Dogs from the past: Exploring morphology in mandibles from Iberian archaeological sites using 3D geometric morphometrics

We describe the shape variability of nine dog hemimandibles recovered from two Holocene archaeological sites on the Iberian Peninsula. In this study we mainly focus on the Chalcolithic age dog remains recovered from Barrio del Castillo (Torrejón de Ardoz, Madrid), but also, make comparisons to dog specimens from El Portalón (Sierra de Atapuerca, Burgos) Bronze Age. We used geometric morphometrics (3D) to describe mandibular morphology and compared these specimens with a modern sample of Iberian wolves, dogs, and red foxes. As complete mandibles are rarely found in the archaeological record, we also analysed the variability of the shape on fragments of mandibles. Here, we examine if there is morphological variability or a continuity in size between Chalcolithic and Bronze Age dogs. A scenario of very similar dogs, with a continuity in the size, is expected in the inner regions of the peninsula in contrasts with the coastal sites (influenced by a higher commercial activity). Our results suggest a continuity in the size and morphology of M₁. These dogs still conserved diagnostic wolf traits in relation to the carnassial zone. Additionally, we observe that the region behind the M₁ in Chalcolithic and Bronze Age dogs is slightly different when we analysed the fragmentary mandibles.