Mytilidae: Musculus (Modiolarca) impactus (Hermann, 1782) (‘nesting mussel’)

Synonym(s): impactus Hermann, 1782.
Typical shell-length 30 mm. Lives subtidally and offshore amongst rocks and seaweed. Native. Occurs in southeastern and southwestern Australia (QLD, NSW, TAS, VIC, SA and WA); also New Zealand. In Tasmanian waters, this is a widespread species; most common in the N, where the largest shells occur.