Petrobius Brevistylus, Leach, 1809

Introduction
In the British Isles this species is thought to be widely distributed around the coast, alongside the very similar looking Sea Bristletail, Petrobius Maritimus. The two species can be determined, in well pigmented individuals, by the antennae patterning, p. brevistylus being plain in contrast to p.maritimus which is usually clearly ringed. In addition adult males of p.brevistylus have lobed subcoxae of the 8th abdominal segment and a pear shaped penis.

Taxonomy
Order Archeognatha, Family Machilidae , Genus Petrobius

Distribution
Thought to be distributed around all coasts of the UK, except for unsuitable stretches of the East coast. Not usually found inland.

Habitat
Typically occurs within the splash zone, in narrow crevices, within walls, rocks and cliffs.

Behaviour
Studied by Dixon 1970, Davies and Richardson 1970 and Davies 1990.