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Pre-Columbian diets in the Soconusco revisited : a dietary study through stable isotopic analysis Moreiras Reynaga, Diana Karina 2013

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i    PRE-COLUMBIAN DIETS IN THE SOCONUSCO REVISITED:  A DIETARY STUDY THROUGH STABLE ISOTOPIC ANALYSIS   by   Diana Karina Moreiras Reynaga   B.A. (Hons), The University of British Columbia, 2010    A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF    MASTER OF ARTS    in    The Faculty of Graduate Studies   (Anthropology)    THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver)   April 2013    ? Diana Karina Moreiras Reynaga, 2013     ii  ABSTRACT  This MA thesis focuses on the study of pre-Columbian subsistence and dietary patterns through the use of stable carbon and nitrogen isotopic analysis of human samples (n = 20) recovered from the Acapetahua, Mazat?n, and R?o Naranjo zones in the Soconusco region?located in the present-day state of Chiapas, M?xico and the Northeastern coast of Guatemala. The stable isotope results in this study demonstrate the heterogeneity of ancient human diets in the Soconusco region, illustrating the complexity of ancient people?s lifeways from the Late Archaic (3500-1900 cal. B.C.) to the Late Postclassic (A.D. 1250-1530) periods. Further, the presence of C4 plant (i.e., maize) consumption was minor isotopically compared with the consumption of a variety of locally available wild and cultivated food resources. As a result, there is an absence of a clear subsistence transition towards maize agriculture as the main subsistence practice in the region, based on the human samples analyzed in this study. While the quantification of every food source in the diet, including maize, is more difficult without additional data and other lines of evidence, I suggest that other food products like marine, estuarine, and riverine resources, as well as other wild and cultivated plant foods may have been more important in the every-day diets of Soconusco inhabitants across time (particularly at Mazat?n). This appears to have been a common pattern indicative of the wide diversity of food resources found in tropical environments across Mesoamerica.        iii  PREFACE   The archaeological collection studied in this M.A. research project was collected by Michael Blake, John E. Clark, Barbara Voorhies, Richard Lesure, and their students and colleagues from 1985 and 1997 as part of the Soconusco Project. The human samples of this collection were previously studied by Michael Blake, Brian Chisholm, and colleagues in the early 1990s and again in 2006. The isotopic results produced from this M.A. research are provided in Table 3 and the Appendix, Table 2. I was granted permission by Drs. Blake and Chisholm to integrate their previously published and unpublished isotopic results (Table 4) into this M.A. thesis. Moreover, Dr. Chisholm and Dr. Blake collected local flora and fauna to produce baseline isotopic data which they published in 2006. This M.A. thesis uses these published baseline data as well as other published baseline data from other Mesoamerican regions (Norr [1991]; van der Merwe et al. [2002]; VanDerwarker [2006]; Warinner et al. [2013]; White and Schwarcz [1989, 1993], and Wright [1994]) for the purposes of the dietary analysis and can be found in Tables 3 and 4 of the Appendix.       iv   TABLE OF CONTENTS  ABSTRACT ................................................................................................................................................. ii PREFACE ................................................................................................................................................... iii TABLE OF CONTENTS .......................................................................................................................... iv LIST OF TABLES ..................................................................................................................................... vi LIST OF FIGURES .................................................................................................................................. vii ACKNOWLEDGEMENTS .................................................................................................................... viii DEDICATION............................................................................................................................................. x  INTRODUCTION ....................................................................................................................................... 1 Previous Stable Isotopic Analyses in the Soconusco ......................................................................... 1 Re-Analyzing Soconusco Skeletal Samples ....................................................................................... 2  THE SOCONUSCO REGION ................................................................................................................... 4 Soconusco?s Geography and Environment ........................................................................................ 4 Soconusco Environmental Zones: Archaeological Sites and Samples .............................................. 6 Acapetahua ..................................................................................................................................... 6 Mazat?n .......................................................................................................................................... 7 R?o Naranjo .................................................................................................................................... 8  PRE-COLUMBIAN SOCONUSCO SUBSISTENCE: THE ARCHAEOLOGICAL EVIDENCE .. 10 Archaic Period .................................................................................................................................. 10 Formative Period .............................................................................................................................. 11 Classic and Postclassic Periods ........................................................................................................ 12  MATERIALS AND METHODS ............................................................................................................. 14 Human Samples ............................................................................................................................... 14 Baseline Data ................................................................................................................................... 14 Laboratory Procedures: Sample Preparation and Analysis .............................................................. 15  RESULTS .................................................................................................................................................. 17 Human Isotope Results .................................................................................................................... 17 Isotopic Composition of Food Sources ............................................................................................ 17 Terrestrial Plant Resources ........................................................................................................... 20 Terrestrial Fauna........................................................................................................................... 21 Estuarine/Freshwater Fauna ......................................................................................................... 21 Marine Fauna ................................................................................................................................ 22 Riverine Fauna ............................................................................................................................. 22  DISCUSSION ............................................................................................................................................ 23 General Dietary Patterns .................................................................................................................. 23 Temporal Dietary Trends ................................................................................................................. 24 Late Archaic (3500-1900 cal. B.C.) ............................................................................................. 24 The Early Formative (1900-1000 cal. B.C.) ................................................................................. 28 The Middle Formative (1000-500 cal. B.C.) ................................................................................ 29 The Middle to Late Classic (A.D. 500-900) ................................................................................. 30   v  The Late Postclassic (A.D. 1250-1530) ....................................................................................... 30 Spatial Dietary Trends...................................................................................................................... 31 Ancient Soconusco Diets in the Broader Mesoamerican Context ................................................... 32 Archaic Patterns ........................................................................................................................... 32 Early Formative Patterns .............................................................................................................. 33 Middle to Terminal Formative Patterns ....................................................................................... 38 Middle to Late Classic Patterns .................................................................................................... 38 Postclassic Patterns....................................................................................................................... 39 Highlands vs. Lowlands ............................................................................................................... 40  CONCLUSIONS ....................................................................................................................................... 42 Heterogeneous Diets Between and Within Soconusco Sites ........................................................... 42 Dietary Diversity between Environmental Zones ............................................................................ 42 Maize: A Supplementary Role in Soconusco Diets ......................................................................... 43 Reassessing Previous Soconusco Dietary Isotopic Patterns ............................................................ 44 Soconusco Diets in the Mesoamerican Context ............................................................................... 45 Observations and Recommendations for Future Research .............................................................. 46 The Potential of Sulphur Isotope Analysis ................................................................................... 46 More Robust Local Baseline Data and Micro-Botanical Studies ................................................. 47 Exploring the Potential Effects of Adhesives and Consolidants on Bone .................................... 48  REFERENCES CITED ............................................................................................................................ 49  APPENDIX ................................................................................................................................................ 56    vi  LIST OF TABLES  Table 1. Archaeological phases in the Soconusco region, 5500 B.C. to A.D. 1530 .............................. 3 Table 2. Total number of acceptable Soconusco human samples represented by environmental zone, periods, and sites. ................................................................................................................................... 7 Table 3. Human ?13C and ?15N results at the Laboratory of Archaeology (UBC). .............................. 18 Table 4. Human ?13C and ?15N results from Blake et al. (1992a, b), Chisholm and Blake (2006), and unpublished data by Chisholm. ............................................................................................................ 18 Table 5. Modern and archaeological plant and animal ?13C and ?15N total mean values with S.D. .... 19 Table 6. Soconusco modern (flesh) shrimp and crab ?13C and ?15N values by habitat in Chisholm and Blake (2006). ........................................................................................................................................ 28 Table 7. Human ?13C and ?15N values by period in neighboring Mesoamerican sites/regions. .......... 35          vii  LIST OF FIGURES  Figure 1. Map showing the location of the Soconusco region in Chiapas, M?xico and Guatemala. ..... 5 Figure 2. Scatterplot showing the Soconusco human ?13C and ?15N results along with the faunal and floral baseline data. .............................................................................................................................. 24 Figure 3. Boxplot of Soconusco human ?13C? values by period. ...................................................... 25 Figure 4. Human ?13C? and ?15N? values by period. ....................................................................... 27 Figure 5. Boxplot of human ?13C? values by Soconusco environmental zone. ................................. 32 Figure 6. Map showing the location of the Mesoamerican archaeological sites mentioned in this study. The map also depicts the highland (brown) vs. lowland (green) regions. ................................. 34 Figure 7. Scatterplots of Mesoamerican and Soconusco human ?13C? and ?15N? values by period............................................................................................................................................................... 37 Figure 8. Boxplot of Mesoamerican human ?13C? values by highland and lowland regions and Soconusco environmental zones. ......................................................................................................... 41        viii  ACKNOWLEDGEMENTS   I would like to thank my M.A. supervisor Dr. Michael Blake for his never-ending support, guidance, and helpful constructive feedback through my undergraduate and my graduate career. He has always believed in me and in my passion for Mesoamerican archaeology, and has been an extraordinary mentor and supervisor. It has been a real honor to have been his student and to have had the opportunity to work with him as a Research Assistant in very fascinating projects. Thank you to Dr. Brian Chisholm for teaching and guiding me through the isotopic method and having the confidence in me to continue to expand this isotopic project. Thanks for providing me with all the relevant information and project data necessary to produce this M.A. thesis. Many thanks to Dr. Michael Richards for all his support and guidance throughout my M.A. He integrated me to the Graduate Seminar Lab meetings with the rest of his students and this provided a great space to learn more about isotopic analysis and share laboratory and research knowledge amongst graduate peers. He also provided me with a Research Assistantship this past summer to get hands on experience working in the Archaeological Chemistry Laboratory processing my collagen samples for isotopic analysis. The isotopic results from this M.A. research were possible with the financial support of the Laboratory of Archaeology (UBC) so a big thank you to Dr. Richards for this support as well.   I would also like to thank the Department of Anthropology (UBC) for their continuous professional and financial support during my M.A. in the form of the Faculty of Arts Entrance Award and Teaching Assistantship opportunities. Thanks to Dr. Martindale, Dr. Jing, and Dr. Carrier-Moisan for their helpful guidance and exceptional mentorship while working as their Teaching Assistant.   Thank you to Elizabeth Jarvis, our Lab Technician, for providing me with knowledge on the ins and outs of the isotopic sample preparation procedure and for having the patience to answer my questions along the way. Thank you also to Dr. Olaf Nehlich for providing helpful and constructive feedback as well as sharing with me his experience about assessing the quality of isotopic results, and different ways of analyzing isotopic results. Thanks to Alejandra Canela, my laboratory assistant, for volunteering her time for the cataloguing and re-bagging process of the Soconusco bone collection. Thanks to Peter Merchant for revising and providing feedback on earlier versions of this thesis.  A special thanks to my parents, Jos? and Lourdes, for their unconditional love and support. They have provided me with their emotional and moral support, advice, and have always believed in my vision of becoming an archaeologist. Thanks to my brother, Pepe, for always being there for me, and for providing me with helpful revisions and feedback on my written work, including this thesis.   ix  A big thank you to Sam Badhan for providing me with love and emotional support, encouragement, and being there for me in the good and not so good days. Thank you for being so understanding and caring, and for supporting my professional goals.   