical aspect. This thesis starts by comparing the ‘gold standard’ keratometry measurements to commonly used topographic systems. Keratometric analogues were found to be significantly different and in addition provided spurious vertical anterior ocular surface (AOS) profiles. These findings revealed a need to establish an accurate model. Magnetic resonance imaging (MRI) potentially offers the best opportunity to image the entire AOS structure. However, preliminary studies in this thesis demonstrated that the use of a 3-Tesla MRI scanner was unable to obtain sufficiently resolute data to meet requirements. As an alternative, ocular impression taking techniques were adopted during the remainder of this work to acquire the AOS data. Eye casts from impression moulds were scanned using active laser triangulation and virtual 3-dimensional surfaces rendered. Further investigations defined the most suitable material for impression taking and the amount of deformation of the AOS caused by the procedure. The ocular impression casting and scanning process was examined for accuracy and reliability. This protocol was used to sample a population of normal white European eyes in order to establish a database and define wide-field AOS variability. Volumetric and 2-dimensional topographic profiles were extracted from the digital 3-dimensional representation obtained, allowing for the analysis of point-to-point curvature differences. For the first time, the entire AOS shape has been defined with known accuracy. In addition, effects of myopic refractive error and gender are presented. This data is of potential importance to ophthalmic surgeons, ocularists, contact lens practitioners, vision scientists and researchers, in the form of a digital archive of normal white European wide-field AOS topography as a reference source.
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Sharda, Gaurav VinodKumar. "Cerebral aneurysm morphometrics from 2D biplane angiograms." Thesis, University of Iowa, 2011. https://ir.uiowa.edu/etd/5058.
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Cerebral aneurysm is a local dilation in a blood vessel in brain that can rupture and cause hemorrhagic stroke. A study by International Study of Unruptured Intracranial Aneurysms (ISUIA) has collected a large database of bi-plane cerebral angiograms from patients who were followed longitudinally. This unique data may be mined for testing hypotheses on the role of morphology metrics in rupture risk. A method of reconstructing an approximate 3D geometry of aneurysms from bi-plane angiograms was developed using techniques in curve morphing. Aneurysms from a pilot population of 150 patients were reconstructed to assess the effectiveness of the proposed method. The aim of the research is to develop a methodology for 3D reconstruction of aneurysm surface from biplane angiograms, estimate size & shape characteristics, validate the method for 3D morphometric and compare these metric against the ones estimates based on radiologic measurements.
The 3D methodology was developed and validated for the correctness of the developed method of surface reconstruction from biplane angiograms with good correlation coefficient values using a 10 patient data set. Then this method was applied on the 150 patient population studies for calculation of morphologic metric. The results showed that this method was better able to capture the shape characteristics of the aneurysm than the radiologists' way of approximating aneurysm as an ellipsoid formed from the three anatomical dimensions.
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Chiotakis, Christina. "Pliocene crocodilians of chinchilla: Identification using dental morphometrics." Thesis, Queensland University of Technology, 2018. https://eprints.qut.edu.au/119219/1/Christina_Chiotakis_Thesis.pdf.
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The key research problem of this project was to identify Australian crocodilian species from isolated teeth, which make up the largest available fossil data set. Three-dimensional images of the teeth were created from computed tomography (CT) data and statistical comparisons allowed several extinct species to be distinguished from each other and from modern crocodiles. The research provides a new methodology for identifying crocodilian teeth, and potential for further usage of this methodology including identifying theropod dinosaurs and other species from isolated teeth.
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Dibble, Jacob Leonard. "Urban morphometrics : towards a quantitative science of urban form." Thesis, University of Strathclyde, 2016. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27955.
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The field of Urban Morphology is a branch of academic research focussing on the study of urban form. Although prior works in this field had been undertaken earlier, the formal establishment of the discipline of Urban Morphology can be traced back to the establishment of the International Seminar on Urban Form in 1994, and the subsequent Journal of Urban Morphology. The efforts in this field are found to be largely reliant, from the point of view of methods and definitions, on two foundational research roots, the Conzenian and the Muratorian processes. Both of these dominant traditions emerged independently in the 1960’s. Contemporary works in the field are found to consistently uphold the status quo within the discipline and fail to challenge or validate the very definitions of form used so frequently and implicitly in all assessments. This thesis recognises that the field of Urban Morphology lacks a rigorous lexicon of the urban form, as well as a quantitatively-driven, systematic and comprehensive means of analysing and comparing urban form. A methodology is developed as a systematic, quantitative and comprehensive process of measuring,defining and classifying urban form. This process entails the study of the measurements of urban form and is termed Urban Morphometrics. Central to Urban Morphometrics is the assignment of rigorous definitions to the urban elements, called Constituent Urban Elements. A Methodology of measuring these elements and their inter-relationships at the scale of the Sanctuary Area is tested rigorously against Validation, Robustness and Universality criteria, and culminates in the first taxonomy of urban form. Largely following statistical processes of biological morphometrics, this analysis reveals the relative importance of the various measurements of urban form and derives a minimal set of criteria for measuring urban form. Urban Morphometrics is then integrated into a more typical study of Urban Morphology and later tested to reveal its relevance in professional planning practice. Finally, the classification of urban form is used as a platform for discussing the theory of Urban Evolution and the first bifurcation in the evolutionary pathways of cities, evidenced through the resulting classification of urban form.
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Grass, Andy Budd Ann F. "Examining ecosystem structure and disparity through time using geometric morphometrics." [Iowa City, Iowa] : University of Iowa, 2009. http://ir.uiowa.edu/etd/367.
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Woo, Johnathan. "Evaluating facial ontogeny of avian embryos using 3D geometric morphometrics." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/50056.
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Objectives: In order to study abnormal facial development, reference standards of normal development are required. It is challenging to obtain 3D data on early embryos, since they are comprised of non-differentiated tissue. We used optical projection tomography (OPT) (Bioptonics, UK), which images transparent specimens with UV light. Here we used carefully staged chicken embryos to measure facial morphogenesis over time.
Methods: Chicken eggs (n=32) were incubated for 3.5-6 days (stage 20, 24, 28, 29). Embryo heads were fixed in formaldehyde, embedded in agarose, dehydrated in methanol, and then cleared in Benzyl Alcohol Benzyl Benzoate. Embryos were scanned with the OPT, images were reconstructed, and then the head was digitally resliced in the frontal plane using NRecon and CTan. Resliced files were imported into Amira, facial prominences were outlined, and isosurfaces were created. Volumetric measurements were assessed using Amira. Landmarks were applied to the surface of each prominence using Landmark. These landmarks were then superimposed from different embryos using MorphoJ, whereby they underwent Procrustes superimposition, Principal Component Analysis, Canonical Variate Analysis, and Discriminant Function Analysis.
Results: Traditional morphometrics revealed that the greatest amount of growth was a 24-fold difference in volume of the lateral nasal prominence between stages 20 and 29, followed by the maxillary, mandibular, and frontonasal mass. Geometric morphometrics revealed that embryonic facial prominences had minimal changes in shape between stages 20 and 24, however, after this time, there was more separation of the data in morphospace. Strikingly, the greatest morphological change was between stages 28 and 29, which was only 12 hours apart. This rapid change suggests that other mechanisms in addition to cell proliferation are involved. In addition, the data show that major morphological changes precede lip fusion. Therefore, we can pinpoint our studies to stage 28, when critical events in the mesenchyme are taking place.
Conclusion: Embryonic chicken facial prominences undergo major shape changes. Each prominence varies in morphology with respective stage, with the frontonasal mass and mandibular prominence having the most dynamic shape changes.Dentistry, Faculty of
Graduate
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Björkeson, Felix. "Autonomous Morphometrics using Depth Cameras for Object Classification and Identification." Thesis, Linköpings universitet, Datorseende, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-95240.
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Identification of individuals has been solved with many different solutions around the world, either using biometric data or external means of verification such as id cards or RFID tags. The advantage of using biometric measurements is that they are directly tied to the individual and are usually unalterable. Acquiring dependable measurements is however challenging when the individuals are uncooperative. A dependable system should be able to deal with this and produce reliable identifications. The system proposed in this thesis can autonomously classify uncooperative specimens from depth data. The data is acquired from a depth camera mounted in an uncontrolled environment, where it was allowed to continuously record for two weeks. This requires stable data extraction and normalization algorithms to produce good representations of the specimens. Robust descriptors can therefore be extracted from each sample of a specimen and together with different classification algorithms, the system can be trained or validated. Even with as many as 138 different classes the system achieves high recognition rates. Inspired by the research field of face recognition, the best classification algorithm, the method of fisherfaces, was able to accurately recognize 99.6% of the validation samples. Followed by two variations of the method of eigenfaces, achieving recognition rates of 98.8% and 97.9%. These results affirm that the capabilities of the system are adequate for a commercial implementation.
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Carpiaux, Weston. "GEOMETRIC MORPHOMETRICS CLUSTERS CRANIOFACIAL MORPHOLOGY DIFFERENTLY THAN TRADITIONAL CEPHALOMETRIC MEASUREMENTS." Master's thesis, Temple University Libraries, 2014. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/284644.
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Oral BiologyM.S.
