A dental study comparing age estimations of the human remains from the Swedish warship Vasa

The great Swedish warship Vasa capsized and sank in Stockholm harbour on her maiden voyage in 1628. The ship was raised from the seabed in 1961 and skeletal remains were recovered from at least 25 individuals, with teeth and jaws from 17 of them. The skeletal material was odontologically examined, including dental radiographs. Teeth lost both ante‐mortem and post‐mortem were recorded and variations in tooth anatomy noted. Acquired changes were recorded including enamel hypoplasia, attrition, dental caries and periodontal recession. Age estimations based on a separate odontological study, osteological changes and tooth attrition had been made in 1989. Ages were estimated additionally by three non‐destructive dental methods based on (a) the length of the apical translucent zone, (b) selected measurements both on intact teeth and from ratios on dental radiographs and (c) ratios of the length and width measurements on dental radiographs from selected teeth. Several sources of post‐mortem changes had been observed, among them vivianite in 33 teeth from four individuals. The results of the dental examination showed that few teeth had been lost ante‐mortem, there was a low caries rate and little loss of periodontal attachments. With few exceptions, there is fairly good agreement between the different methods of estimating age. Age estimates based on dental attrition were, however, significantly different from the other dental methods and age estimates calculated from apical translucency ought to be regarded with scepticism due to post‐mortem changes. The chronological ages of the victims will never be known, but age estimates based on all the age‐markers available will probably reach a fairly close approximation. Copyright © 1999 John Wiley & Sons, Ltd.     

Statistical methods for bioarchaeology: applications of age-adjustment and logistic regression to comparisons of skeletal populations with differing age-structures

Previous studies of patterns of osteoarthritis involvement in prehistoric skeletal populations have been used to suggest differences in lifestyle or subsistence patterns. In spite of the intriguing nature of such studies, inadequate controls for the potential confounding effects of age have made results less secure than they appear. While researchers remain unable to control for the inherent limitations imposed by preservation bias, meaningful advancement could be made in the analysis of these data. Here we propose two methods from epidemiology that would allow more robust comparisons between populations with differing age-structures: age-adjustment and logistic regression. We apply these two methods to previously published data from prehistoric populations of the American Great Basin. In doing so, we are able to discern sex differences in risk for osteoarthritis at the shoulder (beta = −1.82, SE = 0.74, OR = 0.16, 95% CI = 0.04–0.69, p = 0.013), elbow (beta = −2.07, SE = 0.82, OR = 0.13, 95% CI = 0.03–0.63, p = 0.011), and in the foot (beta = −3.11, SE = 1.57, OR = 0.04, 95% CI = 0.00–0.97, p = 0.048), that were not noted in previous analyses of these data. These findings suggest that greater clarity of results and more precise comparisons of risk may be achieved by using these methods. We conclude that further application of these methods to bioarchaeological studies would potentially improve what can be said about prehistoric health patterns and lifeways.     

Assessing the variability in taphonomic studies of modern leporid remains from Eagle Owl (Bubo bubo) nest assemblages: the importance of age of prey

The Eagle Owl (Bubo bubo) is an important leporid remains accumulator at archaeological sites. Taphonomical studies of modern leporid remains from nest assemblages of this nocturnal raptor aim to establish the main characteristics that define the taphonomic signature of Eagle Owls in order to distinguish them from that of other leporid predators, namely diurnal raptors, terrestrial carnivores and humans. However, analyses carried out so far have shown that the identification of diagnostic features of Eagle Owls leporid nest accumulations is not a straightforward issue – variability has been observed. Age and size of prey are pointed among others as accountable factors but little research has been done on the study of these variables. Here we present the analysis of two samples of modern leporid remains recovered from Eagle Owls nests with the aim of contributing new data to this subject. The high presence of juvenile individuals in both samples enables us to assess anatomical representation, breakage and digestion patterns of immature leporid remains and also to compare them with other assemblages richer in adult prey. Results show that the main characteristic features noted in previous works which recognise Eagle Owls as agents of leporid bones accumulations in the fossil record, are not significantly affected by the age of prey. Less variability than originally thought occurs which means other variables need to be further investigated.     

Same island, different diet: Cultural evolution of food practice on Öland, Sweden, from the Mesolithic to the Roman Period

The Mesolithic–Neolithic transition in north-west Europe has been described as rapid and uniform, entailing a swift shift from the use of marine and other wild resources to domesticated terrestrial resources. Here, we approach the when, what and how of this transition on a regional level, using empirical data from Öland, an island in the Baltic Sea off the Swedish east coast, and also monitor changes that occurred after the shift. Radiocarbon dating and stable carbon and nitrogen isotope analyses of bones and teeth from 123 human individuals, along with faunal isotope data from 27 species, applying to nine sites on Öland and covering a time span from the Mesolithic to the Roman Period, demonstrate a great diversity in food practices, mainly governed by culture and independent of climatic changes. There was a marked dietary shift during the second half of the third millennium from a mixed marine diet to the use of exclusively terrestrial resources, interpreted as marking the large-scale introduction of farming. Contrary to previous claims, this took place at the end of the Neolithic and not at the onset. Our data also show that culturally induced dietary transitions occurred continuously throughout prehistory. The availability of high-resolution data on various levels, from intra-individual to inter-population, makes stable isotope analysis a powerful tool for studying the evolution of food practices.     

Funerary practices and kinship in an Early Bronze Age society: a Bayesian approach applied to the radiocarbon dating of Argaric double tombs

The main aim of this paper is to test the hypothesis on kinship relations (affinity/marriage vs descent/consanguinity, and matrilocality) expressed in the funerary record of the El Argar Bronze Age society (South-east Iberia, 2200–1550 cal BCE), taking into account the absolute chronological dimension of double adult tombs. A set of 23 double tombs having radiocarbon dates for both skeletons were selected, and radiocarbon calibration and Bayesian probability analysis was conducted. The results support the ‘descent’ hypothesis, since for most of the cases the chronological distance between individuals buried together was larger than two decades. Finally, several guidelines for future research are suggested in order to overcome shortages in current chronological and archaeological data.     

Comment on ‘A Bayesian approach to ageing perinatal skeletal material from archaeological sites: implications for the evidence for infanticide in Roman Britain’ by R.L. Gowland and A.T. Chamberlain

In 1993, I published a paper noting that the age distribution of perinatal infants for some Romano-British sites did not conform to a natural mortality pattern but rather showed a pronounced peak at a gestational age corresponding approximately to a full term infant. I interpreted this as suggestive of infanticide, given that the deed is generally carried out immediately after birth. Gowland and Chamberlain have recently published in this journal (J. Archaeol. Sci. 29 (2002) 677) a reconsideration of the problem of Roman infanticide in which they suggest that the peak I observed in the Romano-British perinatal age at death distribution may have been an artefact of the particular ageing technique I used, and they hence call into question the evidence for Roman infanticide. In this comment I argue that their work is seriously flawed and, using a re-analysis of my 1993 data, I demonstrate that the perinatal peak I observed in the Romano-British age distribution is a robust result that supports an interpretation of infanticide.