Tetrapodomorpha

Tetrapodomorphs
Temporal range: Early Devonian-Recent, 406–0 Ma
The basal tetrapodomorph Tiktaalik
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Sarcopterygii
Subclass: Tetrapodomorpha
Ahlberg, 1991
Subgroups
  • See text

Tetrapodomorpha is a clade of vertebrates, consisting of tetrapods (four-limbed vertebrates) and their closest sarcopterygian relatives that are more closely related to living tetrapods than to living lungfish. Advanced forms transitional between fish and the early labyrinthodonts, like Tiktaalik, have been referred to as "fishapods" by their discoverers, being half-fish half-tetrapods, in appearance and limb morphology. Tetrapodomorpha contains the crown group tetrapods (the last common ancestor of living tetrapods and all of its descendants) and several groups of early stem tetrapods. Tetrapodomorpha contains several groups of related lobe-finned fishes, collectively known as the osteolepiforms. The Tetrapodamorpha minus the crown group Tetrapoda is the Stem Tetrapoda, a paraphyletic unit encompassing the fish to tetrapod transition.

Among the characters defining tetrapodomorphs are modifications to the fins, notably a humerus with convex head articulating with the glenoid fossa (the socket of the shoulder joint).

Tetrapodomorph fossils are known from the early Devonian onwards, and include Osteolepis, Panderichthys and Kenichthys.

Contents

Classification

Taxonomy

After Benton, 2004 [1]:

Phylogeny

Cladogram modified after Ruta, Jeffery, & Coates (2003)[1]:

Tetrapodomorpha 

Eusthenopteron




Panderichthys




Livoniana




Elpistostege



 Elginerpetidae 

Elginerpeton



Obruchevichthys






Metaxygnathus



Ventastega




Tetrapoda








References

  1. ^ Ruta, M.; Jeffery, J. E.; and Coates, M. I. (2003). "A supertree of early tetrapods". Proceedings of the Royal Society B 270 (1532): 2507–2516. doi:10.1098/rspb.2003.2524. PMC 1691537. PMID 14667343. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1691537.