Also thanks to my thesis-writing peers, Lindi Masur and Naomi Smethurst, for all the early mornings and late evening writing-sessions, for providing me with motivation and camaraderie, and for making the thesis-writing process not as lonesome as it could have been. Lastly, many thanks (merci beaucoup) to the Pich? family for their support and for opening their beautiful home to me, where I had very productive thesis-writing sessions.         x  DEDICATION        To my parents, Pepe, and Sam                      1  INTRODUCTION  In recent decades, archaeologists have increasingly used stable isotopic analysis1 of skeletal remains to study ancient Mesoamerican paleodiets. This biochemical approach has been successful in providing new insights and direct evidence about the diets of ancient Mesoamericans in M?xico and Central America. In this thesis, I use stable carbon and nitrogen isotope analysis of human bone collagen, to analyze human bone samples from excavated sites in the Soconusco region of Chiapas, M?xico, in order to contribute to our understanding of subsistence practices and ancient diets throughout this region.  Previous Stable Isotopic Analyses in the Soconusco As an additional line of evidence to the archaeo-faunal and botanical analyses, Blake et al. (1992a, 1992b) carried out stable isotopic analyses as an initial attempt to reconstruct Soconusco diets by directly analyzing bone collagen of pre-Columbian individuals. These isotope studies had the main objective of investigating the degree of importance that maize played in people?s diets in this Mesoamerican region, particularly during Formative times. The stable isotope results suggested that during the Late Archaic period (3500-1900 cal. B.C.) people in the Acapetahua zone may have consumed substantial quantities of C4 plants2, possibly including maize, in their daily diet due to the higher carbon isotope values (Blake et al. 1992a:88-89). During the Early Formative period (1900-1000 cal. B.C.), the stable isotope results indicated that Mazat?n (Mokaya) people mainly practiced fishing, hunting, and gathering in addition to producing crops (i.e., maize, beans), and that agricultural foods, particularly maize, may not have been as significant a component of the Early Formative Mazat?n diets as they were in later periods. Instead, it appeared that a mixed diet, including estuarine fauna and C3 plants (i.e., beans, avocado, squash) may have been equally or more important.  Contrasting with the Mazat?n samples, the stable carbon isotope ratios from the Acapetahua and R?o Naranjo zones revealed that from the Middle Formative onwards there was a pronounced shift towards an increased dependence on C4 plants (including maize). The marked contrasts between the different Soconusco zones, where people at Mazat?n mainly subsisted on hunting and fishing, while people at Acapetahua and R?o Naranjo began to subsist on agricultural                                                    1 For further information and overview about this technique please refer to: Chisholm 1989; Lee-Thorp 2008; Kelly 2000; Schoeninger et al. 1983. 2 For a detailed description of C4 and C3 plants refer to the ?Results? section (page 15) of this thesis and the Appendix, Table 3 for examples of C4 and C3 plant species.   2  crops consuming larger amounts of maize, indicated that there were regional differences in production and consumption strategies during the Middle Formative, which continued at least until the Late Classic period. A third stable isotope analysis was carried out more recently by Chisholm and Blake (2006). These newer isotope results agreed with the initial stable isotope analyses of the early 1990s, except a new hypothesis about the Late Archaic period was introduced: that the somewhat high carbon isotope values could be the reflection of a significant consumption of food sources such as marine crab and brine shrimp that have similar stable carbon and nitrogen isotope signatures to C4 plants such as maize. Re-Analyzing Soconusco Skeletal Samples  The earlier stable isotope studies in the Soconusco region carried out by Blake, Chisholm, and colleagues (1992a, 1992b, 2006) began the task of exploring subsistence and dietary practices as well as providing new hypotheses of possible pre-Columbian Soconusco dietary patterns. At the same time, these studies left many questions unanswered: Were there dietary differences between and within archaeological sites? Is it possible to confirm dietary contrasts between Soconusco environmental zones? Were the Late Archaic diets principally composed of C4 plants (i.e., maize) during the Late Archaic period, followed by a period of more mixed subsistence during the Early Formative? And, how pronounced was the shift towards increased maize consumption by the Middle Formative period?  In an attempt to answer these kinds of questions, I have re-analyzed human samples in the laboratory that were recovered during the 1980s and 1990s, from multiple archaeological sites located through the Soconusco. Since no other dietary isotopic studies have been conducted in the region besides those already discussed, the reassessment of these human remains may provide new insights to help evaluate previous subsistence and dietary hypotheses in pre-Columbian Soconusco and contribute more nuanced information about dietary patterns in this region from the Late Archaic to the Late Postclassic periods (Table 1). The main questions I address are:  1) do the isotopic data, point towards similar diets between individuals from different Soconusco sites, or towards dietary differences between and within sites?  2) do the isotopic data show a shift towards increasing reliance on maize, and if so, when? 3) in what ways are the dietary patterns from this study similar to and/or different from previously proposed dietary isotope patterns? and, 4) how do the results of this study compare with other Mesoamerican dietary patterns?   3  In an attempt to answer the above research questions, I first provide a brief overview of the region of study, looking at the overall geography and environment, as well as the three environmental zones in the Soconusco region. I then summarize the previous archaeological and paleo-environmental studies conducted in the region. Next, I proceed to outline the materials and methods of analyses, and the results. Finally, I integrate these results with those from published (Blake et al. 1992a, 1992b; Chisholm and Blake 2006) and unpublished (Chisholm and Blake personal communication, 2012) materials. This larger sample set (n = 20) allows me to expand the discussion relating to subsistence strategies and dietary patterns in pre-Columbian Soconusco, and discuss how these dietary patterns compare with other paleo-dietary patterns across Mesoamerica. Table 1. Archaeological phases in the Soconusco region, 5500 B.C. to A.D. 1530                                    Based on: Clark and Cheetham (2005:292, Fig. 3) and Clark et al. (2005:7, Fig. 1.3).   Period Phase Names Calibrated Calendar Years (cal. B.C./A.D.) Late Postclassic A.D. 1250-1530 Early Postclassic Remanso A.D. 900-1250 Late Classic Peistal Metapa A.D. 600-900 Middle Classic Loros A.D. 500-600 Early Classic Kato Jaritas A.D. 250-500 Late Formative Hato Guill?n B.C. 300-A.D. 100 Middle Formative Frontera Escal?n Duende Conchas  500-300 750-500 850-750 1000-850 Early Formative Jocotal Cuadros Cherla Oc?s Locona Barra  1200-1000 1300-1200 1400-1300 1500-1400 1700-1500 1900-1700 Archaic Chantuto B Chantuto A  3500-1900 5500-3500   4  THE SOCONUSCO REGION  The geography and environmental characteristics of the Soconusco region had an enormous impact on both the general types of subsistence practices (i.e., fishing, hunting, gathering, cultivating) carried out by the inhabitants of this region as well as the specific types of food consumed. These in turn determined the carbon and nitrogen isotopic signatures of the fauna, flora, and humans, since these values are a result of the chemical processes in the environment. In this section I briefly describe the three distinct environmental zones within the Soconusco?Acapetahua, Mazat?n, and R?o Naranjo?as well as the major archaeological sites and isotope samples selected for this study.  Soconusco?s Geography and Environment The Soconusco region (Xoconochco in n?huatl) extends for 240 km along the Pacific Coast of Chiapas M?xico and neighboring Guatemala (Figure 1) (Voorhies 1989:2). It is composed of a littoral zone with a sandy coastal shoreline backed by an inland canal system, which includes shallow estuaries and lagoons and extensive mangrove and cattail swamps (Voorhies 1989:2-3). Inland, from this littoral zone, the vegetation is mainly composed of mangrove trees and corozal palms that experience seasonal flooding during the rainy season. Still farther inland, the terra firma is comprised of the alluvial plain that is well-drained by the many short rivers that descend from the coastal range and flow into the estuaries and swamps of the littoral zone (Voorhies 1989:3-4). The combined width of the littoral zone and terra firma is only about 15 km at its northwest end, but widens to 35 km towards the southeast (Clark 1994: 47; Voorhies 1989:4). Immediately inland from this coastal strip, the piedmont of the imposing Sierra Madre de Chiapas Mountains rises abruptly, eventually reaching altitudes of 4,000 m. One of the most prominent peaks in the Sierra Madre range is the Tacan? volcano, a dominating presence that straddles the M?xico-Guatemala border. Just as the geography of the Soconusco is very uneven, the environmental conditions of the region also vary, especially when contrasted with the Tonal? region of coastal Chiapas to the northwest or the Suchitepeques region of coastal Guatemala to the southeast (Voorhies 1989:2-4). The Soconusco experiences high precipitation, increasing gradually from northwest to southeast, with the amount of rainfall intensifying considerably as one moves inland towards the Sierra Madre Mountains (Voorhies 1989:4). Consequently, the productivity of the land is much higher in comparison to neighboring zones which are significantly more arid (Voorhies 1989:4). Adding   5  to this productivity, the villages in the Soconusco were often located adjacent to bajos?humid zones that formed in ?old stream channels or old oxbow lakes? (Clark et al. 1987:8). During the rainy season, the bajos acted as runoff channels for the main rivers. During the dry season, when these bajos partially drained, they continued to hold fish and other estuarine species that could be easily caught. Even when bajos lost their surface water, they continued to retain a great deal of underground moisture, allowing farmers to cultivate crops during the dry season (Clark et al. 1987:8). In short, the Soconusco region is a highly productive and fertile coastal region, thanks to the high levels of precipitation, deep and arable soils, abundant rivers, estuaries, swamps and bajos, and lush forests that support an enormous variety of plant and animal species (Blake and Clark 1999; Voorhies 1989).  Figure 1. Map showing the location of the Soconusco region in Chiapas, M?xico and Guatemala. The map locates the three environmental zones as well as the archaeological sites in this study (Re-drawn from Blake et al. 1992a).    6  In the Soconusco region, the most varied habitats are the estuaries, coastal lagoons, swamps, and rivers that support a variety of freshwater and/or brackish water animal species. For instance, coastal lagoons experience seasonal changes in salinity due to the amounts of rainfall during the wet versus dry periods, as well as variations in salinity across space?with some areas dominated by freshwater and others by more brackish water?within an individual lagoon (Voorhies 2004:12). This unique characteristic of salinity in estuarine-lagoons enhances the production of nutrients, allowing filter feeders such as oysters, clams, shrimp, and crabs to reproduce and spread rapidly (Voorhies 2004:12-13). As a result, these coastal lagoon and estuary systems are considered to be among the most highly productive ecosystems in the world (Contreras Espinoza in Voorhies 2004:12). Even so, fluctuations in rainfall would impact the salinity of the estuaries and lagoons, in turn affecting the availability of food resources during the wet and dry seasons (Kennett and Voorhies 1996:700). Soconusco Environmental Zones: Archaeological Sites and Samples To answer the research question?were there similarities and/or differences in human diets within the Soconusco region??it is first necessary to understand some of the key environmental differences among the three main zones within the Soconusco. This will allow the selection of human samples from archaeological sites within each environmental zone and ultimately help understand the variation observed in isotope samples across the Soconusco region. Acapetahua The Acapetahua zone (Figure 1) is composed of an estuary and a coastal plain, within which are three distinct sub-zones (Michaels and Voorhies 1999:42): 1) The mangrove forest: A swamp with fauna that includes birds, opossums, raccoons, porcupines, and crabs.  2) The herbaceous swamp: Situated at the eastern and western margins of the estuary. To the west, the swamp occurs in small patches mostly covered by a single species of cattail (Typha). To the east is a large swamp known as El Hueyate (Figure 1) created by the discharge of the Huixtla and Despoblado rivers. During the rainy season, El Hueyate can double in area from 30 sq. km to 60 sq. km. The fauna includes several species of turtles and migratory birds (plentiful from October to March), as well as other local birds that are available year round.   7  3) The open water lagoons and canals: Located within the estuary. Present are many species of fish, turtles, crocodiles, shrimp, and mollusks, as well as clam (Polymesoda radiata) and shrimp. Clams shells have been found in shell middens across the Acapetahua zone, while shrimp may have also been important in the subsistence systems of the Archaic people, but concrete archaeological evidence to support this hypothesis is still lacking (Voorhies et al. 1991). The coastal plain adjacent to the Acapetahua estuary is known to have a very low gradient, allowing it to flood during the rainy season. Its vegetation is presently composed of palm savanna, but it is possible that in earlier times it was a tropical deciduous forest. Michaels and Voorhies (1999:42) speculate that some species like deer, rabbit, jaguar, kinkajou, monkeys, tepescuintle, iguana, among others may have been indigenous to this habitat, as well as tree fruits, fibers, roots, and other plant products that Archaic people could have hunted and collected.  The five human samples recovered from this zone and analyzed in the present study came from burials at four sites: Tlacuachero, R?o Arriba, Las Morenas, and Zapotillo (Figure 1, Table 2; refer to the Appendix, Table 1 for supplementary information on the burials).  Table 2. Total number of acceptable Soconusco human samples represented by environmental zone, periods, and sites. Environmental Zone N Periods Archaeological Sites Acapetahua 5 Late Archaic; Middle and Late Classic; Late Postclassic Tlacuachero; R?o Arriba; Las Morenas; Zapotillo Mazat?n 11 Early and Middle Formative; Late Classic; Late Postclassic Paso de la Amada; Aquiles Serd?n; Huanacastal; El Varal; Chilo R?o Naranjo 4 Middle Formative; Late Postclassic La Blanca; La Victoria  Mazat?n The Mazat?n zone is situated south of the Acapetahua zone. It is bordered by the Hueyate Swamp to the northwest, and extends southeast towards the Suchiate River, with the Pacific Ocean on one side and the Sierra Madre Mountains on the other3 (Figure 1). Besides the                                                    3 The environmental, plant, and animal species information for this section comes from: Blake et al. 1992b; Blake and Neff 2011, Table 3.1; Clark et al. 1987; Clark 1994; Feddema 1993; Lesure 2009; Michaels and Voorhies 1999; Voorhies 1989, and Wake and Steadman 2009.   8  piedmont area inland, there is little topographic relief in this zone. The coastal plain has elevations below 30 m.a.s.l. and it extends inland 15 to 20 km from the ocean. Within the region there is minimal temperature variation throughout the year, with the monthly average always exceeding 20?C.  The flora used to be dense, especially in the piedmont area, which was covered with tropical evergreen forest. The coastal plain was mainly sub-tropical deciduous forest and savanna, and along the edges of rivers and swamps there was tropical, riparian forest. As a result of the increased rainfall in this zone, and across the region, the land is very fertile, providing ideal conditions for growing crops such as maize, beans, cacao, to name a few. There was also an extensive variety of terrestrial faunal species, such as turtles, deer, armadillos, crocodiles, iguanas, peccary, rabbits, as well as estuarine, marine, and riverine fish, shellfish (i.e., crabs, shrimp, clams, oysters, etc.), and waterfowl species available for human consumption. In this zone there was little seasonal variation in the availability of most animal species making local food resources predictable, plentiful, and readily available year-round.  