Despite the restricted morphology and distribution of sloths today, fossils sloths show a wide variety of forms and behaviors and used to range from South America to Alaska. These extinct forms have in the past simply been lumped together as "ground sloths", separated from modern "tree sloths". However there are intermediate forms that have been posited to be semi-arboreal. In other groups such as primates the shape of the shoulder blade has been shown to vary significantly between groups with different arboreal behaviors. This study used geometric morphometrics to examine the scapulae of modern and extinct sloths to show that these three locomotor groups can in fact be distinguished by their shoulder blade shape. Juveniles of giant ground sloths also have significantly different shoulder blade shapes than the much larger adults, however they do not overlap with the smaller intermediate sloths, so may have been just as terrestrial as their parents despite their much smaller size. Finally, ontogenetic trajectories of several sloth genera do not show evidence of having different slopes. They start and end in different areas of morhospace but are all on parallel paths. This argues against the hypothesis of convergence in modern tree sloths, which despite both having an unusual suspensory lifestyle are not closely related. Rather they are both retaining an ancestral growth trajectory that all sloths have possessed.

In contexts such as natural disasters, humanitarian efforts, and other forensic investigations, the timely and accurate development of the biological profile (sex, age, ancestry, and stature of skeletonized remains) is vital to the identification of decedents. At present, the term “Hispanic” is a socio-linguistic classifier that includes all persons of South or Central American, Mexican, Cuban, Puerto Rican, or other Latino and Spanish-speaking persons into a single category; the term is also the current designator used by forensic anthropologists—in ancestry estimation—to identify anyone from a Latin American country. From a biological standpoint, the term is ineffective in describing these individuals because the human biological variation within and among different Hispanic populations cannot be encompassed by a single category. With regards to the development of the biological profile, ancestry estimations for these individuals are tenuous at best. This is due to the poor nature of the single reference sample used to create the current methods in ancestry and sex estimation—a common trend in forensic anthropology. The untested assumption that all Hispanic individuals are skeletally homogenous results in haphazard identifications and hinders effective forensic investigation. The primary objective of this research is to examine geometric morphometric variability in 547 documented individuals from three contemporaneous Latin American groups represented by Colombian, Mexican, and Migrant (U.S./Mexico border crossers) samples in order to ascertain whether it is possible to distinguish specific Hispanic populations. Using geometric morphometric (GM) analyses, the effects of shape-related variation independent of size can be implemented to isolate where on the cranium differences between groups are expressed. The results suggest that GM-derived population-specific criteria for Hispanic individuals possess the discriminatory power that is necessary towards improving the underdeveloped methods of identification for diverse Hispanic individuals living in the U.S. and abroad. Canonical variate analyses of the three samples separates the groups distinctly along both axes (CV1 and CV2). The morphological differences are predominantly seen in cranial height and sagittal vault shape, with Colombians having taller cranial vaults than the Mexican samples. The final results of this study demonstrate the utility that GM approaches have in forensic anthropology with respect to ancestry estimation and can be used to update various techniques required to develop the biological profile. Without constantly updating, refining, and re-validating the techniques, forensic anthropologists fail to provide the caliber of service required to approach the various forensic contexts.

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.

