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135 h i j k be seen in fi gures 1 and 2, with the pulp cavity representing the inner core of the tusk, dentin comprising the majority of the tusk’s outer surface area, cementum protecting the outer layer and exposed components of the root, and enamel covering only the endpoint of the tusk. For the sake of this paper, dentin comprises the most signifi cant feature of a tusk. As the main component seen in carved ivory objects, it is formed by layers of mineralized connective tissue with an organic matrix of collagenous material deposited around the pulp cavity and makes up the majority of the tooth and tusk structure. Dentin has micro-canals called dentinal tubules that radiate through the dentin from the pulp cavity and have unique biological fi ngerprints that are paramount for the proper identifi cation of the species of origin. AFRICAN AND ASIAN ELEPHANT, MAMMOTH, AND MASTODON Loxodonta africana, Elephas maximus, Mammuthus spp., and Mammut americanum (among other species) Most of the current controversy and illicit trade of ivory revolves around the ivory derived from elephants, which has long been a ubiquitous presence in tribal art (fi gs. 3, 11, 12c, 13, and 14). However, it is important to note that there is a range of different ivory types derived from modern-day African and Asian elephants, and their long-extinct proboscidean relatives, mammoths and mastodons. Despite their extinction some 10,000 years ago (fi g. 6), the tusks of mammoths found in Alaska, Canada, Northern Europe, and Siberia have been well preserved in these cold regions and are a source of excellent-quality ivory that is readily carved into art objects. It is sometimes used in objects that appear on the tribal art market, particularly certain Inuit items, keris handles, and items of tremendous antiquity.13 Although commonly called mastodon ivory, at least 98% of the ancient proboscidean ivory from Alaska, Siberia, or Canada is actually mammoth ivory, and mastodon tusks are so rare that they are of little relevance to the art trade. Most ancient proboscidean ivory from lower latitudes has fossilized and is not used in traditional art. Elephant and mammoth tusks share many similarities. Both have cross sections that are rounded, where the dentin that makes up 95% of the tusk displays broad circular bands like tree rings, resulting from the layers of dentinal deposition as the tusk develops.14 The outer layer of cementum around the dentin in mammoth tusks appears thick and layered in contrast to modern-day elephants’ cementum, which is characteristically thinner. FIG. 4a–l (this spread): Cross sections of various types of ivory and ivory-like materials. a: Elephant tusk showing obtuse angle of Schreger lines. b: Mammoth tusk showing acute angle of Schreger lines. c: Walrus tooth showing large area of secondary dentin. d: Walrus tusk showing large area of secondary dentin in characteristic crystalline pattern. e: Sperm whale tooth. f: Narwhal tusk. g: Hippopotamus upper canine. h: Hippopotamus lower canine. i: Hippopotamus incisor. j: Warthog tusk. k: Enlarged segment of carved bone object showing Haversian pits. l: Tagua nut. Authorization of the reproduction of scientifi c images has been graciously given by Dr. Ed Espinoza, C.W.F.S., Deputy Director, National Fish and Wildlife Forensic Lab.


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