Dental Analysis of Classic Period of Population Variability in the Maya
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DENTAL ANALYSIS OF CLASSIC PERIOD POPULATION VARIABILITY IN THE MAYA AREA A Dissertation by ANDREW KENNETH SCHERER Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY December 2004 Major Subject: Anthropology © 2004 ANDREW KENNETH SCHERER ALL RIGHTS RESERVED DENTAL ANALYSIS OF CLASSIC PERIOD POPULATION VARIABILITY IN THE MAYA AREA A Dissertation by ANDREW KENNETH SCHERER Submitted to Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved as to style and content by: Lori E. Wright D. Gentry Steele (Chair of Committee) (Member) David L. Carlson Rodney L. Honeycutt (Member) (Member) David L. Carlson (Head of Department) December 2004 Major Subject: Anthropology iii ABSTRACT Dental Analysis of Classic Period Population Variability in the Maya Area. (December 2004) Andrew Kennerth Scherer, B.A., Hamline University Chair of Adivsory Committee: Dr. Lori E. Wright In this dissertation I examine population history and structure in the Maya area during the Classic period (A.D. 250-900). Within the Maya area, archaeologists have identified regional variation in material culture between archaeological zones. These cultural differences may correspond to biological differences between Classic Maya populations. I test the hypothesis that Classic Maya population structure followed an isolation by distance model. I collected dental nonmetric and metric traits on 977 skeletons, from 18 Classic period sites, representing seven different archaeological zones. I corrected the data for intraobserver error. For the dental nonmetric data, I developed a Maya-specific trait dichotomization scheme and controlled for sex bias. I tested the dental metric data for normality and age affects. I imputed missing dental metric data for some traits and the remaining set of traits was Q-mode transformed to control for allometric factors. I analyzed the dental nonmetric and metric datasets with both univariate and multivariate tests. I found, with a log likelihood ratio, that 50% of the nonmetric traits exhibited statistically significant differences between Maya sites. I performed a Mean Measure of Divergence analysis of the dental nonmetric dataset and found that majority of the resulting pairwise distance values were significant. Using cluster analysis and multidimensional scaling, I found that the dental nonmetric data do not support an isolation by distance organization of Classic Maya population structure. In the ANOVA and MANOVA tests, I did not find major statistically significant differences in dental metrics between Maya iv sites. Using principal components analysis, a Mahalanobis Distance test, and R matrix analysis, I found a generally similar patterning of the dental metric data. The dental metric data to not support an isolation by distance model for Classic Maya population structure. However, the geographically outlying sites from Kaminaljuyu and the Pacific Coast repeatedly plotted as biological outliers. R matrix analysis indicates that gene flow, not genetic drift, dominated Classic Maya population structure. Based on the results of the dental nonmetric and metric analyses, I reject the hypothesis that isolation by distance is a valid model for Classic Maya population structure. From the multivariate analyses of the dental nonmetric and metric data, a few notable observations are made. The major sites of Tikal and Calakmul both demonstrate substantial intrasite biological heterogeneity, with some affinity to other sites but with little to one another. Piedras Negras demonstrates some evidence for genetic isolation from the other lowland Maya sites. In the Pasión Zone, Seibal and Altar de Sacrificios demonstrate some affinity to one another, though Dos Pilas is an outlier. The R matrix analysis found evidence of Classic period immigration into Seibal from outside the network of sites tested. The Belize Zone exhibited substantial heterogeneity among its sites, with the site of Colha showing some affinity to the Central Zone. Copan, despite being a geographic outlier, demonstrates genetic affinity with the rest of the Maya area. Kaminaljuyu and the Pacific Coast were both found to be outliers. These results indicate that dental nonmetric and metric data are a useful tool for investigating ancient biological variability in the Maya area and contribute to our expanding understanding of population history in that region. v This research is dedicated to my parents, for their infinite support throughout this endeavor. vi ACKNOWLEDGEMENTS A large part of the success of this research was due to an extremely supportive dissertation committee. Lori Wright went beyond the call of duty as a graduate