The Nile crocodile Crocodylus niloticus currently has an extensive range throughout the African continent and Madagascar, though fossil and subfossil remains show that its historic range was considerably larger and included parts of the Sahara Desert, Mediterranean coast, and Arabian Peninsula. Recent molecular studies have yielded genetically distinct populations of C. niloticus, leading to the possibility that C. niloticus is actually multiple cryptic species, while morphological variation remains unassessed. This study compares skulls of C. niloticus to other members of the genus Crocodylus in dorsal view using geometric morphometrics to evaluate intraspecific and interspecific variation. The morphometric analysis is coupled with a geographic analysis to determine if the species is morphologically variable by geographic region as well as a model-based cluster analysis to determine and morphological clusters irrespective of other factors. These analyses indicate that C. niloticus exhibits populational variation that exceeds almost every other species of Crocodylus, with differences between geographic regions statistically disctinct. These results support the presence of a cryptic species complex. Additionally, an osteological description of Crocodylus niloticus is provided.

Objective: Variation in dental arch shape and arch relations from the primary to the permanent dentition were studied in an untreated longitudinal sample from the Iowa Fluoride Study and Growth Study data (55 females and 63 males). Methods: 3D coordinate data from 68 landmarks located on maxillary, mandibular, and occlusal dental cast scans from ages 5, 9, and 13 were submitted to a Procrustes fit prior to a Principal Component (PC) analysis to capture symmetric and asymmetric aspects of arch shape variation. Covariance pattern models were used to determine longitudinal arch shape changes from the primary to the permanent dentition and to correlate these changes with Angle class molar classification. Results: The first 3 principal components capture 52-78% of the variation in arch shape. PC1 explains 30-44% of the variance and captures changes in overall dentoalveolar height. PC2 explains 14-22% and shows mainly variation in dentoalveolar height and width at the canines. Lastly, PC3 explains 8-12% and captures overall arch width and perimeter differences and changes in anteroposterior arch relations. Results on symmetric shape variation for the occlusal data set captured significant differences (p < 0.0001) in morphology for PC2 and PC3. For PC2, initial morphology in the deciduous dentition for an individual classified as Class II was significantly different than a Class I individual. Initial shape characteristics for the Class II features stepped down maxillary incisors and an increased curve of Spee with deep overbite. For PC3, the initial morphology for both the distocclusion and Class II individuals demonstrated characteristics such as stepped up maxillary incisors and increased overjet relative to their flush terminal plane and Class I counterparts. The rate of arch shape changes at which the distal step group transitions to the mixed dentition was also significantly different from the flush terminal plane sample. Conclusions: Initial findings summarize the main aspects of arch shape variation throughout 3 dentition stages. The covariance pattern models estimated individual trajectories and dynamics of arch shape changes from the primary to the permanent dentition and correlated these changes with Angle molar classification. In the symmetric dataset, significant shape characteristic differences of both initial starting morphology and change in shape over time were discovered for two occlusal phenotypes highlighting differences primarily in the vertical and anteroposterior dimensions. The results found in the present study provide an excellent foundation for describing and identifying dental arch shape differences in the primary dentition that can aid in earlier detection, diagnosis, and treatment of malocclusion, or at a minimum warrant closer observation by the clinician.

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.

The reliability of foraminifera as stratigraphic index fossils, and as isotopic proxies of marine environments, is based on the assumption that the fossil concepts represent uniform species, responding consistently to their ambient environments. Understanding sources of uncertainty is, therefore, critical. In this dissertation, I explore a potential bias in the application of planktonic foraminifera utilized extensively for Cenozoic paleo-reconstruction and, to a lesser extent, biostratigraphy: the Globigerinoides ruber-elongatus plexus (‘plexus’ meaning a complex network of interconnected members). Taxonomic revisions since 1826 have resulted in the merging of multiple Globigerinoides species names under one general designation (“Globigerinoides ruber”), the implications of which are now under scrutiny. These “morphotypes” of G. ruber have been shown to incorporate stable isotopes and trace elements in seawater dissimilarly, and correspond to multiple genetic species, some of which occupy different environments. Various criteria exist to sub-divide, group, or distinguish members of the Globigerinoides plexus, most notably the recurring use of Globigerinoides elongatus as a less spherical, less symmetrical counterpart to G. ruber. But the efficacy of these various taxonomic criteria has not been tested quantitatively. Most rely on the traits of visually distinctive “end-members,” while specimens in the morphological “transitional zone” are left to an observer’s subjective interpretation. This prevents quantification in census counts, and may lead to erroneous geochemical analyses. Furthermore, molecular clock estimates suggest that the G. elongatus species evolved significantly later than G. ruber, affecting its potential as a biomarker. In this dissertation, I examine the potential of a minimal-criteria system for classifying Globigerinoides-type morphologies using only three conditions: final chamber compression, final chamber asymmetry, and aperture compression. Morphometric analyses on specimens grouped according to this new system allow us to assess to what degree visual classification reflects morphospace discontinuity. Armed with this information, I then explore potential isotopic offsets between members of the Globigerinoides plexus, and its use in reconstructing regional differences in climate or habitat influences in the Gulf of Mexico and Caribbean basins. Finally, having shown that G. ruber and G. elongatus can be reliably visually distinguished, I tracked the species’ fossil presence individually in a deep core from the South China Sea, and confirmed the presence of G. ruber in the South China Sea through the late Miocene, and G. elongatus through the Pleistocene. While it is believed that neither species was traced to its true first occurrence (FO), the relative FO of G. ruber was shown to be 4–5 Ma before G. elongatus