Objectives: The purpose of the study was to compare a geometric morphometric approach for grouping different skeletal malocclusions to a traditional cephalometric approach for a subject population undergoing orthognathic surgery for treatment of malocclusion. Methods: Traditional cephalometric measurements were used to diagnose the skeletal malocclusion each subject in both the sagittal (SNA, SNB, ANB, Facial Angle) and vertical dimensions (SN-MP, FMA, Downs Y-Axis, Facial Axis, P-A Face Height). These were compared to skeletal diagnoses given by the treating surgeon. Lastly, geometric morphometrics was used to identify shape variance within the population, cluster homogeneous subsets, and identify variance between the clusters. Results: Traditional cephalometric analysis identified 21 Class II open, 18 Class II normal, 5 Class II deep, 3 Class I open, 4 Class I normal, 2 Class I deep, 2 Class III open, 4 Class III normal, 3 Class III deep. The surgeon identified 17 Class II open, 20 Class II normal, 13 Class II deep, 1 Class I open, 0 Class I normal, 0 Class I deep, 4 Class III open, 3 Class III normal, 4 Class III deep. Geometric morphometrics identified 6 clusters showing greatest variance through 1) vertical divergence, 2) sagittal positioning of the jaws, and 3) ramus height. Conclusion: Cephalometric analysis and a geometric morphometrics approaches to classification of malocclusion grouped subjects into distinct populations. However, the groupings did not agree between the two approaches.
Temple University--Theses
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Grass, Andy Darrell. "Examining ecosystem structure and disparity through time using geometric morphometrics." Thesis, University of Iowa, 2009. https://ir.uiowa.edu/etd/367.
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Functional morphology and morphometric studies on various mammalian groups have shown marked differences in crania and mandible shape based on dietary preferences and feeding habits. In this study I used three-dimensional geometric morphometric methods to measure the shape of crania and mandibles of herbivorous and omnivorous mammals from three formations in northwestern Nebraska to explore the structure and disparity of ecosystems through time: The White River Group (Chadronian/Orellan/Whitneyan), the Arikaree Group (Arikareean), and the Ogallala Group (Hemingfordian/Barstovian/Clarendonian). Throughout the time period compromising these formations the climatic conditions were becoming more arid, grasslands were expanding and the large mammalian faunal compositions were shifting from browser dominated to grazer dominated. Relative warps analysis show a visible separation of faunas between the three formations that cannot be attributed to phylogeny in plots based on either the crania or the mandibles. Phylogenetic effects were taken into account using generalized least squares. These results indicate that it may be possible to differentiate fossil taxa from different formations and environments based on the shape of cranial and mandibular elements as well as to infer the environment or diet of a fossil if other unequivocal data are not available.
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Schilling, Daniel Edward. "Assessment of morphological and molecular genetic variation of freshwater mussel species belonging to the genera Fusconaia, Pleurobema, and Pleuronaia in the upper Tennessee River basin." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/54030.
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Select freshwater mussels in the genera Fusconaia, Pleurobema, and Pleuronaia were collected primarily in the upper Tennessee River basin from 2012 to 2014 for phylogenetic and morphological assessments. Freshwater mussels in these genera are similar in appearance, hence the need for phylogenetic verification and morphological assessment. Phylogenetic analyses of the mitochondrial gene ND1 and the nuclear gene ITS1 revealed three unrecognized, phylogenetically distinct species. These species were separated from their closest congener by 2.85%, 3.17%, and 6.32% based on pairwise genetic distances of ND1. Gaps created from aligning ITS1 sequences were coded as fifth characters, which phylogenetically separated most closely related species. Analyses of ND1 agreed with previous literature on the phylogenetic distinctiveness of Pleuronaia species, with the exception of the DNA sequences of P. gibberum, which grouped outside this genus based on the analyses conducted in this study.
Morphological variation was recorded for eight of the species to include quantitative and qualitative characters as well as geometric morphometric analyses. Three decision trees were created from quantitative and qualitative characters using classification and regression tree analyses. The best-performing tree used quantitative and qualitative characters describing shell-only scenarios and obtained 80.6% correct classification on terminal nodes. Canonical variates analysis on geometric morphometric shell data revealed large morphological overlap between species. Goodall's F-tests between pairs of species revealed significant differences (a=0.05) between all but one species pairs; however, examination of landmarks on shells concluded large overlap of landmarks between species pairs. Lack of morphologically distinct characters to readily identify these phylogenetically distinct species indicates large morphological overlap among these species. Biologists need to be cognizant that morphologically cryptic species may exist in systems often explored.
Three dichotomous keys were created from classification trees to identify select individuals in the genera Fusconaia, Pleurobema, and Pleuronaia; two of these keys, one for shells and one for live mussels were tested by participants with varying mussel identification skills to represent novices and experts. Both keys used continuous (quantitative) and categorical variables to guide participants to identifications. Novices, who had no prior mussel identification experience, correctly identified mussels with a 50% accuracy using the shell key and with a 51% accuracy using the live key. Experts, who had at least three years of experience identifying mussels, correctly identified mussels with a 58% accuracy using the shell key and with a 68% accuracy using the live key; however one expert noted that they did not use the live key to correctly identify one mussel. Morphological overlap of variables between mussels likely resulted in failure to consistently identify mussels correctly.
Important management decisions and project implementations require accurate assessment of species' localities and populations. Incorrect species identification could hinder species' recovery efforts or prevent projects that otherwise could have continued if species are misidentified. If a mussel collection is thought to be a new record or could affect a project, I recommend that molecular genetic identifications be used to verify the species identity.Master of Science
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Champagne, Tracy Ann Neil. "Oligocene coral evolution in Puerto Rico and Antigua: morphometric analysis of Agathiphyllia, Antiguastrea, and Montastraea." Thesis, University of Iowa, 2010. https://ir.uiowa.edu/etd/1128.
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The University of Iowa Paleontology Repository maintains an extensive collection of Caribbean coral specimens. This study includes 285 specimens, of which approximately 75 are thin-sections of three previously identified Oligocene genera including: Montastraea Blainville, 1830 (=Orbicella Dana 1846), Antiguastrea Vaughan, 1919, and Agathiphyllia Reuss, 1864 (=Cyathomorpha Reuss, 1868). This study includes: photography of colony surfaces and thin-sections of representative specimens of each species, and the identification of the three Oligocene genera Montastraea, Antiguastrea, and Agathiphyllia to the species level. This study compared the collections with the agathiphyllid stratigraphic ranges in the Paleobiology Database, curated these specimens, and then entered the information into the database, SpecifyTM. These continued efforts aid in better understanding diagnostic morphologic characters of three genera: Antiguastrea, Agathiphyllia, and Montastraea. Two of the genera, Antiguastrea and Agathiphyllia, are extinct. Because the differences in morphology are subtle and not very well understood, previous biodiversity studies using the colony surface for correct species identification have been difficult and often inaccurate. Montastraea is further complicated by recent research that suggests it is polyphyletic and contains multiple species complexes, based on the combined use and creation of more morphological characters and on molecular phylogenetics. Additionally, this study assists with the understanding of the biodiversity of these Oligocene coral genera in the Caribbean region prior to the Plio-Pleistocene extinction event, and the evolutionary history of coral diversity in this region. Though there was an extinction event across the Caribbean, the locality species richness, using Fisher's α and Shannon's H, showed no significant differences between the Late Oligocene formations and the Early Miocene formations.
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Cassara, Jason Anthony. "Patterns of variation within the Montastraea "annularis" species complex: results from 2-D and 3-D geometric morphometrics." Thesis, University of Iowa, 2010. https://ir.uiowa.edu/etd/786.
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Geometric morphometrics are a useful tool for studying morphological variation in scleractinian corals, extant and extinct. In the case of modern specimens, three-dimensional features of the calical surface can be measured. These features are rarely preserved in fossil corals, however, necessitating measurement of 2-D landmarks in transverse thin-sections of corallites. Unfortunately, 2-D and 3-D methods often yield differing answers to questions about interspecific, intraspecific and intracolonial variation. This issue is addressed in the present study by directly comparing results of 2-D and 3-D geometric morphometric analyses of identical colonies of extant members of the Montastraea "annularis" species complex.
Ten colonies of each extant species in the complex (M. annularis s.s., M. faveolata and M. franksi), identified in the field during collection and verified by molecular data, were selected for analysis. Slabs of colony surfaces and transverse thin-sections from ~1 cm below the surface were cut from tops and edges of each colony. Six corallites from each slab were measured in 3-D using a Reflex microscope, and six measured in 2-D on digital images of each transverse thin-section. Both datasets were explored using geometric morphometric methods and analyzed statistically to address questions related to measurement error, intracolonial variation in corallite morphology between tops and edges of colonies, and interspecific morphological differences. The shape data were superimposed using Procrustes generalized least squares, and examined using principal components and canonical variates analyses. Shape differences implied by axes obtained from PCA and CVA were depicted as deformations using the thin-plate spline, to identify which morphological features are correlated with axes of greatest total variance (PCA) and greatest between-group variance (CVA). Goodall's F-test was used to detect significant morphological differences among species and colony positions. All of the data used in these analyses are available in the supplementary file that accompanies this thesis (see Appendix C for a description of the contents of this file).
Measurement error analyses show significant differences among variances associated with replicate measurements of 2-D and 3-D landmarks. In many cases the variance is asymmetrical, and for 2D data especially, this asymmetry coincides with orientation of anatomical features. Significant shape differences between corallites from tops and edges of colonies of M. annularis and M. faveolata are found when 3-D data are used. These intracolonial differences are due in large part to height and shape of the septal margin. As a result, 2-D data are unable to find significant differences within colonies.
Both datasets find significant interspecific differences, but different anatomical features are found to be responsible. Important interspecific differences for 2-D data are relative thickness of the corallite wall and lengths of septa and costae. When 3-D data are used, results are most influenced by height of primary and secondary septa above the calical surface, as well as length of septa from the corallite wall toward the columella. Patterns of relative morphological similarity among species also differ between datasets. 2-D data show closest similarity between M. annularis and M. faveolata, while M. faveolata and M. franksi are most similar when 3-D data are used. The former result is consistent with previous 2-D analyses, while the latter conclusion is without precedent. Neither is consistent with relationships inferred using molecular data.
