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The evolutionary significance of placental interdigitation in mammalian reproduction: Contributions from comparative studies

Capellini, I.


I. Capellini


The placenta is fundamental to mammalian reproduction and is surprisingly diverse in gross morphology among species. Whether and how this diversity affects maternal investment and fetal growth is still poorly understood. Contrary to suggestions that highly invasive hemochorial placentation is beneficial to fetal development, recent comparative studies have revealed that interdigitation – the degree of contact between maternal and fetal tissues at the area of exchange – strongly influences fetal growth rates. Species with labyrinthine placentae give birth to neonates of similar size to those of species with villous or trabecular placentae but in less than half the time. These findings suggest that there might be tradeoffs between fetal growth rates (higher with greater interdigitation) and gestation time (shorter with greater interdigitation), in association with type of interdigitation. Such tradeoffs might be the results of maternal-offspring conflict over the allocation of maternal resources, with paternal genes favouring greater interdigitation and so higher fetal growth, and maternal genes responding by reducing gestation time. These results emphasize the role of interdigitation as a means to increase the surface area for exchange, and are consistent with within species studies demonstrating that a higher surface area for exchange is associated with heavier neonates. Further studies could investigate the role of other traits in the evolution of placental diversity and their impact on fetal development.


Capellini, I. (2012). The evolutionary significance of placental interdigitation in mammalian reproduction: Contributions from comparative studies. Placenta, 33(10), 763-768.

Journal Article Type Article
Acceptance Date Jul 5, 2012
Online Publication Date Jul 25, 2012
Publication Date Oct 1, 2012
Deposit Date Mar 20, 2015
Publicly Available Date Mar 20, 2015
Journal Placenta
Print ISSN 0143-4004
Electronic ISSN 1532-3102
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 33
Issue 10
Pages 763-768
Keywords Comparative placentation, Phylogenetic comparative methods, Parent-offspring conflict, Evolution, Phylogeny, Foetal development
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Publisher URL
Additional Information NOTICE: this is the author’s version of a work that was accepted for publication in Placenta. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Placenta, v.33, issue 10 (2012) DOI:10.1016/j.placenta.2012.07.004


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