Rock Bristletail vs Mahogany Dun

Side-by-side species comparison

Attribute Rock Bristletail Mahogany Dun
Scientific Name Petrobius brevistylis Isonychia harperi
Order Archaeognatha Ephemeroptera
Family Machilidae Isonychiidae
Size 9-12 mm 13-17 mm
Habitat Beaches & Coastal Rivers & Streams
Diet Omnivores Omnivores
Regions Europe North America
Conservation Least Concern Least Concern

Rock Bristletail

A coastal bristletail found on rocky shores from Scandinavia to the Mediterranean. It has shorter cerci than the related P. maritimus.

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Did You Know?

It can tolerate brief immersion in seawater during high tides.

Mahogany Dun

A large reddish-brown mayfly with impressive filter-feeding forelegs. Nymphs prefer moderate to fast riffles with clean gravel substrates.

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Did You Know?

Adults hold their forelegs forward in flight, making them easy to identify on the wing.