Matching Items (19)

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Analysis of Native American Scalping from the Chavez Pass Population

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Scalping has been practiced by the Native Americans since pre-Columbian times in North America and is observed as cut-marks in the form of a rough circle on the superior aspect

Scalping has been practiced by the Native Americans since pre-Columbian times in North America and is observed as cut-marks in the form of a rough circle on the superior aspect of the cranium of the individual. For this study, there are 7 crania with cut-marks evident of scalping from the Southwest population of Chavez Pass. These crania were excavated from the site of Nuvakwewtaqa located in north-central Arizona, in the middle of the Coconino National Forest. Unfortunately, the site was heavily looted through pot-hunter activity, leading to a large collection of commingle remains. The objectives of this study are summarized into three basic question words: Who? Where? And, How? More specifically: [1] whether there is a relationship between age or sex and being a victim of scalping; [2] whether there is a relationship between the burial location and having been scalped; and, [3] whether the age or sex of an individual affected the manner in which they were scalped. For this analysis of scalping, three statistical tests were used: Fisher's exact test, Chi-Square test and two-sample t-tests.

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  • 2014-05

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The Evolution of Human Cervical Lordosis

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Many of the derived features of the human skeleton can be divided into two adaptive suites: traits related to bipedalism and traits related to encephalization. The cervical spine connects these

Many of the derived features of the human skeleton can be divided into two adaptive suites: traits related to bipedalism and traits related to encephalization. The cervical spine connects these adaptive suites and is itself unique in its marked lordosis. I approach human cervical evolution from three directions: the functional significance of cervical curvature, the identification of cervical lordosis in osteological material, and the representation of the cervical spine in the hominin fossil record.

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  • 2014-05

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Environmental Impacts on Light Stable Isotope Systems

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Isotopic analyses of archaeological and modern materials are commonly used to reconstruct diet, climate, and habitat. This study analyzes 15 camelid samples from three sites (two archaeological, one modern) in

Isotopic analyses of archaeological and modern materials are commonly used to reconstruct diet, climate, and habitat. This study analyzes 15 camelid samples from three sites (two archaeological, one modern) in South America to determine their carbon and nitrogen isotopic values to further explore the relationship between stable isotopes and environments. Camelid individuals in the modern site of Cuenca, Ecuador had a diet of almost entirely C3 vegetation, while those in Chen Chen, Peru had slightly higher values, still consistent with C3 plants. Those in the higher altitude site of Pumapunku, Bolivia had higher δ13C values than expected, indicating they may have been foddered with a mixed diet. These isotopic data indicate that vegetation, and therefore herbivore diets, are influenced by altitude. Additionally, it was found that a positive linear relationship exists between δ15N values and aridity of a site. Results indicate that aspects of the environment such as aridity are reflected in isotopic signatures. These results contribute to the increasing amount of data on isotopic variation in South American camelids, both modern and archaeological.

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  • 2016-05

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The roles of positional behavior and brain growth in generating ontogenetic variation in the human cranial base

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Previous studies have demonstrated that cranial base anatomy is influenced primarily by three different characteristics: brain shape, positional behavior, and facial growth (Lieberman et al. 2000). Although the timing of

