Evolution of the Placenta in Eutherian Mammals

摘要: We review recent advances in our understanding of placental evolution with particular focus on the interhaemal barrier. It seems likely that non-invasive, epitheliochorial placentation living eutherians is a derived state. However, there disagreement whether last common ancestor eutherian mammals had an endotheliochorial placenta or haemochorial one. Research has been stimulated by improved relations between orders provided molecular phylogenetics. In part, uncertainties arise from doubt about how to root mammalian tree. Resolution this issue will require taxon sampling analyses. At same time, we need foster research comparative relevant taxa, particularly at ultrastructural level. Only then can ensure information available adequate capitalise future Examples are given findings could benefit cladistic analysis evolution.