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Johnson, Lisa. "Investigating morphometrics, movement and oviposition in the Lissotriton and Triturus newts." Thesis, University of Chester, 2015. http://hdl.handle.net/10034/617674.
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This thesis focuses on the UK pond newts, the smaller bodied species known as Lissotriton newts and the larger Triturus. The primary aims were to identify and address gaps in the current Tritus/Lissotriton literature; to provide a more complete understanding of this group as many assumptions about morphology and physiology exist untested, for example that larger/fatter females will lay more eggs. Specifically for Lissotriton helveticus, many assumptions are based on the similarly sized Lissotriton vulgaris, potentially missing any species specific differences. A further focus of the work was to provide a clearer view over the whole breeding season; using measures of condition over a season and egg-laying.
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Borobia, Mônica. "Distribution and morphometrics of South American dolphins of the genus Sotalia." Thesis, McGill University, 1989. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=61865.
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Groote, Isabelle Elisabeth Peter Maria De. "A Comprehensive Analysis of Long Bone Curvature Using 3D Geometric Morphometrics." Thesis, University College London (University of London), 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505127.
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Miglori, Nicole. "Quantifying intraspecific shape variation in the Kangaroo Humerus using geometric morphometrics." Thesis, Miglori, Nicole (2015) Quantifying intraspecific shape variation in the Kangaroo Humerus using geometric morphometrics. Honours thesis, Murdoch University, 2015. https://researchrepository.murdoch.edu.au/id/eprint/30273/.
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Kangaroos exhibit one of the largest variations in body size for any vertebrate, with males being 1.5 times larger in body mass compared to females. Therefore it is assumed that sexual selection plays a major role in the behavioural and physical characteristics of kangaroos. Male and female kangaroos demonstrate marked differences in musculature of the forelimb. I investigated if the humerus (the upper bone of the forearm) of the western grey kangaroo (Marcopus)fuliginosus) displays sexual dimorphic characteristics, and if these characteristics are correlated with muscle mass. 28 landmarks were digitised in 72 male and 23 female humeri and analysed using geometric morphometric approaches. Muscles were collected from fine dissection and residual muscle masses were calculated for analyses of each sex. Males and females were sexually dimorphic in shape, with the most obvious change at the deltoid crest where the crest was significantly increased in size and the shaft was in a bent orientation. This study suggests that a humerus from a western grey kangaroo can be classified by correct sex 92% of the time. There was a significant relationship between muscle mass and bone shape that indicate that muscles affect the morphology of the humerus. Male humeri are robust and slightly bent, conversely female obtain a more gracile form. Geometrics morphometrics is an advantageous technique that allows the morphology of shape to be investigated; by including fine muscle dissection we have determined how shape and muscles influence one another. The methods in this study can be applied to multiple studies that wish to investigate the morphology of shape and the influence of muscles.
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Tzeuschner, Dominique. "Untersuchung zum Gesichtswachstum von Patienten mit Lippen-Kiefer-Gaumenspalten operiert nach dem Leipziger Konzept zur funktionellen Rehabilitation von Lippen-Kiefer-Gaumenspalten." Doctoral thesis, Universitätsbibliothek Leipzig, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-141025.
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In der vorliegenden Dissertation wurde anhand von 1042 extraoralen Fotos im Profil und en face untersucht, wie sich das Wachstum longitudinal bei 166 gesunden Kindern, je zehn Kindern mit isolierter Gaumenspalte, einseitiger Lippen-Kiefer-Gaumenspalte sowie doppelseitiger Lippen-Kiefer-Gaumenspalte operiert nach dem Leipziger Konzept entwickelt, sowie inwiefern sich die einzelnen Gruppen in verschiedenen Altersstufen voneinander unterscheiden. Dazu wurden pro Gruppe jeweils fünf Jungen und fünf Mädchen kaukasischer Herkunft, geboren in den Jahren 1994 bis 2001, mit einer nichtsyndromalen Spalte ausgewählt, die ab der Geburt über mehrere Jahre hinweg fotografiert wurden. Diese Fotos wurden digitalisiert und denen von Kontrollpatienten gegenüber gestellt. Anhand von Winkeln der klassischen Morphometrie und Grafiken und Statistiken der geometrischen Morphometrie wurden die Veränderungen im Wachstum analysiert und die Kontrollpatienten mit dem Leipziger OP-Konzept verglichen. Es konnte gezeigt werden, dass die geometrische Morphometrie durchaus geeignet ist, das Gesichtswachstum anhand von extraoralen Fotos zu beurteilen. Weiterhin konnte bestätigt werden, dass mit dem Leipziger Konzept zur funktionellen Rehabilitation von Patienten mit Lippen-Kiefer-Gaumenspalten sehr gute Operationsergebnisse und vor allem Langzeitergebnisse erzielt werden können.
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Robart, Bruce W. Armstrong Joseph E. "The systematics of Pedicularis bracteosa morphometrics, development, pollination ecology, and molecular phylogenetics /." Normal, Ill. Illinois State University, 2000. http://wwwlib.umi.com/cr/ilstu/fullcit?p9986730.
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Thesis (Ph. D.)--Illinois State University, 2000.Title from title page screen, viewed May 9, 2006. Dissertation Committee: Joseph E. Armstrong (chair), Roger Anderson, Angelo Capparella, Christopher Horvath, Diane Byers. Includes bibliographical references (leaves 223-234) and abstract. Also available in print.
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Li, Ping. "Floral morphometrics, development and evolution of homostyly from distyly in Amsinckia (Boraginaceae)." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ66635.pdf.
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Leipertz, Steven Lee. "Morphometrics and the evolutionary history of fishes of the teleost subfamily Pleuronectinae /." Thesis, Connect to this title online; UW restricted, 1987. http://hdl.handle.net/1773/5330.
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Tompsett, Scott. "Taxonomy, morphometrics, and phylogeography of the cheilostome bryozoan genus Schizoporella in Europe." Thesis, Aberystwyth University, 2010. http://hdl.handle.net/2160/fe2d54b9-b4c2-4bf2-bcea-e98d897d81f9.
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Cuesta, Torralvo Elisabeth. "Geometric morphometrics and topographic analyses of dental wear in modern human populations." Doctoral thesis, Universitat de Barcelona, 2021. http://hdl.handle.net/10803/673455.
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Dental wear is a natural, complex, physiological process of gradual enamel tissue loss that occurs during an individual’s life span and provides information about dietary habits, food processing techniques and cultural practices. Many studies have characterised dental wear in human populations by using observer-dependent, qualitative methods. In contrast, more objective, quantitative approaches have been scarcely used. This thesis aims to assess differences in molar morphology among modern human populations and the effect of dental wear on shape by using novel quantitative methods, such as the percentage of dentine exposure (PDE), 3D geometric morphometrics (GM) and dental topography. The PDE of mandibular permanent first molars recorded in a known-age Baka Pygmy forager population showed an close relationship between wear and age, no sexual dimorphism in wear patterns and reduced PDE values of ≈4% for a foraging population relying on Underground Storage Organs (USO) consumption, likely due to culture-specific dietary proclivities that influenced dental wear rates. Three-dimensional (3D) dental crown analyses (GM and dental topography) carried out in maxillary and mandibular permanent first and second molars of the Coimbra International Exchange known age-at-death skull collection showed significant regressions between the morphometric variables and age-at-death, with a significant portion of the overall shape variation attributed to anatomical traits (e.g. cusp and groove patterns) independently of wear, while another significant portion attributed to the loss of dental crown height with age. The 3D-GM PCA procedure applied to the repeated measurement test showed an intra-observer methodological error <5%. Dental topographic analysis of the Portuguese sample showed negative correlations with age in all analysed teeth, with surface curvature (DNE), complexity (OPCR) and crown relief (RFI) scores decreasing with age. Dental topography procedures applied to maxillary permanent molars of Central African populations with distinct dietary habits (Pygmy foragers and Bantu-speaking agriculturalists) and distinct degrees of dental wear patterns showed DNE and occlusal relief (OR) scores that also decreased with wear, while ambient occlusion (PCV) and OPCR increased with wear. The Pygmy foragers showed higher OPCR and DNE values than the Bantu-speaking agriculturalists. These variables also proved to effectively distinguish between foragers and agriculturalists in the PC analysis. This research has also shown that it is important to pay attention to the different cropping methods used in the quantification of RFI and OR since the different methodological perspectives may cause distinct methodological errors.El desgaste dental es un proceso fisiológico, natural y complejo de pérdida gradual del esmalte que se produce durante la vida de un individuo y que proporciona información sobre los hábitos alimentarios, las técnicas de procesamiento de alimentos y las prácticas culturales. Muchos estudios caracterizaron el desgaste en poblaciones humanas mediante métodos cualitativos dependientes del observador. En cambio, pocos estudios utilizaron métodos objetivos y cuantitativos. Esta tesis pretende evaluar las diferencias morfológicas de los molares en poblaciones humanas modernas, así como el efecto del desgaste en la forma del diente mediante métodos cuantitativos novedosos, como el porcentaje de exposición de dentina (PDE), la morfometría geométrica (MG) en 3D y la topografía dental. El PDE de los primeros molares inferiores de una población de cazadores recolectores de pigmeos Baka de edad conocida mostró una relación significativa entre desgaste y edad, sin dimorfismo sexual en los patrones de desgaste y valores reducidos de PDE del ~ 4% para una población cazadora recolectora dependiente del consumo de Underground Storage Organs (USO), probablemente debido a las particularidades culturales relacionadas con la dieta que influyeron en el desgaste. Los análisis 3D (MG y topografía dental) en primeros y segundos molares superiores e inferiores de la colección de Trocas Internacionais de cráneos de Coímbra, con edad de la muerte conocida, mostraron regresiones significativas entre las variables morfométricas y la edad de la muerte, con una parte de la variación de la forma del diente atribuida a su anatomía (p. ej. patrones de cúspides y surcos) e independiente del desgaste, y otra, a la pérdida de altura de la corona con la edad. El ACP de la MG en 3D aplicada a la prueba de medición repetida mostró un error metodológico intraobservador del <5%. El análisis de la topografía de la muestra portuguesa mostró correlaciones negativas con la edad, con valores de curvatura (DNE), complejidad (OPCR) y relieve de la corona (RFI) que disminuyen con la edad. Los análisis de topografía en molares superiores de poblaciones centroafricanas con dietas distintas (pigmeos cazadores recolectores y agricultores de habla bantú) y distintos grados de desgaste mostraron valores de DNE y relieve oclusal (OR) que disminuían con el desgaste, mientras que la oclusión ambiental (PCV) y OPCR aumentaba. Los cazadores recolectores mostraron además valores de OPCR y DNE más altos que los agricultores. Estas variables fueron efectivas para distinguir entre ambas dietas en el análisis de CP. También se demostró la importancia de prestar atención a los métodos de corte utilizados en la cuantificación de RFI y OR, ya que pueden causar errores metodológicos.