Previous studies have demonstrated that cranial base anatomy is influenced primarily by three different characteristics: brain shape, positional behavior, and facial growth (Lieberman et al. 2000). Although the timing of cranial base growth is not fully understood, features of the cranial base are frequently used to interpret the hominin fossil record (Guy et al. 2005; White et al. 1994; Brunet et al. 2002). While specific aspects of cranial base morphology may be species-specific, there is sparse information on the developmental mechanisms driving these adult morphologies. The aim of this study is to 1) examine changes in the human cranial base form throughout ontogeny and 2) determine their relationship to the development of positional behavior and brain growth. This research asks: to what extent does human cranial base morphology vary before and after adult positional behavior is acquired? The null hypothesis is that there is no relationship between features of the cranial base and the development of positional behavior. Data are collected using 3D landmarks on n=35 human crania and analyzed with both Morphologika (O'Higgins and Jones 1999) and MorphoJ (Klingenberg 2011) to identify age related changes in shape. Results of this study demonstrate that most of the changes in cranial base form occur between dental eruption stages N and NJ1 between 0 and 2 years of age. These changes consist of a relative shortening of the anterior-posterior cranial base length, a more posterior positioning of the foramen magnum, and a more anterior position of the occipital condyles and separate the N and NJ1 dental development groups from other groups. This change coincides with the transition to upright posture in human children (Abitbol 1993), a significant period of brain growth (Neubauer 2009) and has implications for reconstructing positional behavior in fossil hominins. Despite new insights into the development of cranial base morphology, the utility of the cranial base in assigning hominin taxonomy remains inconclusive.

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  • 2015-05

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Lemur Biorhythms and Life History Evolution

Description

Skeletal histology supports the hypothesis that primate life histories are regulated by a neuroendocrine rhythm, the Havers-Halberg Oscillation (HHO). Interestingly, subfossil lemurs are outliers in HHO scaling relationships that have

Skeletal histology supports the hypothesis that primate life histories are regulated by a neuroendocrine rhythm, the Havers-Halberg Oscillation (HHO). Interestingly, subfossil lemurs are outliers in HHO scaling relationships that have been discovered for haplorhine primates and other mammals. We present new data to determine whether these species represent the general lemur or strepsirrhine condition and to inform models about neuroendocrine-mediated life history evolution. We gathered the largest sample to date of HHO data from histological sections of primate teeth (including the subfossil lemurs) to assess the relationship of these chronobiological measures with life history-related variables including body mass, brain size, age at first female reproduction, and activity level. For anthropoids, these variables show strong correlations with HHO conforming to predictions, though body mass and endocranial volume are strongly correlated with HHO periodicity in this group. However, lemurs (possibly excepting Daubentonia) do not follow this pattern and show markedly less variability in HHO periodicity and lower correlation coefficients and slopes. Moreover, body mass is uncorrelated, and brain size and activity levels are more strongly correlated with HHO periodicity in these animals. We argue that lemurs evolved this pattern due to selection for risk-averse life histories driven by the unpredictability of the environment in Madagascar. These results reinforce the idea that HHO influences life history evolution differently in response to specific ecological selection regimes.

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  • 2015-08-12

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Identifying the Lagomorphs of 111 Ranch

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This study was conducted in order to determine whether the lagomorphs of 111 Ranch- Aztlanolagus agilis, Hypolagus arizonensis, and Sylvilagus cunicularius- could be distinguished based on femora. This is because

This study was conducted in order to determine whether the lagomorphs of 111 Ranch- Aztlanolagus agilis, Hypolagus arizonensis, and Sylvilagus cunicularius- could be distinguished based on femora. This is because while there is a large quantity of disarticulated lagomorph postcranial fossils from 111 Ranch, the chief diagnostic traits of A. agilis and H. arizonensis are the enamel patterns on their third premolars, leaving a large swath of specimens unidentifiable by diagnostic traits alone. Specimens from the Arizona Museum of Natural History were measured and compared to specimens known to be from these genera. Additionally, morphological traits in mandibles were used to identify mandible specimens, which in turn were used to identify fossils with the same specimen label. Statistical tests such as t-tests and principal components analyses were used to examine the distributions of sizes and locate clusters of datapoints likely corresponding to each genus. Some of these could be linked to a genus based on one particular specimen, P15156, which had been identified as Hypolagus based on its mandible morphology and size. The majority of the Museum'a specimens were thus associated with one of the three species, save for those which were too damaged and intermediate in size to confidently categorize.

