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Ichthyostega stensioi


Ichthyostega
from the late Devonian of Greenland,  is the first described early tetrapod and has been popularized as a transition fossil between fish and tetrapods. Since a few other tetrapods were discovered and found to be even more primitive than Ichthyostega. Ichthyostega was characterized by a stockier built than the almost contemporary Acanthostega, had a powerful finned tail and hindlimbs with 7 digits. The number of digits of the forelimbs is unknown as no preserved hands have been discovered. Ichthyostega might have been able to haul iself on land, as often depicted, but more recent studies suggest that it was more aquatic than previously thought. The different species of Ichthyostega initially described by
Säve-Söderbergh in 1932, might or might not be synonyms, but a 2005 study considers the following to be distinct: I. stensioi, I. watsoni and I. eigili.




Name


Ichthyostega stensioi


Authority
   

Säve-Söderbergh, 1932


Meaning of the generic name


Fish Roof


Size


Length: 1.5 m


Remains


Articulated skeletons of several individuals.


Age and Distribution


Celsius Berg Group, Aina dal Fm and Britta dal Fm (Upper Famennian), Eastern Greenland


Classification


Tetrapoda Ichthyostegidae

  Further Reading

  Save-Soderbergh, G., 1932, Preliminary note on Devonian Stegocephalians from East Greenland: Meddelelser om Grönland, BD. 94, n. 7, p. 1-107.
Jarvik, E. 1996. The Devonian tetrapod Ichthyostega. Fossils and Strata, 40: 1-213.
Ahlberg, P. E., Clack, J. A. and Blom, H. 2005 The axial skeleton of the Devonian tetrapod Ichthyostega. Nature. 437, 137-140.

 Synonyms
Ichthyostega watsoni Säve-Söderbergh, 1932; Ichthyostega eigili Säve-Söderbergh, 1932; Ichthyostega kochi Säve-Söderbergh, 1932; Ichthyostegopsis wimanni Säve-Söderbergh, 1932







Life reconstruction of Ichthyostega stensioi (© N. Tamura)
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