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- All Subjects: Physical anthropology
- Creators: Reed, Kaye
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 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.
ContributorsNalley, Thierra Kénnec (Author) / Kimbel, William H. (Thesis advisor) / Reed, Kaye (Committee member) / Shapiro, Liza (Committee member) / Arizona State University (Publisher)
Created2013
Description
Arguments of human uniqueness emphasize our complex sociality, unusual cognitive capacities, and language skills, but the timing of the origin of these abilities and their evolutionary causes remain unsolved. Though not unique to primates, kin-biased sociality was key to the success of the primate order. In contrast to ancestral solitary mammals, the earliest primates are thought to have maintained dispersed (non-group living) social networks, communicating over distances via vocalizations and scent marks. If such ancestral primates recognized kin, those networks may have facilitated the evolution of kin-biased sociality in the primate order and created selection for increased cognitive and communicative abilities. I used the gray mouse lemur (Microcebus murinus) to model whether vocalizations could have facilitated matrilineal and patrilineal kin recognition in ancestral primates. Much like mouse lemurs today, ancestral primates are thought to have been small-bodied, nocturnal creatures that captured insects and foraged for fruit in the thin, terminal ends of tree branches. Thus, the mouse lemur is an excellent model species because its ecological niche is likely to be similar to that of ancestral primates 55-90 million years ago. I conducted playback experiments in Ankarafantsika National Park, Madagascar testing whether mouse lemur agonistic calls contain matrilineal kin signatures and whether the lemurs recognize matrilineal kin. In contrast to large-brained, socially complex monkeys with frequent coalitionary behavior, mouse lemurs did not react differently to the agonistic calls of matrilineal kin and nonkin, though moderate signatures were present in the calls. I tested for patrilineal signatures and patrilineal kin recognition via mating and alarm calls in a colony with known pedigree relationships. The results are the first to demonstrate that a nocturnal, solitary foraging mammal gives mating calls with patrilineal signatures and recognizes patrilineal kin. Interestingly, alarm calls did not have signatures and did not facilitate kin recognition, suggesting that selection for kin recognition is stronger in some call types than others. As this dissertation is the first investigation of vocal kin recognition in a dispersed-living, nocturnal strepsirrhine primate, it greatly advances our knowledge of the role of vocal communication in the evolution of primate social complexity.
ContributorsKessler, Sharon E (Author) / Nash, Leanne (Thesis advisor) / Reed, Kaye (Thesis advisor) / Radespiel, Ute (Committee member) / Zimmermann, Elke (Committee member) / Arizona State University (Publisher)
Created2014
Description
Objectives: The objective of this research is to develop a better understanding of the ways in which Transition Analysis estimates differ from traditional estimates in terms of age-at-death point estimation and inter-observer error. Materials and methods: In order to achieve the objectives of the research, 71 adult individuals from an archaeological site in northern Sudan were subjected to Transition Analysis age estimation by the author, a beginner-level osteologist. These estimates were compared to previously produced traditional multifactorial age estimates for these individuals, as well as a small sample of Transition Analysis estimates produced by an intermediate-level investigator. Results: Transition Analysis estimates do not have a high correlation with traditional estimates of age at death, especially when those estimates fall within middle or old adult age ranges. The misalignment of beginner- and intermediate-level Transition Analysis age estimations calls into question intra-method as well as inter-method replicability of age estimations. Discussion: Although the poor overall correlation of Transition Analysis estimates and traditional estimates in this study might be blamed on the relatively low experience level of the analyst, the results cast doubt on the replicability of Transition Analysis estimations, echoing the Bethard's (2005) results on a known-age sample. The results also question the validity of refined age estimates produced for individuals previously estimated to be in the 50+ age range by traditional methods and suggest that Transition Analysis tends to produce younger estimates than its traditional counterparts. Key words: age estimation, Transition Analysis, human osteology, observer error
ContributorsPhillips, Megann M. (Author) / Baker, Brenda (Thesis director) / Norris, Annie Laurie (Committee member) / School of International Letters and Cultures (Contributor) / School of Human Evolution and Social Change (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
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 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.
