Tetrapodomorph

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Tetrapodomorphs
Temporal range: early Devonian-Recent
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. It is a subclass of the Sarcopterygii consisting of tetrapods (four-limbed vertebrates) and their closest relatives.

Advanced transitional fossils between fish and the early labyrinthodonts, like Tiktaalik, are informally called 'fishapods' by their discoverers. They are half-fish half-tetrapods, in appearance and limb morphology.

Tetrapodomorpha contains

  1. the stem group tetrapoda, extinct fossil relatives of the crown group. This is a paraphyletic unit covering the fish to tetrapod transition. Tetrapodomorpha contains several groups of related lobe-finned fishes, collectively known as the osteolepiforms.
  2. the crown group tetrapods, the last common ancestor of living tetrapods and all of its descendants.

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 Eusthenopteron, Osteolepis, Panderichthys, Tiktaalik, Ventastega and Kenichthys.

The fossils of the early Mississippian, Pederpes and Whatcheeria are regarded as early tetrapods whose relationships are not yet clear.

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