In the Mazat?n zone, 11 human samples were recovered from five sites: Paso de la Amada, Chilo, Aquiles Serd?n, Huanacastal, and El Varal (Figure 1, Table 2; refer to the Appendix, Table I for supplementary information on the burials).  R?o Naranjo  The R?o Naranjo zone lies to the southeast of the Mazat?n zone (Figure 1). It is situated on the Guatemalan Pacific coastal plain which was formed by the erosion of sediment from the piedmont area. This erosion of sediment created deep soils that regularly replenished by alluvial and aeolian deposits, and thus, are very fertile for agriculture (Love 1999:91). There is minimal topographical variation in this zone. This affects soil characteristics in so far as it leads to well-drained and fertile soils in most areas but also creates patches with poorly drained, low quality soils. In comparison with the slower moving, meandering rivers in the two northern zones, in the R?o Naranjo zone, the two largest rivers, the Naranjo and the Suchiate, drain more directly into the ocean. Only a few of the smaller drainages on the coastal plain provide water to very productive estuary/lagoon systems. The heavy rainfall in the R?o Naranjo zone facilitates the cultivation of at least two maize and other crops per year, and according to Love (1999:92, 95), ?a third crop may be harvested by using humid depressions that occur on the plain 5-12 km inland, where the water table is shallow.? Besides the highly productive soils in areas throughout this zone, there are also plenty of terrestrial, riverine, and estuarine animals that would have been   9  available for human consumption such as turtles, deer, dogs, fish, birds, and other reptiles and mammals.  The four human samples from the Naranjo zone came from the archaeological sites of La Victoria and La Blanca (Figure 1, Table 2).      10  PRE-COLUMBIAN SOCONUSCO SUBSISTENCE: THE ARCHAEOLOGICAL EVIDENCE  In order to provide a baseline for analyzing the stable carbon and nitrogen isotope values of the archaeological human samples, we will first consider the archaeological subsistence data and the paleoenvironmental record4. Below I present the archaeological evidence of the overall pre-Columbian subsistence patterns from the Archaic to the Postclassic periods (Table 1) based on reported research to date5.  Archaic Period The best representation of this earliest period (Table 1) comes from Cerro de Las Conchas, located on the margin of the Hueyate Swamp and from Acapetahua estuary sites such as Tlacuachero (Figure 1). According to Michaels and Voorhies (1999:39-42), the Chantuto people were residentially mobile hunter/fisher/gatherers who focused most of their time and energy exploiting estuarine food sources mainly composed of marsh clams (Polymesoda radiata), fish, and possibly shrimp. While we still lack direct archaeological evidence for shrimp, they are, at present, an important resource in the lagoons during the dry season (Voorhies et al. 1991). Based on the archaeological data found at these Archaic estuary sites?substantial seasonal shell middens with very little evidence of residential structures and a small number and narrow range of tools?it has been suggested that the Chantuto people were ?collectors? who had specialized sites for the processing and procurement of upper estuary resources. Meanwhile, their primary residential areas are hypothesized to have been located inland on the coastal plain. One possible example of such a residential site is Vuelta Lim?n so it is possible that the Chantuto occupants also maintained a varied terrestrial subsistence besides their reliance on marsh clams and other estuarine fauna (Voorhies 2004). Additionally, the presence of Zea mays phytoliths and pollen                                                    4 The Soconusco region was explored and excavated by archaeologists as early as the late 1950s to the mid-1970s (Coe 1961; Coe and Flannery 1967; Ekholm 1969; Lowe 1967). In the 1980s and early 1990s, the region continued to be researched through a number of archaeological projects. The excavations at the Archaic-period site of Tlacuachero was undertaken by Voorhies beginning in the 1970s and continued for many seasons (1976, 2004). In the early to mid-1980s, Love (1989; 2002) surveyed Early and Middle Formative sites in the R?o Naranjo region in Guatemala, and excavated La Blanca. Meanwhile, Clark and Blake (Clark et al. 1987; 1990) surveyed and excavated various Archaic and Early Formative sites in the Mazat?n region, Pye and Demarest excavated El Mesak in Guatemala, and Demarest and colleagues excavated El Carmen in El Salvador (Blake et al. 1995:162). Blake, Clark, Lesure, and colleagues continued the excavations at the Early and Middle Formative site Paso de la Amada in 1990, 1992, 1993, and 1995. Lesure (2009, 2011) also undertook a salvage operation along with Clark and P?rez Su?rez at the Early Formative site of El Varal. Rosenswig (2010 excavated and surveyed the Early Formative Cuauht?moc site, near the Suchiate River, recovering subsistence remains. 5 The basic information for the following two sub-sections comes from Blake et al. 1992b, 1995; Blake and Neff 2011; Clark et al. 1987; Lesure 2009; Michaels and Voorhies 1999, and Neff et al. 2006.   11  micro-botanical remains in shell middens at Late Archaic sites (i.e., Tlacuachero) and at Vuelta Lim?n could indicate an initial introduction of maize and possibly other domesticates such as Cucurbita (squash) into the Chantuto phase diets before transitioning into the Early Formative period (Jones and Voorhies 2004; Blake and Neff 2011).  Formative Period The Formative period in the Soconusco has been divided into the Early Formative composed of the Barra, Locona, Oc?s, Cherla, Cuadros, and Jocotal phases; the Middle Formative with four phases Conchas, Duende, Escal?n, and Frontera, and the Late Formative (Table 1). These Formative phases were delineated based on the defined ceramic and artifact styles present in the region. The Barra to Oc?s phases represent the Mokaya tradition, while the Cherla to Conchas phases represent ceramics, figurines, and other artifacts similar to the Olmec-style tradition found in neighboring Mesoamerican regions (i.e., Gulf Coast, Oaxaca, Chiapas, Guatemala). The analyses of macro-botanical remains from the Mazat?n zone during the Early Formative period registered the presence of three main cultigens: maize (Zea mays), beans (Phaseolus spp.), and avocado (Persea americana) (Feddema 1993), suggesting that these plant species were being cultivated at inland Mokaya villages. Along with the botanical evidence, well-made manos and metates (grinding stones) were recovered from Early Formative Soconusco sites. Furthermore, the paleoenvironmental evidence from sediment cores by Neff et al. (2006:307) illustrates important changes to the landscape after the Archaic period, in particular the human adaptive shift towards forest clearance across the Guatemalan coastal region (i.e., Manch?n, Sipacate, and lower R?o Naranjo at the far southern end of the Soconusco). Neff and colleagues (Neff et al. 2006) propose that this adaptive shift indicates a more pervasive human impact on the land for intensified agricultural activity (see also Lesure 2009).  Besides the plant remains, the excavations from Early Formative Mazat?n sites yielded a wide variety of faunal remains such as diverse freshwater, brackish, and marine fish species, a variety of crab species, reptiles such as turtle, crocodile, iguana, and snake, and minimum quantities of shellfish which contrasts with the Acapetahua sites. The terrestrial faunal remains recovered include turtle, white-tailed deer, domestic dog, peccary, pocket gopher, armadillo, cottontail rabbit, opossum, among some, as well as a range of bird species. Above all, fish were the most frequent remains at Mazat?n sites between the Barra and Cherla phases. Both the archaeological floral and faunal evidence suggest that the Mokaya villagers of the Early   12  Formative were engaging in maize, bean, and avocado cultivation, as well as continuing to consume a wide range of estuarine, marine, and terrestrial food sources (Clark 1994; Lesure 2009). During the Middle Formative period (Conchas phase), the archaeological data recovered from R?o Naranjo sites included complete and fragmentary grinding stones that, in Love?s (1999:95) words, were ?omnipresent? in both surface collections and excavated levels. This indirect evidence for the processing of cultivated plants (presumably maize) pointed to the idea that cultivated plants may have become a much more central part of the diet than in the Early Formative. Moreover, the faunal remains recovered at La Blanca were composed of dog, white-tailed deer, freshwater turtle, green iguana, rabbit, and collared peccary (Love 1999:95). The results of the faunal analysis indicated that there were two important trends in animal resource use during this time: 1) a focus on a more limited number of species, in this case the domestic dog, deer, and freshwater turtle which dominated the assemblage, and 2) an increased use of a domestic protein source like the dog since this animal was the most frequent in the assemblage (calculated by MNI). Thus, it has been hypothesized that by the Middle Formative there could have been a shift away from estuarine fauna as a prominent subsistence system and towards a more intensified and efficient subsistence based on agriculture, hunting, and an increased emphasis on food production by using the domestic dog as a food source.  Classic and Postclassic Periods  Based on archaeological remains recovered from Acapetahua sites such as Las Morenas and R?o Arriba (Figure 1) there are subsistence data on faunal trends from the Early Classic to Late Postclassic periods (Table 1). Both archaeological sites had a similar total faunal assemblage in which the most common faunal class was mammal (around 50 percent), followed by fish (between 25-30 percent), turtle and other reptiles (20 percent), and bird (only 2 percent) (Hudson et al. 1989:141).  The researchers explain that the relative importance of mammal and fish shifted through time since there was an overall trend towards a decreased emphasis on mammal and an increased emphasis on fish between the Middle Classic and Late Postclassic periods (Hudson et al. 1989). For instance, during the Middle Classic the percentage contribution of mammal seemed to have declined quickly, whereas the contribution of fish increased. During the Late Classic, the percentage of mammal increased back to its Early Classic level, while fish had a brief but visible decrease in importance (Hudson et al. 1989:146-147; Figure 5-4). During the Early to Late   13  Postclassic the importance of fish increased while the importance of mammal declined. This faunal trend is also supported by the artifacts recovered from the Late Postclassic since it was the first time that net sinkers appeared in the archaeological record in the Acapetahua zone indicating that ?for the first time Soconusco inhabitants used a fishing method that allowed the mass capture of fish? (Voorhies and Gasco 2004:81); however numerous ceramic net sinkers were recovered as early as the Early Formative period from sites in the Mazat?n zone (see Blake et al. 1992b).   Besides the faunal trends showing an increased emphasis on fish, other archaeological artifacts recovered during the Postclassic period show evidence of the importance of plants in the Soconusco diets. For instance, milling stones and manos and metates were commonly found during the Late Postclassic period in the Soconusco for the processing of agricultural plants such as maize, as well as mortars (molcajetes) and pestles to process spices and condiments (Voorhies and Gasco 2004:179). While there is no direct archaeological evidence yet, cacao seems to have been a common plant grown in the Soconusco during the Postclassic period since the region has adequate environmental conditions for its successful growth and it had become an important ingredient in ritual beverages and a commodity across Mesoamerica by this time (Voorhies and Gasco 2004:180).          14  MATERIALS AND METHODS  Human Samples Bone collagen samples from 48 individuals were analyzed for the present study (Appendix, Table 2). These individuals come from excavations carried out between late 1985 and 1997 in the Soconusco region by Michael Blake, John E. Clark, Barbara Voorhies, Richard Lesure, and their students and colleagues. Most of the human samples (except for 11 samples from Paso de la Amada) are from the same excavation units as the individuals analyzed in the previous isotopic studies excavated at a number of sites from the Acapetahua, Mazat?n, and R?o Naranjo zones (Blake et al. 1992a, 1992b; Chisholm and Blake 2006). Information about the sex and age are only available for the few human samples which were well-enough preserved and could be included in previous osteological studies of this collection (Appendix, Table 1). Baseline Data To understand and interpret stable carbon and nitrogen isotope values of human bone collagen within the context of dietary reconstruction, it is necessary to establish the isotopic food web, in which ?13Cand ?15N values6 of various fauna and flora from the same environmental context are measured, either archaeological and/or modern, to provide baseline comparisons for the species of interest (Richards et al. 2008), ancient Soconusco humans in this case. When the isotopic composition of local fauna and flora that were potential food sources is known, more reliable interpretations and assumptions about the diet of an archaeological population can be made (Cheung et al. 2011; Chisholm et al. 1982; Norr 1991:29; Schoeninger et al. 1983; Tykot 2002). In order to do this, I use a compilation of archaeological and modern local faunal and floral ?13C and ?15N data from the previously published analysis in the Soconusco region (Chisholm and Blake 2006; Appendix, Tables 2 and 3)7. To complement these data, I include additional archaeological and modern faunal and floral isotopic data in the Appendix (Tables 2 and 3) from other dietary isotopic studies in Mesoamerica and Central America, most of these come from relatively similar tropical environments (Norr 1991; van der Merwe et al. 2002;                                                    6 The resulting ratio of 13C to 12C per sample is compared to the ratio for the standard Pee Dee Belemnite (PDB) and the results are expressed in parts per mil (?) (Chisholm 1989). The resulting ratio of 15N to 14N per sample is compared to the ratio for the standard AIR (atmospheric nitrogen) and the results are expressed in parts per mil (?) (Schoeninger and DeNiro 1984). 7 For this study, the available archaeological faunal samples were processed for analysis but due to poor preservation conditions no useful carbon and nitrogen isotope results were achieved in the laboratory. As a result, I rely on previously published baseline data.   15  VanDerwarker 2006; Warinner et al. 2013; White and Schwarcz 1989, 1993; Wright 1994), with the main purpose of having a more reliable baseline to help reconstruct the possible diets of the human samples in this study. Laboratory Procedures: Sample Preparation and Analysis The bone samples used for this analysis included vertebrae, ribs, and long bone fragments that were unused during the previous Soconusco isotope analyses (Blake and Chisholm personal communication, 2012). All individuals had been packaged and stored in the laboratory, free from external contaminants or other preservatives. To extract collagen from each bone sample, I followed the standard laboratory procedures outlined by Richards and Hedges (1999). First, the bone surface was scraped off in case of any external contaminants remaining on the outside of the bone. One sample (S-UBC 593), that had been coated in Duco Cement (cellulose nitrate) as a consolidant for conservation purposes following its recovery from the field, was submerged in acetone for an initial two hours. The process was repeated with fresh acetone for another 24 hours as a pre-treatment to remove the consolidant (Moore et al. 1989). The sample was allowed to fully dry for 48 hours and then processed as the rest of the samples. Since most of these samples were, in general, poorly preserved (as is common in humid tropical environments), I extracted substantial bone mass per sample in the hopes of obtaining sufficient collagen for analysis. This produced a bigger mass per sample than usually analyzed?ranging from 0.800 g to 1.500 g?so I divided each extracted sample into two test tubes of ~500-600 mg each to provide more surface area for the following steps. The samples were then demineralized in 0.5 M HCl for several days (4-6) at 4?C, replacing the acid every 48 hours. Once the bone had demineralized, pH3 HCl solution was added to each sample and heated at approximately 75?C for 48 hours to solubilize. Following this, the samples were EZEE filtered and ultra-filtered (cut-off 30 kDa). The filtrate was frozen and then freeze-dried for 48 hours. The resulting collagen was weighed and placed into a tin capsule for combustion.  