Testacella haliotidea Draparnaud, 1801 in The Netherlands (Gastropoda Pulmonata, Testacellidae)

This is the first formal report of the occurrence of a Testacella species in The Netherlands. In 2010 at least 20 specimens of Testacella haliotidea were discovered in a garden near Middelburg, Prov. of Zeeland, ranging from small juveniles to adults, indicating the presence of a reproducing population. In the collection of the Netherlands Centre for Biodiversity Naturalis, Leiden (RMNH) are also four samples from various parts of the country, collected between 1961 and 1988, which were never published. Asingle shell probably belonging to this species was found in the province of Limburg in 2009. Testacella haliotida is probably an incidentally introduced species that can reproduce and establish temporary populations. However, it may overlooked due to its subterraneous habits. The external appearance, radula and genitalia of Dutch specimens are described. Genitalia of specimens attributed to T. haliotidea in the literature vary considerably, and suggest the presence of more than one species. Sequences (‘barcodes’) of the Cytochrome oxydase subunit 1 gene (CO1) are provided of three recently collected specimens.