Mactridae – Mactrinae: Spisula (Notospisula) trigonella (Lamarck, 1818) (‘triangular trough-shell’)

Synonym(s): trigonella Lamarck, 1818 parvum Petit, 1853 corbuloides Reeve, 1854 cretacea Angas, 1867 producta Angas, 1867 fluviatilis Angas, 1871.

Typical shell-length 20 mm. Similar to Anapella cycladea, but usually smaller, with swollen umbones and a narrowly triangular but rounded outline. Lives subtidally in sand and mud in sheltered environments. Native. Occurs all around Australia (QLD, NSW, TAS, VIC, SA, WA and NT); not recorded elsewhere. In Tasmanian waters, this is a widespread species but seldom common.