application of a dichotomous key to the classification of sea lamprey ...

DICHOTOMOUS KEY FOR CLASSIFYING SEA LAMPREY MARKS ON
LAKE STURGEON
1a. Pit:
• Definite perforation (pit) exists through the
skin/scutes
• Musculature may or may not be exposed 2
1b. Pit absent:
• Skin is largely intact, but an abrasion or broken
blood vessels are evident
• Skin may slough off, exposing the musculature;
but there is no perforation
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Fig. 2. Example of marks with perforations
through the skin exposing muscle.
Fig. 3. Example of marks with perforations
through the skin not exposing muscle.
Fig. 4. Example of marks with no perforation
through the skin (no musculature exposed).
Fig. 5. Example of marks with no perforation
through the skin; musculature is exposed via
skin sloughing.
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