Geometric morphometric analysis of cranium shape differences in sheep from colonial Sydney, Australia

Abstract

Geometric morphometrics (GMMs) is a valuable tool that can be used to identify variability within species, thereby distinguishing between breeds and closely related animals (e.g. sheep and goats). Identifying fine morphological differences is key to better understanding early herd management practices. Interestingly, GMMs has yet to be used in a colonial Australian context, particularly in the foundational period of colonial Sydney from 1790 to 1850. Given the overall importance of sheep to the development of colonial Australia, this analytical gap provides an opportunity to identify potential morphological variability, and so better understand colonial herd management strategies. Here we use GMMs to analyse an archaeological assemblage of sheep crania (n = 27) from the colonial Clarence Street site, in Sydney, Australia. These crania are compared to modern sheep specimens to test GMMs’ effectiveness at distinguishing between, as well as potentially allocating individuals to, specific breeds. We found certain morphological variations between the study assemblages, and so discuss our results in the context of a variety of explanatory frameworks such as differences in husbandry practices in colonial Sydney.