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Origin of tetrapods from study of modern walking fish



Ben Creisler
bcreisler@gmail.com

Online in Nature:

Emily M. Standen, Trina Y. Du & Hans C. E. Larsson (2014)
Developmental plasticity and the origin of tetrapods.
Nature (advance online publication)
doi:10.1038/nature13708
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13708.html

The origin of tetrapods from their fish antecedents, approximately 400
million years ago, was coupled with the origin of terrestrial
locomotion and the evolution of supporting limbs. Polypterus is a
member of the basal-most group of ray-finned fish (actinopterygians)
and has many plesiomorphic morphologies that are comparable to
elpistostegid fishes, which are stem tetrapods. Polypterus therefore
serves as an extant analogue of stem tetrapods, allowing us to examine
how developmental plasticity affects the ‘terrestrialization’ of fish.
We measured the developmental plasticity of anatomical and
biomechanical responses in Polypterus reared on land. Here we show the
remarkable correspondence between the environmentally induced
phenotypes of terrestrialized Polypterus and the ancient anatomical
changes in stem tetrapods, and we provide insight into stem tetrapod
behavioural evolution. Our results raise the possibility that
environmentally induced developmental plasticity facilitated the
origin of the terrestrial traits that led to tetrapods.



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Comment

John Hutchinson (2014)
Evolutionary developmental biology: Dynasty of the plastic fish.
Nature (advance online publication)
doi:10.1038/nature13743
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature13743.html

Ambitious experimental and morphological studies of a modern fish show
how developmental flexibility may have helped early 'fishapods' to
make the transition from finned aquatic animals to tetrapods that walk
on land.

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News story with video, podcast interview

How fish can learn to walk
Land-raised bichirs provide insight into evolutionary pressures facing
first vertebrates to live on land.

Noah Baker

http://www.nature.com/news/how-fish-can-learn-to-walk-1.15778

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http://www.newscientist.com/article/dn26109-fish-reared-on-land-replay-the-transition-to-four-legs.html