All samples were analyzed using an Elementar VarioMicro Cube Elemental Analyzer and an IsoPrime IRMS at the Archaeological Chemistry Laboratory at the University of British Columbia (Vancouver, Canada). Methionine, USG-40, and modern seal collagen were used as reference standards in every run to calibrate the reference gas and to monitor the accuracy and precision of the measurements. Machine precision was better than ?0.02? for ?13C and ?15N. When possible reported measurements are average values based on duplicate analyses (where noted) and all sample results are reported in ?permil? (?) with respect to V-PDB (for ?13C) and   16  AIR (for ?15N) standards (Richards et al. 2008). The quality of the collagen was assessed using carbon and nitrogen percentage yields (percent C and percent N) and atomic C:N ratios (Bocherens and Drucker 2003). These ratios are used since they are remarkably stable but are likely to increase in bone that yields low levels of collagen which may indicate bone diagenesis (Dobberstein et al. 2009:33).     17  RESULTS  From the 48 individuals, 72 collagen samples were prepared and processed for carbon and nitrogen isotope analysis. As a result of the poor preservation conditions of the individuals, only 39 samples produced sufficient collagen for combustion. Out of these 39 results, however, only six yielded acceptable carbon and nitrogen values (Table 3). Samples that did not meet the conditions of having C:N ratios within the range of 2.9 to 3.6 and a N yield of 10.0% or more (Bocherens and Drucker 2003) are listed in the Appendix (Table 2) but excluded from the following results and discussion sections.  Human Isotope Results The six remaining human collagen samples that had acceptable carbon and nitrogen isotope ratios, had collagen yields averaging 39 ? 2.1 percent carbon and 13.3 ? 0.8 percent nitrogen and their C:N ratios ranged between 3.4 and 3.6 (mean = 3.4 ? 0.04) (Table 3). Of the six samples, five are from carefully excavated burial contexts (Table 4): one each from the sites of Huanacastal, Tlacuachero, and Zapotillo (Cs-8), and two from El Varal. A sixth sample was a surface find from a disturbed site near Mazat?n.  For the purposes of discussion and analysis, I combine these six new isotopic results with the 14 previous samples from the Soconusco region (Table 4) (Blake et al 1992a, 1992b; Chisholm and Blake 2006). Of the 20 samples in this combined set, 19 have both carbon and nitrogen measurements, while one has only carbon measurements. All 20 of these samples are within the acceptable standards with a mean C:N ratio of 3.2 ? 0.3 (range 2.8 to 3.6) (DeNiro 1985).  Isotopic Composition of Food Sources  Before moving on to a discussion of the human isotope results of this study I will first discuss the baseline ?13C and ?15N values of both modern and archaeological fauna and flora from the Soconusco and neighboring Mesoamerican and Central American regions. As already mentioned, the purpose of this is to establish an isotopic food web that will provide baseline values with which to compare with the human isotopic signatures. Table 5 presents the ?13C and ?15N compositions of potential food sources found in a wide variety of specific sub-zones and habitats within the Soconusco region. These are discussed in brief below to help create a baseline template for interpreting ancient diet.    18  Table 3. Human ?13C and ?15N results at the Laboratory of Archaeology (UBC). S-UBC Lab No. Zone Site Burial No. Provenience Period Phase Ave ?13C (?) Ave ?15N (?) C:N % C % N 366/416 Mazat?n El Varal 5 N10 E4, East side Early Formative Cuadros-Jocotal -10.4 8.3 3.4 41.0 14.2 380 Mazat?n  El Varal* 1 N45/E4 Early Formative Cuadros-Jocotal -11.4 9.1 3.5 38.0 13.0 382 Soconusco Unknown n/a Surface Late Post-Classic Late Post-Classic -11.5 11.0 3.3 43.2 15.2 412 Acapetahua Zapotillo (Cs-8) 3 N3E3 Late Post-Classic Late Post-Classic -10.3 7.9 3.5 29.5 10.0 414 Mazat?n Huanacastal 1 Pit 1, bottom Middle Formative Conchas -11.8 7.8 3.6 38.5 12.7 415 Acapetahua Tlacuachero* 1 N0E2 Late Archaic Chantuto B -11.0 8.2 3.5 43.8 14.7 Site* = Samples with single measurements since no acceptable duplicate was available for an average measurement of C and N.  Table 4. Human ?13C and ?15N results from Blake et al. (1992a, b), Chisholm and Blake (2006), and unpublished data by Chisholm. Lab No. Zone Site Burial No. Provenience Period Phase ?13C (?) ?15N (?) C:N 1685 Mazat?n Paso de la Amada 2 Pit 5, Level 4 Early Formative Cherla -21.5 n/a 3.3 1901+ Mazat?n Paso de la Amada 1 Mound 6, Level 7 (N48-E46) Middle Formative Conchas -14.5 8.3 3.2 1688 Mazat?n Paso de la Amada n/a Mound 6, E24, Level 6 Early Formative Oc?s -15.9 5.3 3.6 2289 Mazat?n Paso de la Amada  Trench 2, Pit T 46-90cm Early Formative Cherla -9.4 9.0 2.8 1886 Mazat?n Chilo 3 Pit 2, Level 7 Early Formative Locona -19.3 13.0 2.9 1649 Mazat?n Chilo 2a Pit 2, ext. SE Early Formative Locona -13.3 7.4 2.8 1829 Mazat?n Aquiles Serd?n S.P. Trench 1K, Level 13 Early Formative Cherla -17.8 13.1 3.0 1691+ Acapetahua Tlacuachero 19 Unit S3E0, Below floor, Cat. 403 Late Archaic Chantuto B -9.9 8.9 2.8 1656 Acapetahua R?o Arriba 2 Operation 10 Middle Classic Loros -9.5 9.1 2.8   19  Lab No. Zone Site Burial No. Provenience Period Phase ?13C (?) ?15N (?) C:N 1657 Acapetahua Las Morenas 1 Operation 1 Late Classic Metapa/Peistal -11.3 8.5 2.8 1651 Naranjo La Blanca 4 Operation 27, sub 2, 230 cm Middle Formative Conchas B -13.3 8.8 3.2 1652 Naranjo La Blanca 5 Operation 27, sub 2, F39 Middle Formative Conchas B -10.8 9.3 3.2 1649+ Naranjo La Blanca 2 Operation 26, sub 5, 225 cm Middle Formative Conchas C -13.0 7.4 3.1 1913 Naranjo La Victoria  Pit Late Post-Classic  -8.2 8.0 2.9 Lab number+ = Measurements based on duplicate analyses. The human isotope data presented here comes from previous isotopic analyses performed by Blake et al. 1992a and 1992b, Chisholm and Blake 2006, and unpublished data analyzed by Chisholm (personal communication, 2012) at the Laboratories of Fukuoka and Nagoya University in Japan.  Table 5. Modern and archaeological plant and animal ?13C and ?15N total mean values with S.D. Flora/Fauna Habitat N ?13C(?) SD ?15N(?) SD C3 Legumes Terrestrial 4, 3 -24.4 2.6 2.4 1.7 C3 Non-legumes Terrestrial  29, 11 -25.9 2.0 4.7 2.2 CAM plants Terrestrial 6, 3 -11.5 2.3 4.6 2.3 Maize (C4) Terrestrial  8 -8.9 0.7 2.9 1.7 Amaranth (C4) Terrestrial  3 -10.9 0.7 3.9 2.7 C3 Fauna Terrestrial 63, 47 -21.4 1.0 4.4 1.2 Mixed (C3 & C4) Fauna Terrestrial 24, 22 -15.4 1.5 8.6 2.1 Freshwater Fauna Estuary 45, 36 -22.0 2.6 6.6 3.8 Fauna Marine 2 -11.7 n/a 11.9 n/a Fauna Riverine 3 -24.4 5.1 11.9 0.4 Floral data: Chisholm and Blake (2006); Norr (1991); Wright (1994). Faunal data: Chisholm and Blake (2006); Norr (1991); van der Merwe et al. (2002); VanDerwarker (2006); Warinner et al. (2013); White and Schwarcz (1989, 1993), and Wright (1994) (Appendix, Tables 3 and 4). Modern specimens were corrected in their ?13C by +1.5? to account for the ?industrial effect?.   20  Terrestrial Plant Resources  The plant food sources8 sampled by Chisholm and Blake (2006), Norr (1991), Wright (1994), and Warinner et al. (2013) are shown in the Appendix, Table 39 and I have identified them as C3, C4, or CAM since their ?13C values differ depending on their photosynthetic pathway (Chisholm 1989; Lee-Thorp 2008; Schwarcz 2006). Plants identified as C3 tend to have more negative or lower10 ?13C values. As shown in Table 5, the average ?13C value for legumes such as beans (Phaseolus vulgaris) is -24.4 ? 2.6? while non-leguminous C3 plants, such as fruits, root and tree crops have values averaging -25.9? 2.0? (Appendix, Table 3). Terrestrial plants overall lean towards lower stable nitrogen isotope signatures and they may be influenced by factors such as soil types and aridity levels, temperature, cultivation practices, and the use of artificial fertilizers if the samples come from modern plants (Lee-Thorp 2008; Schoeninger and DeNiro 1984; Schoeninger et al. 1983;Wright 1994). In this sample set, legumes?which are N2-fixing plants?have a very low ?15N average value approaching 0? (Wright and White 1996:172), while other non-leguminous plants have a slightly higher ?15N average value (Table 5).  Plants that use the C4 photosynthetic pathway are known to have less negative or higher ?13C values, distinguishing them from C3 plants that have lower ?13C values. C4 plants include maize (Zea mays) and some species of amaranths (Wright 1994:197-198). As seen on Table 5, maize has a ?13C average value of -8.9 ? 0.7? and amaranth (Amaranthus spp.) also has a ?13C value of -10.9 ? 0.7?. It is likely that CAM plants like nopal cactus (Opuntia sp.), pi?uela (Bromelia karatas), pitaya (Hylocereus undatus), and Agave spp. (consumed as a fermented drink known as pulque) would have been available for human consumption. CAM plants in predominantly C4 dominant regions (i.e., Soconusco, Guatemala, and Lower Central America) tend to have higher ?13C values similar to C4 signatures (Table 5). It is difficult to distinguish consumption of CAM plants and C4 plants in these regions through ?13C ratios alone (Wright 1994:203; Warinner et al. 2013), but since CAM plants are not rich in protein their presence may be more background noise. Further analyses of these plants, including oxygen and hydrogen isotope analyses to help distinguish them from C4 plants (Kelly 2000; Warinner et al. 2013), must                                                    8 All modern plant and animal ?13C values have been corrected by +1.5? to account for the changes in atmospheric carbon after the industrial revolution, also known as the ?industrial effect? (Tieszen and Fagre 1993; Tykot 2002; Wright 1994).  9 All plant samples identified by the authors as either archaeological or modern are classified as such in the Appendix, Table 3. 10 For the purpose of clarity I will continue to use the word ?low? or ?lower? to describe more negative ?13C values in the rest of this thesis. Likewise, I use the word ?high? or ?higher? to describe less negative ?13C values.   21  be carried out to assess the importance of these plants in Mesoamerican diets. The ?15N average value of C4 plants is somewhat low as the case of legumes and CAM plants have a slightly higher ?15N average value comparable to C3 non-leguminous plants (Table 5). Terrestrial Fauna There are archaeological (n = 33) and a few modern ( n = 5) terrestrial fauna represented in Table 5 that are either C3 or C4 plant consumers or have a mixed diet composed of both C3 and C4 food sources. The majority of the white-tailed and brocket deer have C3-like ?13C signatures, yet a few of these deer species have ?13C values resembling a more mixed diet (-14.8?) that would have included the consumption of C4 plants (Table 5; Appendix, Table 4). Other common C3 plant consumers are the collared peccary, Baird?s tapir, cottontail rabbit, pocket gopher, iguana, terrestrial snake species (Appendix, Table 4). Overall the C3 plant consumers have low ?13C and ?15N averages (Table 5), excluding the terrestrial snakes since these have higher ?15N values (between 8.8 and 17.8?), indicative of a carnivorous diet. There are some terrestrial fauna that have ?13C values resembling a mixed diet (?13Crange -18.1 and -13.6?) that includes a few deer, peccary, domestic dog, nine-banded armadillo, and two large felids (i.e., ocelot) (Appendix, Table 4) with a ?13C average value in between C3 and C4 signatures and a slightly higher ?15N average value (Table 5). The felids have particularly high ?15N values (?15N = 10.7?) reflecting carnivory (Appendix, Table 4).  Estuarine/Freshwater Fauna  The estuarine/freshwater fauna have lower ?13C values (Table 5) similar to those of C3 terrestrial consumers. Freshwater and estuarine fauna are known to be usually distinguishable from terrestrial fauna in their ?15N composition since estuarine and freshwater fauna tend to have higher ?15N values (Wright 1994). However, there is high variability in the ?15N values (range = -1.8 to 12.7?) of the estuarine fauna in Table 4 (Appendix) (Table 5). As a result, some estuarine/freshwater fauna have similar ?15N values to some terrestrial fauna and plants. Reptiles such as snakes and crocodiles have higher ?15N values (between 11.0 and 12.7?) like those of terrestrial carnivores (Appendix, Table 4). There are some estuarine fauna like the Muscovy duck (Cairina moschata) and a turtle (Chelonidae) that have higher ?13C values (Appendix, Table 4) and their ?15N values (5.7? and 6.6?, respectively) are comparable to those of terrestrial herbivores and indicate a mixed diet composed of both aquatic and terrestrial foods (Wright 1994).    22  While there are no ?13C and ?15N values for shells of species of clam (Protothaca metodon, Chione subrugosa, Polymesoda radiata) commonly found in the faunal assemblage at some Soconusco sites, an archaeological sample of clam (unidentified species) was measured from the periostracum of its shell (Brian Chisholm personal communication, 2012) and its ?13C value is similar to other estuarine fauna ?13C values, while its ?15N value is extremely low (Appendix, Table 4). The flesh ?13C value of this clam would have been similar to the value of the periostracum of its shell (Brian Chisholm personal communication, 2012; Delong and Thorp 2009). Nonetheless, further research on the ?13C and ?15N composition of shellfish meat and shell from this region needs to be carried out to better understand the overall isotopic signatures of these common species of clams.  Marine Fauna Marine fauna overall tend to have higher ?13C values than terrestrial fauna since their source of carbon is dissolved as oceanic bicarbonates which have isotopic values differing from atmospheric CO2 by about 7%, depending what these organisms consume (i.e., some sea mammals might be affected by deltaic/lagoon species that would in turn affect their isotopic values) (Chisholm 1989:12-13; Kelly 2000:4; Lee-Thorp 2008). Moreover, marine fauna have higher ?15N values (i.e., 15-17?) due to longer marine food chains, compared to terrestrial ones?the more trophic levels, the higher the enrichment of 15N (Lee-Thorp 2008:928; Schoeninger and DeNiro 1984; Schoeninger et al. 1983). The marine fauna in this sample set has high ?13C and ?15N values (Table 5). While this is a very small sample (n = 2), these ?13C and ?15N values fall within the expected values for marine fauna. Future isotopic studies should focus on expanding the archaeological baseline data for this habitat to demonstrate that these values are representative. Riverine Fauna There are a few riverine species (n = 3) represented in Table 5. Their ?13C average value resembles to the average of estuarine fauna (Appendix, Table 4). Yet, their ?15N average value resembles to the marine fauna ?15N values (Table 5). Since rivers, including the Soconusco region, experience seasonal fluctuations in water (i.e., increased precipitation during the rainy season), runoff from the mountain slopes (Clark 1994) which have terrestrial ?13C signatures, and changing degrees in water salinity levels, the ?13C and ?15N values of these kinds of fauna should be further researched with a more representative sample to better understand this type of water habitat and the isotope composition of its animal species.   23  DISCUSSION   To answer this study?s research questions (see page 2), I first present a general outline of my findings, followed by a more detailed examination of the similarities and differences in diet between and within Soconusco sites, the possible temporal dietary shift towards an increased reliance on maize, and how these trends compare with those of other Mesoamerican sites/regions. General Dietary Patterns The combined 20 stable isotope human samples have a very wide distribution in their ?13C values, ranging between -21.5 and -8.2? (Tables 3 and 4). This broad ?13C range indicates that pre-Columbian Soconusco individuals were consuming different types of protein sources from which they obtained dietary carbon to produce the observed ?13C signatures. This wide ?13C distribution deserves a closer look at each individual?s possible dietary carbon sources, and therefore, will be addressed in more detail below.  There is less variation in the distribution of the ?15N values (n = 19) (Tables 3 and 4). Most individuals (n = 15) have ?15N values ranging between 7.4 and 9.3??with the exception of three upper outliers and one lower outlier which will be discussed separately below. The overall ?15N range is more clustered together and indicates that most Soconusco individuals do not have the higher ?15N values (i.e., 14-17?) commonly observed in individuals whose diets are solely based on marine food sources (Lee-Thorp 2008). Plant-based diets commonly have a ?15N ? 7? (Wright 1994) so the sample set, with a ?15N average of 8.4 ? 0.6? (n = 15), suggests that most of the Soconusco diets included sufficient quantities of animal protein as well as some plant foods.  