Index to Creationist Claims,  edited by Mark Isaak,    Copyright © 2004

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Claim CC212:

Source:

Response:

1. There are several good transitional fossils:
   
   
   1. Most fish have anterior and posterior external nostrils. In tetrapods, the posterior nostril is replaced by the choana, an internal nostril opening into the roof of the mouth. Kenichthys, a 395-million-year-old fossil from China, is exactly intermediate between the two, having nostrils at the margin of the upper jaw (Zhu and Ahlberg 2004).
      
      
   2. A fossil shows eight bony fingers in the front fin of a lobed fish, offering evidence that fingers developed before land-going tetrapods (Daeschler and Shubin 1998).
      
      
   3. A Devonian humerus has features showing that it belonged to an aquatic tetrapod that could push itself up with its forelimbs but could not move it limbs back and forth to walk (Shubin et al. 2004).
      
      
   4. Acanthostega, a Devonian fossil, about 60 cm long, probably lived in rivers (Coates 1996). It had polydactyl limbs with no wrists or ankles (Coates and Clack 1990). It was predominantly, if not exclusively, aquatic: It had fishlike internal gills (Coates and Clack 1991), and its limbs and spine could not support much weight. It also had a stapes and a lateral sensory system like a fish.
      
      
   5. Ichthyostega, a tetrapod from Devonian streams, was about 1.5 m long and probably amphibious. It had seven digits on its rear legs (its hands are unknown). Its limbs and spine were more robust than those of Acanthostega, and its rib cage was massive. It had fishlike spines on its tail, but these were fewer and smaller than Acanthostega's. Its skull had several primitive fishlike features, but it probably did not have internal gills (Murphy 2002).
      
      
   6. Tulerpeton, from estuarine deposits roughly the same age as Acanthostega and Ichthyostega, had six digits on its front limbs and seven on its rear limbs. Its shoulders were more robust than Acanthostega, suggesting it was somewhat less aquatic, and its skull appears to be closer to later Carboniferous amphibians than to Acanthostega or Ichthyostega.

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