Acanthostega

From Freepedia

Acanthostega gunnari is an extinct amphibian tetrapod species, among the first animals to have recognizable limbs. It appeared in the Upper Devonian (Famennian) and is a candidate for being one of the first vertebrates to be capable of coming onto land. It had eight fingers on each hand, the hindlimbs had seven digits, it lacked wrists, and was generally poorly adapted to come onto land. The limbs could not support the animal's weight. Therefore, paleontologists surmise that it was probably the first lobe-finned fish to come onto land.

The fish had both lungs and gills, also indicating it was a link between lobe-finned fishes and terrestrial vertebrates.

The fossilized remains are generally well preserved, with the famous fossil by which the significance of this species was discovered coming from East Greenland by Jenny Clack in 1987, though a fragment of the skull had been discovered in 1933 by Gunnar Säve-Söderberg and Erik Jarvik.

Acanthostega is closely related to Ichthyostega.

Sources

• http://tolweb.org/tree?group=Acanthostega&contgroup=Terrestrial_Vertebrates
• http://faculty.uca.edu/~benw/biol4402/lecture8c/sld004.htm
• http://gatito.valdosta.edu/fossil_pages/fossils_dev/a1.html
• http://faculty.evansville.edu/de3/b39903/PDFs/12_Land_InvasionII.pdf
• http://www.wfiu.indiana.edu/amos/library/scripts/acanthostega.html