Clausilia rugosa is a clausiliid living in forests on limestone rocks. Its shell measure up to 9.5 mm and it is the smallest species in the genus Clausilia.
The locality is Průchodnice Nature Reserve in the Czech Republic. It is a deciduous forest reserve with European beech Fagus sylvatica on limestone rocks. There are also remnants of caves by Upper Paleolithic men (Magdalenian culture). It is a nice reserve especially in April:
Hlaváč J. Č. (2002) Molluscan fauna of the Javoříčský Karst (Czech Republic, central Moravia). Malacological Newsletter, 20: 93–105.
Horsák M., Juřičková L. & Picka J. (2013) Měkkýši České a Slovenské republiky. Molluscs of the Czech and Slovak Republics. Kabourek, Zlín, 264 pp. (in Czech and English). page 89.