An extinct primitve Paleozoic amphibian [LCOTE

Acanthostega is an extinct tetrapod genus, among the first vertebrate animals to have recognizable limbs. It appeared in the Upper Devonian (Famennian) about 360 million years ago, and was anatomically intermediate between lobe-finned fishes and the first tetrapods fully capable of coming onto land.Jennifer A. Clack, Scientific American, http://www.scientificamerican.com/print_version.cfm?articleID=000DC8B8-EA15-137C-AA1583414B7F0000 Getting a Leg Up on Land Nov. 21, 2005.