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Lawrence, Wujek Jessica Danielle. "A fresh look at the genus Ichthyosaurus : species characteristics, morphometrics, and phylogeny." Thesis, University of Southampton, 2018. https://eprints.soton.ac.uk/418172/.
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Ichthyosaurs are among the best known of Mesozoic marine reptiles, ranging from the Early Triassic (252-247 Ma) to the end of the Cenomanian (93.9 Ma; Fischer et al., 2016). The genus Ichthyosaurus was one of the first genera to be named and is arguably one of the most iconic of ichthyosaurs. Due to this abundance of specimens, and to initial inadequacies in the definition of the genus and its constituent species, Ichthyosaurus has become a waste-basket taxon; a poorly classified taxon with many morphologically variable specimens (Smith and Radley, 2007). Ichthyosaurus is known from an enormous number of specimens, many of which possess confusing combinations of anatomical features. Both the quantity of data and distribution of anatomical characters make it difficult to recognise distinct species within our understanding of this taxon. To study this genus in depth, a modern problem of inaccessible specimens displayed in museums is an obstacle that needed to be overcome. A new method of parallel laser photogrammetry to bridge to gap of inaccessibility and scientific study was explored. This method has been used in other fields, but has not transitioned into palaeontology yet. The marine reptile gallery of the Natural History Museum, in London was utilised to test this method. The findings from that method were utilized in the other analyses performed. This new method allows researchers to get some scientific data from specimens that would otherwise not be utilized, but it is not a complete substitute for an up close in person examination of specimens. To better understand the current breadth of the species Ichthyosaurus, multiple morphometric and phylogenetic studies were performed with a starting dataset of over 320 specimens and 66 different measurements. Each of these studies was done at the specimen level, which is a rarity. These analyses also help to determine if there is more diversity present in Ichthyosaurus than is currently recognized. During the course of this PhD 3 new species have been named to this genus confirming that there is a larger amount of diversity than originally thought at the beginning of this project (Lomax and Massare, 2015 and 2016). The morphometric study focused on the measurements used in ratio characters, to determine if they were useful in separation of species. The analyses show that just measurements used in the previously defined ratios are not sufficient to separate species out by themselves. The phylogenetic study was done at the specimen level to truly see how much variation there is in the genus and species. The characters used in that study were also defined in detail as to produce replicable results. The phylogenetic results show that the species of this genus need to be more strictly defined, or that there are more species present in the genus still to be identified.
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Jessee, Lance D., Austin Gause, and Blaine W. Schubert. "Intervertebral Variation of North American Pit Vipers (Squamata, Viperidae) Using Geometric Morphometrics." Digital Commons @ East Tennessee State University, 2019. https://dc.etsu.edu/asrf/2019/schedule/95.
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Within Pleistocene cave deposits, snake fossils tend to be relatively common and generally occur as isolated vertebrae. However, the specific, and sometimes generic, identification of isolated snake vertebrae is often hindered by the significant amount of intra- and interspecific variation along the precloacal vertebral column, a subject that has largely been neglected in many fossil snake identifications. Identifications are typically based on the vertebrae of disarticulated modern specimens with preference given to mid-trunk vertebrae. This study utilizes 2-D geometric morphometrics to determine the extent of intervertebral variation along the precloacal vertebral column of North American pit vipers of the genera Crotalus (rattlesnakes) and Agkistrodon (copperheads and moccasins), two closely related genera geographically sympatric in northeast Tennessee and much of the eastern United States with similar vertebral morphologies. The focus of this study is to determine the need for identifying the morphological regionalization of the precloacal vertebral column and determining the regional position of isolated vertebra prior to identification. Using one individual from each genus, every third vertebra was chosen and analyzed in anterior view using geometric morphometrics and relative warp analyses. A discriminant function analysis was then performed to distinguish between the two genera. Viperid fossils from Hickory Tree Cave in northeast Tennessee underwent the same geometric morphometric and discriminant function analyses as a means of identification. It is expected that the relative warp analyses will show some morphological regionalization of the precloacal vertebral column, but may prove to not be significant enough for use in the identification of isolated vertebrae. In that case, comparison to mid-trunk vertebrae for identification may prove accurate. This study also shows the need for more modern skeletal specimens in herpetological collections and the need for preserving the vertebral order of those specimens.
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Schaaf, Lisa Nicole. "Comparative Morphometrics of the Sacral Vertebra in Aneides (Caudata: Plethodontidae)." Digital Commons @ East Tennessee State University, 2010. https://dc.etsu.edu/etd/1703.
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The genus Aneides (Caudata: Plethodontidae) is an arboreal salamander with a prehensile tail and a distribution that spans North America. It is hypothesized that adaptations for arboreality will be visible in the osteology of the sacral vertebra either by qualitative analysis or linear and morphometric analysis in comparison with other plethodontid salamanders. This study demonstrates that while qualitative and quantitative analyses are successful at making genus-level distinctions between taxa, identification to lower taxonomic levels remains inconclusive. Linear morphometrics and dorsal Procrustes landmarks were the most successful metrics to identify known taxa. Two unidentified fossil salamander sacral vertebrae from Oregon Caves National Monument are examined with the same techniques and are tentatively identified as Hydromantes based on qualitative similarities to modern Hydromantes specimens, as the quantitative analyses were unable to confidently diagnose the unknown specimens.
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Ménard, Josephine Mira. "Investigating craniodental sexual dimorphism in bandicoots and bilbies using 3D geometric morphometrics." Thesis, Ménard, Josephine Mira (2018) Investigating craniodental sexual dimorphism in bandicoots and bilbies using 3D geometric morphometrics. Honours thesis, Murdoch University, 2018. https://researchrepository.murdoch.edu.au/id/eprint/41726/.
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Evolution through natural selection enables species to adapt to their surroundings and optimise themselves for reproduction and survival. Sexual selection, on the other hand, reflects modifications to improve reproductive fitness of individuals within species. Animal morphology, therefore, often represents a compromise between these two selective pressures.
Bandicoots and bilbies (Marsupialia; Peramelemorphia) are small to medium sized omnivorous marsupials, of which roughly 30 species inhabit varied habitats throughout Australia and Papua New Guinea.
This study sought to quantify craniodental variation in a range of bandicoot and bilby species to investigate the relationship between natural selection and sexual dimorphism in this clade of animals.
Micro-CT and laser scanning techniques were employed to obtain three-dimensional scans of the crania and dentition of the 25 study species and subspecies (total n=124; 63 female and 61 male). Landmark analysis was conducted on 54 landmarks placed on the cranium and upper dentition to pinpoint areas of variation within and between the genera, species and sexes.
Interspecific variation in cranial morphology between genera and species does reflect taxonomic groups and likely reflects adaptation by natural selection for different ecologies in different clades. Macrotis was the closest to the consensus shape for Peramelemorphia. Within family Peramelidae, genera formed discrete clusters, reflecting diagnostic differences in cranial shape between the two genera, separating Australian the short-nosed bandicoots (Isoodon) from the long-nosed or barred bandicoots (Perameles). The Peroryctidae clustered together, with Peroryctes nested within Echymipera, and Microperoryctes between Echymipera and Macrotis. Echymipera kalubu was the only exception and nested within Macrotis, quite distinct from the other species of Echymipera.
Intraspecific variation showed strong evidence of sexual dimorphism in the species Macrotis lagotis and Isoodon fusciventer, while most other species did not have sexual dimorphism. In the two species that did show dimorphism in skull shape, there is also significant dimorphism in body mass, with males typically being larger. Shape changes did have allometric correlations with skull size, in PC axis 1 in M. lagotis and interestingly in PC axis 2 in I. fusciventer. In P. papillon, one of the smallest species, there was a trend towards female biased sexual dimorphism both size and skull shape, though this was not significant in our sample.
This study highlights the large range of expressions of craniodental sexual dimorphism present in Peramelemorphia, and quantifies distinctions between expression within and between genera.
