Common Rough Woodlouse Porcellio scaber
The species below often accompanies the Common Shiny Woodlouse and actually is as common. It is not shiny however and has little bumps on the skeleton. For this reason it is called the Common Rough Woodlouse. Usually it is dark gray all over, but sometimes it shows other colours, such as yellow, red, green and blue. When it does, it's often suffering from an endoparasite, usually a virus. Like the other species, the Common Rough Woodlouse eats all kinds of decaying organic materials.
The Common Rough Woodlouse is very similar to the Common Shiny Woodlouse. The latter is more grey, usually without lighter spots, rough and not shiny and slightly smaller. Both animals live in the same way and may be seen at the same spots, often in mixed groups.
In the bottom picture both species together. The top animal is a Common Shiny Woodlouse. It is shiny and has few and little bumps. The two bottom animals are rather wierd coloured Common Rough Woodlice. They are not shiny and have a rather rough appearence.