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  • 2019-05

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Morphological and Development Analysis of Teeth Recovered from an Archaeological Teratoma

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Teratomas are germ cell tumors that can generate a broad spectrum of biological tissues including: hair, oil glands, bones, and teeth. Little research has focused on the detailed comparison of

Teratomas are germ cell tumors that can generate a broad spectrum of biological tissues including: hair, oil glands, bones, and teeth. Little research has focused on the detailed comparison of teeth from growing within teratomas to teeth that grew normally within the oral cavity. Broad similarities in the overall pattern of dental growth have previously been observed using average enamel thickness, a measurement of enamel height, comparisons. Enamel thickness is used to infer functional aspects of dentition. Relative enamel thickness values have not been used in previous studies to account for the difference in size of the teeth.

ASU’s Bioarchaeology of Nubia Expedition (BONE) led by Dr. Brenda Baker discovered the remains of a female individual from the Classic Kerma period with a preserved large teratoma containing hard tissue components including two molariform teeth. There are only three previous recorded instances of teratomas in a paleopathological setting.

This study analyzed the characteristics of teeth found within a teratoma and compared them to permanent oral dentition to ascertain the degree to which dental development is affected by local growth environment. Permanent (oral) molars from multiple individuals and 2 teratoma teeth from a singular individual from the BONE site were analyzed alongside a comparative sample of permanent (oral) molars from an unrelated, more modern population. MicroCT scans were used to create digital renditions of the teeth to create 3D and 2D models to analyze the enamel and dentine of the teeth to measure their morphological characteristics. The relative enamel thickness and the absolute occlusal enamel volumes were calculated. The study found that there are significant differences in enamel thickness between the teratoma teeth and any of its oral cavity counterparts.

This study is unique in that it is the first study to analyze teeth from a teratoma to permanent teeth from the oral cavity using 2D and 3D digital dental models created from microCT data. It is also the first study to analyze these morphological characteristics in an archaeological sample.

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  • 2019-12

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Positional behaviors and the neck: a comparative analysis of the cervical vertebrae of living primates and fossil hominoids

Description

Despite the critical role that the vertebral column plays in postural and locomotor behaviors, the functional morphology of the cervical region (i.e., the bony neck) remains poorly understood, particularly in

Despite the critical role that the vertebral column plays in postural and locomotor behaviors, the functional morphology of the cervical region (i.e., the bony neck) remains poorly understood, particularly in comparison to that of the thoracic and lumbar sections. This dissertation tests the hypothesis that morphological variation in cervical vertebrae reflects differences in positional behavior (i.e., suspensory vs. nonsuspensory and orthograde vs. pronograde locomotion and postures). Specifically, this project addresses two broad research questions: (1) how does the morphology of cervical vertebrae vary with positional behavior and cranial morphology among primates and (2) where does fossil hominoid morphology fall within the context of the extant primates. Three biomechanical models were developed for the primate cervical spine and their predictions were tested by conducting a comparative analysis using a taxonomically and behaviorally diverse sample of primates. The results of these analyses were used to evaluate fossil hominoid morphology. The two biomechanical models relating vertebral shape to positional behaviors are not supported. However, a number of features distinguish behavioral groups. For example, the angle of the transverse process in relation to the cranial surface of the vertebral body--a trait hypothesized to reflect the deep spinal muscles' ability to extend and stabilize the neck--tends to be greater in pronograde species; this difference is in the opposite of the direction predicted by the biomechanical models. Other traits distinguish behavioral groups (e.g., spinous process length and cross-sectional area), but only in certain parts of the cervical column. The correlation of several vertebral features, especially transverse process length and pedicle cross-sectional area, with anterior cranial length supports the predictions made by the third model that links cervical morphology with head stabilization (i.e., head balancing). Fossil hominoid cervical remains indicate that the morphological pattern that characterizes modern humans was not present in Homo erectus or earlier hominins. These hominins are generally similar to apes in having larger neural arch cross-sectional areas and longer spinous processes than modern humans, likely indicating the presence of comparatively large nuchal muscles. The functional significance of this morphology remains unclear.