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Powell, Matthew G. "Morphometric Characterization of a Mercenaria spp. (Bivalvia) Hybrid Zone: Paleontological and Evolutionary Implications." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/33094.
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Paleontological documentation of hybridization events has the potential to address a multitude of evolutionary and paleobiological issues unanswerable by purely biological means. However, previous studies of modern hybrids suggest that their morphology is often insufficient for their reliable discrimination. This study analyzes the morphology of an extant, genetically-identified Mercenaria spp. (Bivalvia: Veneridae) hybrid zone using Bookstein coordinates and multivariate methods to answer two questions: (1) can hybrid Mercenaria spp. individuals be identified based on morphology alone, and (2) would a Mercenaria spp. hybrid zone be recognizable in the fossil record?
Multivariate statistical procedures (principal components analysis, canonical variate analysis, etc.) using Bookstein coordinates demonstrate that, within the hybrid zone, hybrid individuals cannot be identified due to extreme overlap with the parental taxa. The hybrid zone as a whole, however, can be identified by comparison with pure-species populations sampled from outside the hybrid zone. Hybrid zones occupy parental species morphospace plus intermediate morphospace. The technique of using multiple pure-species populations to establish species morphospace is introduced to control for processes that may also result in morphological intermediates at ecological time scales (dimorphism, ecophenotypy, and geographic variation). Four alternative causal explanations of morphological intermediates through geological time (primary intergradation, uncoupled genetic and morphological divergence, time-averaged evolving populations, and developmentally instable populations) are evaluated. A literature survey strongly suggests that neither time-averaging nor developmental instability is occurring at the beginning of a lineageâ s evolutionary history, and that hybridization may be much more extensive than paleontological data suggest.
Master of Science
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Jansky, Kyle J. "Identifying Myotis Species Using Geometric Morphometrics and its Implications for the Fossil Record and Conservation." Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/etd/1145.
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Dentaries of the 6 species of Myotis that occur in the eastern United States were analyzed using landmark-based geometric morphometrics. The species could be distinguished with a high degree of accuracy. Evidence was found of a phylogenetic signal in the morphology of the Neotropical and Nearctic Myotis sub-clades. There is also evidence of convergence in the morphology of the dentary among Myotis species that feed primarily by gleaning. When analyzed together there was no evidence of sexual dimorphism among the 6 eastern U.S. Myotis, but when analyzed individually some dimorphism may be present. A sample of fossil Myotis of unknown species from Bat Cave, Kentucky, was analyzed in an attempt to identify the specimens to species. Results indicate that Myotis austroriparius and M. sodalis predominate the sample, possibly with smaller numbers of M. grisescens and M. leibii. This study demonstrates the ability to differentiate Myotis taxa from historic and prehistoric sites and provides a tool for researchers to better understand and potentially conserve these species.
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Surtees, D. P. "Multivariate morphometrics and cytotaxonomy of the West African Simulium damnosum complex (Diptera : Simuliidae)." Thesis, University of Liverpool, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233866.
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Damasceno, Silva Elis. "Quantitative genetics of skull shape in Soay sheep (Ovis aries) using geometric morphometrics." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/quantitative-genetics-of-skull-shape-in-soay-sheep-ovis-aries-using-geometric-morphometrics(8b233fd9-76dc-4dd9-9a38-621548a835ac).html.
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Analysing variation of skull shape in wild populations can give us an insight into evolutionary processes. By looking into patterns of morphological variation within populations, we can extrapolate and make assumptions on the patterns of variation on higher taxonomic levels. In this thesis, I collected data on skull shape of a wild population of Soay sheep using geometric morphometrics methods. I applied a multitude of quantitative genetics and geometric morphometrics methods to explore the factors behind the evolution of skull shape. I analysed several aspects of skull shape, including integration and modularity, predicted response to hypothetical selection, estimates of natural selection, presence of heterochrony, and fluctuating asymmetry (FA) in an ecological and genetic point of view. I found low levels of integration in the Soay sheep skull, along with the presence of two modules: face and neurocranium. Both the levels of integration and the pattern of modularity were found across different origins of variation, individual, genetic and developmental (FA), indicating a strong correspondence between levels. Although genetic integration is not strong, I found that most of hypothetical selection regimes result in as much correlated selection as direct selection responses. But the nose region has shown to be quite independent from the rest of the skull, with a retraction of the nose causing almost no correlated changes. Selection on skull shape is comparatively strong in the Soay sheep. The skull shape selected for in males differs from the shape selected in females. Males are selected to have wider nasal bones along with longer, flatter braincase, whereas females are selected towards narrower nasal bones, along with smaller braincases. But selection is not the only factor influencing changes in skull shape. Changes in temperature along the past 30 years are causing a change in developmental timing in Soay sheep, causing a decrease in overall body size in the population. And I found that skull shape is also being affected, thus indicating that this population might be undergoing heterochronic processes. Finally, I found that factors such as vegetation quality, parasite load and breeding success are related to FA levels, whereas population density and climate are not. I also found no significant heritability nor dominance in FA of skull shape. Overall, this thesis certainly contributes to the understanding of evolution of skull shape in natural populations. By successfully combining quantitative genetics and geometric morphometrics methods, I was able to tackle questions about the evolution of complex shapes, and give valuable insights into this still underexplored field.
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Fouefack, Jean-Rassaire. "Geometric morphometrics for 3D dense surface correspondence: population comparisons of shoulder bone morphology." Master's thesis, Faculty of Health Sciences, 2018. http://hdl.handle.net/11427/30024.
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Background: Comparisons in morphological shape/form across population groups could
provide population differences that might assist in making decisions on diagnosis and
prognosis by the clinician. Geometric morphometrics (GM) is one of the fields that help
to provide such population comparisons. In medical imaging and related disciplines, GM
is commonly done using annotated landmarks or distances measured from 3D surfaces
(consisting of triangular meshes). However, these landmarks may not be sufficient to
describe the complete shape. This project aimed to develop GM for analysis that consider
all vertices in the triangular mesh as landmarks. The developed methods were applied to
South African and Swiss shoulder bones (scapula and humerus) to analyse morphological
differences.
Methods: The developed pipeline required first establishing correspondence across the
datasets through a registration process. Gaussian process fitting was chosen to perform
the registration since it is considered state-of-the-art. Secondly, a novel method for automatic identification of vertices or areas encoding the most shape/form variation was
developed. Thirdly, a principal component analysis (PCA) that addressed the high dimensionality and lower sample size (HDLSS) phenomenon was adopted and applied to
the dense correspondence data. This approach allowed for the stabilisation of the distribution of the data in low-dimensional form/shape space. Lastly, appropriate statistical
tests were developed for population comparisons of the shoulder bones when dealing with
HDLSS data in both form and shape space.
Results: When the mesh-based GM analysis approach was applied to the training datasets
(South African and Swiss shoulder bones), it was found that the anterior glenoid which is
often the site of the shoulder dislocation is the most varied area of the glenoid. This has
implications for diagnosis and provides knowledge for prosthesis design. The distribution
of the data in the modified PCA space was shown to converge to a stable distribution when
more vertices/landmarks are used for the analysis. South African and Swiss datasets were
shown to be more distinguishable in a low-dimensional space when considering form rather
than shape. It was found that left and right South African scapula bones are significantly
different in terms of shape.
Discussion: In general, it was observed that the two populations means can be significantly
different in shape but not in form. An improved understanding of these observed shape
and form differences has utility for shoulder arthroplasty prosthesis design and may also
be useful for orthopaedic surgeons during surgical preoperative planning.
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Nwotchouang, Blaise Simplice Talla. "SKULL-BASED MORPHOMETRICS AND BRAIN TISSUE DEFORMATION CHARACTERIZATION OF CHIARI MALFORMATION TYPE I." University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1595877233083287.
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Tse, Yuen Ting. "Quantifying the link between craniodental morphology and diet in Soricidae using geometric morphometrics." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1594934856370846.
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Meek, John D. "Ethnic differences in bone morphometrics of the distal humerus: Implications for plate design." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/106916/3/John_Meek_Thesis.pdf.
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The primary aim of the thesis was to investigate the correlation between height and ethnicity on the variation of shape of the distal humerus and to empirically qualify these ethnic differences. This was accomplished by utilising 3D models of bones reconstructed by computerised tomography (CT) scan data from Europe, Japan and Thailand. This information was then utilised to assess and document the implications that stature and ethnic origin have on bone morphology, as it relates to plate design and fracture fixation. The findings of this research project will contribute to the understanding in this field as well as allowing the establishment of clinically relevant fit criteria of plates on the distal humerus.
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Kaleme, Prince K. "Habitat fragmentation, patterns of diversity and phylogeography of small mammal species in the Albertine rift." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/18110.
