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Rhipidistia
| Rhipidistia Fossil range: Early Devonian - Recent | |
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| Scientific classification
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Class | |
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Infraclass | |
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Order (Unranked) |
Rhipidistia |
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Orders |
See text.
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•Panderichthys, suited to muddy shallows;
•Tiktaalik with limb-like fins that could take it onto land;
•Early tetrapods in weed-filled swamps, such as;
•Acanthostega, which had feet with eight digits,
•Ichthyostega with limbs.
Descendants also included pelagic lobe-finned fish such as coelacanth species.
Added by Meghunter99The Rhipidistia were lobe-finned fishes that are the ancestors of the tetrapods. Taxonmists traditionally considered the Rhipidistia a subgroup of Crossopterygii that described a group of fish that lived during the Devonian consisting of the Porolepiformes and Osteolepiformes. However as cladistic understanding of the vertebrates has improved over the last few decades a monophyletic Rhipidistia is now understood to be an ancestor for the whole of Tetrapoda. Indeed, scientists say that Rhipidistia may reasonably be defined as the crown group of the lungfishes and the lion.
Taxonomy
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Rhipidistia
However it is common to see Tetrapoda and Rhipidistia as sibling groups within Gnathostomata.
