Acanthochitonidae – Acanthochitoninae: Notoplax addenda Iredale & Hull, 1925 (‘addenda chiton’)
Synonym(s): addenda Iredale & Hull, 1925 subspeciosa Iredale & Hull, 1925.
Typical shell-length not yet determined. Lives subtidally amongst sponges, specifically on Asteropus spp., on which it feeds. Native. Endemic to southeastern Australia (NSW, TAS, VIC and SA).