Full textAbstract:
Thesis (PhD) - Stellenbosch University, 2011.ENGLISH ABSTRACT: The Albertine Rift is characterized by a heterogeneous landscape which may, at least in part, drive the exceptional biodiversity found across all taxonomic levels. Notwithstanding the biodiversity and beauty of the region, large areas are poorly understood because of political instability with the inaccessibility of most of the region as a contributing factor. The majority of studies in the Albertine Rift have focussed on charismatic mega fauna, with other taxa receiving less attention. One of the taxonomically and numerically more abundant small mammal genera is the genus Praomys, an African endemic with a wide distribution range spanning most of west, central and east Africa. Four species are typically recognized from the Albertine Rift namely P. degraaffi, P. jacksoni, P. misonnei and P. verschureni. In this study I used a combination of DNA sequence data (mitochondrial control region, mitochondrial cytochrome b and 7th intron of the nuclear ß-fibrinogen gene) as well as morphometric data (traditional and geometric) to investigate the systematics of the Praomys taxa occurring in the Albertine Rift. To allow meaningful DNA assessments and in an attempt to identify potential drivers of diversifications, other Praomys species were also included from public sequence data bases for comparisons. The main focus was on P. jacksoni (the numerically most abundant taxon; also, up to 2005, all Praomys in the Albertine Rift were mostly collected as “jacksoni”) and P. degraaffi (an Albertine Rift endemic). A surprising finding was the presence of P. mutoni; this represents a range extension for this species into the Albertine Rift. Distinct evolutionary lineages were found in both P. jacksoni (confirmed by sequence data as well as morphometrics) as well as P. degraaffi (based only on sequence data; insufficient samples precluded a full morphometric investigation). These lineages (in both P. jacksoni as well as P. degraaffi) appear to be separated along a north – south gradient; however, further investigations should confirm this. To further investigate the genetic patterns at local scales across the Albertine Rift, as well as introgression between species as revealed by sequence data, a species-specific microsatellite library was developed for P. jacksoni. Twelve polymorphic markers were identified of which nine also amplified in P. degraaffi. Introgression was confirmed between the two focal species with almost 20% of the individuals analysed being jacksoni-degraaffi hybrids. This is perhaps not so surprising given that there is considerable overlap in their ranges (between ~ 1500 m a.s.l. to 2450 m a.s.l.) as well as the relative ages of the species (the divergence time between these two species were estimated at 3.8 Mya). The presence of distinct lineages within each of these species was confirmed by microsatellite analyses (these lineages diverged approcimately at same time at ca. 3.4 Mya). As suggested by sequence and morphometric data, these lineages had a largely north – south distribution but with considerable overlap in the central Albertine Rift in the vicinity of Lake Kivu. The phylogeographic patterns obtained for both focal species were not consistent with the physical barriers such as the rivers, lakes or mountains, nor were they exclusively associated with Pleistocene phenomena such as the change of the course of the rivers or uplift; rather, the lineages predate the Pleistocene and fall firmly in the Pliocene (>3 Mya). Biogeographically, the north - south location of lineages with a centrally - located contact zone could be a result of parapatric speciation due to habitat fragmentation or past climate change, followed by secondary contact. Barcoding using genetic information provides a useful tool to identify unknown taxa, cryptic diversity or where different life stages are difficult to identify. From an invasion biology perspective, it allows for the rapid identification of problem taxa against a known data base. By adopting such a barcoding approach (senso lato), the presence of three invasive rodents was confirmed in the Democratic Republic of the Congo (DRC); these are Rattus rattus (black rat), R. norvegicus (Norway rat) and Mus musculus domesticus (house mouse). A comparison with global data available for these species revealed two possible introduction pathways namely via the shipping port at Kinshasa/Matadi (with strong links to Europe) and via the slave trade routes in the east (strong links to the Arab world and the east). Of these three taxa, only R. rattus is currently documented from the DRC although the others have received mention in the gray literature. These findings draw attention to the lack of any official policy regarding biosecurity in the DRC, and argue for the development of strict control measures to prevent further introductions.
AFRIKAANSE OPSOMMING: Die Albertine Rift word gekenmerk deur 'n heterogene landskap wat kan, ten minste gedeeltelik, die uitsonderlike biodiversiteit wat oor al die taksonomiese vlakke gevind word teweeg bring. Nieteenstaande die biodiversiteit en die skoonheid van die streek, is groot gebiede onbekend as gevolg van politieke onstabiliteit met die ontoeganklikheid van meeste van die streek as 'n bydraende faktor. Die meerderheid van studies in die Albertine Rift het gefokus op die charismatiese mega fauna, met ander taxa wat minder aandag ontvang. Een van die taksonomies en numeries meer volop klein soogdier genera is die genus Praomys, 'n Afrika endemiese groep met 'n wye verspreiding wat strek oor die grootste deel van van wes-, sentraal en oos-Afrika. Vier spesies word tipies erken van die Albertine Rift naamlik P. degraaffi, P. jacksoni, P. misonnei en P. verschureni. In hierdie studie het ek 'n kombinasie van DNA volgorde data (mitochondriale beheer streek, mitochondriale sitochroom b en 7de intron van die kern ß-fibrinogeen geen) sowel as morfometriese data (tradisioneel en meetkundig) gebruik om die sistematiek van die Praomys taxa te ondersoek. Om betekenisvolle DNA aanslae toe te laat en in 'n poging om potensiële aandrywers van diversiteit te identifiseer, is ander Praomys spesies van openbare volgorde data basisse vir vergelykings ingesluit. Die hooffokus is op P. jacksoni (die numeries volopste takson, ook, tot en met 2005 is alle Praomys in die Albertine Rift meestal as "jacksoni" versamel) en P. degraaffi ('n Albertine Rift endemiese spesie). 'n Verrassende bevinding was die teenwoordigheid van P. mutoni, dit verteenwoordig' n verspreidingsuitbreiding vir hierdie spesie in die Albertine Rift. Bepaalde evolusionêre ontwikkelingslyne was in beide P. jacksoni (bevestig deur die volgorde data sowel as morfometrie) sowel as P. degraaffi (wat slegs gebaseer is op die volgorde data, onvoldoende monsters verhinder 'n volledige morfometriese ondersoek). Hierdie lyne (in beide P. jacksoni sowel as P. degraaffi) word geskei langs 'n noord - suid gradiënt, maar verdere ondersoeke moet dit bevestig. Om die genetiese patrone op plaaslike skaal oor die Albertina Rift verder te ondersoek, sowel as introgressie tussen spesies soos geopenbaar deur die volgorde data, is 'n spesie-spesifieke mikrosatelliet biblioteek ontwikkel vir P. jacksoni. Twaalf polimorfiese merkers is geïdentifiseer waarvan nege ook amplifiseer in P. degraaffi. Introgressie is bevestig tussen die twee brandpunt spesies met byna 20% van die individue wat ontleed is as jacksoni-degraaffi basters. Dit is miskien nie so verbasend gegee dat daar aansienlike oorvleueling is in hul gebiede (tussen ~ 1500 m bo seespieel tot 2450 m bo seespieel), sowel as die relatiewe ouderdomme van die spesies (die divergensie tussen hierdie twee spesies is geskat op 3,8 Mya). Die teenwoordigheid van verskillende lyne in elk van hierdie spesies is bevestig deur mikrosatelliet ontleding (hierdie lyne het gedivergeer ongeveer 3,4 Mya). Soos voorgestel deur die DNA volgorde en morfometriese data, het hierdie lyne 'n grootliks noorde – suid verspreiding, maar met 'n aansienlike oorvleueling in die sentrale Albertine Rift in die omgewing van die Kivumeer. Die filogeografiese patrone wat vir beide die brandpunt spesies gevind is nie in ooreenstemming met die fisiese struikelblokke soos die riviere, mere of berge nie, en hou ook nie uitsluitlik verband met die Pleistoseen verskynsels soos die verandering van die loop van die riviere nie; die afstammelinge is eerder veel ouer as die Pleistoseen en val binne die Plioseen (> 3 Mya). Biogeografies, die noorde – suid plasing van die lyne met 'n sentraal geleë kontak sone kan die gevolg wees van parapatriese spesiasie te danke aan habitatfragmentasie as gevolg van verandering in die klimaat, gevolg deur 'n sekondêre kontak. Strepieskodering met behulp van genetiese inligting verskaf 'n nuttige instrument om onbekend taxa, kriptiese diversiteit of waar verskillende lewensfases moeilik is om te identifiseer, te identifiseer. Vanuit 'n indringerbiologie perspektief, maak hierdie benadering dit moontlik om vinnige identifikasies van die probleem taksa teen' n bekende data basis te bekom. Deur gebruik te maak van so 'n strepieskoderingsbenadering (senso lato), is die teenwoordigheid van drie indringende knaagdiere bevestig in die Demokratiese Republiek van die Kongo (DRK), naamlik Rattus rattus (swart rot), R. norvegicus (Noorweë rot) en Mus musculus domesticus (huis muis). 'n Vergelyking met die globale data wat beskikbaar is vir hierdie spesies het aan die lig gebring dat twee moontlike betree-roetes bestaan, naamlik via die skeepshawe by Kinshasa / Matadi (met sterk skakels na Europa), en via die slawehandel roetes in die ooste (sterk skakels na die Arabiese wêreld en die ooste) . Van hierdie drie taxa, is tans slegs R. rattus van die Demokratiese Republiek van die Kongo gedokumenteer, hoewel die ander melding ontvang in die grys literatuur. Hierdie bevindinge vestig die aandag op die gebrek aan enige amptelike beleid ten opsigte van biosekuriteit in die Demokratiese Republiek van die Kongo, en argumenteer vir die ontwikkeling van streng beheermaatreëls om verdere indringerspesies te voorkom.
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Krause, Richard Alan. "Ecological, Evolutionary, and Taphonomic Comparisons of Brachiopods and Bivalves at Multiple Spatial and Temporal Scales." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/27278.
Full textAbstract:
The fossil record is the primary source of information on the history of life. As such, it is important to understand the limitations of this record. One critical area in which there is still much work to be done is in understanding how the fossil record, and our interpretation of it, may be biased.
Herein, the fidelity between the life and death assemblage of an extant brachiopod with respect to morphological variability is studied using geometric morphometrics. The results from several analyses confirm a high degree of morphological variability with little change in mean shape between the living and sub-fossil assemblage. Additionally, there is no evidence of distinct morphogroups in either assemblage. These trends persist at all depths and size classes indicating that this species could be recognized as a single, rather than multiple, species if only fossil data were available.
