Comparative histology of antelope placentomes

The histological structure of ruminant (family: Bovidae) placentomes in eight antelope species was compared to that of domestic cattle and sheep. The chorioallantoic villi differed in degree of branching, surface corrugation, and complexity of utero-placental junction. All species had the epitheliochorial type of placenta, with the epithelial lining of maternal caruncular crypts varying between cellular and syncytial types. Uganda kob (Kobus kob, Reduncinae) and common duiker (Sylvicapra grimmia, Cephalophinae) had the simplest structures with minimal villous branching, round to polygonal villous cross-sections, and cellular crypt lining. Common eland (Taurotragus oryx, Tragelaphinae) and greater kudu (Tragelaphus strepsiceros, Tragelaphinae) had moderate villous branching, polygonal to mildly corrugated villous cross-sections, and cellular crypt lining with slight signs of syncytium. Wildebeest (gnu, Connochaetes gnou, Alcelaphinae) and sable antelope (Hippotragus niger, Hippotraginae) had moderate villous branching with corrugated surface and almost completely syncytial crypt lining. Steenbok (Raphicerus campestris, Neotraginae) and impala (Aepyceros melampus, Aepycerotinae) had the most complicated branching of villi and corrugation, and their crypt lining was clearly syncytial. Cattle (Bos taurus) and sheep (Ovis aries) had villous branching and corrugation similar to impala, and their crypt lining resembled that of eland and impala, respectively.