Porcellio dilatatus Brandt in Brandt & Ratzeburg, 1831


GB IUCN status: Least Concern

ID Difficulty


Porcellio dilatatus is a large species (to 15 mm body length) with a pale ‘dusty’ grey brown coloration.  It can be confused with P. scaber, but P. dilatatus is much broader and the telson has a characteristic rounded tip.  The presence of two flagella segments and two pairs of pleopodal lungs distinguishes it from Oniscus asellus.

J.P. Richards
Keith Lugg
Keith Lugg
Keith Lugg
Keith Lugg


This apparently uncommon species is scattered throughout Britain and Ireland, with isolated records as far north as the Outer Hebrides of Scotland.  For such a large species it is very under-recorded. For example targeted surveys of cattle sheds and stables found it to be common in Leicestershire (Daws, 1994, pg.12). 


Porcellio dilatatus is a characteristic woodlouse of stables, cow sheds and dairy farms, often found within well-established manure heaps, but also under planks, stones and pieces of manure or amongst straw and other debris.  It is typically associated with the common Porcellionides pruinosus and the inevitable Porcellio scaber.  It also inhabits churchyards, gardens and allotments, typically within compost heaps and inside glasshouses. 

This summary is based on the detailed account in Gregory (2009).


Gregory, S. (2009) Woodlice and Waterlice (Isopoda: Oniscidea & Asellota) in Britain and Ireland.  Field Studies Council/Centre for Ecology & Hydrology.

BRC code