ganoid scale

zoology

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June 29, 2026

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Ganoid scales are a type of fish scale composed of an inner bone layer and an outer layer of ganoin, an enamel-like substance. These scales are characteristic of primitive bony fishes and are found in species like gars and bowfins. Ganoid scales are considered a modification of placoid scales, which are found in cartilaginous fishes.123

While providing protection, ganoid scales are relatively thick and less flexible than the cycloid and ctenoid scales found in modern teleost fishes. The term "ganoid" also refers to fish that possess these types of scales, such as sturgeons and gars.435

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The skin
In ganoid scales the hard outer layer is different chemically and is called ganoin. Under this is a cosminelike layer and then a vascular bony layer. The thin, translucent bony scales of modern fishes, called cycloid and ctenoid (the latter distinguished by serrations at the edges),…
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In ganoid scales the hard outer layer is different chemically and is called ganoin. Under this is a cosminelike layer and then a vascular bony layer. The thin, translucent bony scales of modern fishes, called cycloid and ctenoid (the latter distinguished by serrations at the edges),…
Read More