Document Detail


Morphology and development of the placentae in Eulamprus quoyii group skinks (Squamata: Scincidae).
MedLine Citation:
PMID:  22420511     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Frequent evolutionary changes in reproductive mode have produced a wide range of placental structures in viviparous squamate reptiles. Closely related species with different placental structures and resolved phylogenetic relationships are particularly useful for reconstructing how placentae might have transformed during the evolutionary process. We used light microscopy to study placental morphology in mid- to late stage embryos of four closely related species of Eulamprus, a genus of viviparous scincid lizards that we had reason to suspect may display significant interspecific variation in placental morphology. Embryos from all four species possess a chorioallantoic placenta, an omphaloplacenta and an interomphalopleuric membrane, characteristics present in other viviparous skinks. However, unlike other viviparous skinks but characteristic of oviparous skinks, the allantois expands to surround the yolk sac in each species, supplanting the omphalopleure with a larger area of chorioallantois until a chorioallantoic placenta surrounds the entire egg in one specimen that is only a few days from birth. All four Eulamprus species share the same extraembryonic membrane morphology, but the cellular morphology of the uterine epithelium in the chorioallantoic placenta and omphaloplacenta varies between species. We determined that the interomphalopleuric membrane is a shared derived character of the Eulamprus quoyii species group. New phylogenetic information indicates that variation in the chorioallantoic placenta is a result of two independent transitions, but that variation in the omphaloplacenta can be explained using a single change within the species studied. Our results indicate that E. quoyii group skinks are a valuable model for investigating the evolution of viviparity, as extraembryonic membrane development in these species shows features characteristic of both oviparous and viviparous skinks.
Authors:
Bridget F Murphy; Matthew C Brandley; Christopher R Murphy; Michael B Thompson
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2012-03-16
Journal Detail:
Title:  Journal of anatomy     Volume:  220     ISSN:  1469-7580     ISO Abbreviation:  J. Anat.     Publication Date:  2012 May 
Date Detail:
Created Date:  2012-04-10     Completed Date:  2012-06-07     Revised Date:  2014-05-12    
Medline Journal Info:
Nlm Unique ID:  0137162     Medline TA:  J Anat     Country:  England    
Other Details:
Languages:  eng     Pagination:  454-71     Citation Subset:  IM    
Copyright Information:
© 2012 The Authors. Journal of Anatomy © 2012 Anatomical Society.
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MeSH Terms
Descriptor/Qualifier:
Animals
Biological Evolution
Chorioallantoic Membrane* / anatomy & histology,  embryology
Female
Lizards / anatomy & histology*,  embryology
Microscopy
Oviparity*
Pregnancy
Uterus / anatomy & histology
Viviparity, Nonmammalian*
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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