 - 1. Seta 2-C usually absent
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 - 2. Seta 3-C located dorsally
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 - 3. Seta 12-I always present
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 - 4. Pecten (Pt) and comb (C) present
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 - 5. Saddle (Sa) usually complete, sometimes incomplete and greatly
reduced but never divided into dorsal and ventral sclerites
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 - 6. Siphon with three or more pairs of prominent setae (seta 1-S)
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