The overall Soconusco ?13C and ?15N values indicate consumption of C3 and some C4/CAM plants as well as animal food sources (Figure 2). These results also suggest that most individuals consumed sufficient animal protein (i.e., ?15N values > 7?). As expected in an environment with a wide variety of resources such as the Soconusco region (Appendix, Tables 2 and 3), these pre-Columbian diets were composed of a variety of plant and animal food resources. Thus, Soconusco diets had a sufficient protein intake and were generally wide-ranging and diverse.     24   Figure 2. Scatterplot showing the Soconusco human ?13C and ?15N results along with the faunal and floral baseline data. The ovals represent the ?13C and ?15N approximate average values with standard deviations for fauna and flora (refer to Table 5).  Temporal Dietary Trends  This section discusses the isotope results for each period in the Soconusco region to explore one of my key research questions: was a clear transition in subsistence?and in particular, a trend towards increasing reliance on maize agriculture?reflected in the human ?13C and ?15N values? Late Archaic (3500-1900 cal. B.C.) The two Chantuto phase individuals from this period come from the site of Tlacuachero in the Acapetahua zone (Figure 1; Tables 3 and 4). Both individuals11 have relatively high ?13C values  (-11.0 and -9.9?) compared to the subsequent Early and Middle Formative samples (Figure 3). Based on these ?13C values it is possible that the Chantuto phase individuals consumed some C4 and/or CAM plants (Kennett and Voorhies 1996). While there is an absence                                                    11 The bone collagen of the individual from sample S-UBC 415 was radiocarbon dated at Nagoya University, Japan and has an uncalibrated age of 4680 ? 40 B.P. (3519-3371 cal. B.C.) (Voorhies 2004:66).  0.05.010.015.020.0-30 -25 -20 -15 -10 -5?15 N (?, AIR)   ?13C (?, VPDB)  Soconusco Human ?13C and ?15N Results Compared to Modern and Archaeological Flora & Fauna TlacuacheroPaso de laAmadaEl VaralChiloAquiles Serd?nLa BlancaHuanacastalR?o ArribaLas MorenasLa VictoriaZapotillo (Cs-8)UnknownMazat?nC3 Plants C4 Plants Estuarine Fauna Mixed  Terrestrial Fauna Riverine Fauna C3  Terrestrial Fauna CAM Plants Marine Fauna   25  of macro-botanical remains recovered in this zone, Voorhies (2004:321) reported that Zea mays phytoliths were recovered at Tlacuachero and were present in three different samples (although their age is debatable due to soil disturbance at the site [Blake and Neff 2011:52]). Kennett and Voorhies (1996:702) have suggested that ?maize can be produced in a limited way within the estuary? based on present-day maize cultivation in some areas of the estuary, and its productivity increases moving from the coast to the piedmont area (20-40 km inland). It is possible that these high ?13C values could also be reflecting the consumption of marine food sources that would increase the ?13C values. Since the Chantuto phase individuals have slightly higher ?15N values (8.2 and 8.9??though not as high as would be expected in consumers of high trophic level marine resources) (Figure 4a), they probably consumed animal protein from the available riverine, estuarine, and some marine resources?the latter contributing to their higher ?13C values.    Figure 3. Boxplot of Soconusco human ?13C? values by period.   26             0.05.010.015.0-15.0 -10.0 -5.0?15N (?, AIR)  ?13C (?, VPDB)  Late Archaic TlacuacheroA) 0.05.010.015.0-20.0 -15.0 -10.0 -5.0?15 N (?, AIR) ?13C (?, VPDB)  Early Formative Chilo Paso de la AmadaAquiles Serd?n El VaralB) 0.05.010.015.0-20.0 -15.0 -10.0 -5.0?15 N (?, AIR)  ?13C (?, VPDB)  Middle Formative La Blanca Paso de la Amada HuanacastalC) 0.05.010.015.0-15.0 -10.0 -5.0?15 N (?, AIR)  ?13C (?, VPDB)  Middle to Late Classic R?o Arriba (MC) Las Morenas (LC)D)   27   Figure 4. Human ?13C? and ?15N? values by period (MC= Middle Classic and LC = Late Classic).  According to Kennett and Voorhies (1996:691), the fish vertebrae found at Tlacuachero suggests that the fish collected and consumed by Chantuto people were quite small (less than 15 cm long). Voorhies (2004:400-402) has hypothesized that both small fish and shrimp may have played as important a role as marsh clams (Polymesoda radiata) in the Chantuto subsistence system, even though there is no archaeological faunal evidence for shrimp. Primary consumers such as small fish, shrimp, crab, and marsh clams would have lower ?15N values than aquatic and marine fauna from higher trophic levels, based on the ?15N ?trophic level effect? (Tykot 2006:137). For instance, a clam shell sample has a very low ?15N value of -1.8? (Appendix, Table 4), marine shrimp meat samples have a ?15N value of 2.1? (Table 6), and riverine and estuarine crab meat samples have ?15N values of 3.3? and 5.8?, respectively (Table 6). This being said, it is possible that if the Chantuto phase individuals consumed these aquatic/marine food sources as part of their every-day diet, their ?15N values would not be high enough (i.e., 14-17?) so as to reflect a significant aquatic and/or marine component in the diet. Additionally, marine shrimp and riverine crab have somewhat higher ?13C values (-13.3 and -15.7?) than most terrestrial species (Tables 5 and 6), and which overlap with the isotopic signatures of CAM plants (?13Cmean= -11.5 ? 2.3?; ?15Nmean= 4.6 ? 2.3?) and C4 plants (?13Cmean= -9.9?; ?15Nmean= 3.4?). This makes it difficult to distinguish with certainty if the higher ?13C values in the Chantuto phase diets are due to the significant consumption of estuarine, riverine, and marine primary consumers or C4 and/or CAM plants. Based on these results, I hypothesize that these Chantuto phase individuals probably consumed C4 and/or CAM plants in a supplementary 0.05.010.015.0-15 -10 -5?15N (?, AIR)  ?13C (?, VPDB)  Late Post-Classic La Victoria Zapotillo (Cs-8)Unknown Mazat?nE)   28  manner and mainly ate fauna (especially primary consumers) from marine, estuarine, and riverine habitats. However, more fauna of this kind should be analyzed to produce a representative sample of ?13C and ?15N (and possibly ?34S) values to confirm this hypothesis.  Table 6. Soconusco modern (flesh) shrimp and crab ?13C and ?15N values by habitat in Chisholm and Blake (2006). Common name Scientific Name Habitat N ?13C(?) S.D. ?15N(?) S.D. shrimp unidentified Estuary 3 -22.4 3.0 5.7 0.8 shrimp unidentified Marine 2 -13.3 n/a 2.1 n/a giant shrimp  unidentified Marine 1 -12.9 n/a 10.7 n/a tiger shrimp unidentified Marine 1 -12.7 n/a 12.2 n/a shrimp unidentified River 1 -14.2 n/a 10.5 n/a crab unidentified Estuary 2 -21.5 n/a 5.8 n/a crab unidentified River 1 -15.7 n/a 3.3 n/a These modern flesh samples were corrected in their carbon values by +1.5? to account for the ?industrial effect? (Tykot 2002; Wright 1994).  The Early Formative (1900-1000 cal. B.C.) Overall there is a wider distribution of ?13C values throughout the Early Formative than in any other time period in the Soconusco (Figure 3). Unfortunately, there are no samples from the initial Early Formative Barra phase but there are two samples from Locona phase deposits at Chilo in the Mazat?n zone (Figure 1). One of the individuals, with a ?13C value of -19.3?, appears to have had a diet combining estuarine and terrestrial foods as well as C3 plants (Figure 4b). This individual also has a ?15N value of 13.0?, one of the highest observed in the entire group. This diet contrasts with the other Chilo individual which has a significantly higher ?13C value (-13.3?) and lower ?15N value (7.4?), suggesting a reliance on a mixture of estuarine and terrestrial fauna along with some C4 and/or CAM plants (Figure 4b). Thus, at Chilo there is a clear indication, in the case of one individual, of the consumption of C4 and/or CAM plants during the Locona phase in the Early Formative. Comparison of these two individuals also shows a clear example of dietary differences within the same archaeological site.  There is only one individual representing the succeeding Oc?s phase, and this comes from the site of Paso de la Amada (Figure 1). Its isotope values (?13C -15.9?; ?15N 5.3?) show the consumption of estuarine fauna as well as C3 plants, especially legumes such as beans because this individual has a quite low ?15N value compared with the rest of the Early Formative human samples (Figure 4b).    29  Two Mazat?n zone samples from the following Cherla phase deposits at Aquiles Serd?n and Paso de la Amada have different values from each other. The individual from Aquiles Serd?n has a ?13C value of -17.8? and a ?15N value of 13.1?, reflecting an estuarine and marine fauna diet along with some terrestrial fauna, while the Paso de la Amada individual has a ?13C value of -9.4? and ?15N value of 9.0?, suggesting a mixed diet of marine fauna and C4 and/or CAM plants (Figure 4b).  The two Late to Terminal Jocotal phases samples (Burials 1 and 5) from El Varal in the Mazat?n zone (Figure 1) have ?13C values of -11.4 and -10.4? and ?15N values of 9.1 and 8.3?, indicating the consumption of a mixture of marine, riverine, and some estuarine fauna, but also some C4 and/or CAM plants (Figure 4b). Fish were the most common vertebrate fauna recovered at El Varal (Wake and Steadman 2009:100) and other sources of animal protein included a range of crab and clam species (Dietler and Wake 2009:94-95)12. All of these estuarine, riverine, and marine resources would have been easily accessible and, in most cases, available year round (Lesure et al. 2009:216-217). Similar to the situation at Tlacuachero, the modern estuary and riverine crab flesh ?15N values (Table 6) and clam shell ?15N value (Appendix, Table 4) indicate that these resources were mainly primary consumers so if El Varal occupants were consuming these aquatic/marine food sources as part of their every-day diet, their ?15N values would not be very high?and this is exactly what we see at this site (Figure 4b). Therefore, it is likely that these individuals consumed estuarine, riverine, and marine fish, crabs, and marsh clams.  Macro-botanical remains at El Varal included two Zea mays (maize) cupules and a possible kernel fragment recovered from the flotation samples (Popper and Lesure 2009:113-114). While there were not many maize macro-botanical remains found, this archaeological evidence reveals that El Varal inhabitants did consume maize. While it is not certain if this plant was cultivated at the site or brought from inland areas of the region, based on the El Varal ?13C and ?15N results, it seems that some inhabitants were certainly consuming C4 and/or CAM plants as a supplement by the Terminal Early Formative period.  The Middle Formative (1000-500 cal. B.C.)  There are five samples from this period: three from La Blanca in the R?o Naranjo zone, one from Huanacastal, and one more from Paso de la Amada in the Mazat?n zone (Figure 1). The ?13C   (-13.3 and -13.0?) and ?15N (8.8 and 7.4?) values from two La Blanca individuals are similar to those of one Early Formative individual from Chilo, so it is likely that these individuals                                                    12 For further information about the archaeo-faunal analyses at El Varal refer to Lesure 2009.   30  consumed a mix of estuarine and terrestrial fauna and some C4 and/or CAM plants (Figure 4c). The third La Blanca individual has higher ?13C (-10.8?) and ?15N (9.3?) values, indicating the consumption of some estuarine and marine fauna as well as C4 and/or CAM plants (Figure 4c).  The Huanacastal individual has ?13C (-11.8?) and ?15N (7.8?) values that suggest a reliance mainly on estuarine and terrestrial fauna, few C3 plants, and some C4 and/or CAM plants (Figure 4c). The Paso de la Amada individual (Burial 1) has ?13C (-14.5?) and ?15N (8.3?) values indicative of a mixed diet composed of animal protein and a blend of C3, C4, and/or CAM plants (Figure 4c). Even though this is the period that has been proposed as the time of maize consumption as an every-day staple for the region, this does not seem to be shown clearly in the isotopic signatures from individuals in the R?o Naranjo and Mazat?n zones, except for one individual at La Blanca, but rather that C4 and/or CAM plants were still used in a supplementary manner. The Middle to Late Classic (A.D. 500-900)  One Middle Classic sample from the site of R?o Arriba in the Acapetahua zone (Figure 1) has a very high ?13C value compared with the rest of the sample set. This individual had a diet composed of a combination of animal protein (perhaps marine fauna due to a slightly high ?15N 9.1?), as well as plant protein from C4 and/or CAM plants since its ?13C (-9.5?) is very high (Figure 4d). It is possible to infer, even though this is just one sample, that in some cases people consumed more maize?and perhaps some CAM plants as well?in this zone by this period. During the Late Classic period there is a drop in the ?13C value compared with the Middle Classic (Figure 3). One human from the Acapetahua site of Las Morenas (Figure 1) has a slightly lower ?13C (-11.3?) value than the individual from R?o Arriba and a slightly high ?15N (8.5?) value (Figure 4d). It appears this individual was mainly consuming marine and riverine fauna and less C4 and/or CAM plants than the R?o Arriba individual.  The Late Postclassic (A.D. 1250-1530) Late Postclassic samples seem to have similar ?13C values to the previous Middle and Classic periods as seen on Figure 4. One sample comes from Zapotillo (Cs-8), one from La Victoria (Figure 1), and one from unknown provenience at a disturbed Postclassic site near Mazat?n. The individual from Zapotillo has a high ?13C (-10.3?) value so it is possible its diet relied on marine and riverine food sources as well as some C4 and C3 plant consumption since its ?15N value (7.9?) is average (Figure 4e). The sample from La Victoria has a ?13C value of -8.2?, notably higher than the Middle Classic individual from R?o Arriba (Figures 4d and 4e).   31  This individual would have consumed more C4 and/or CAM plants as well as some C3 plants and animal protein (Figure 4e). The sample from Mazat?n has a lower ?13C (-11.5?) value than the other two, along with a high ?15N (11.0?) value so it probably acquired most of its dietary protein from estuarine, riverine, and marine food sources (Figure 4e). These samples show diversity and regional differences in diets across the Soconusco region in spite of the fact that maize was the primary food staple across much of Mesoamerica by this time. Spatial Dietary Trends The Acapetahua zone samples (n = 5) are somewhat clustered together in their ?13C values (Figure 5). The overall ?13C results are higher when compared with the Mazat?n zone (Figure 5). Based on these stable isotope results, it appears that individuals from this environmental zone subsisted on a variety of estuarine, riverine, and marine resources, and some terrestrial fauna, while a few cases (including samples from the Late Archaic period) showed the consumption of C4 and/or CAM plants as well. The diets in this zone seem to have been mainly mixed and it is not until the Middle Classic period that there is more isotopic evidence of the consumption of larger quantities of C4 and/or CAM plants. Even so, as we would expect for people living in such a rich aquatic environment, there was always significant consumption of protein in the form of estuarine, marine, riverine, and/or terrestrial animals. Maize does not seem to have been the only, or necessarily the most important source of protein, except for the one Middle Classic period individual from R?o Arriba where C4 plants (and possibly CAM plants) were probably consumed more than by other inhabitants of the region. The samples from the Mazat?n zone (n = 11) have the broadest distribution and most diversity in the ?13C values (Figure 5) compared with the other two zones. Based on these results, we can assume that individuals from this environmental zone had the most diverse diets as they subsisted on the local animal and plant foods. The consumption of C4 plants such as maize is not as evident isotopically, even though it is clearly present in the macro-botanical remains from the region. Nevertheless, there are a few individuals in the Early and Middle Formative periods that seem to have included maize, and possibly CAM plants, as a significant supplement to their diets already rich in animal protein.  The R?o Naranjo zone is represented by a smaller number of samples (n = 4), making it difficult to assess with confidence the diets of this zone. Nonetheless, during the Middle Formative period there is evidence of the consumption of estuarine, marine, and terrestrial fauna, and some C4 and/or CAM plants. During the Late Postclassic, it is apparent that individuals in   32  this zone consumed larger quantities of C4 plants (no doubt, maize) and/or CAM plants in their every-day diet based on the isotope results from La Victoria.   Figure 5. Boxplot of human ?13C? values by Soconusco environmental zone. Ancient Soconusco Diets in the Broader Mesoamerican Context Stable isotope analysis has been applied to a number of archaeological cases in Mesoamerica as early as the 1980s for the purposes of reconstructing pre-Columbian diets. In this section I present a brief evaluation of the overall Soconusco dietary patterns compared to other Mesoamerican dietary trends by period based on isotopic data from a number of archaeological sites/regions in Honduras, Belize, Guatemala, and M?xico.  