Transitional Vertebrate Fossi12

Transitional Vertebrate Fossi12 - Transitional Vertebrate...

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Transitional Vertebrate Fossils Transitions among amphibians Temnospondyls, e.g Pholidogaster (Mississippian, about 330 Ma) -- A group of large labrinthodont amphibians, transitional between the early amphibians (the ichthyostegids, described above) and later amphibians such as rhachitomes and anthracosaurs. Probably also gave rise to modern amphibians (the Lissamphibia) via this chain of six temnospondyl genera , showing progressive modification of the palate, dentition, ear, and pectoral girdle, with steady reduction in body size (Milner, in Benton 1988). Notice, though, that the times are out of order, though they are all from the Pennsylvanian and early Permian. Either some of the "Permian" genera arose earlier, in the Pennsylvanian (quite likely), and/or some of these genera are "cousins", not direct ancestors (also quite likely). Dendrerpeton acadianum (early Penn.) -- 4-toed hand, ribs straight, etc.
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This note was uploaded on 11/22/2011 for the course GLY GLY1100 taught by Professor Jaymuza during the Spring '10 term at Broward College.

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