Chiton biramosus Quoy & Gaimard, 1835Diaphoroplax biramosus Iredale & Hull, 1932; Dell, 1951; Powell, 1979 Plaxiphora biramosa is an uncommon chiton in the family Mopaliidae,[2] endemic to New Zealand.

P. biramosa is a medium-sized chiton, oval and very flat, with the head and tail valves much reduced in size.

Wavy grooves run lengthwise along the central areas of the valves, which can be cream through yellow to light olive-green.

These are often coated in pink coralline algae and other small growths, much like the rocks the animal lives around, giving it a cryptic disguise.

It inhabits crevices in smooth rocks on wave-exposed coasts around New Zealand, although it is not known from the warmer north-eastern areas of the North Island.