Archaic Patterns  We can compare the Soconusco Chantuto phase diets based on their ?13C values (-11.0 and -9.9?) with the ?13C values from the stable isotope study (Farnsworth et al. 1985) carried out in the Tehuac?n Valley of M?xico, a highland region (Figure 6, Table 7). During the Archaic period the Tehuacanos initially practiced a hunting and gathering economy, but this subsistence   33  shifted towards an economy dependent on tropical grasses such as maize and Setaria or CAM plants (i.e., cacti, maguey) by 4500 B.C. The carbon isotope results (?13C = -6.1?) show that C4 and/or CAM plants, including maize, began to dominate the Tehuac?n diets by the Coxcatl?n phase (4000 B.C.-3000 B.C.)13 (Farnsworth et al. 1985; Tykot 2002). While the Tehuac?n isotope results indicate that maize gained dietary importance in a highland region during the Archaic period, the Chantuto phase ?13C values suggest that Soconusco diets were composed of mixed food resources from marine, estuarine, and riverine habitats, and possibly some maize and CAM plants. Evidently, Soconusco diets would not have been solely based on maize and/or CAM plants during this period since their ?13C values are not as high as those from Tehuac?n. Early Formative Patterns  For this period I plot the ?13C and ?15N sample values (n = 7) from the Mazat?n zone alongside the average values for Cuello, Belize and the Pasi?n region in Guatemala (Figures 6 and 7a, Table 7). At this time, diets at Cuello were mainly composed of terrestrial animal protein (i.e., dog and armadillo) as well as some maize either consumed directly?but accounting for less than ca. 30 percent of the total Cuello diet?or indirectly through the consumption of animals that fed on maize (i.e., dogs), and that accounted for ca. 50-55 percent of the collagen C4 carbon content (van der Merwe et al. 2002:29-30). One Mazat?n individual approximates the Cuello ?13C and ?15N average ranges suggesting a similar diet of terrestrial fauna and C4 and/or CAM plants, wherein maize would have been consumed in a supplementary manner. In the Pasi?n region, the samples from Altar de Sacrificios and Seibal indicate that C4 plants like maize were consumed in significant quantities along with some C3 plants and terrestrial animal meat (Tykot 2002; Wright 1994). Wright (1994) suggests that while maize?and to a lesser extent other C4 (i.e., amaranth) and CAM plants?may have been a significant dietary component for the Pasi?n people, consumption of herbivores and freshwater fish could have also been an important source of protein in their diets. Three Mazat?n zone samples lie within the Pasi?n ?13C and ?15N average ranges shown in Figure 7a so it is very likely that these individuals had similar diets composed of maize and possibly other C4 and CAM plants as well as terrestrial and aquatic fauna. Based on this comparison with the Pasi?n region, it appears that the two Mazat?n zone individuals, both from El Varal, consumed slightly more C4 and/or CAM plants, suggesting that maize may have become an increasingly important food source by the end                                                    13 However, until these Tehuac?n individuals are directly dated using radiocarbon dating their ages remain uncertain.   34  of the Early Formative period. The rest of the Mazat?n zone samples (n = 3) have different diets from those at Cuello and the Pasi?n region. Two Mazat?n individuals show very different diets based on lower ?13C and higher ?15N values, while the third Mazat?n individual probably consumed some estuarine and terrestrial fauna as well as significant quantities of C3 plants (Figure 7a).  Figure 6. Map showing the location of the Mesoamerican archaeological sites mentioned in this study. The map also depicts the highland (brown) vs. lowland (green) regions.    35  Table 7. Human ?13C and ?15N values by period in neighboring Mesoamerican sites/regions. Period Site(s) Location Highland vs. Lowland Environment/Ecology n ?13C (?) S.D. ?15N (?) S.D. References Archaic Tehuac?n  Tehuac?n Valley, M?xico H Xeric shrubland ecoregion; pine-oak and dry forests 1 -6.1 n/a n/a n/a Farnsworth et al. 1985; Tykot 2002   Early Formative Cuello Northern Belize L Tropical ecosystem 28, 23 -12.9 0.9 8.9 1 Tykot et al. 1996 Altar de Sacrificios, Seibal Pasi?n River Valley, Guatemala L Tropical ecosystem; moist subtropical forest; wetland environment (rivers, lagoons) 16 -10.2 1.2 8.8 1.1 Wright 1994  Middle-Late Formative Cahal Pech West-central Belize L Tropical; near river valley; access to reef fish/shellfish species 4, 3 -12.8 1.3 8.2 0.4 Powis et al. 1999 Bezuapan Gulf Coast, M?xico H Sierra de los Tuxtlas; tropical and subtropical moist broadleaf forest 3 -10.5 0.6 9 0.3 VanDerwarker 2006        Middle- Late Classic Altar de Sacrificios, Seibal, Dos Pilas, Aguateca, Itz?n Pasi?n River Valley, Guatemala L Tropical ecosystem; moist subtropical forest; wetland environment (rivers, lagoons)  88, 87  -9.2  1.1  9.1  1.1  Wright 1994 Alt?n Ha Northern Belize L Tropical; diverse ecology; near ocean 23, 19 -12.6 0.8 10.3 0.3 White et al. 2001 Mojo Cay Northeastern Belize L Coastal; tropical; accessible reef resources 7 -8.5 0.4 10.4 0.4 Norr 1991 Yaxun? North-central Yucat?n Peninsula L Low scrub jungle 3 -12.3 0.4 7.1 0.3 Mansell et al. 2006   Chunchucmil Yucat?n Peninsula L Low rainfall and poor soil for agriculture; diverse ecology: savanna and coast nearby 3 -14.7 1.1 7.0 0.5 Mansell et al. 2006   Cop?n Honduras H Closed mountain valley 41, 38 -10.2 0.9 7.6 0.8 Gerry 1993  Postclassic    Lamanai North-western Belize  L Swamp, savanna, and jungle inland; lagoon, river, estuary, coastal reef, and ocean resources  25, 24  -9.3  0.8  9.5  0.9  White and Schwarcz 1989 Iximche Western Guatemala H Pine forests; rivers and deep ravines nearby 13 -7.8 0.4 7.9 0.4 Whittington and Reed 1996   36      0.05.010.015.0-20.0 -15.0 -10.0 -5.0?15N (?, AIR) ?13C (?, VPDB)  Early Formative ?13C and ?15N  Mesoamerican Patterns  Mazat?nCuello Pasi?n A) 0.05.010.015.0-20.0 -15.0 -10.0 -5.0?15N (?, AIR) ?13C (?, VPDB)  Middle-Terminal Formative ?13C and ?15N  Mesoamerican Patterns  Mazat?n R?o NaranjoBezuapan Cahal Pech B)   37      Figure 7. Scatterplots of Mesoamerican and Soconusco human ?13C? and ?15N? values by period. The squares/rectangles represent the ?13C and ?15N approximate average values with standard deviations for each corresponding site/region (refer to Table 7).  0.05.010.015.0-20.0 -15.0 -10.0 -5.0?15N (?, AIR) ?13C (?, VPDB)  Middle-Late Classic ?13C and ?15N  Mesoamerican Patterns  AcapetahuaAlt?n Ha Pasi?n Chunchucmil Cop?n Yaxun? Mojo  Cay C) 0.05.010.015.0-15.0 -10.0 -5.0?15N (?, AIR) ?13C (?, VPDB)  Postclassic ?13C and ?15N  Mesoamerican Patterns Mazat?n R?o Naranjo AcapetahuaIximche Lamanai D)   38  Middle to Terminal Formative Patterns In the Middle Formative period there are samples from the Mazat?n (n = 2) and R?o Naranjo (n = 3) zones plotted alongside the ?13C and ?15N averages for Cahal Pech in west-central Belize and Bezuapan in the Gulf Coast region of M?xico (Figures 6 and 7b, Table 7). The overall dietary trends at Cahal Pech suggest that people had a quite broad subsistence base which may have included a wide variety of food sources including herbivores, reef fish, and possibly freshwater fish. While maize may have been consumed at this site, Powis et al. (1999) indicate that its consumption would not have been significant or dominant in Cahal Pech diets. There are two Mazat?n and two R?o Naranjo samples very close to or within the Cahal Pech ?13C and ?15N average ranges (Figure 7b) and these individuals had a similar mixed diet that included terrestrial and estuarine fauna, as well as C3 and some C4/CAM plants. This is not surprising considering that Cahal Pech, like the Soconusco, lies within a tropical ecosystem with a wide ecological diversity and access to a broad range of food sources (Table 7).  One R?o Naranjo sample has stable isotope values within the ?13C and ?15N average ranges for Bezuapan, a Terminal Formative Olmec site located in the highlands of the Tuxtla Mountains (Figure 6). VanDerwarker (2006) concluded that the Olmecs at this site considered maize an important dietary staple by this time and that the consumption of maize was supplemented by the consumption of herbivores and freshwater aquatic food sources. It is possible that this R?o Naranjo individual may have had a somewhat similar diet based on estuarine and terrestrial fauna as well as some C4/CAM plants (Figure 7b). This R?o Naranjo diet is an indication that maize could have been consumed more frequently and perhaps in more significant quantities by some R?o Naranjo inhabitants by this period. However, maize would not have been a dietary staple like at Bezuapan since the other two R?o Naranjo individuals did not consume maize to the same extent and had different diets based on a variety of resources. Middle to Late Classic Patterns In the Middle to Late Classic periods there are samples (n = 2) from the Acapetahua zone plotted alongside the ?13C and ?15N averages for Alt?n Ha and Mojo Cay in Northern Belize, Cop?n in the Honduran highlands, the Pasi?n region (Altar de Sacrificios, Seibal, Dos Pilas, Aguateca, and Itz?n) in Guatemala, and Yaxun? and Chunchucmil in the Yucat?n Peninsula of M?xico (Figures 6 and 7c, Table 7). Overall the Pasi?n dietary patterns showed that maize consumption increased throughout the span of the Classic period and that there was also substantial consumption of animal protein from terrestrial and aquatic fauna. The Acapetahua individual is lying to the left of the Pasi?n   39  ?13C and ?15N average ranges and within the upper left-side of the Cop?n ?13C and ?15N average ranges (Figure 7c). The Middle to Terminal Classic diets at Cop?n were mainly composed of maize as well as some C3 plants such as beans and limited animal protein from terrestrial habitats (Tykot 2002). Since the Acapetahua individual falls within the more negative side of the Cop?n ?13C and the upper range of ?15N values, it is likely that it consumed less maize than individuals at Cop?n, but possibly consumed terrestrial fauna that fed on maize as well as some estuarine and riverine fauna which contributed to a slightly higher ?15N value.   The Soconusco diets in the Classic period differ from Belize diets at Alt?n Ha and Mojo Cay since the latter were composed of a combination of C4 plants (i.e., maize) and animal protein from marine and reef resources (Tykot 2002; White et al. 2001). It is evident on Figure 7c that people at these Belize sites were less dependent on C4 foods due to their higher ?15N values than people at Cop?n and the Pasi?n and Soconusco regions. The Yucat?n sites also had different diets from those in the Soconusco region. At Yaxun?, maize and other C4 and CAM plants were important and significant to the overall Maya diets (Mansell et al. 2006), but both their ?13C and ?15N values are lower than those in the Soconusco. At Chunchucmil, maize was far less important in the diet when compared to Yaxun? and the Mesoamerican regions plotted on Figure 7c, possibly due to lack of fertile agricultural land near the site, the presence of trading routes to attain other food products, and a varied ecology with other food sources available for the Maya people living at this particular site (Mansell et al. 2006:167). Postclassic Patterns Postclassic samples from the Mazat?n (n = 1), Acapetahua (n = 1), and R?o Naranjo (n = 1) zones are plotted alongside the ?13C and ?15N averages for Lamanai in Northwestern Belize and Iximche in the Guatemala highlands (Figures 6 and 7d, Table 7). Lamanai was strategically located for trade and has a wide variety of terrestrial and aquatic habitats (Table 7) which provided a wide range of food resources to the Maya people at this lowland site, similar to the wide ecological diversity present in the Soconusco region. Maize was identified as a staple at Lamanai but its importance in Maya diets shifted through time. While maize consumption decreased during the Classic period, it seems to have increased during the Postclassic period (White and Schwarcz 1989). The stability and slight enrichment of the ?15N values at Lamanai indicate that the Maya people consumed animal protein such as herbivores as well as marine fauna. The Acapetahua individual is lying close to the Lamanai ?13C and ?15N average ranges but has lower ?13C and ?15N values (Figure 7d), showing less consumption of maize than Lamanai inhabitants, and possibly more consumption   40  of C3 plants as well as some estuarine and riverine fauna rather than marine resources. Iximche Maya diets seem to have been mainly composed of maize, certainly more maize dependence than at Lamanai, but it remains uncertain if the somewhat low ?15N values are due to the consumption of beans and other plant foods or to environmental factors given that there are no local fauna or flora baseline data to assess this (Tykot 2002:10). The R?o Naranjo individual has ?13C and ?15N values that lie within the Iximche ?13C and ?15N average ranges (Figure 7d), suggesting a heavier reliance on maize and possibly the consumption of other C3 plant foods and limited animal protein. The individual from Mazat?n has a distinctly different diet compared to the Lamanai and Iximche examples. This person seems to have relied heavily on estuarine, riverine, and marine food sources, and probably consumed little C3 and C4/CAM plants (Figure 7d). Highlands vs. Lowlands  It is possible that some differences in dietary patterns could be due to differences in local ecology and a few stable isotope studies (i.e., van der Merwe et al. 2002) have observed dietary differences between highland and lowland regions. I have divided the above Mesoamerican sites into highland or lowland regions based on their geographic locations (Figure 6, Table 7) to identify differences in ?13C values between these regions using boxplots on Figure 8. I also plotted alongside three boxplots by Soconusco environmental zone to compare their ?13C values to the highland and lowland ?13C dietary trends. The boxplot results indicate that highland regions had, on average, higher ?13C values than lowland regions and the Soconusco region. The highland regions discussed above had stable isotope results that indicated increased or heavy dependence on maize as a staple food. For instance, Cop?n is situated in a closed mountain valley in the Honduran highlands ?where a concentration of people would rapidly eradicate wildlife and forest in the cause of agriculture? (van der Merwe 2002:34). In contrast, Maya sites in lowland regions (i.e., Alt?n Ha, Lamanai, Cahal Pech) appeared to have more diversified diets based on multiple food resources so people were not as dependent on maize and relied on other food sources from the nearby oceans, lagoons, rivers, estuaries, and so forth. Thus, it is apparent that the dietary patterns in the three Soconusco zones coincide with the overall trends in lowland regions with tropical environments, with the Mazat?n zone having the most diversified diets of all based on the ?13C results (Figure 8).    41   Figure 8. Boxplot of Mesoamerican human ?13C? values by highland and lowland regions and Soconusco environmental zones.    42  CONCLUSIONS  The results of the present study, combined with previous isotopic results from the region, have helped to refine our understanding of changing subsistence practices and diets of individuals from a number of archaeological sites in the Acapetahua, Mazat?n, and R?o Naranjo zones of the Soconusco region. More specifically, this study focused on answering these questions: 1) what were the dietary similarities and differences among the Soconusco sites in the three environmental zones?, 2) do the isotopic signatures show an increased reliance on maize agriculture in the Soconusco, and if so, when?, 3) do the six new samples in this study show different dietary isotope patterns than those previously proposed based on the earlier samples?, and 4) how do the isotope patterns in the Soconusco compare with other published dietary isotope studies in Mesoamerica? In the following sections I provide some answers to these questions and attempt to draw some additional observations, conclusions, and recommendations for future research in this region. Heterogeneous Diets Between and Within Soconusco Sites  Even though the total sample size is relatively small (n = 20), the isotope results show that Soconusco inhabitants had for the most part diverse and mixed diets. The results at Early Formative Chilo illustrate this clearly since different individuals maintained different diets, each of which was diverse. Moreover, during the Middle Formative at La Blanca the individuals? isotopic signatures indicate that people were consuming a combination of marine, estuarine, and terrestrial fauna as well as plant protein, however not all La Blanca individuals consumed exactly the same foods or quantities. One particular individual probably consumed significant quantities of C4 and/or CAM plants, whereas the other two La Blanca individuals did not. It is evident that no homogenous regional diet, and certainly no pan-Mesoamerican diet existed in this region?a conclusion similar to one drawn by White et al. (2006:154) in their dietary isotopic analysis of multiple Classic Maya archaeological sites. Thus, this isotopic study has been able to demonstrate the heterogeneity of ancient human diets in the Soconusco region which in itself illustrates, through a dietary lens, the complexity of ancient people?s lifeways spanning almost 5000 years from the Late Archaic through to the Late Postclassic periods.  