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11 Cards in this Set
- Front
- Back
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The first complete vertebrate fossils came from the ____ _____.
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late Ordovician
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Jawless fishes were traditionally considered as the class called _____.
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Agnatha
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Agnathans consisted of two groups called:
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extinct "ostracoderms"
extant "cyclostomes" |
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The placoderms..?
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the first vertebrates with jaws and two pairs of paired ventrolateral appendages
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A supposed shark ancestor
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Thelodont
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Antiarch
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Jawed placoderm that resembled holocephalins
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Arthodire
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Armored, jawed placoderm with jointed neck
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In placoderms, some bone appeared in the endoskeleton, called _____ _____.
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Endochondral bone
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Main structural component in placoderms
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Notochord
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Third eye in primitive fishes
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Pineal eye
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Symplesiomorphies of early cartilaginous fishes
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- notochord unrestricted
- cartilaginous neural arches present - mouth nearly always terminal - jaw suspension amphistylic - fins supported by cartilaginous rods |