Abstract This study uses different morphometric methods to study morphological variation in the population of Engyprosopon grandisquama near the southwestern coast of Taiwan. In addition to the traditional multivariates method , geomorphmetric methods, including the Baselined method and General resistant fit method were used and the results were compared. Results from ocular-side and blind-side analysis are similar. Appearance among locations is different. Overall, each sample including all specimens from all stations can be classified into either two or three groups, depending on the employed method, as well as characters of blind and ocular sides being used. The groups are¡GYung-an, Tso-ying, and Kao-ping-hsi. The latter area appeared to be shifting between the other two groups. Bigger fish, estaminated by centroid-size, morphometric methods, appeared to stay in deeper water(60~80m), and their morphometric performance is different from those in shallow water. Analysis of variance from the General linear model showed significant regression relationships of centroid-size against distances of sampling site to different harbor estuary. The orders of their effectiveness of dosal-side are Tso-ying, Kaohsiung, Yung-an and Kao-ping-hsi respectively. Effectiveness based on blind-side characters are Tso-ying, Kaohsiung, Kao-ping-hsi and water depth. Generally speaking, most samples can be separated into three area-groups, which are¡G(1)Yung-an, (2)Tso-ying and (3)Kao-ping-hsi. Effect of water depth are better expressed by the blind-side characters, whereas effect of the area-sites are better expressed by the ocular-side characters.

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.

The purpose of this study was to use geometric morphometrics (GM) to investigate the relationships between non-metric traits of the human hip bone: the greater sciatic notch (GSN), the ventral arc (VA), the subpubic contour (SPC), and the ischiopubic ramus ridge (IPRR), estimated skeletal sex, and shape. Fifty-nine undocumented left hip bone specimens were visually assessed for skeletal sex using recognized standards of sex estimation for the GSN (Buikstra and Ubelaker, 1994). The VA, SPC, and IPRR were assessed according to Klales et al., (2012). The Non-metric traits were scored on a five-scale scheme. Skeletal sex was classified as either male, possible male, indeterminate sex, possible female, or female. Three-dimensional computer models were created of the hip bones using the NextEngine 3D desktop surface scanner. Thirty landmarks were selected to represent the hip bone in three-dimensional shape for GM analysis. Twenty-seven of the selected landmarks were reliable according to suggested digitizing error measurements. The apex of the auricular surface, the arcurate eminence, and the anterior gluteal line were the least precise in the test for digitizing error. Geometric morphometric analysis of the computer models were performed using MorphoJ software. Principal component analysis identified the patterns of hip bone shape within the sex categories. A Procrustes ANOVA and a Spearman's correlation tested the significance between hip bone shape and estimated skeletal sex, and between hip bone shape and non-metric trait morphology. Patterns of hip bone shape in the ischium could not be identified by sex, however sex differences were identified in ischium size. Patterns of hip bone shape in the whole hip bone, segmented ilium and segmented pubis were distinguishable by larger sex groups (males = male and possible male categories; females = female and possible female categories). Shape patterns alluded to differences between females and possible females, however, shape patterns did not distinguish males from possible males. Individuals of indeterminate sex shared similar hip bone shapes as males and were therefore included in that larger sex group. Hip bone shape was also correlated with GSN, SPC, IPRR, and VA. However, the strength of the correlation differed between non-metric traits and certain components of hip bone shape. The GSN and SPC had the strongest correlation (p=<0.01) with the whole hip bone, the ilium and the pubis at distinguishing between larger male and female sex groups. The IPRR, and GSN had the strongest correlation (p=<0.01) with the pubis at distinguishing females and possible females. The results of the study suggest that non-metric traits can discern patterns of female shape better than patterns of male shape. Further research into discerning patterns of male hip bone shape and non-metric trait variation using GM is suggested. The results of the study also suggest that patterns of pubis shape might exist among females and could be identifiable using pubis non-metric trait scores. This result lends credence to the practice of estimating sex on a five-scale gradient rather than on a male/female dichotomous division, in order to capture the morphological variation of female hip bone better. / Graduate / 0327 / 0339 / heatherisobelrobertson@gmail.com