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Date Created
  • 2013

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Variation in dental morphology and bite force along the tooth row in anthropoids

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Modern primate diet is well-studied because of its considerable influence on multiple aspects of morphology, including the shape of the facial skeleton and teeth. It is well-established that differences in

Modern primate diet is well-studied because of its considerable influence on multiple aspects of morphology, including the shape of the facial skeleton and teeth. It is well-established that differences in craniofacial form influence feeding abilities by altering the nature of bite force production. Tooth morphology, likewise, has been shown to vary with diet across primates, particularly in the details of occlusal form. It has also been suggested that tooth form (e.g., tooth root size and shape and crown size) reflects, in part, the demands of resisting the stresses generated during feeding. However, while they are central to our efforts to infer diet in past species, the relationships between bite force production, craniofacial morphology and tooth form are not well-established. The current study is separated into two parts. In Part I, the hypothesis that crown size and root surface area are adapted to resist masticatory stress is evaluated by testing whether these features show correlated variation along the tooth row in a taxonomically diverse sample of primates. To further explore the adaptive nature of this correlation, pair-wise comparisons between primates with mechanically resistant diets and closely-related species consuming less resistant foods are performed. If crown size and root surface area covary along the tooth row, past research suggests they may be related to bite force. To test this hypothesis, Part II examines the variation of these dental characteristics in comparison to theoretically-derived bite force patterns along the tooth row. Results suggest that patterns of maximum bite force magnitude along the tooth row are variable both within and between species, underscoring the importance of individual craniofacial variation on masticatory force production. Furthermore, it is suggested that some adaptations traditionally associated with high bite force production (i.e., facial orthognathy) may increase anterior biting force at the expense of posterior biting force. Taken together, results from the current study reveal that both tooth root and crown size vary in conjunction with the mechanical properties of diet and with bite force patterns along the tooth row in anthropoids.

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Date Created
  • 2012

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A dental topographic analysis of deciduous tooth wear in hominoids

Description

Early weaning, slow somatic and dental growth, and late age at reproduction are all part of a suite of energetic trade-offs that have shaped human evolution. A similar suite of

Early weaning, slow somatic and dental growth, and late age at reproduction are all part of a suite of energetic trade-offs that have shaped human evolution. A similar suite of energetic trade-offs has shaped the evolution of the indriid-palaeopropithecid clade, though members of this clade exhibit extremely fast dental development and nearly vestigial deciduous teeth. The development and functional occlusion of the primary postcanine dentition (i.e., deciduous premolars and molars) coincides with several life history parameters in great apes and indriids. This dissertation explored great ape dental macrowear, molar development in indriids, and molar size in lemurs with a broader goal of improving reconstructions of life history profiles in extinct primates. To this aim, macrowear and dental development were analyzed in apes and lemurs, respectively. Occlusal casts (six great ape species; N=278) were scanned to track mandibular fourth deciduous premolar (dp4) macrowear. Utilizing dental topographic analyses, changes in occlusal gradient and terrain were quantified. A subset of the great ape data (four species; n=199) was analyzed to test if differences in dp4 wear correlate with age at weaning. Using dental histology, molar development was reconstructed for Indri indri (n=1) and Avahi laniger (n=1). Life history and molar size data were collected from the literature. The results of this dissertation demonstrate that most great apes exhibited evidence of topographic maintenance, suggesting dp4s wear in a manner that maintain functional efficiency during growth and development; however, the manner in which maintenance is achieved (e.g., preservation of relief or complexity) is species specific. Dp4 macrowear is not correlated with age at weaning in great apes and is probably unreliable to reconstruct age at weaning in hominins. The pace of molar development in members of the indriid- palaeopropithecid clade did not correlate with body or brain size, an association present in several other primates. Associations of molar size with age at weaning suggest that expanding other developmental models (e.g., the inhibitory cascade) to life history is worth consideration. The broad variation in macrowear, dental development, and size highlights how the primary dentition may correlate with different life history parameters depending on the species and ecological setting, an important consideration when using teeth to reconstruct life history profiles.

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Date Created
  • 2016