The second chapter involves the recognition and quantification of a worker bias in monographs of brachiopods and bivalves. Most specimens studied came from the 65th to 69th percentile of their species' bulk-collected size-frequency distribution. This indicates a significant bias toward monograph specimens that are larger than the mean size of the bulk sample. When compared at the species level, this bias was found to be highly consistent among the 86 species included in the study. Thus, size measurements of monographed specimens reliably and consistently record a similar size class for any given species, and this bias is easily corrected during meta-analyses.
Chapter three focuses on bivalves and brachiopods from a modern tropical shelf and quantifies the magnitude of time averaging (temporal mixing) for these two different organisms. This is accomplished by dating a suite of shells from each site using amino acid racemization calibrated with several radiocarbon dates. By studying the age distributions for each species it is determined that, despite some site to site differences, both bivalve and brachiopod species exhibit a similar time averaging magnitude when collected from the same region or depositional system. This indicates that fossil assemblages of these species may have very similar resolution.Ph. D.
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Smith, Amy C. "Description of Tanytrachelos ahynis and its implications for the phylogeny of Protorosauria." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/37652.
Full textAbstract:
Tanytrachelos ahynis, a small (21 cm long) aquatic protorosaur from the Upper Triassic sediments in the Cow Branch Formation of the Newark Supergroup, has been briefly described in 1979 by P. E. Olsen. A growing addition of nearly 200 specimens and the availability of CT imaging allow for an extensively detailed redescription. This redescription fills in missing data in cladistic analyses of Protorosauria, allowing for protorosaur monophyly to be retested with a more robust data set.
Two hundred and ninety specimens and two CT scans of specimens were examined, with seventy linear measurements, four angular measurements, and five derived variables comprising the quantitative observations. These qualitative and quantitative observations then provided data for Tanytrachelos in two cladistic analyses of Protorosauria. The first analysis included the outgroup Petrolacosaurus, twenty-one protorosaurs, and nine other archosauromorphs. The second analysis included the twenty taxa within this sample that had a data completeness of 50% or higher.
Diagnostic qualities of Tanytrachelos include large orbits (11% - 13% the lateral area of the skull), a fused axis and atlas, a tail that spans half the vertebral length, and paired curved heterotopic bones in some specimens (a sign of sexual dimorphism). The disparity of size between the hind and fore limbs, as well as traces of soft tissue, suggest that Tanytrachelos propelled through the water with its back legs. This taxon is similar to Gwyneddosaurus, found in the Lockatong Formation (Newark Supergroup) in Montgomery County, PA, but should maintain its generic name due to lack of diagnostic qualities for Gwyneddosaurus.
With the new observations of Tanytrachelos included, each of the two cladistic analyses yielded a single most parsimonious tree presenting a paraphyletic Protorosauria. Both results placed Prolacerta within the confines of Protorosauria, in contrast with the previous suggestion by three publications that Prolacerta was not a true protorosaur. The analysis of all taxa presented Boreopricea as the most basal protorosaur, while the analysis of the twenty most complete taxa presented Protorosaurus as most primitive. Neither tree fully agrees with any previously published data, partly due to differences in taxa sampling between studies.Ph. D.
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Clutts, Stephanie A. "Systematics of Anguispira (Pulmonata: Discidae) based on molecular and morphometric data." Available to subscribers only, 2008. http://proquest.umi.com/pqdweb?did=1674100491&sid=2&Fmt=2&clientId=1509&RQT=309&VName=PQD.
Full textAbstract:
Thesis (M.S.)--Southern Illinois University Carbondale, 2008."Department of Zoology." Keywords: Anguispira, Molecular, Mollusks, Morphometrics, Systematics. Includes bibliographical references (p. 111-115). Also available online.
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Harris, William Henry. "Ontogenesis in the Cranium of Alligator mississippiensis Based on Disarticulated Cranial Elements." Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etd/2492.
Full textAbstract:
The American alligator, Alligator mississippiensis, is a large extant archosaur and member of the Order Crocodilia. Crocodilian ontogeny has been studied in great detail, the skull being of particular interest. One aspect of the skull left unstudied is how individual cranial elements change through ontogeny independent of one another. This study observed morphological change in a growth series of 34 specimens of A. mississippiensis from ETSU Vertebrate Paleontology Lab collections. The premaxilla, maxilla, nasal, jugal, frontal, and parietal were analyzed using landmark morphometrics. The frontal, jugal, and parietal showed more allometric growth with the orbits reducing in size posteriorly. The premaxilla, maxilla, and nasal showed more isometric growth. This suggests the common observation that the snout elongates with age is mistaken. The cranium showed allometric growth in very early in life but more isometric growth after that. Unique to this study, the premaxilla showed almost no shape change throughout ontogeny.
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Foster, Austin Prescott. "Developmental variation and morphological integration between chondrocranial- and intramembranous-derived craniofacial skeletal components in a cross-sectional sample of C57BL6/J and C3H/HeJ mice." Thesis, University of Iowa, 2018. https://ir.uiowa.edu/etd/6103.
Full textAbstract:
Introduction: Chondrocranial-derived components of the craniofacial skeleton are thought to exert a morphogenetic influence on surrounding intramembranous-derived skeletal structures. In our previous study (Foster and Holton, 2016), we found that the ontogenetic relationship between the nasal septum (derived primarily from the chondrocranium) and surrounding intramembranous-derived facial skeleton was highly variable in BL6 and C3H mice. The purpose of our present study was to examine samples of BL6 and C3H mice from 3 to 15 weeks of age to determine whether the variable interaction noted previously extends to chondrocranial- and intramembranous-derived components throughout the cranium. Methods: Cross-sectional samples of male C57BL/6J (BL6) and C3H/HeJ (C3H) at 3 (n=18) and 15 (n=30) weeks of age were studied. All mouse crania were scanned using a Skyscan 1272 microCT scanner, and a series of three-dimensional traditional and semilandmark coordinate landmarks were collected. Geometric morphometric techniques were utilized for data analysis. Results: During the period of 3-15 weeks of age, there was considerable variation in the ontogeny of chondrocranial- and intramembranous-derived craniofacial regions. Conclusions: During the period of 3-15 weeks of age, C3H mice were characterized by a relative enlargement of the chondrocranial-derived craniofacial skeleton. The chondrocranial morphology of the C3H mice may be a causal factor in the increased magnitude of variation seen in the C3H intramembranous-derived facial skeleton. Developmental variation within specific components of the craniofacial complex may account for taxonomic variation in facial height that accompanies anteroposterior facial skeletal reduction characteristic of taxa such as anthropoid primates.
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Drumheller-Horton, Stephanie Katarina. "An actualistic and phylogenetic approach to identifying and interpreting crocodylian bite marks." Diss., University of Iowa, 2012. https://ir.uiowa.edu/etd/3446.
Full textAbstract:
Bite marks provide direct evidence of trophic interactions, feeding behavior, and inter- or intraspecific conflict in the fossil record. However, their utility as a source of taphonomic and paleoecologic data requires differentiation from traces left by other processes. Since the 19th century, taphonomists have often relied on actualistic observations of modern bite marks and feeding behaviors in order to identify diagnostic traces and patterns. A recent increase in interest in taphonomic research has resulted in a large body of work describing patterns of bite marks from many different clades. Most research has been focused on mammalian taxa, but a smaller number of non-mammalian groups, including crocodylians, have also drawn interest.
Crocodylians are taphonomic agents who consume and modify bones, often depositing them in the active depositional systems in which they live. However, actualistic observations of crocodylian bite marks have been limited to forensic case studies and surveys of two taxa: Crocodylus niloticus and Crocodylus porosus. Both surveys utilized captive animals, which often exhibit atypical morphologies that may bias ensuing bite mark datasets. In order to address this issue, a 2D morphometric analysis of Alligator mississippiensis crania from captive and wild specimens was performed. A principal component analysis and a canonical variates analysis revealed some statistically significant differences between the two groups, while crossvalidation had mixed resuts. An ANCOVA test of the covariance of centroid size and origin against shape (principal component scores) revealed that the effects of ontogeny introduced a stronger signal than captivity. This implies that while using captive crocodylians in fine scale analyses should be avoided, they are suitable for gross scale research, such as bite mark analyses.
To explore crocodylian bite mark patterns in greater depth, a large scale survey of traces left by A. mississippiensis was performed. Bite mark types on samples taken from individual feedings were discussed in light of vital statistics and collection protocols. Bite mark types on samples taken from group feedings were classified by location and orientation on bone and type. The results were compared to pre-existing crocodylian datasets with regards to potentially diagnostic traits: bisected marks, hook scores, and a lack of furrows. Bisected marks were found in rates similar to those seen in C. niloticus, and rates of hook scoring and bone breakage were higher. These traces were present in higher rates than those reported in C. porosus. Furrows were identified, but rare.
Finally, a survey of bite marks from 21 of the 23 generally recognized species of extant crocodylians was performed to better characterize marks found across Crocodylia and to test methods for synthesizing taphonomic datasets. Bite marks were identified, and specimens were then coded for presence or absence of mark subscores. Attempts to find statistical correlation between mark types, animal vital statistics, and sample collection protocol were unsuccessful. Mapping bite mark character states on a eusuchian phylogeny successfully predicted the presence of bisected marks in previously published, extinct taxa. Predictions for clades that may have created multiple subscores, striated marks, and extensive crushing were also generated. Inclusion of fossil bite marks which have been positively associated with extinct species allow this method to be projected beyond the crown group. The results of this study indicate that phylogenies can and should be explored further for use as predictive tools in a taphonomic framework.
