title: Placentation and fetal membrane development in the South American coati, Nasua nasua (Mammalia, Carnivora, Procyonidae).
abstract: BACKGROUND
  Placental research in carnivores has concentrated on domestic species, which have zonary, labyrinthine placentas with an endotheliochorial barrier. Although the coati, Nasua nasua, is a widely distributed species in South America, data on the development of the placenta and the fetal membranes in this species are very sparse.
  
  
  RESULTS
  Four placentas from mid-gestation to near term were collected from wild individuals and were investigated based on gross morphology, histology, immunohistochemistry and electron microscopy. The available data support the concept that the ancestral condition of placentation in carnivores is phylogenetically characterized by a zonary and labyrinthine placental type with an endotheliochorial fetomaternal barrier, comprising extended epitheliochorial and haemochorial zones, such as hemophagous organs for iron supply and histiotrophe uptake and a yolk sac placenta.
  
  
  CONCLUSIONS
  Because of the foundational mechanisms that lead to the considerable complexity of fetomaternal contact zones in carnivores have not been studied, carnivores are interesting animal models for interhaemal barrier differentiation.
authors: Department of Surgery, School of Veterinary Medicine and Animal Science, University of Sao Paulo, Av, Prof, Dr, Orlando Marques de Paiva, 87, Cidade Universitária, 05508-270 São Paulo, SP, Brazil. phelipe.favaron@yahoo.com.br.
authors: Phelipe O
authors: PO
authors: Favaron
authors: João C
authors: JC
authors: Morini
authors: Andrea M
authors: AM
authors: Mess
authors: Maria A
authors: MA
authors: Miglino
authors: Carlos E
authors: CE
authors: Ambrósio
mesh_terms: D000818:Animals; D001938:Brazil; D005321:Extraembryonic Membranes / Q000196:embryology* / Q000378:metabolism / Q000648:ultrastructure; D005260:Female; D047109:Fetal Development; D007150:Immunohistochemistry; D007633:Keratins / Q000378:metabolism; D008855:Microscopy, Electron, Scanning / Q000662:veterinary; D046529:Microscopy, Electron, Transmission / Q000662:veterinary; D010920:Placenta / Q000098:blood supply / Q000378:metabolism / Q000648:ultrastructure; D010929:Placentation; D011247:Pregnancy; D045988:Procyonidae / Q000196:embryology / Q000502:physiology*; D014746:Vimentin / Q000378:metabolism
chemical_list: D014746:Vimentin; D007633:Keratins