The extinct taxon Dasypus bellus has long been considered identical to the extant Dasypus novemcinctus osteologically when disregarding allometric differences. In this study, we undertake a preliminary investigation into this extinct taxon and an extant relative D. novemcinctus, by comparing the calcanea of these two dasypodids. Clear osteological differences are observed including a mediolaterally-reduced facet region, an anteriorly-shortened calcaneal head, a reduced peroneal process, and a curved and dorsoventrally-shortened calcaneal foot in D. bellus. Such characters are not allometric and likely correlate to distinct behavioral differences. Specifically, we suggest that D. novemcinctus maintains a more fossorial lifestyle, while the larger D. bellus was likely more terrestrial, with potentially little digging behavior. Such lifestyle differences could not only explain the osteological differences present, but also why fossils of D. bellus have been recovered farther north than the present range of D. novemcinctus. Fossils of Dasypus may need to be re-evaluated to determine how these two taxa relate temporally and geographically, which may have further implications regarding some past interpretations and provide new details on the behavior and potential relationships between these (and other) xenarthrans.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18109号 / 理博第3987号 / 新制||理||1575(附属図書館) / 30967 / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 中務 真人, 教授 山極 壽一, 教授 疋田 努 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第21650号 / 医博第4456号 / 新制||医||1034(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 大森 孝一, 教授 斎藤 通紀, 教授 戸口田 淳也 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24465号 / 理博第4964号 / 新制||理||1709(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)准教授 平﨑 鋭矢, 教授 髙井 正成, 教授 今井 啓雄 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Snake vertebrae are common throughout the Cenozoic fossil record, but identification of isolated vertebrae often proves difficult due to inter- and intra-columnar variability. Most fossil identifications are based on comparisons with disarticulated modern specimens, with a focus on mid-trunk vertebrae. One focus of this study was to determine the necessity of identifying a true mid-trunk vertebra prior to identification and to develop a method of locating the columnar position of an isolated vertebra for both modern and fossil identifications. Colubrid genera Farancia and Heterodon were chosen for the analysis because they share distinct morphological similarities, articulated modern specimens were available, and fossil species in these genera need to be reassessed. Every third pre-cloacal vertebra was selected from each specimen to undergo geometric morphometric analysis on its anterior face. Relative warp analyses detailed the inter-columnar variation of each specimen and found that the only significant difference in the column was between the anterior most vertebrae, which are already identifiable, and the remainder of the pre-cloacal vertebrae. Despite concern, the convention of using mid-trunk vertebrae for identification may prove accurate for these genera. Due to Farancia and Heterodon’s vertebral similarities, a discriminant function analysis was utilized to distinguish the two genera from one another. To evaluate this method’s utility in paleontology, vertebrae of two extinct species, Heterodon brevis and Paleofarancia brevispinosus, will undergo identical morphometric and discriminant analyses. This study also emphasizes the need for more modern snake skeletons in collections and the necessity of stringing the vertebral column prior to disarticulation.

Understanding how biodiversity evolves is a major goal in evolutionary developmental biology because changes in developmental processes are tightly linked with evolutionary diversification. Heterochrony--alteration to the rate or timing of development--can significantly alter the appearance of descendant species. Heterochronic shifts in gene expression and associated morphological change may explain the morphological divergence between the threatened June sucker (Chasmistes liorus) and the sympatric Utah sucker (Catostomus ardens) in Utah Lake, UT, USA. June sucker are endemic to Utah Lake and have subterminal mouths adapted for pelagic feeding, while Utah sucker (Catostomus ardens) have ventral mouths adapted for benthic feeding. As larvae, both June sucker and Utah sucker have terminal mouths. However, within the first 14 weeks of development, the Utah sucker's mouth shifts to a ventral position, whereas the June sucker's mouth only shifts to a subterminal position. Using geometric morphometrics and RNA-seq time courses, we document a difference in the timing of shape development and a corresponding change in the timing of gene expression between June sucker and two Utah sucker lineages. Our results suggest that the distinctive mouth morphology in June sucker may be the result of paedomorphosis in which adult June sucker exhibit an intermediate mouth morphology between that of the larval (terminal) and ancestral (ventral) states. On a broader scale, additional Chasmistes / Catostomus pairs exist in the Intermountain West that are also morphologically divergent, but genetically similar. These pairs could be the result of repeated convergent evolution driven by differential expression of genes in response to environmental cues.