abstract: The bony pelvis is a pivotal component of the locomotor system, as it links the hindlimb with the trunk and serves as anchorage for the primary propulsive musculature. Its shape is therefore expected to be adapted to the biomechanical demands of habitual locomotor behavior. However, because the relationship between locomotor mechanics and pelvic morphology is not well understood, the adaptive significance of particular pelvic traits and overall pelvic shape remains unclear. This study used an integrative, dual approach to elucidate the relationship between form and function in the primate pelvis. A biomechanical cylinder model of pelvic stress resistance was tested using in vitro strain analysis of monkey and ape cadaver specimens. These results were used to refine adaptive hypotheses relating pelvic form to locomotor mechanics. Hypotheses of adaptation were then tested via univariate and geometric morphometric methods using a taxonomically broad, comparative sample of 67 primate taxa. These results suggest that the pelvis exhibits some iliac and ischial adaptations to stress resistance that are associated with the biomechanical demands of habitual locomotor loading and of body size. The ilium and ischium exhibit relatively low levels of strain during experimental loading as well as adaptations that increase strength. The pubis exhibits relatively high strains during loading and does not vary as predicted with locomotion. This integrated study clarifies the relationship between strain and adaptation; these results support the hypothesis that bones adapted to stress resistance exhibit low strains during typical loading. In general, the cylinder model of pelvic biomechanics is unsupported. While the predictions of loading regimes were generally rejected, the inability of these methods to test the possible occurrence of overlapping loading regimes precludes outright rejection of the cylinder model. However, the lack of support for predicted global responses to applied loading regimes suggests that pelvic stress resistance may be better explained by a model that accounts for local, functional subunits of pelvic structure. The coalescence of a localized model of pelvic biomechanics and comparative morphometrics has great potential to shed light on the evolution of the complex, multi-functional structure of the pelvis. / Dissertation/Thesis / Ph.D. Anthropology 2010

The objective of this study was to examine whether the premolars and molars found at Sterkfontein Sts Mbr. 4 and StW Mbr. 5 are morphometrically similar to the degree that all individuals could belong to the same species, A. africanus. Mesial-distal (MD) and buccal-lingual (BL) measurements were obtained from maxillary premolars (P3 and P4) and molars (M1, M2, and M3) of Homo, Pan, and Gorilla, and compared to their counterparts attributed to A. africanus from Sterkfontein. Specimen samples were statistically analyzed using univariate and multivariate analyses. The results support the acceptance of the null hypothesis, indicating that the dental remains from Sts Mbr. 4 and StW Mbr 5 are from the same species.

Geometric morphometrics, the science about the study of shape, has developed much in the last twenty years. In this thesis I first study the reliability of the phylogenies built using geometric morphometrics. The effect of different evolutionary models, branch-length combinations, dimensionality and degrees of integration is explored using computer simulations. Unfortunately in the most common situations (presence of stabilizing selection, short distance between internal nodes and presence of integration) the reliability of the phylogenies is very low. Different empirical studies are analysed to estimate the degree of evolutionary integration usually found in nature. This gives an idea about how powerful the effect of integration is over the reliability of the phylogenies in empirical studies. Evolutionary integration is studied looking at the decrease of variance in the principal components of the tangent shape space using the independent contrasts of shape. The results suggest that empirical data usually show strong degrees of integration in most of the organisms and structures analysed. These are bad news, since strong degree of integration has devastating effects over the phylogenetic reliability, as suggested by our simulations. However, we also propose the existence of other theoretical situations in which strong integration may not translate into convergence between species, like perpendicular orientation of the integration patterns or big total variance relative to the distance between species in the shape space. Finally, geometric morphometrics is applied to the study of the evolution of shape in proteins. There are reasons to think that, because of their modular nature and huge dimensionality, proteins may show different patterns of evolutionary integration. Unfortunately, proteins also show strong functional demands, which influence their evolution and that cause strong integration patterns. Integration is then confirmed as a widespread property in the evolution of shape, which causes poor phylogenetic estimates.