OSTEOMETRIC STUDY OF THE METAPODIALS OF AMSTERDAM ISLAND FERAL CATTLE

The analysis of fossil and sub-fossil bones of wild Bos primigenius Bojanus, 1827 and domestic cattle Bos taurus Linnaeus, 1758 has been handicapped by the absence of modern comparative material. The feral cattle of Amsterdam Island have lived in the wild since 1871 and have been free from artificial selection since that period. We give here a complete description of metapodial bones of this population in order to offer archaeologists a modern comparative material with patterns of sexual dimorphism and extent of intra- and inter-individual variability. This work is based on the measurements of 90 sets of 4 metapodials belonging to 48 adult females and 42 adult males. We show that the cattle of Amsterdam Island are morphologically homogeneous, thus probably forming a single breed. Sexual dimorphism is important and was studied by univariate comparisons and ordination techniques. A discriminant analysis revealed that differences in depth of diaphysis alone could correctly classify 96.7% of individuals as far as metacarpal bones are concerned, whereas differences in breath of distal end alone could correctly classify 91.1% of individuals when metatarsal bones were measured. Inclusion of two more variables increased the accuracy to 98.8% and 97.8% of individuals correctly classified for metacarpal and metatarsal bones, respectively. Allometric relations within sexes are described and should prove to be usefull to archaelogists who work with fragmentary material and wish to estimate lacking measurements. Comparisons of size and shape of metapodial bones with data from the literature reveal that the feral cattle of Amsterdam Island are smaller than aurochs and recent breeds of domestic cattle, but that they compare well with old breeds of domestic cattle and also recent breeds of Bos indicus living in Africa.