Ichthyostega
| Ichthyostega | ||||||||||
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Reconstruction of Ichthyostega's skull in the Geological Museum of Copenhagen |
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| Temporal occurrence | ||||||||||
| Upper Devonian | ||||||||||
| 370 to 360 million years | ||||||||||
| Locations | ||||||||||
| Systematics | ||||||||||
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| Scientific name | ||||||||||
| Ichthyostega | ||||||||||
| Säve-Söderbergh , 1932 |
Ichthyostega ( gr . Ichthys 'fish' and stega "roof", "Skull") was one of the first tetrapods (land vertebrates), who temporarily live in the country. It was about five feet long. The number of his fingers and toes is usually given today as seven. The Ichthyostega expert Erik Jarvik was of the opinion that this number was due to a misinterpretation of the fossil record and believed Ichthyostega to be fifteen. Only the hind feet of the extremities are fossilized; they are built in the shape of a paddle. Having the typical tetrapod extremity makes Ichthyostega an amphibian ; However, the exact way of life has not yet been clarified due to special features such as the noticeably rigid chest.
Remains of Ichthyostega have been found in Greenland . Their age was set at approximately 370 million years dated ( Devonian ). Ichthyostega is one of the oldest known tetrapods. Besides him, other very primitive tetrapods have meanwhile been discovered, such as B. Acanthostega . This represents an even more primitive stage of development of the tetrapods; like a fish , it probably lived exclusively in the water, and its limbs - fins with many radial little toes - were ideally suited for a life on muddy ground or in the overgrown shore area. Due to its characteristics, which include both fish and amphibian characteristics, Ichthyostega also served as an important bridging animal and thus as morphological evidence of the theory of evolution .
literature
- Erik Jarvik: The Devonian tetrapod Ichthyostega . In: Fossils and Strata Vol. 40, 1996, pp. 1-213
- Jennifer A. Clack: Gaining Ground. The origin and evolution of Tetrapods. Indiana University Press, 2002. ISBN 978-0-253-35675-8
