School of Biological Sciences, Heydon Laurence Building A08, University of Sydney, NSW 2006, Australia.
Placenta. 2013 Jun;34(6):510-1. doi: 10.1016/j.placenta.2013.03.002. Epub 2013 Mar 20.
Placentation is a common feature of live-bearing reptiles and mammals. Placentae are variable between species and can be classified by the extent that embryonic tissue breaches (invades) the uterus. Non-invasive placentation in eutherians is maternally imposed as extra-uterine embryos of species with epitheliochorial placentation will readily invade non-uterine tissues. This study documents the first observation of an extra-uterine pregnancy in a reptile; Pseudemoia entrecasteauxii, which in-utero exhibits non-invasive epitheliochorial placentation. The extra-uterine embryo did not invade maternal tissue suggesting fundamental differences between the nature and evolution of placentation in P. entrecasteauxii and eutherian mammals.
胎盘是活胎动物和哺乳动物的共同特征。胎盘在物种之间存在差异，可以根据胚胎组织侵入（侵袭）子宫的程度进行分类。真兽类的非侵入性胎盘是由母体施加的，因为具有上皮绒毛胎盘的物种的胚胎在子宫外会轻易侵入非子宫组织。本研究首次观察到爬行动物中的子宫外妊娠；Pseudemoia entrecasteauxii 在子宫内表现出非侵入性的上皮绒毛胎盘。子宫外的胚胎没有侵入母体组织，这表明 P. entrecasteauxii 和真兽类哺乳动物的胎盘的性质和进化存在根本差异。