ContributorsCatlett, Kierstin Kay (Author) / Schwartz, Gary (Thesis advisor) / Barton, Michael (Committee member) / Godfrey, Laurie (Committee member) / Reed, Kaye (Committee member) / Arizona State University (Publisher)
Created2016
Description
Craniofacial morphology in primates can vary on the basis of their diet because foods are often disparate in the amount and duration of force required to break them down. Therefore diet has the potential to exercise considerable selective pressure on the morphology of the masticatory system. The zygomatic arch is a known site of relatively high masticatory strain and yet the relationship between arch form and load type is relatively unknown in primates. While the relative position and robusticity of the arch is considered a key indicator of craniofacial adaptations to a mechanically challenging diet, and central to efforts to infer diet in past species, the relationships between morphology and diet type in this feature are not well established.
This study tested hypotheses using two diet categorizations: total consumption percent and food material properties (FMPs). The first hypothesis that cortical bone area (CA) and section moduli (bone strength) are positively correlated with masticatory loading tests whether CA and moduli measures were greatest anteriorly and decreased posteriorly along the arch. The results found these measures adhered to this predicted pattern in the majority of taxa. The second hypothesis examines sutural complexity in the zygomaticotemporal suture as a function of dietary loading differences by calculating fractal dimensions as indices of complexity. No predictable pattern was found linking sutural complexity and diet in this primate sample, though hard object consumers possessed the most complex sutures. Lastly, cross-sectional geometric properties were measured to investigate whether bending and torsional resistance and cross-sectional shape are related to differences in masticatory loading. The highest measures of mechanical resistance tracked with areas of greatest strain in the majority of taxa. Cross-sectional shape differences do appear to reflect dietary differences. FMPs were not correlated with cross-sectional variables, however pairwise comparisons suggest taxa that ingest foods of greater stiffness experience relatively larger measures of bending and torsional resistance. The current study reveals that internal and external morphological factors vary across the arch and in conjunction with diet in primates. These findings underscore the importance of incorporating these mechanical differences in models of zygomatic arch mechanical behavior and primate craniofacial biomechanics.
This study tested hypotheses using two diet categorizations: total consumption percent and food material properties (FMPs). The first hypothesis that cortical bone area (CA) and section moduli (bone strength) are positively correlated with masticatory loading tests whether CA and moduli measures were greatest anteriorly and decreased posteriorly along the arch. The results found these measures adhered to this predicted pattern in the majority of taxa. The second hypothesis examines sutural complexity in the zygomaticotemporal suture as a function of dietary loading differences by calculating fractal dimensions as indices of complexity. No predictable pattern was found linking sutural complexity and diet in this primate sample, though hard object consumers possessed the most complex sutures. Lastly, cross-sectional geometric properties were measured to investigate whether bending and torsional resistance and cross-sectional shape are related to differences in masticatory loading. The highest measures of mechanical resistance tracked with areas of greatest strain in the majority of taxa. Cross-sectional shape differences do appear to reflect dietary differences. FMPs were not correlated with cross-sectional variables, however pairwise comparisons suggest taxa that ingest foods of greater stiffness experience relatively larger measures of bending and torsional resistance. The current study reveals that internal and external morphological factors vary across the arch and in conjunction with diet in primates. These findings underscore the importance of incorporating these mechanical differences in models of zygomatic arch mechanical behavior and primate craniofacial biomechanics.
