Small Square-Gilled Mayfly vs Mountain Flathead Mayfly

Side-by-side species comparison

Attribute Small Square-Gilled Mayfly Mountain Flathead Mayfly
Scientific Name Caenis luctuosa Cinygmula ramaleyi
Order Ephemeroptera Ephemeroptera
Family Caenidae Heptageniidae
Size 3-6 mm 7-10 mm
Habitat Ponds & Lakes Mountains
Diet Omnivores Omnivores
Regions Europe North America
Conservation Least Concern Least Concern

Small Square-Gilled Mayfly

A minute mayfly with distinctive square-shaped gills on its nymphs. Adults swarm in enormous numbers near water at twilight.

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Did You Know?

The enlarged second gill plate acts as a protective cover over the remaining delicate gills.

Mountain Flathead Mayfly

An alpine mayfly restricted to high-elevation cold streams in the Rocky Mountains. Nymphs feed on diatom films on boulder surfaces.

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Did You Know?

This species cannot survive in water temperatures above 15 degrees Celsius.