Rhyncosaurs and cynodonts are far more common, and in fact the rhyncosaur Scaphonix accounts for half of all tetrapod fossils. |
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The limbs of tetrapod vertebrates evolved from fins, with the digits as a novel feature. |
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He pointed out, for example, that the developmental genetic explanation of the prevalence of pentadactyly assumes tetrapod monophyly. |
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So, for example, the tetrapod splenial developed a medially-directed twist of the ventral margin, exposing the splenial ventrally and mesially. |
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I also noticed another protruding bone called the ischium and I became very excited because I knew that this was not a fish but a tetrapod. |
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The most basic branched polytypic crystal that can therefore be produced using these materials is a tetrapod. |
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Late in this succession came the first terrestrial tetrapod vertebrates, which are thought to have inhabited freshwater streams and rivers. |
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Unlike the deltaic, lowland assemblages of the southwestern United States, the Bromacker assemblage contains neither fish nor obligate aquatic tetrapod remains. |
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Structurally, the tetrapod limb can be derived from the pattern found in the paired fins of Sarcopterygii, a class of lobe-finned fishes. |
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The difficulty in deciding tetrapod ancestry stems from the inability to determine conclusively which traits are ancestral and which traits arose after one group diverged from another. |
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Jacobson's organ, also called vomeronasal organ, an organ of chemoreception that is part of the olfactory system of amphibians, reptiles, and mammals, although it does not occur in all tetrapod groups. |
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They included a number of basal tetrapod groups classified in early books under the Labyrinthodontia. |
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This early tetrapod could be the earliest example of a reptile and explain the origin of amniotes, all vertebrates that belong to reptiles, birds and mammals. |
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Like their amphibious tetrapod predecessors, they had lungs and limbs. |
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