Parvicardium minimum
Habitat: it lives on muddy and sandy-muddy bottoms in the circalittoral zone. It is collected even in remarkable depths. Distribution: making a comparison with its similar ones, it is the species living in the deepest waters. It can be found all over the Mediterranean. Locally common.
Notes: shell roundish in form, not much variable in its form and sculpture, brittle, valves rather convex, equivalve, inequilateral. Sculpture, visible from inside too since transparent, is made by little radial ribs (about 30) on which there are numerous spines lamellated partially too. Interspaces, narrow but deep ones, are adorned by lamellae thin and close. Internal ventral margin is crenulated. Uniform white in colour. It is recognizable from P carrozzai since its posterior side is straighter, since it has a larger number of little radial ribs (30 in¬stead of 25) having a different sculpture too, since it has a different hinge and a different size of prodissoconch. According to CLEMAM's opinion, on the basis of Kirkendale's (2009) work, this species could be transferred to the genus Papillicardium. Average measures of adult specimens are around 6-7 mm in diametre.