Identifying sheep (Ovis aries) fetal remains in archaeological contexts

• We propose qualitative anatomical criteria to distinguish sheep fetal remains.
• Different developmental fetal phases can be identified.
• Identification of fetal remains provides important economical information of farming communities.
• We have study a modern sheep collection and an archaeological assemblage.
• Qualitative anatomical criteria application is easy in assemblages affected by breakage.

Studies on the identification of fetal sheep remains in archaeological sites are scarce in comparison to the abundant literature addressing methods for postnatal age determination. However, perinatal studies can provide important information about sheep flock management in the Neolithic period.Motivated by the extensive fetal and neonatal assemblages recovered in the Neolithic and Bronze Age levels of El Mirador cave (Sierra de Atapuerca, Spain), we have identified and distinguished the remains using morphological criteria complemented by osteometric criteria.Skeletal development during the fetal period is less affected by the agents that can influence postnatal skeletal development (genetic, environmental, etc.). A priori, this makes age determination using actualistic data in fetal remains more reliable than in postnatal remains. Starting from these premises, the perinatal remains from El Mirador cave were analyzed using the osteological collection of fetal and neonatal individuals of the Rasa Aragonesa breed from the IPE (Instituto Pirenaico de Ecología, Jaca, Spain). Veterinary studies based on bone center ontogenesis and fetal age identification methods using metric criteria were also employed.The identification of age and the distinction of fetal and neonatal remains in the El Mirador cave assemblages based on qualitative anatomical criteria were consistent with the results obtained from osteometric data, specifically from the diaphyseal length measurement. In addition, the large number of specimen in the El Mirador assemblages made it possible to distinguish different fetal phases in accordance with skeletal developmental phenomena.