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RESEARCH PRODUCT

Enamel Prism Patterns of European Hominoids — and Their Phylogenetical Aspects

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description

Everybody concerned with questions of taxonomy and phylogeny knows that a large part of information used to classify fossil vertebrates is derived from teeth. This comes from the reasoning that teeth are the best mineralized portions of the skeleton and thus usually also the best preserved remains. The best preserved portion of teeth is again the most highly mineralized — the enamel. That the enamel shows a so-called prism pattern, which differs markedly within mammals and also within the primates, is well known since Carter (1922) and Regan (1930) published articles concerning the variability of enamel prism patterns. These were for the first time described by Tomes in 1848. An intensive investigation of enamel microanatomy and histochemistry was undertaken, besides others, by the anatomist Shobusawa (1952) who pointed out that these structures could possibly be good markers for taxonomic purposes within the primates. Meaningful publications were undertaken by Boyde (1965a,b, 1969, 1971), Gustafson and Gustafson (1967), Helmcke (1955,1967), Osborn (1970), and other authors, which provided information about the way in which enamel structures are formed. For some years primatologists have been interested in this particular field in order to differentiate among fossil primates, whose remains are mostly represented by teeth and jaw fragments (as is the case in most of the Miocene hominoids). This group is of special interest as it is expected to have given rise to the hominoid lineage and lineages leading to the extant great apes. The theory of differentiation which has received widest support among palaeontologists is based on Ramapithecus, a Middle Miocene hominid, which is considered to be the phyletic ancestor of Australopithecus (Simons 1961, 1977, Simons and Pilbeam 1965; Early Divergence Hypothesis A).