Scale Type
One trait we use for identification in the museum is the shape of a fish’s scales. Fish scales protect the fish from parasites, and predators, and help fishes to move through the water more easily. What type of scales do you see on this fish?
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Cycloid: One of the two main scale types for bony fishes. These scales are round, but not spiny like ctenoid are.
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Ctenoid: One of the two main scale types for bony fishes. Distinguished by the spiny or comb-like edge these scales have.
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Ganoid: These scales are diamond-shaped, and can be found on species such as sturgeons and gars.
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Placoid: Found in sharks and rays, these have a ridge or spine on them, giving them the name “dermal denticles” (because they look like teeth).
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Cosmoid: Found in lungfishes and some other fossil fishes, this scale type is not found in the Green River Formation. No need to worry about this right now.