Dietary Diversity between Environmental Zones  Diets in the three Soconusco environmental zones were quite diverse and composed of both animal and wild as well as cultivated plant food sources from the local estuarine, riverine, marine, and terrestrial habitats. Also, based on observed ?15N ratios, diets in all three environmental zones   43  contained significant amounts of animal protein. However, there are some observable dietary differences between environmental zones. For instance, the Mazat?n zone had the most diverse ?13C ratios indicative of very wide-ranging diets compared with the other two zones. While it is not within the scope of this thesis to identify all the possible reasons why the Mazat?n zone had such diversified and wide-ranging dietary patterns compared to the other zones, I hypothesize that these dietary differences between zones may reflect differences in subsistence economies, and possibly were even linked to certain sociopolitical processes and activities at the archaeological sites between Soconusco zones. This last point requires further exploration based on comparative studies, both spatial and temporal, between the three environmental zones. While all the Soconusco environmental zones show isotopic evidence of the consumption of C4 and/or CAM plants, it is observable at different points in the chronological sequence at each zone. For example, at Acapetahua there is evidence of the supplementary consumption of C4 and/or CAM plants both in the Late Archaic period and the Middle and Late Classic periods. In the R?o Naranjo zone there is an indication that one individual in the Middle Formative was consuming significant quantities of C4 and/or CAM plants, and by the Late Postclassic, maize was likely being consumed as an every-day staple food. At Mazat?n, C4 and/or CAM plant consumption is not as apparent isotopically due to the wide diversity in the diets, yet there is evidence of the consumption of C4 and/or CAM plants by a few individuals during the Early (i.e., Chilo, Paso de la Amada, El Varal) and Middle (i.e., Huanacastal) Formative periods indicating that maize, and possibly other C4 and CAM plants, could have been an important supplement at least for some ancient Mazatecos.  Maize: A Supplementary Role in Soconusco Diets  While it would be fascinating to have observed, isotopically, a clear transition towards the consumption of maize as an every-day staple within the temporal sequence, it is even more intriguing that there is an absence of a clear change in subsistence in the Soconusco based on the human samples analyzed in this study. People?s subsistence in the Soconusco focused on the procurement of wild and cultivated plants as well as animals through hunting and fishing in the nearby estuarine, riverine, and marine habitats. While there is some evidence of the consumption of maize as early as the Late Archaic and up to the Late Postclassic periods, its consumption appears to have been supplementary in nature throughout most of the chronological sequence. There are a few cases at La Blanca, R?o Arriba, and La Victoria in which maize was likely consumed in larger quantities between the Middle Formative and the Late Postclassic periods. However, the overall dietary trends suggest that Soconusco occupants had so many food sources available to them that even when maize was   44  cultivated and available for its daily consumption, people continued to practice other subsistence practices in addition to maize agriculture and to consume a wide range of wild and cultivated plants as well as estuarine, marine, riverine, and terrestrial resources as part of their every-day diets.  These results resonate with other subsistence and dietary studies that have re-evaluated the importance of maize as a staple food and shown that it may not have been the most important food source in some Mesoamerican diets (Arnold 2009; Powis et al. 1999; VanDerwarker and Kruger 2012; White and Schwarcz 1989). For instance, building on their own archaeobotanical results, the social competition and aggrandizement theory put forth by Clark and Blake (1994), and the ideas regarding the initial uses of maize for its sweet juices and fermenting properties by Smalley and Blake (2003), VanDerwarker and Kruger (2012) propose that maize production and consumption at Early and Middle Formative Olmec sites along the southern Gulf Coast may have been associated with centers of sociopolitical power. In such places, maize?perhaps in the form of drinks like atole and/or maize beer?was used as a supplementary food source at rituals and feasting events. It is possible that maize gained sacred and/or symbolic properties linked to sociopolitical and religious activities in Mesoamerica such as in the Gulf Coast and the Soconusco, long before it became the dominant staple crop that we think of in later periods. While maize may not have been the dominant source of nutrition in the diets of some pre-Columbian inhabitants, as seen in the stable isotope results of Soconusco occupants, it may have been an important cultigen prepared at rituals and feasts acting as a supplement to their overall diets. Moreover, the recent discovery of sophisticated and intensive cultivation of manioc in elevated planting beds at the Maya site of El Cer?n in El Salvador (Figure 6) during the Classic period (Sheets et al. 2011 and 2012) provides a new archaeological example of the importance of other plant foods as staples such as manioc in Mesoamerican diets.  Reassessing Previous Soconusco Dietary Isotopic Patterns  As a product of this isotopic study we can now reassess the dietary patterns from previous isotopic studies by Blake et al. (1992a, 1992b) and Chisholm and Blake (2006). Blake et al. (1992a) proposed that the Late Archaic individuals in Acapetahua had been most likely consuming C4 plants, however the present study resonates with the newest hypothesis by Chisholm and Blake (2006) suggesting that individuals at Tlacuachero seem to have mainly consumed estuarine, marine, and riverine resources, some of which may have ?13C and ?15N signatures similar to those of C4 plants. I would further add that these Chantuto phase diets may have been complemented by slight quantities of C4 plants (i.e., maize), but emphasizing that their diets were probably not solely based on C4 and/or CAM plant consumption. Just as previous hypotheses made about the Mazat?n zone by Blake   45  et al. (1992a), the results from this study show that the Mazatecos had really mixed and diversified diets based on the variety of locally available estuarine, riverine, marine, and terrestrial resources in the zone and that maize (and possibly CAM plants) was not a significant food product since it was only present in some cases as a supplement to their estuarine, riverine, and terrestrial dietary staples, especially towards the Terminal Early Formative period (i.e., El Varal).  Blake et al. (1992a) hypothesized that during the Middle to Late Formative periods the coastal people of the Acapetahua and R?o Naranjo zones began to consume maize in larger quantities, while the Mazat?n zone continued to subsist on estuarine resources. Based on the results presented here, it seems that the inhabitants of the R?o Naranjo zone began to consume slightly more C4 and/or CAM plants in the Middle Formative and the Late Postclassic, while Acapetahua individuals consumed more C4 and/or CAM plants during the Middle and Late Classic periods. While there are no human samples representing the Late Formative and the Early Classic periods, we can still observe that during the Middle Formative (i.e., La Blanca) people in these zones continued to consume other food sources besides C4 plants, as did people in the Mazat?n zone. There is no evident rapid shift (isotopically) of an increased dependence on C4 plants in these zones as suggested by Blake et al. (1992b:145). It seems more likely, that people in all three of the Soconusco zones still considered estuarine, riverine, and marine food sources important in their every-day diet and continued to consume them up to the Late Postclassic period (i.e., Zapotillo). However, it is apparent that the differences in dietary patterns between environmental zones discussed above do reflect some regional differences in production and consumption strategies throughout the temporal sequence.  Soconusco Diets in the Mesoamerican Context  While the isotopic applications across Mesoamerica discussed in this study are by no means exhaustive, these studies have served the purpose of 1) illustrating the dietary trends in some Mesoamerican communities across time, and 2) comparing these with the Soconusco isotope results to situate Soconusco diets within the broader Mesoamerican context. Needless to say, it is evident that there were a wide variety of diets across Mesoamerican communities as well as across time. For instance, the Tehuacanos seem to have adopted maize and/or other C4 and CAM plants as dietary staples as early as 4,000 B.C., while during the Late Archaic period people in the Acapetahua zone were relying on a mixture of estuarine, riverine, and marine resources as well as some C4 and/or CAM plants. During the Early Formative, a few Mazat?n individuals had comparable diets to Cuello and the Pasi?n region based on a mix of terrestrial and aquatic fauna with C4 and/or CAM plants consumed as a supplement, while the rest of the Mazat?n individuals showed distinctly different diets   46  from those seen at Cuello and Pasi?n?diets that included the significant consumption of estuarine fauna and C3 plants. In the Middle Formative, there is an indication that some inhabitants in the R?o Naranjo zone may have consumed C4 and/or CAM plants in more significant quantities as in the Olmec site of Bezuapan. Meanwhile, people at both the Mazat?n and R?o Naranjo zones continued to rely on a mixture of resources that included terrestrial and estuarine fauna as well as some C3, C4 and/or CAM plants like at the Maya site of Cahal Pech.  It is during the Middle to Terminal Classic periods that we observe that most of the diets at Cop?n, Pasi?n, Yaxun?, and the Acapetahua zone have higher ?13C values and people seem to be consuming more C4 plants (and possibly some CAM plants), particularly at Cop?n. However, at other communities in the Maya regions of Belize (Lamanai, Alt?n Ha) and Yucat?n (Chunchucmil), many people did not consume maize as the dominant staple food. In the Late Postclassic, people in the Mazat?n and Acapetahua zones continued to rely on estuarine and riverine fauna as well as C3 and some C4 and CAM plants as a supplement, unlike the observed diets at Lamanai where people ate more C4 and/or CAM plants by this time. At R?o Naranjo there was an increased reliance on C4 and CAM plants comparable with the patterns at Iximche where maize appears to have been a staple food consumed in the every-day diet complemented with some C3 plants and limited animal protein. The diets in the Soconusco region were quite diverse, wide-ranging, and were not protein deficient, contrary to some of the studies reported in the adjacent Maya region (White et al. 2001). The Mazat?n zone stands out when compared with other Soconusco zones and Mesoamerican dietary patterns because people had overall very diversified diets. While the quantification of every food source in the diet, including maize, is more difficult without additional data and other lines of evidence, it is possible that other food products like marine, estuarine, and riverine resources were more important in the every-day diets of Soconusco inhabitants across time, particularly at Mazat?n. This is similar to the results from Cahal Pech suggesting that many Maya people living in favorable environments had mixed diets that took advantage of the extensive variety and plentiful supply of diverse food resources available. This appears to have been a common pattern indicative of the wide diversity seen in tropical environments across Mesoamerica (Powis et al. 1999); a pattern that, based on the stable isotope results in this study, also includes the Soconusco region.  Observations and Recommendations for Future Research The Potential of Sulphur Isotope Analysis While the preservation of this human collection has been demonstrated to be poor, there were a few samples that still produced acceptable stable carbon and nitrogen isotope results within the   47  recommended standards. With this in mind, if enough collagen (5-10 mg per sample) from some of these human samples becomes available, a study of human bone collagen through sulphur isotope analysis could be a potential avenue for further research. Sulphur isotopic values in bone collagen of humans and fauna can be obtained as with other isotopes and they can function as a baseline to determine the sulphur isotope signatures of the local food web (Richards et al. 2003). Since the sulphur isotopic difference (fractionation) between the food source and the consumer has been reported to be reasonably small (-0.5? to -1?) (McCutchan et al. 2003), the ?34S values have been successful at identifying the sulphur dietary sources of species, including humans (Privat et al. 2007:1197; Richards et al. 2003).  Sulphur isotope analysis has been used in archaeological contexts to differentiate dietary protein consumption between terrestrial versus aquatic sources (Nehlich and Richards 2009; Nehlich et al. 2010; Privat et al. 2007). Since more work needs to be done in this region to find ways to differentiate between terrestrial and aquatic food sources, there is potential to use sulphur isotopes to discriminate what Soconusco occupants were consuming between multiple rich environments (some of which are affected by different degrees of salinity), and assess the degree of importance of aquatic resources in these pre-Columbian diets. Sulphur isotope analysis has also been successful in identifying non-locals from locals in archaeological contexts (Privat et al. 2007). It is possible that some Soconusco individuals who had very distinct diets from others could have been non-locals so sulphur isotopic analysis would provide an avenue to test this possibility.  More Robust Local Baseline Data and Micro-Botanical Studies  It is important to continue to expand the local baseline database with more stable carbon, nitrogen, and potentially sulphur and hydrogen isotope values that include more locally available species from the different families and habitats to continue to compare with the human isotope data now available. Cadwallader et al. (2012) have recently argued that too much attention has been paid to stable carbon isotope signals for C4 plants equating to strictly maize consumption and that other food sources including other C4 and CAM plants need to be taken into consideration in dietary studies. This baseline database needs to include more isotope values of locally available C4 and CAM plants such as species of amaranths, cacti, and succulents (i.e., agave) that may have been available for consumption in this region in pre-Columbian times. Furthermore, hydrogen isotope analysis may help distinguish CAM plant from C4 plant consumption (Ehleringer 1991; Kelly 2000; Lajtha and Marshall 1994; Sternberg 1989), so having hydrogen isotope values for plants besides carbon and nitrogen ones could potentially provide a more nuanced assessment about the importance of these   48  two types of plants in pre-Columbian Soconusco diets. Moreover, further research on the ?13C, ?15N, and ?34S composition of shellfish meat and shell of riverine and marine species also needs to be carried out to better understand the overall isotopic signatures of these Soconusco food sources (already identified in the archaeo-faunal analyses).  To know more about what other C4 and CAM plant species may have been consumed by Soconusco inhabitants besides maize, it will be important to conduct further micro-botanical studies (i.e., phytoliths, starch) in Early Formative ceramic vessels since not many plant remains nor a range of plant species have been successfully recovered from previous excavations at archaeological sites in the Soconusco. Micro-botanical studies (i.e., Zarrillo et al. 2008) as well as chemical analyses of residues recovered from ceramic vessels (i.e., Powis et al. 2008) could be promising and an additional avenue of research to understand more about other C4 and CAM plants that could have been consumed, even if they were consumed in lesser quantities than other local food sources by ancient Soconusco inhabitants. Exploring the Potential Effects of Adhesives and Consolidants on Bone  Many kinds of adhesives and consolidants have been commonly used in the preservation of archaeological human bone after its recovery during excavation. It remains uncertain how the use of these adhesives like Duco Cement may affect archaeological bone and if there could be any differences in the stable isotope results. While the effects of commonly used adhesives and consolidants are slowly re-emerging as a topic of investigation in archaeology (i.e., France et al. 2011), this topic is certainly worth exploring further by conducting experiments in the laboratory to compare the stable isotope results from bone free of adhesives and consolidants with those of bone with different types of commonly used consolidants such as Duco Cement. It may be the case that there is actually no effect on the isotope results from bone preserved with adhesives or consolidants due to the more up-to-date sample preparation procedure with ultra-filtration as it was done for this study; nevertheless, it must be explored first in order to be able to confirm this hypothesis.    