Introduction

As can be seen in the chapters contained in this volume, almost every aspect of Rapanui skeletal morphology has been examined. This chapter deals specifically with the dental morphology of prehistoric Rapanui. Some research has been conducted on the dentition of the Rapanui, though these studies have been limited in their scope. The first dental study done on the 1981 Expedition sample of Rapanui skeletons involved dental pathology only (Owsley et al., 1983, 1985), and not dental morphology. An exhaustive search of the literature has revealed relatively few publications dealing with dental morphology of the Polynesians or specifically the Rapanui, a situation that has not changed significantly since Turner and Scott conducted a literature review in 1977 (Turner and Scott, 1977).

The earliest publications dealing with the dentition and dental morphology of the Polynesians, either directly or indirectly, are those written by Hrdliĉka (1920), Chappel (1927), Wissler (1931), and Riesenfeld (1956). Hrdliĉka (1920), Chappel (1927), and Wissler (1931) discussed the frequency of shovel-shaped, central, and lateral incisors among prehistoric Hawaiian individuals in comparison to a worldwide distribution of the shovel-shaped incisor trait among other populations. In addition to his examination of incisors, Chappel examined cusp numbers for the maxillary and mandibular molars (Chappel, 1927). Riesenfeld (1956) also discusses shovel-shaped incisors among native peoples of the Pacific, but only mentions an enigmatic “Polynesian” sample, without any description of its composition. Suzuki and Sakai (1964) continued the investigation of the frequency of shovel-shaped incisors among Polynesians, however, they utilized a modern, living sample of 12- to 13-year-old Polynesians of the Samoan Islands (living at the time dental casts were obtained in 1959).

More recent investigations and analyses of Polynesian dentition, or the utilization of Polynesians as reference samples, primarily involve the research of Christy G. Turner and colleagues. In 1977, Turner and Scott published the “Dentition of Easter Islanders” (1977). Data from this research, as well as those from Katich and Turner (1975), provided the “Polynesian” reference sample for an analysis of the dental crown morphology of the New Britain West Nakanai Melanesians (Turner and Swindler, 1978). In 2005, Turner utilized Polynesian samples in the analysis of a sample of Rotuma Islanders, in an attempt to identify a Polynesian or Melanesian origin (Turner, 2005).

The origin, migration, evolution, and interaction of Polynesian populations as a whole, as well as focused examination of specific islands or archipelagoes (i.e., Rapanui [Easter Islanders], Marquesas Islands, etc.) have been the center of Pacific investigation for many years. The prehistoric Polynesians are a culturally, linguistically, and biologically distinct group of humans. As one of the most widely dispersed peoples of the earth, the Polynesians have excited extensive theorizing about their origins. For over 200 years, theories have been multitudinous, confusing, contradictory, and ranging from scholarly to charlatanic and even on the lunatic fringe (Bellwood, 1979). No progress was made into the question of Polynesian origins until serious archaeological investigations were conducted, with primary attention focused on the migration route by which the ancestral Polynesians reached the islands of the Pacific.

The development of an ancestral Polynesian society from a Lapita Cultural Complex (Green, 1976; Kirch, 1989), and the subsequent dispersal of Polynesian colonizers throughout the Eastern Pacific had been readily accepted by most authorities. The Lapita Cultural Complex was believed to have originated in mainland Southern China and dispersed to Taiwan circa 4000 BC, with further dispersal to Melanesia via the Philippines and the Indonesian Archipelago occurring circa 3000 BC (Bellwood, 1979; Suggs, 1960; Van Tilburg, 1994). Bellwood (1991) refined this hypothesis concerning Polynesian origins, suggesting that the Polynesians originated in a demic expansion of Austronesian-speaking agriculturists from the South China mainland, approximately 6,000 years ago, and spread successively to Taiwan, the Philippines, Eastern Indonesia, and then Melanesia, reaching Fiji by about 3,500 years ago. From Fiji, they dispersed through Somoa/Tonga into East Polynesia about 2,000 years ago (Burley and Dickinson, 2001). This scenario has also come to be known as the “express train to Polynesia” (Diamond, 1988).

