Stem tetrapoda
The Stem Tetrapoda are a
phylogeny rather than to traits as in traditional systematics. Thus, some finned sarcopterygians
are considered to be stem tetrapods.
Content of the group
Stem tetrapods are members of Tetrapodomorpha, the total group and clade that also includes their descendants, the crown tetrapods:[1]
The stem Tetrapoda encompass three distinct grades successively closer to crown group Tetrapoda:[2]
- Osteolepidae
- fishapods" (genera such as Panderichthys and Tiktaalik)
- loxommatids.[1]
Both Ichthyostegalia and Labyrinthodontia constitute paraphyletic
Tetrapoda itself should be defined (i.e. as a crown group, or as an apomorphy-based group, using the limb with digits),[5] making the actual content of the group uncertain.[6][7][8]
References
- ^ doi:10.1146/annurev.ecolsys.38.091206.095546. Archived from the original(PDF) on 29 October 2013.
- S2CID 4430783. Archived from the original(PDF) on 29 March 2017.
- .
- S2CID 67823991.
- PMID 14965901.
- S2CID 59359868. Archived from the original(PDF) on 2012-09-30.
- ^ Laurin, M. (1996): Phylogeny of Stegocephalians, from the Tree of Life Web Project
- .