Mytilidae: Xenostrobus securis (Lamarck, 1819) (‘axe-head mussel’)

Synonym(s): securis Lamarck, 1819 vexillum Reeve, 1857 confusus Angas, 1871 fluviatilis Hutton, 1878.

Typical shell-length 38 mm. Shell typically blue-black and often worn to white towards the umbones. Lives intertidally amongst seaweed and seagrass in estuarine and other environments with freshwater influence. Native. Occurs in southeastern and southwestern Australia (QLD, NSW, TAS, VIC, SA and WA); also New Zealand, Japan and the Mediterranean. In Tasmanian waters, this is a widespread species; locally common in the S; rarer elsewhere.