Dissertation/Thesis Abstract

Phenotypic variation among ancient human crania from the northern Channel Islands of California: Reconstructing population history across the Holocene
by Sholts, Sabrina Bannister, Ph.D., University of California, Santa Barbara, 2010, 375; 3428017
Abstract (Summary)

The archaeological record of the Santa Barbara Channel region presents a unique opportunity to investigate local human population history throughout the Holocene. Extensive excavations on the northern Channel Islands during the early to mid-twentieth century yielded an extensive assemblage of skeletal remains representing over 7,000 years of continuous occupation. By focusing on the crania from this assemblage (from six archaeological sites on Santa Cruz and Santa Rosa Islands, representing three successive time periods), the objectives of this dissertation are to identify local patterns of phenotypic variation across time and space and to demonstrate the usefulness of novel methods in this type of research.

Metric and non-metric data from a total of 378 crania were analyzed with traditional methods of anthropometry and novel methods of digital morphometrics. A laser scanner was used to create digital three-dimensional (3D) models of each cranium, from which as many as 30 inter-landmark distance measurements and three craniofacial outlines were obtained. Distance and outline data were subjected to multivariate statistical procedures in order to identify patterns related to sex, site, and intra-cemetery grave location. In addition, kinship-based relationships were identified though the presence of maxillary canine-first premolar transpositions, a rare dental trait whose high prevalence in the region has been previously documented.

The results of this dissertation demonstrate overall homogeneity in cranial morphology from the Early to Late Holocene, with no evidence of population replacement during any period. Decreasing cranial vault dimensions in men and women of both islands suggest a gradual health decline, consistent with other studies. Although evidence of maxillary canine-first premolar transposition is found at five of the six sites, extremely high prevalence rates of the trait during the Early period indicate that inbreeding was practiced but eventually ceased, most likely due to increased cross-channel travel during the Middle period. Male crania exhibit more variability than female crania at all sites except for the earliest cemetery on Santa Rosa Island (SRI-3), suggesting a shift from patrilocal to matrilocal postmarital residence during the Early period. In addition, the crania in each cemetery form two distinct groupings of facial morphology, which supports the theory that two different human groups co-existed on the islands very early in their settlement history.

Indexing (document details)
Advisor: Glassow, Michael
Commitee: Gamble, Lynn, Jochim, Michael, Lee, Sang-Hee, Miller, Kevin
School: University of California, Santa Barbara
Department: Anthropology
School Location: United States -- California
Source: DAI-A 72/01, Dissertation Abstracts International
Source Type: DISSERTATION
Subjects: Physical anthropology
Keywords: 3D modeling, California, Channel islands, Chumash, Cranial variation, Digital morphometrics, Inbreeding
Publication Number: 3428017
ISBN: 978-1-124-33257-4
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