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- All Subjects: Human Evolution
- All Subjects: paleontology
- Creators: Reed, Kaye
- Resource Type: Text
Description
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.
ContributorsFatica, Lawrence Martin (Author) / Kimbel, William (Thesis director) / Reed, Kaye (Committee member) / Schwartz, Gary (Committee member) / Barrett, The Honors College (Contributor) / School of Human Evolution and Social Change (Contributor) / School of Life Sciences (Contributor)
Created2014-05
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
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.
ContributorsTkacik, Stephanie Marie (Author) / Farmer, Jack (Thesis director) / Reed, Kaye (Committee member) / McCord, Robert (Committee member) / School of Earth and Space Exploration (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05