Agathe Guignet

Southwest and Central Asia were pivotal regions for the domestication and dispersal of domestic herbivores. Here we investigate long-term variation in bony labyrinth morphology of domestic bovids (sheep, goats and cattle) across the last 10 000 years. We focused on the osseous cavity of the inner ear, located within the petrous bone. We analysed semicircular canal (SC) size and shape using micro-computed tomography and geometric morphometrics (GMM) on 78 modern reference specimens and 234 archaeological petrous bones from 51 sites spanning the Iranian Plateau, Central Asia, the Caucasus and the Indus Valley. Bony labyrinth morphometrics yielded a strong taxonomic signal, enabling species-level identification of 228 out of 234 specimens and revealing greater diversity than anticipated. Comparative analyses further documented contrasting, nonlinear diachronic trajectories in SC size and shape among sheep, goats and cattle, reflecting species-specific responses to domestication and long-term herd management. Together, these results demonstrate that bony labyrinth GMM provides a robust, non-destructive framework for taxonomic identification and evolutionary inference and underscore how long-term, interdisciplinary approaches can capture the complex, nonlinear dynamics of animal domestication across the longue durée.

Despite their distinct bio-cultural histories, the morphological similarity of sheep and goats complicates their identification in archaeological contexts and limits within-species analyses. Skull remains are still poorly studied, and the inner ear has only recently gained attention in bioarchaeology as the petrous bone encapsulating it preserves DNA well. We applied three-dimensional geometric morphometrics to analyse skull and its parts (occipital, maxilla and frontal bones), including the inner ear, size and shape variation in 26 sheep (six breeds) and 15 goats (three breeds). Shape-based analyses achieved good to perfect species discrimination for all structures analysed (whole skull and inner ears: 100%; parts of the skull: 72–100%), whereas size-based discrimination performed lower (whole skull: 85.2%; inner ears: 86.5%; and parts of the skull: 72–89.9%). Among breeds, variation in size and shape was detected, offering promising potential for tracking domestic populations in archaeological contexts. Although the results showed little correlation between inner ear and skull morphometrics, the orientation of the inner ear in the skull differed between the two species. Our study highlights micro-computed tomography scanning and geometric morphometrics as powerful, non-destructive tools for species identification, complementing ancient DNA analysis and enhancing bioarchaeological research on domestication, husbandry practices and the long-term history of human–animal interactions.

This contribution contains the 3D models described and figured in the following publication: Skull and Inner Ear Morphometrics in Sheep and Goats: Species and Breed Differentiation with Bioarchaeological Applications (Hemelsdael et al. in press). The models include the external surface of a complete skull and inner ear of both a sheep (Ovis aries) and a goat (Capra hircus), generated from micro-CT scans. In the associated paper, we used 3D geometric morphometric data to assess inter and intra (i.e. between breeds) discrimination based on complete skulls, skull fragments and the semi-circular canals of the inner ear.

The identification of skeletal remains recovered from archaeological contexts is central to the reconstruction of past societies, environments, and human-animal relationships. Among the skeletal el...