Stegocephali
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Stegocephali is a clade of vertebrate animals containing all fully limbed tetrapodomorphs. It is equivalent to a broad definition of the superclass Tetrapoda: under this broad definition, the term "te
Typical 19th-century depiction of a primitive stegocephalian, based on modern anurans and fossils now recognised as belonging to mastodonsaurids and Bromsgroveia
Eucritta 1DB white background
Acanthostega
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Acanthostega, from Ancient Greek ἄκανθα, meaning "spine", and στέγη, meaning "roof", is an extinct genus of stem-tetrapod, among the first vertebrate animals to have recognizable limbs. It appeared in
Stegocephali
…modern amphibians, reptiles, birds and mammals) as well as a portion of the stem group, the earliest limbed tetrapodomorphs such as Ichthyostega and Acanthostega, which evolved in the Devonian period long before the origin of the crown group. Many paleontologists prefer a stricter definition of Tetrapoda which…
lossy page 1 Acanthostega gunnari.TIF
Holotype skull, Zoological Museum of Copenhagen
Simplified phylogeny of the fish–tetrapod transition.