49  REFERENCES CITED  Ardern, W. R. 2003 Early Formative Mortuary Practices and Social Organization in Mazatan, Chiapas, Mexico. Unpublished MA Thesis. Department of Anthropology, Brigham Young University, Provo. Arnold, P. J. III  2009 Settlement and Subsistence among the Early Formative Gulf Olmec. Journal of Anthropological Archaeology 28:397-411. Benz, B. F.  2001 Archaeological Evidence of Teosinte Domestication from Guil? Naquitz, Oaxaca. Proceedings of the National Academy of Sciences 98(4):2104-2106. Blake, M., B. Chisholm, J. E. Clark, B. Voorhies and M. W. Love  1992a Prehistoric Subsistence in the Soconusco Region. Current Anthropology 33(1):83-94. 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Unpublished PhD Dissertation. Department of Anthropology, University of Chicago, Chicago. Zarrillo, S., D. M. Pearsall, S. J. Raymond, M. A. Tisdale and D. J. Quon 2008 Directly Dated Starch Residues Document Early Formative Maize (Zea Mays L.) in Tropical Ecuador. Proceedings of the National Academy of Sciences 105(13):5006-5011.       56  APPENDIX  Table 1. Supplementary information on Soconusco human burials. Burial Number Environmental Zone Archaeological Site Sex Age Description References 3 Acapetahua Las Morenas Male Adult Recovered from a disturbed context; the body had been originally placed in a seated, flexed position, an obsidian labret and copper bell were found near the individual. Voorhies and Gasco 2004 N/A Acapetahua Zapotillo (Cs-8) N/A N/A Human burials at this site were recovered in fragmentary and disturbed conditions. Voorhies 1976 1 Mazat?n Chilo unidentified unidentified Had its feet missing. Clark 1994 2 Mazat?n Chilo unidentified unidentified Had evidence of rodent gnawing, indicating the fill had not consolidated at the time of burial. Clark 1994 1 Mazat?n Huanacastal Male Adult Found at the bottom of the excavated pit, its skull was compared to a contemporaneous Olmec burial since it had a similar frontal occipital flattening. Clark et al. 1987:24 1 Mazat?n El Varal unidentifiable Adult Found with its head oriented towards the northwest and was located 110 cm below ground surface. Lesure 2009:37 5 Mazat?n El Varal unidentifiable Juvenile Found approximately 140 to 150 cm below the surface whose body had been disturbed by a bulldozer resulting in only partial recovery (lower vertebrae, pelvis, and proximal portions of both femora). Lesure 2009:37       57   Table 2. Total human samples processed for carbon and nitrogen isotope analyses in this study in the Laboratory of Archaeology at the University of British Columbia. Lab No. Zone Site Burial No. Provenience Period Phase ?13C (?) ?15N (?) C:N S-UBC 366/416 Mazat?n El Varal 5 N10 E4, East side Early Formative Cuadros-Jocotal -10.4 8.3 3.4 S-UBC 380 Mazat?n  El Varal 1 N45E4 Early Formative Cuadros-Jocotal -11.4 9.1 3.5 S-UBC 382 Soconusco Unknown n/a Surface Late Post-Classic Late Post-Classic -11.5 11.0 3.3 S-UBC 412 Acapetahua Zapotillo (Cs-8) 3 N3E3 Late Post-Classic Late Post-Classic -10.3 7.9 3.5 S-UBC 414 Mazat?n Huanacastal 1 Pit 1, bottom Middle Formative Conchas -11.8 7.8 3.6 S-UBC 415 Acapetahua Tlacuachero 1 N0E2 Late Archaic Chantuto B -11.0 8.2 3.5 S-UBC 321 Mazat?n Paso de la Amada 1 Trench 1, Pit S  Early Formative Cherla n/a n/a n/a S-UBC 322 Mazat?n Paso de la Amada 1 Trench 2, Pit T Early Formative Cherla n/a n/a n/a S-UBC 323 Mazat?n Paso de la Amada 1 Trench 1, Pit C Early Formative Oc?s n/a n/a n/a S-UBC 324 Mazat?n Paso de la Amada 1 Trench 1, Pit B Early Formative Cherla n/a n/a n/a S-UBC 325 Mazat?n Paso de la Amada 1 Trench 1, Pit A Early Formative Oc?s n/a n/a n/a S-UBC 327 Mazat?n Paso de la Amada Paso burial 5 Pit 32D, Burial 1, Unit 5  (3rd Level 40-50cm)    n/a n/a n/a S-UBC 328 Acapetahua Tlacuachero 19 Unit S3E0, Below floor, Cat. 403 Archaic Chantuto B n/a n/a n/a S-UBC 583 Acapetahua Tlacuachero 19 Unit S3E0, Below floor, Cat. 403 Archaic Chantuto B n/a n/a n/a S-UBC 417 Mazat?n El Vivero 1 Pit 1, Level 5 Early Formative Locona n/a n/a n/a S-UBC 329 Mazat?n Paso de la Amada 12 Mound 12, Unit 12   n/a n/a n/a             58  Lab No. Zone Site Burial No. Provenience Period Phase ?13C (?) ?15N (?) C:N S-UBC 330 Mazat?n Paso de la Amada 2 Mound 6, Level 7 (N48-E46) Middle Formative Conchas n/a n/a n/a S-UBC 584 Mazat?n Paso de la Amada 2 Mound 6, Level 7 (N48-E46) Middle Formative Conchas n/a n/a n/a S-UBC 331 Mazat?n Paso de la Amada 1 Trench 1, Pit X Early Formative Locona n/a n/a n/a S-UBC 332 Mazat?n Paso de la Amada n/a Mound 7, Pit E101/N124, Level 6  (100-120cm)     n/a n/a n/a S-UBC 333 Mazat?n Paso de la Amada 2 Trench 1, Pit B Early Formative Cherla n/a n/a n/a S-UBC 334 Mazat?n Paso de la Amada 1 Mound 6, Level 7 (N48-E46) Middle Formative Conchas n/a n/a n/a S-UBC 585 Mazat?n Paso de la Amada 1 Mound 6, Level 7 (N48-E46) Middle Formative Conchas n/a n/a n/a S-UBC 335 Mazat?n Paso de la Amada 11 Mound 12, Individual B   n/a n/a n/a S-UBC 336 Mazat?n Paso de la Amada 1 Trench 1, Pit D Early Formative Oc?s n/a n/a n/a S-UBC 326 Mazat?n Paso de la Amada 2 Trench 1, Pit C Early Formative Oc?s n/a n/a n/a S-UBC 337 Mazat?n Paso de la Amada 3 Pit 32E, Unit 7   n/a n/a n/a S-UBC 338 Mazat?n Paso de la Amada 11 Mound 12, Individual A   n/a n/a n/a S-UBC 339 Mazat?n Paso de la Amada Paso burial 6 Pit 32E, Burial 2   n/a n/a n/a S-UBC 340 Mazat?n Paso de la Amada 1 Mound 1, Pit 4, Level 7   n/a n/a n/a S-UBC 441 Mazat?n Paso de la Amada 3 Mound 6, Level 11-12 20N/7E  (below floor 4)     n/a n/a n/a S-UBC 343 Mazat?n Paso de la Amada n/a Mound 5, Pit 18, Level 9 Early Formative Barra n/a n/a n/a S-UBC 586 Mazat?n Paso de la Amada n/a Mound 5, Pit 18, Level 9 Early Formative Barra n/a n/a n/a S-UBC 362 Mazat?n Paso de la Amada 1 Trench 1, Pit G Early Formative Locona n/a n/a n/a             59  Lab No. Zone Site Burial No. Provenience Period Phase ?13C (?) ?15N (?) C:N S-UBC 363 Mazat?n Paso de la Amada Paso burial 8 Mound 1, Burial 1   n/a n/a n/a S-UBC 364 Mazat?n Paso de la Amada 9 Mound 12   n/a n/a n/a S-UBC 365 Mazat?n Paso de la Amada (Colonia Buenos Aires) aguas potables survey,  MZ-13 (site number), burial Late Classic Metapa/Peistal n/a n/a n/a S-UBC 587 Mazat?n Paso de la Amada (Colonia Buenos Aires) aguas potables survey,  MZ-13 (site number), burial Late Classic Metapa/Peistal n/a n/a n/a S-UBC 367A Naranjo La Victoria  Pit Late Post-Classic  n/a n/a n/a S-UBC 367B Naranjo La Victoria  Pit Late Post-Classic  n/a n/a n/a S-UBC 588 Naranjo La Victoria  Pit Late Post-Classic  n/a n/a n/a S-UBC 368 Acapetahua Cerro de las Conchas 1 Pit 1 (shell midden) Archaic Chantuto A n/a n/a n/a S-UBC 369 Mazat?n Altamira 2 Mound 6, Test Pit A, Level 16 (160-170cm) Late Formative  n/a n/a n/a S-UBC 589 Mazat?n Altamira 2 Mound 6, Test Pit A, Level 16 (160-170cm) Late Formative  n/a n/a n/a S-UBC 370 Mazat?n Altamira 3 Mnd 6, Test Pit A, Level 17 (170-180cm) Late Formative  n/a n/a n/a S-UBC 371 Mazat?n Chilo 3 Pit 2, Level 7 Early Formative Locona n/a n/a n/a S-UBC 593 Mazat?n Chilo 3 Pit 2, Level 7 Early Formative Locona n/a n/a n/a S-UBC 377 Mazat?n Chilo 2 Pit 2A, Level 2 Early Formative Locona n/a n/a n/a S-UBC 590 Mazat?n Chilo 2 Pit 2A, Level 2 Early Formative Locona n/a n/a n/a S-UBC 378 Mazat?n Chilo 1 Pit 1, Level 7 Early Formative Locona n/a n/a n/a S-UBC 591 Mazat?n Chilo 1 Pit 1, Level 7 Early Formative Locona n/a n/a n/a S-UBC 379 Mazat?n  El Varal 2 Profile W4/N80-85 Early Formative Cuadros-Jocotal n/a n/a n/a             60  Lab No. Zone Site Burial No. Provenience Period Phase ?13C (?) ?15N (?) C:N S-UBC 380B Mazat?n El Varal 1 N45/E4 Early Formative Cuadros-Jocotal n/a n/a n/a S-UBC 381 Mazat?n El Varal 3 N95 WO  Early Formative Cuadros-Jocotal n/a n/a n/a S-UBC 383 Mazat?n Aquiles Serd?n S.P. Trench 1K, Level 13 Early Formative Cherla n/a n/a n/a S-UBC 592 Mazat?n Aquiles Serd?n S.P. Trench 1K, Level 13 Early Formative Cherla n/a n/a n/a S-UBC 384 Mazat?n Aquiles Serd?n n/a Pit 3, Level 3 Early Formative Oc?s n/a n/a n/a S-UBC 385 Mazat?n Paso de la Amada (Buenos Aires-Gomez) 2 Pit 5, Level 4 Early Formative Cherla n/a n/a n/a S-UBC 413 Mazat?n Aquiles Serd?n 16 Pit 1B/13 El P2/B/6   n/a n/a n/a S-UBC 415B Acapetahua Tlacuachero 1 N0E2 Archaic Chantuto B n/a n/a n/a n/a = Samples processed that did not yield sufficient collagen for combustion or that yielded inacceptable isotopic results.                   61  Table 3. Modern and archaeological plant ?13C? and ?15N? values by scientific name and location. Location Common Name Scientific Name Pathway Arch/ Modern N ?13C (?) SD ?15N (?) SD OAXACA VALLEY, M?XICO (Warinner et al. 2013) Amaranth Amaranthus spp. C4 M 3 -10.9 0.7 3.9 2.7 Pitaya Hylocereus undatus CAM M 1 -12.4 n/a 2.6 n/a Pulque Agave spp. CAM M 1 -10.7 n/a 4.2 n/a    LOWER CENTRAL AMERICA (PANAM?/COSTA RICA) (Norr 1991)   Maize Zea mays C4 M 4 -8.3 0.2 1.6 0.2 Pineapple Ananas comosus CAM M 1 -11.7 n/a n/a n/a Peach Palm Bactrisgasipaes C3 M 1 -25.6 n/a 2.4 n/a Manioc Manihot esculenta C3 M 1 -24.6 n/a n/a n/a Yam Dioscorea sp. C3 M 1 -27.1 n/a 1.9 n/a Bean Phaseolus vulgaris C3/Legume M 2 -27.0 n/a 0.5 n/a Nance Byrsonima crassifolia C3 M 1 -26.8 n/a n/a n/a  Nopal cactus Opuntia sp. CAM M 1 -8.5 n/a n/a n/a  Chili pepper Capsicum sp. C3 M 1 -28.6 n/a n/a n/a    PASI?N, GUATEMALA (Wright 1994)    Ramon Brosimum alicastrum C3 M 2 -25.9 n/a n/a n/a Beans Phaseolus vulgaris C3/Legume M 2, 1 -26.0 n/a 3.9 n/a Chapay nut Astrocaryum mexicanum C3 M 2 -30.0 n/a n/a n/a Corozo nut Orbignya cohune C3 M 2 -27.5 n/a n/a n/a Zapote fruit Pouteria mamosa C3 M 2 -26.1 n/a n/a n/a Zapote seed Pouteria mamosa C3 M 2, 1 -27.4 n/a 0.6 n/a Achiote seeds Bixa orellana C3 M 1 -28.2 n/a n/a n/a Potato Ipomoea batatas C3 M 1 -24.9 n/a n/a n/a Chili pepper Capsicum sp. C3 M 1 -26.2 n/a n/a n/a Anona fruit Annona sp. C3 M 1 -27.5 n/a n/a n/a Soursop Annona muricata C3 M 1 -26.2 n/a 5.2 n/a Wild papaya Carica sp. C3 M 1 -24.9 n/a 5.5 n/a Cacao Theobroma cacao C3 M 1 -32.6 n/a 3.7 n/a   62  Location Common Name Scientific Name Pathway Arch/ Modern N ?13C (?) SD ?15N (?) SD  Wild tamarind Dialium guianense C3 M 1 -24.6 n/a n/a n/a Maize Zea mays C4 M 2 -9.6 n/a 4.75 n/a  PASI?N, GUATEMALA (cont.)  Yam (macal) Dioscorea alata C3 M 1 -23.5 n/a n/a n/a Epiphyte lingua de vaca C3 M 1 -25.3 n/a n/a n/a Guava Psidium guajava C3 M 1 -25.8 n/a n/a n/a Sunzapote Licania platypus C3 M 1 -27.8 n/a n/a n/a Juco palm leaf unidentifed C3 M 1 -25.2 n/a 4.0 n/a Pepitoria squash Curcubita sp. C3 M 2 -25.7 n/a 8.2 n/a Nance Byrsonima crassifolia C3 M 1 -25.6 n/a n/a n/a Pi?uela Bromelia karatas CAM M 1 -15.2 n/a n/a n/a Water lily unidentifed C3 M 1 -23.0 n/a n/a n/a  Avocado Persia americana C3 A 2 -23.5 n/a 2.3 n/a Bean Phaseolus vulgaris C3/Legume A 2 -23.5 n/a 2.9 n/a  Cacao Theobroma cacao C3 M 3, 2 -28.1 2.7 4.2 n/a  Squash Cucurbita sp. C3 M 1 -23.8 n/a 6.7 n/a SOCONUSCO, M?XICO (Chisholm and Blake 2006) Sweet potato Ipomoea batatas C3 M 3 -25.0 0.9 n/a n/a Legume bean pod Inga preussi C3/Legume M 1 -21.1 n/a 8.4 n/a Sapodilla plum Achras sapota C3 M 3, 1 -22.8 0.4 6.9 n/a  Chili pepper Capsicum annuum C3 M 2 -26.2 n/a 7.2 n/a  Macaw palm (nut) Orbignya cohune C3 M 1 -23.1 n/a 4.6 n/a  Coyol palm (nut) Acrocomia aculeata C3 M 1, 2 -25.8 n/a 6.9 n/a  Manioc Manihot esculenta C3 M 1 -25.3 n/a n/a n/a  Maize Zea mays C4 A 2 -8.8 n/a 2.3 n/a   Nopal cactus Opuntia sp. CAM M 1 -10.4 n/a 7.1 n/a M= All modern samples were corrected in their carbon values by +1.5? to account for the ?industrial effect? (Tykot 2002; Wright 1994)     63  Table 4. Modern and archaeological faunal bone collagen ?13C? and ?15N? values by location, scientific name, and habitat. Location Common name Scientific Name Habitat Arch/ Modern N ?13C(?) S.D. ?15N(?) S.D.   GULF COAST, M?XICO (VanDerwarker 2006)   Domestic dog Canis familiaris Terrestrial A 1 -9.5 n/a 3.2 n/a Domestic dog Canis familiaris Terrestrial A 2 -12.1 n/a 6.3 n/a White-tailed deer Odocoileus virginianus Terrestrial A 1 -10.5 n/a 7.0 n/a White-tailed deer Odocoileus virginianus Terrestrial A 5 -20.0 1.1 3.3 0.8                      PET?N/PASI?N, GUATEMALA (Wright 1994)                      White-tailed deer Odocoileus virginianus Terrestrial A 3 -20.3 1.9 5.4 1.3 Brocket deer Mazama americana Terrestrial A 1 -21.5 n/a 3.1 n/a Brocket deer Mazama americana Terrestrial A 1 -14.0 n/a 5.0 n/a Peccary T cf. pecari Terrestrial A 1 -21.4 n/a 3.3 n/a Large cat unidentified Terrestrial A 1 -14.8 n/a 9.8 n/a Crocodile Crocodylus moreleti Estuary/Freshwater A 1 -22.1 n/a 11.0 n/a Turtle unidentified Estuary/Freshwater A 2 -24.4 n/a 6.9 n/a Ocelot Felis cf. pardalis Terrestrial M 1 -18.1 n/a 11.6 n/a Wild turkey Meleagris gallopavo Terrestrial M 1 -8.4 n/a 8.3 n/a Red-eared slider (turtle) Chrysemys cf. scripta Estuary/Freshwater M 1 -25.1 n/a 7.3 n/a Rat snake Colubridae (various) Terrestrial M 1 -23.3 n/a 9.8 n/a Coral snake Micrurus Estuary/Freshwater M 1 -21.6 n/a 12.7 n/a Jumping viper Porthidium nummifer Terrestrial M 1 -22.8 n/a 17.8 n/a Terciopelo/fer-de-lance viper Bothrops asper Terrestrial M 1 -20.9 n/a 10.0 n/a Colorada fish unidentified Estuary/Freshwater M 2 -26.5 n/a 9.6 n/a Guapote fish Parachromis managuensis Estuary/Freshwater M 2 -28.8 n/a 10.4 n/a Red bay snook Petenia splendida/bass River M 2 -28 n/a 12.1 n/a Catfish Ictalurus River M 1 -20.8 n/a 11.6 n/a   64  Location Common name Scientific Name Habitat Arch/ Modern N ?13C(?) S.D. ?15N(?) S.D.         BELIZE  (van der Merwe et al. 2002; White and Schwarcz 1989, 1993)      Brocket deer Mazama americana Terrestrial A 4 -21.5 0.7 4.6 0.3 White-tailed deer Odocoileus virginianus Terrestrial A 3, 2 -21.6 2.1 6 n/a White-tailed deer Odocoileus virginianus Terrestrial A 5, 6 -20.5 0.9 5.8 1.3 White-tailed deer Odocoileus virginianus Terrestrial A 2 -15.5 n/a 10.1 n/a Domestic dog Canis familiaris Terrestrial A 1 -8.2 n/a 7.3 n/a Domestic dog Canis familiaris Terrestrial A 12 -15.6 3.9 7.5 2.0 Collared peccary Tayassu tayacu Terrestrial A 1 -13.6 n/a 7.8 n/a Peccary Tayassuidae sp. Terrestrial A 6 -20.8 0.7 5.7 0.7 Turtle unidentified Estuary/Freshwater A 2 -21.8 n/a 4.7 n/a Baird?s tapir Tapirus baindii Terrestrial A 1 -23.3 n/a 4.9 n/a Nine-banded armadillo Dasypus novemcinctus Terrestrial A 6, 4 -16.4 2.8 8.2 0.3 Mud turtle Kinosternon sp. Estuary/Freshwater A 4, 3 -20.4 2.5 6.7 2.0        LOWER CENTRAL AMERICA (PANAM?/COSTA RICA) (Norr 1991)        White-tailed deer Odocoileus virginianus Terrestrial A 9 -20.4 1.1 3.1 0.5 Collared peccary Tayassu tayacu Terrestrial A 1 -22.2 n/a 3.2 n/a Armadillo Dasyprocta punctata Terrestrial A 1 -21.2 n/a 4.0 n/a Iguana Iguanidae Terrestrial A 4 -20.6 1.0 4.9 0.9 Dove Colombidae Terrestrial A 1 -20.8 n/a 2.7 n/a Muscovy Duck Cairina moschata Estuary/Freshwater A 1 -11.6 n/a 5.7 n/a Turtle Chelonidae Estuary/Freshwater A 1 -13.5 n/a 6.6 n/a Mangrove crab Cardisoma spp. Estuary/Freshwater A 1 -21.3 n/a n/a n/a Catfish Selenaspis dowii Marine A 3 -13.8 0.9 10.8 1.3 Fish unidentified Marine A 8 -9.6 0.4 13.0 1.3   65  Location Common name Scientific Name Habitat Arch/ Modern N ?13C(?) S.D. ?15N(?) S.D.       SOCONUSCO, M?XICO (Chisholm and Blake 2006)          clam shell unidentified Estuary A 1 -20.8 n/a -1.8 n/a catfish unidentified Estuary A 1 -18.7 n/a 6.9 n/a mojarra Cichlasoma sp. Estuary A 3 -22.8 0.7 n/a n/a alligator gar Atractosteus spatula Estuary A 9, 3 -20.2 1.9 4.0 1.7 fish unidentified Estuary A 2 -20.2 n/a n/a n/a pocket gopher Orthogeomys cuniculus Terrestrial A 3 -22.7 1.4 n/a n/a armadillo Dasypus novencinctus Terrestrial A 3 -21.6 0.9 n/a n/a cottontail rabbit Sylvilagus sp. Terrestrial A 2 -21.2 n/a n/a n/a collared peccary Tayassu tajacu Terrestrial A 1 -21.9 n/a n/a n/a dog Canis familiaris Terrestrial A 1 -19.6 n/a 3.9 n/a opossum Didelphis marsupialis Terrestrial A 1 -20.8 n/a n/a n/a white-tailed deer Odocoileus virginianus Terrestrial A 1 -20.1 n/a 6.4 n/a crocodile Crocodylus acutus Estuary A 4, 2 -19.8 0.7 6.1 n/a boa snake Boa constrictor Estuary A 3 -20.8 1 n/a n/a pond slider turtle Trachemys sp. Estuary A 2 -20.1 n/a 1.4 n/a mud turtle  Kinosternon sp. Estuary A 4, 1 -20.2 0.6 6.8 n/a iguana Iguana iguana Terrestrial A 2 -22.6 n/a n/a n/a snake unidentified Terrestrial A 1 -21.9 n/a n/a n/a All modern samples are collagen samples and were corrected in their carbon values by +1.5? to account for the ?industrial effect? (Tykot 2002; Wright 1994).    

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