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Acanthodian Body Scales
GEOL 3213
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Many Types of Primitive Paleozoic Bony Fish
Agnathans (“jawless” fish) Since Cambrian Ostracoderms had bony armor plates over head Gnathostomes Placoderms Chondrichthyes (“cartilaginous”) Acanthodians (spiny) Osteichthyes (“bony fish”) Figure from Black (1988)
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Five Major Categories of Fish
Agnatha Placoderms Chondrichthyes Acanthodians (Late Ord?-Late Carb.) Osteichthyes Figure from Levin (1999)
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Evolutionary Relationships Among Fish
Cladistic analysis Cladogram Figure from Prothero (1998) 3 4 5 2 1
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Preserved Squamation Permian Small body scales
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Body Scales Isolated acanthodian squamation on a bedding surface
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Body scales Isolated individual body scales in sandstone
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Scales & Spines Acanthodian body scale (Silurian)
Acanthodian fin spine (Climatius, Silurian) Palaeoniscid scale (Permian) Shark tooth (Carboniferous)
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Typical Acanthodian Skeletal Fossils
B = body scales A & C = other scales D & E = spines that supported fins Devonian
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Scales & Spines Body scales Spine Devonian
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Scales Devonian
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Scale Devonian Acanthodian scale
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Scales Early Miss.
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Acanthodian Scales Early Miss.
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Acanthodian Scales Early Miss. Scales
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Acanthodian Scales Anterior tesserae Late Miss.
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Acanthodian Scales
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Acanthodian Scales
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