ContributorsEdmonds, Hallie Margaret (Author) / Reed, Kaye (Thesis advisor) / Schwartz, Gary (Committee member) / Vinyard, Chris (Committee member) / Arizona State University (Publisher)
Created2017
Description
This dissertation examines the interrelationships between stress, frailty, growth, mortality, and diet at the Qinifab School site, Sudan, using a combination of osteological, paleopathological, and biogeochemical methods. The skeletal sample, from the fourth cataract region of Nubia, is comprised of 100 individuals from a Late Meroitic to Christian period (~250-1400 CE) cemetery. Standard osteological methods were used to estimate age and sex, and measurements were taken to assess body dimensions. Preadults were aged by dental and skeletal development, producing two independent ages to categorize individuals as developmentally “normal” or “delayed.” Data were collected on nonspecific indicators of stress, including linear enamel hypoplasias (LEHs), porotic hyperostosis (PH), and cribra orbitalia (CO). In preadults, these were compared to World Health Organization (WHO) growth standards to identify individuals who experienced stunting or wasting. For all ages, evidence of stress was compared with age at death and growth/body size. Finally, stable carbon and nitrogen isotope analyses were conducted on bone collagen and carbonate samples from a representative sample of 60 individuals, of which 46 collagen samples and all carbonates had acceptable preservation.“Delayed” preadults generally showed reduced body size relative to “normal” individuals, they were more likely to be stunted, and their growth trajectories were less similar to WHO standards. However, childhood stress had little impact on adult body size. CO occurred at higher frequencies in preadults and individuals with mixed/active lesions died at younger ages. PH rarely developed before age 6 but was present in most individuals over that age. Individuals with earlier formed LEHs tended to experience more stress overall and die younger. Active/mixed CO was associated with stunting in preadults and reduced brachial index in adults.
A greater proportion of individuals in the Christian period were affected by CO compared to the Post-Meroitic. A temporal shift also occurred in diet between the Post-Meroitic and Christian periods based upon the δ13CCOLL and δ15NCOLL values. Lower δ15N and the greater difference in δ13CAP-COLL suggest a shift toward intensified agriculture and decreased use of animal products and a potential dietary etiology for the increase in CO.
ContributorsNorris, Annie Laurie (Author) / Baker, Brenda J (Thesis advisor) / Knudson, Kelly (Committee member) / Dupras, Tosha (Committee member) / Arizona State University (Publisher)
Created2021
Description
Crown Cercopithecoidea (Old World monkeys) share bilophodont molars characterized by four cusps arranged into two transversely-aligned pairs connected by crests or “loph(id)s”. This derived dental configuration provides a flexible template that has been modified in different lineages of Old World monkeys to meet the mechanical demands of food-processing in species with diverse and varied diets. This molar Bauplan evolved in the early stages of Old World monkey evolution, and one consequence of these morphological changes in occlusal morphology relative to apes and more basal catarrhines is a set of distinct patterns of tooth wear. Adaptive explanations for the origins of bilophodonty have emphasized dietary reconstructions but have not explored the implications of molar crown reorganization on the interaction between tooth wear and tooth function. This study combines description of new fossil material of early Miocene stem cercopithecoids and 3D dental topographic analyses of cross-sectional M2 wear series of extant catarrhines (n=511, 24 species) and Miocene fossil catarhines (n=81, 7 genera) to explore how functional aspects of molar topography are altered by tooth wear, to test whether the acquisition of bilophodont molars resulted in distinct occlusal topographies and patterns of topographic change with wear among Old World monkeys, and to determine whether differences in patterns of topographic change with wear reflect differences in diet.Descriptions of new fossils of the early Miocene stem cercopithecoid Noropithecus bulukensis confirm its generic distinction from Victoriapithecus macinnesi and highlight the dental metric and morphological variation that complicates identification of isolated teeth. Results of dental topographic analyses show that wear-mediated patterns of change in functional topographic metrics do not reflect broad dietary differences in extant catarrhines. While topographic features of unworn molars exhibit a phylogenetic signal, the pattern of wear-mediated topographic change does not. Molar topography of victoriapithecids is similar to extant cercopithecids with frugivorous and hard-object feeding diets, supporting previous dietary reconstructions. Victoriapithecid molar occlusal surfaces exhibit less complexity, less curvature, and higher relief than proconsulids prior to heavy wear stages. They are not distinct from occlusal topographies of small-bodied non-cercopithecoid catarrhines at any wear stage. Overall, these results suggest that the acquisition of bilophodont molar morphology in early and middle Miocene stem cercopithecoids was not associated with a shift in occlusal topography relative to more basal catarrhines. Rather, it is among proconsulids that shifts toward more complex, higher curvature occlusal surfaces are found.
ContributorsLocke, Ellis (Author) / Reed, Kaye (Thesis advisor) / Schwartz, Gary (Committee member) / Kelley, Jay (Committee member) / Arizona State University (Publisher)
Created2021