| None developed the distinctive sail that distinguished many pelycosaur groups. |
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| These basal forms evolved through the primitive pelycosaur stage, to the therapsids or mammal-like reptiles, and finally the mammals themselves. |
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| Whereas the Early Permian pelycosaur record is extensive, Carboniferous pelycosaur remains are rare and poorly known. |
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| A characteristic pelycosaur was Dimetrodon, a large predator from the Permian of Texas. |
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| Pelycosaur, therapsid, and mammal represent three evolutionary grades in a single progressive evolutionary axis. |
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| Also skipping the sand dunes was Pelycosaur Ophiacodon, a flesh-eating reptile-cum-mammal, again only found in this county. |
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| Dasyceps Bucklandi and Pelycosaur Ophiacodon roamed the county's lagoons and sand dunes. |
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