AN ABSTRACT OF THE DISSERTATION OFKaleigh C. Best, for the Doctor of Philosophy degree in Anthropology, presented on May 12, 2023, at Southern Illinois University Carbondale. TITLE: AN INVESTIGATION INTO INTRAINDIVIDUAL VARIATION IN HUMAN SKELETAL SEXUAL TRAIT MORPHOLOGYMAJOR PROFESSOR: Dr. Izumi ShimadaSex estimation is the most vital component of the biological profile assessment as several other subsequent analyses across biological anthropology rely on the correct identification of biological sex. This is especially important in times of commingling, fragmentary and partial remains, in inconsistent sex estimation, or in studies of sex estimation variation. While a multitude of studies have contributed to the documentation of similarities and differences in the morphological expression of a specific trait and how well this trait can be used to classify the sex of an unknown individual, how the expression of these morphological traits relate to each other within the individual has been poorly studied. Further, although several intrinsic and extrinsic factors are known to contribute to sexual trait expression, how they interact to produce morphology, and how that morphology may change in response to different biological conditions is not well understood. This dissertation utilizes 3D scans of 235 individuals collected from the University of Tennessee Donated Skeletal Collection (UTK) and the Robert J. Terry Osteological Collection (Terry) to examine sexual trait expression across the cranium, mandible, os coxae, sacrum and scapula. Specifically, it evaluates: 1) if sexual trait expression is correlated between skeletal regions including localized anatomical regions, through matrix correlation and Pearson correlation tests, 2) if age affects morphological sexual trait expression through M/ANOVA and if so, how and when these changes occur using ANOVA and Tukey post-hoc tests, 3) if the magnitude and pattern of sexual trait expression varies between populations through M/ANOVA and matrix correlations, 4) using discriminate function analyses, how well geometric morphometric analyses capture sexual trait expression compared to published rates, and 5) through M/ANOVA and discriminant function analyses, which intraindividual skeletal regions are the most accurate in sex classification analyses compared to others. For each skeletal element, landmarks were placed on each scan and sexual trait expression and an intra observer placement study was conducted. The landmark configurations were then subjected to a generalized Procrustes analysis, variance- covariance matrices were generated, and a principal component (PC) analyses in MorphoJ for combined sex data, derived male and females from combined sex data, and for independently input males and females. PCs were visually interpreted and subjected to M/ANOVA for three age groups: 18-29, 30-45, and 45 and older. PCs were then subjected to stepwise linear discriminant function analyses with leave- one-out cross validation. The first five PCs for each element were then utilized for a matrix correlation test and evaluated using a strength of correlation test (Chan et al 2003) and for significance using a Pearson’s correlation test. Results indicate that for intraobserver error is low, with scores being mostly considered excellent in reliability. For UTK data, shape changes associated with sexual trait classification were found for each of the five elements. Within these tests, many influential regions were known to sex estimation analyses, but other, such as the basicranium are currently underutilized. M/ANOVA revealed that sex was significant for all five skeletal elements, with some contributions from age and ancestry impacting sexual trait expression, however these interactions were not within a consistent pattern. Through the results of the discriminant function analyses, it appears some skeletal elements, such as the os coxae, scored higher correct classification rates than those reported in the literature, while others were on par or below reported rates. The os coxae and regions around it, were the best elements for correct sex classification accuracy, with the scapula rated as the worst. In the Terry data, sexual trait related shape changes are presented for each of the skeletal elements studied. Known morphological regions, as well as some more subtle ones, were found to be influential. M/ANOVA revealed that all elements, but the scapula had statistically significant shape changes present for sex estimation. Age and ancestry appear to contribute minimally to sexual trait morphology, but again, not in a way that is consistent, either within the collection or similarly to UTK. By examining the discriminant function analyses, some correct sex-estimation rates were on higher or on par with those reported in the literature, but others, such as the scapula were lower. This may be due the size being a larger contributor for sex estimation than shape, and the geometric morphometric analyses minimizing its effects in these analyses. Also using these tests, the os coxae was selected as the best element for high levels of sex classification accuracy, but which element was next best was different than the UTK results. This likely indicates biocultural influences are affecting sexual trait morphology and should be considered in future analyses. Significant inter-element correlations were detected in both skeletal collections, with UTK having more pairings than Terry. The most common and most statistically significant inter-element correlation across collections was between the cranium-mandible, which may be reflective of the integrated nature of these two elements. Different element correlations existed between each collection, with no clear pattern in pairings present in both collections, which may suggest that biocultural influences are impacting sexual trait expression. However, in both collections, females had more overall correlations, and more statistically significant correlations than males, although there was less of a difference between sexes in Terry than in UTK. This result may be due to circulating hormones present during puberty, which may be contributing to more correlation between elements in females and not males. It also suggests that once again, biocultural differences between the Terry and UTK collections may be impacting the magnitude and patterns of correlation. This research highlights the complex dynamic nature of sexual trait expression in bone in relation to several intrinsic and extrinsic factors. It supports the idea that sexual trait expression is not concordant between skeletal regions among the same individual and that these inter-element correlations appear to be different between skeletal collections. Likewise, it suggests that age and ancestry may minimally be affecting sexual trait expression, but not in a consistent way across skeletal elements or between collections. It also suggests that while geometric morphometrics may help in capturing shape variation, it does not always translate to higher correct classification rates. This research also supports previous literature that the os coxae is the best element for sex estimation, although is not clear on what element is next best. Future studies in sexual trait expression should account for biocultural influences, as this research suggests that sexual trait expression is influenced by poorly understood intrinsic and extrinsic factors.