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Cossette, Adam Patrick. "The early history of character evolution in alligatoroids." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6397.
Full textAbstract:
This project seeks to explore, name, and describe some of the earliest known members of Alligatoroidea. Explorations of Bottosaurus harlani and Deinosuchus reveal that early in their evolutionary history alligatoroids had attained bauplans that are highly divergent from the ancestral condition in both body size and morphology.
Bottosaurus harlani preserves aspects of the skull table – including constricted supratemporal fenestrae, a linear frontoparietal suture, and a large trapezoidal dorsal supraoccipital exposure – that are similar to those of caimans. Optimal trees from phylogenetic analysis recover B. harlani in three different positions; as a sister either to the modern dwarf caimans (Paleosuchus), or either living species of Paleosuchus. That a substantial stratigraphic gap separates B. harlani from both species of Paleosuchus, which first appears in the Miocene, along with low character and nodal support raises questions about this relationship. However, should the relationships recovered here be true, Bottosaurus harlani would be the oldest known caiman. The taxon indicates that morphologies common to modern caimans date to the earliest record of the clade.
In addition to the enigmatic B. harlani, the Campanian giant Deinosuchus was re-evaluated as part of this project. Recent consensus has been that the three named species of Deinosuchus (D. hatcheri, D. riograndensis, and D. rugosus) represent a single, widely ranging species. Newly-collected material from the Big Bend region of western Texas and increased sampling of the lineage from throughout North America allowed for a review of species-level systematics of Deinosuchus and helped refine its phylogenetic placement among crocodylians. Deinosuchus from western and eastern North America can be consistently differentiated and represent different species.
As a result of the lack of diagnostic characters in the very incomplete holotype specimen, the name Deinosuchus is restricted to D. hatcheri. To encompass specimens formerly included in Deinosuchus a new genus, Deinosuchoides, is erected. In addition to naming a new genus, the holotype specimen for Deinosuchus rugosus is determined to be undiagnostic to species level and is therefore a nomen dubium. A new species, Deinosuchoides schwimmeri, is erected upon a cranial specimen from Mississippi.
The snout of Deinosuchoides is very long and wide. Almost invariably, crocodylian snouts are either long or wide, but not both. In addition to the unusually long and wide snout, the skull table of this taxon bears hallmarks found in species of other long-snouted taxa such as Tomistoma and Gavialis.
To explore the variability of the crocodylian skull table a morphometric analysis was conducted with the inclusion of fossil taxa. As the skull table is robust and likely to be recovered in the paleontological record this element was an ideal fit for a morphometric study. In addition to establishing the morphospace occupation of fossil taxa, the morphometric analysis found considerable overlap in morphospace between Alligatoroidea and Crocodyloidea – the overlap between these groups may be the product of shared ancestry. Additionally, similarities exist in the ecologies of these groups as evidenced by shared snout shape categories. This project finds association between skull table shape and snout length. As such, plotting isolated skull tables in morphospace, may indicate snout length and thus ecology of fossil taxa.
When landmarks representing the supratemporal fenestrae are included in the analysis Gavialoidea is broadly separated from the other groups in morphospace. It has been long hypothesized that the size of the supratemporal fenestrae reflect the length of the snout as a result of jaw musculature attaching to their medial margins. However, this relationship is not as straightforward as previously hypothesized; the snouts of the crocodyloids Tomistoma and Euthecodon may exceed the length of the snout in gavialoids but their supratemporal fenestrae are proportionally smaller. This study suggests that a phylogenetic constraint on the size of the supratemporal fenestrae may be present in crocodyloids.
In addition to exploring morphospace occupation, allometric trajectories of all extant taxa with available ontogenetic sequences were explored. The smallest extant taxa (O. tetraspis, P. palpebrosus, and P. trigonatus) demonstrate allometric trajectories that plot alongside the juveniles of the other taxa in this analysis. This may suggest that the small sizes of the skull tables in these species were achieved through paedomorphosis, or the maintenance of juvenile morphologies into adulthood.
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Camp, Jessica Amber. "Morphological variation and disparity in Lystrosaurus (Therapsida: Dicynodontia)." Thesis, University of Iowa, 2010. https://ir.uiowa.edu/etd/650.
Full textAbstract:
The dicynodont genus Lystrosaurus, a relative of the Kannemeyerids, is one of few terrestrial vertebrate genera which can be found on both sides of the Permian-Triassic (P-T) boundary (Botha and Smith, 2006); indeed, a single species, Lystrosaurus curvatus, is known from both periods. In the Permian, Lystrosaurus was of average abundance relative to other genera. Shortly following the P-T extinction, it drastically increased in abundance until it dominated the faunas it was present in (Botha and Smith, 2006). To date, Lystrosaurus fossils have been found in South Africa, India, Antarctica, China, and Russia (Grine et al., 2006). Abundance, survivorship, and expansive geographic presence give Lystrosaurus extreme potential as a model organism for multiple questions involving ideas such as extinction survivorship, biogeography, and ecology; however, Lystrosaurus has been subject to the practice of an extreme version of "splitter" taxonomy in the past. Here I quantify Lystrosaurus morphology using geometric morphometrics. Chinese Lystrosaurus taxonomy has not been analyzed in light of this. My results show that they are different from Gondwanan Lystrosaurus and represent at least one if not two unique species.
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Dunn, Shanna K. "Analyzing Spatial Patterns in Reefscape Ecology Via Remote Sensing, Benthic Habitat Mapping, and Morphometrics." NSUWorks, 2009. http://nsuworks.nova.edu/occ_stuetd/234.
Full textAbstract:
A growing number of scientists are investigating applications of landscape ecology principles to marine studies, yet few coral reef scientists have examined spatial patterns across entire reefscapes with a holistic ecosystem-based view. This study was an effort to better understand reefscape ecology by quantitatively assessing spatial structures and habitat arrangements using remote sensing and geographic information systems (GIS).
Quantifying recurring patterns in reef systems has implications for improving the efficiency of mapping efforts and lowering costs associated with collecting field data and acquiring satellite imagery. If a representative example of a reef is mapped with high accuracy, the data derived from habitat configurations could be extrapolated over a larger region to aid management decisions and focus conservation efforts.
The aim of this project was to measure repeating spatial patterns at multiple scales (10s m2 to 10s km2) and to explain the environmental mechanisms which have formed the observed patterns. Because power laws have been recognized in size-frequency distributions of reef habitat patches, this study further investigated whether the property exists for expansive reefs with diverse geologic histories.
Intra- and inter-reef patch relationships were studied at three sites: Andavadoaka (Madagascar), Vieques (Puerto Rico), and Saipan (Commonwealth of the Northern Mariana Islands). In situ ecological information, including benthic species composition and abundance, as well as substrate type, was collected with georeferenced video transects. LiDAR (Light Detection and Ranging) surveys were assembled into digital elevation models (DEMs), while vessel-based acoustic surveys were utilized to empirically tune bathymetry models where LiDAR data were unavailable. A GIS for each site was compiled by overlying groundtruth data, classifications, DEMs, and satellite images. Benthic cover classes were then digitized and analyzed based on a suite of metrics (e.g. patch complexity, principle axes ratio, and neighborhood transitions).
Results from metric analyses were extremely comparable between sites suggesting that spatial prediction of habitat arrangements is very plausible. Further implications discussed include developing an automated habitat mapping technique and improving conservation planning and delimitation of marine protected areas.
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van, Heteren Anna Helena. "Masticatory adaptations of extant and extinct Ursidae : an assessment using three-dimensional geometric morphometrics." Thesis, University of Roehampton, 2012. https://pure.roehampton.ac.uk/portal/en/studentthesis/masticatory-adaptations-of-extant-and-extinct-ursidae(a636d685-de0b-43f8-8438-7ef0e5c2a9f6).html.
Full textAbstract:
The diet of Pleistocene cave bears (Ursus spelaeus, U. deningeri) is debated extensively. Traditionally, cave bears were thought to be herbivorous, but more recent studies have proposed that they were more omnivorous. To test this, their skull morphology and that of their confamilials were analysed using 3D geometric morphometrics. The eight extant Ursidae occupy various dietary niches, which are expected to affect the functional morphology of the skull; the resulting dietary morphospace is used to determine the position of cave bears. Landmarks for 3D digitisation were chosen to reflect functional morphology. Extant and extinct Ursidae were digitised with a Microscribe G2. Generalised Procrustes superimposition was performed on the raw coordinates and allometry removed by regressing these onto the log (ln) centroid size pooled per species. Principal component analyses (PCA) and two-block partial least squares analyses (2B-PLS) were conducted on the regression residuals, and (multivariate) analyses of (co)variance ((M)AN(C)OVA) and discriminant function analyses (DFA) performed on the PC scores. PCA and 2B-PLS differentiate between known dietary niches in extant Ursidae. (M)AN(C)OVA and DFA results suggest that cave bears were herbivorous. Differences in the results between the temporalis and the masseter are seen primarily in the position in morphospace of the extant spectacled bear (Tremarctos ornatus), probably due to the influence of its premasseteric fossa on the morphology of the masseteric fossa. Additionally, ANOVAs suggest that there was intraspecific variation within U. spelaeus contradicting lineages proposed on the basis of mitochondrial DNA. This variation may be attributable to environmental factors, such as timberline altitude, influencing the cave bears’ diet.
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Gold, Maria Eugenia Leone. "Cranial osteology and braincase morphometrics of Gavialis gangeticus: implications for crocodylian phylogenetics." University of Iowa, 2011. http://ir.uiowa.edu/etd/2428.
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