chair—allowing me to tag along on her Tikal osteology project, introducing me to the Piedras Negras project, assisting with access to skeletal materials, tirelessly editing my work, and being cheerful and encouraging throughout it all. D. Gentry Steele set an example, through his own work on the peopling of the New World, that in biological distance research we must be careful not to let our interpretations proceed further than the data permit—I hope I have followed that example here. David Carlson offered invaluable statistical advice throughout this endeavor and helped me overcome a number of tricky computational quandaries. Rodney Honeycutt provided insight on population genetics beyond the field of anthropology. I would also like to thank my former professors at Hamline University for providing an excellent undergraduate education in anthropology and more than adequately preparing me for the rigors of graduate school. I am indebted to Barbara O’Connell for introducing me to the exciting field of bioarchaeology and convincing me that teeth were not so bad after all. Susan Myster continued that education and introduced me to biological distance research through her own work on the biological affinities of Midwest American Indians. Lewis “Skip” Messenger gave me my introduction to Maya archaeology. It was during January of 1997, while writing a final exam for Skip in a hotel in Merida, Mexico that this dissertation project was first conceived. I would like to acknowledge the tremendous assistance of the following institutions and individuals who graciously facilitated my study of the skeletal collections under their supervision: Héctor Escobedo of the Universidad del Valle and Stephen Houston of Brigham vii Young University (Piedras Negras); the Instituto de Antropología e Historia de Guatemala (Tikal, Petexbatun sites, Kaminaljuyu, Balberta, Montana Complex); Takeshi Inomata of the University of Arizona (Aguateca); Frederic Bove of the Universidad del Valle (Balberta, Montana Complex); Thomas Hester and Laura Nightengale of the Texas Archaeological Research Laboratory and Harry Shafer of Texas A&M University (Colha); Sharon Misdea and Christopher Jones of the University Museum of the University of Pennsylvania (Tikal); Michele Morgan of the Peabody Museum of Harvard University (Altar de Sacrificios, Seibal, Baking Pot, Barton Ramie, Copan, Kaminaljuyu); Hermann Helmuth of Trent University (Altun Ha); Vera Tiesler and Andrea Cucina of the Universidad Autónoma de Yucatán (Calakmul); and William Folan and Mario Coyoc of the Universidad Autonóma de Campeche (Calakmul). I would also like to thank Kristin Bjork for her assistance with the archives at the Peabody Museum of Harvard. I would like to thank Joseph Powell for much needed input on the methods and logic of certain statistical procedures. John Relethford kindly provided copies of two statistical programs that he authored: RMET 5.0 and MANTEL 3.1. David Webster, Joel Palka, William Folan, and Eleanor King all provided useful comments on ancient Maya demography. I would like to acknowledge the excellent service provided by the Interlibrary Loan Services at Evan’s Library at Texas A&M. Without them, I never would have been able to write this dissertation “on the go.” Conversations and mutual support from my fellow graduate students in anthropology not only stimulated new insights in osteology, biological distance, and the ancient Maya, but also provided necessary encouragement along the way. At Texas A&M, Cassady Yoder, Maria Parks, Jason Barrett, Eric Bartelink, Jason Wiersema, and Amador Minijares all helped me adjust to the culture of College Station. Throughout the course of this research, I have been viii fortunate to enjoy many adventures (and misadventures) in Guatemala with Charles Golden, Rene Muñoz, James Fitzsimmons, Edwin “Pollo” Roman, Fabiola Quiroa, Ana Lucía Arroyave Prera, Amy Kovak, Zac Hruby, Zac Nelson, Heather Hurst, Sarah Jackson, Alejandro “Guille” Gillot, and Mark and Jessica Child. In New York City, a number of budding forensic anthropologists and packaging engineers provided encouragement and feigned interest including Ben Figura, Lisa Conlon, Jacqueline Kagan, Derrell Ferrar, Audrey Scott, Jamie Tippens, and, of course, Giovanna Vidoli. I would like to thank Dan Schmitz, Tony and Jodi Johnson, Ryan and Lisa Utecht, Jeremy and Holly Scherer, Matt Marrin, and Beau Hansen for housing, airport transportation, and much needed distractions throughout my graduate career. Last but not least I would like to express my appreciation for my family for all of their support—the Val and Gary Hansen clan (Allison, Ashley, and Amanda), the Kathy and Bob Jaeger clan (Beth, Kyle, and Leigh), my brother, Don, who left us much too soon, and, his