Dental calculus and other dental disease in a human skeleton of the Okhotsk Culture unearthed at Hamanaka-2 site,Rebun-Island,Hokkaido, Japan

A human skeleton of the Okhotsk Culture from the Hamanaka-2 site of Rebun Island, northern part of Hokkaido, was found with abnormally large deposits of dental calculus, especially on the right upper 2nd and 3rd molars. This may relate to the early loss of the corresponding right lower molars. Root apex cementum hyperplasia and resorption of alveolar bone due to periodontal disease were also observed; these may have been associated with the calculus. The severe dental calculus and other diseases observed appear to have nothing to do with the subsistence pattern and ethnological background of the Okhotsk Culture, but rather with the individual's poor oral hygiene and digestive dysfunction.     

Changes in shell gathering in an early agricultural society at the head of Ise Bay,Japan

We examined changes in shell gathering in an early agricultural society at the head of Ise Bay, Japan based on the analysis of almost 20,000 individual shell remains from four coastal settlements. We analyzed historical changes in the composition and size range of the shell species Meretrix lusoria. The most common species went from Crassostrea gigas in the early Middle Yayoi period (about 400–350BC) to M. lusoria in the mid-Middle Yayoi period (about 320–200BC). It is possible that the seacoast tideland, an environment suitable for C. gigas, was buried in sediment from the rivers and thereby transformed into muddy sand bottoms, an environment more suitable for M. lusoria. We also analyzed historical changes in the size range of M. lusoria. The mean size of M. lusoria increased significantly from the early Final Jomon (about 1250–1000BC) to the late Early Yayoi (about 500–400BC), from the late Early Yayoi to the early Middle Yayoi, and from the early to the mid-Middle Yayoi periods. Evidence suggests that during the Yayoi period, the demand for shells decreased and therefore, the pressure to collect M. lusoria also decreased. We concluded that the larger specimens of M. lusoria were collected selectively.     

Salt weathering of sandstone at the Angkor monuments,Cambodia: identification of the origins of salts using sulfur and strontium isotopes

The Angkor monuments in northwestern Cambodia, which are primarily made of sandstone, are suffering from deterioration due to salt weathering. In order to elucidate the sources of the salts and salt weathering process, this paper analyzed bulk chemical compositions and S (sulfur) and Sr (strontium) isotopic ratios for the salts and surrounding environmental materials. At places where bats inhabit the structures, various kinds of sulfate and phosphate salts are formed on the surface of the sandstone. The results of the analysis demonstrate that the S and P (phosphorus) components in the salts are primarily derived from bat guano. Moreover, Ca (calcium), which is the major element in the salts, is suggested to be derived from both bat guano and the sandstone. The isotopic data strongly suggests that bat guano is related to salt weathering. Removal of these animal excrements is essential for future conservation of these monuments. On the other hand, exfoliation of sandstone commonly occurs due to crystallization of calcite (CaCO₃) on platform surfaces of pyramid-type monuments. A large amount of Ca in calcite is suggested to be derived from calcite cement of the building sandstone.     

Early Maya Ritual Practices and Craft Production: Late Middle Preclassic Ritual Deposits Containing Obsidian Artifacts at Ceibal,Guatemala

This article examines Preclassic Maya ritual practices and craft production by means of a study of ritual deposits containing obsidian artifacts dated mostly to the late Middle Preclassic period (700–350 b.c.) at Ceibal, Guatemala. New ritual practices developed at Ceibal during this period, possibly through political interactions and negotiation involving emerging elites and other diverse community members. Common objects in ritual deposits in the public plaza shifted from greenstone celt caches to other artifacts, including those made of obsidian. The inhabitants of Ceibal engaged in various kinds of craft production, including the manufacture of obsidian prismatic blades. They also conducted public rituals in the Central Plaza, depositing exhausted polyhedral obsidian cores and other artifacts with symbolic significance in caches and as offerings in incipient elite burials and interments of sacrificed individuals. These cores clearly demonstrate the use of a sophisticated blade technology. Like greenstone objects, exhausted polyhedral obsidian cores deposited in cruciform arrangements along the east–west axis of the central E-Group plaza were used as symbols and markers of the center and four cardinal directions within the Maya cosmos. Public rituals were important for creating collective identities and for processes of political negotiation within the community. Emerging elites likely came to play an increasingly important role in public rituals as principal performers and organizers, setting the stage for later public events centered on rulers.