Chromosomal and mitochondrial DNA research has provided much information regarding the origins of the Polynesians. Several nuclear DNA markers (α-globin gene cluster – chromosome 16p13.3; β-globin gene cluster – chromosome 11p15; phenylalinine hydroxylase gene – chromosome 12q22-q24.1; human leukocyte antigen) have been examined and have indicated a close relationship to populations of Southeast Asia (Hertzberg et al., 1991; Hill et al., 1987; Serjeantson, 1985; Serjeantson et al., 1987; Trent et al., 1988). Analysis of these DNA markers has also indicated no or limited relationship to the Melanesians.

Introduction

This general description of the ancient Rapanui, based upon skeletal characteristics, addresses a number of dimensions. Craniometrics are utilized to provide insight into the general appearance of these prehistoric people, such as cranial and facial size and shape. Facial reconstructions on both male and female crania have also been produced, and provide additional details regarding appearance. These “living faces” have also yielded surprising results relating to the continuity of some facial characteristics from ancient times right on up into the modern era, as expressed among the living Rapanui people.

More extensive craniometrics, along with DNA research, have been our best line of inquiry into the origins and relationships of the prehistoric Easter Islanders, but that subject will be the focus of subsequent chapters of this book (especially Stefan, Chapter 5; Hagelberg, Chapter 11), and not the purpose of this descriptive chapter. The only craniometric features to be discussed here beyond the very basic descriptive ones are a few that have real significance in defining population variation, in forensic and other contexts. These are things like the quite useful dimensions relating to shape of the palate and size and shape of the mastoid processes, and also those pertaining to nasal projection. Some select measurements of the mandible have also been included.

Postcranial metrics of the femur and humerus are discussed here because of their importance in defining sexual dimorphism and population differences that are useful in forensic science contexts, and some other areas of inquiry. Calculations of living stature of these prehistoric people have been made from lengths of long bones. Adult femoral and humeral head diameters are also presented. These male and female averages differ from those published in the textbooks of human osteology and forensic anthropology based upon the usual samples of White and Black populations. Such variations among the Polynesians are important differences that not only will be fully described here but also need to eventually be noted in the broader osteological literature. A high degree of femoral platymeria constitutes another important difference documented here between the ancient Rapanui and large well-documented samples of Black and White peoples.

Mystery surrounds Easter Island at a number of levels, and this has made the tiny island and its interesting people, with their surprisingly advanced prehistoric culture, a focal point of interest for the outside world. Especially Western scholars have made great efforts to explore the island since its discovery by Europeans in 1722, with an attempt to answer the many questions raised by its isolated existence in the midst of a vast ocean. Who are these far away people who look similar to Europeans? Where did they come from? How did they get to this tiny island? How could they produce monumental architecture within such a small, remote location? What happened to bring an end to their advanced society? As pointed out in the early chapters of this volume, these “big questions” have riveted the attention of scientists and others for a very long time, as have other questions at a level of greater specificity, such as: How exactly were the statues carved? How were they moved and erected? What exact forces precipitated the social decline?

The contributions within this volume by mostly biological anthropologists and geneticists have helped answer some of these questions (e.g., origins and relationships), contributed important information towards answering others (e.g., settlement theories, injuries and conflict, social decline), and have lent little or nothing to others (e.g., carving and moving of statues). We biologists have little to offer regarding statue production and transport, and will leave the resolution of those mysteries to the engineers and archaeologists!

The major findings presented within the chapters of this volume are briefly summarized here under three primary subject headings: 1. basic skeletal structure and the physical appearance of the ancient Rapanui, 2. genetic composition and relationships, and 3. conflict and injury. Some of our findings also bear upon settlement theory (i.e., potential routes to Easter Island) and will be discussed in a fourth and final section on origins and settlement.

As outlined earlier in the Introduction (Chapter 1), the inspiration for much of the research work presented here grew out of the 1981 Easter Island Anthropological Expedition.